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Jurado-Ruiz M, Riera L, Fontecha CG. How to avoid genu recurvatum in leg-length discrepancy treated with tension-band plates. A volumetric magnetic resonance analysis. J Orthop 2024; 57:35-39. [PMID: 38957798 PMCID: PMC11214944 DOI: 10.1016/j.jor.2024.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 06/05/2024] [Indexed: 07/04/2024] Open
Abstract
Aims and objectives Genu recurvatum deformity after treatment of leg-length discrepancy (LLD) with tension-band plating is a recognized, but poorly described phenomenon in medical literature. The aim of this study was to evaluate clinical and radiological features of patients treated with tension-band plating for LLD assessing the development of a recurvatum deformity and its relationship to plate and screw disposition in a transversal plane, thus attempting to establish optimal plate positioning. Materials and methods Retrospective study of children with LLD treated with tension-band plating. Primary endpoints were clinical and radiological knee recurvatum and anterior and posterior physeal areas measured drawing a line spanning from the lateral to the medial tension-band plates in the transverse plane using volumetric magnetic resonance imaging (vMRI). These findings were compared between patients with and without knee recurvatum. Results Twelve children (mean age 11.7 years) were included. Average follow-up was 2.6 years (1.5-5.0). Tension-band plating led to a significant reduction in LLD (mean, 15 mm). Six patients (50 %) developed clinical genu recurvatum (mean, 22°). According to vMRI, patients with genu recurvatum had a larger posterior to anterior physeal area ratio in both distal femur (1.6 versus 0.9, p < 0.05) and proximal tibial physes (2.2 versus 1.0, p < 0.05). Conclusion The optimal position of the tension-band plates in distal femoral and proximal tibial physes should be in a point where a posterior to anterior physeal areas ratio is around 1.0, so as to achieve an even distribution of the physeal areas in the multidimensional physeal transverse plane. This point anatomically corresponds in the sagittal X-ray view to an imaginary line located just anterior to the posterior diaphyseal cortical bone on a true lateral radiograph for both femur and tibia.
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Affiliation(s)
- Maria Jurado-Ruiz
- Department of Orthopedic Surgery and Traumatology, Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, Passeig de la Vall d'Hebron, 119, 08035, Barcelona, Spain
- Reconstructive Surgery of the Locomotor System, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Passeig de la Vall d'Hebron, 129, 08035, Barcelona, Spain
| | - Luis Riera
- Department of Pediatric Radiology, Vall d’Hebron University Hospital, Passeig de la Vall d'Hebron, 119, 08035, Barcelona, Spain
| | - César G. Fontecha
- Reconstructive Surgery of the Locomotor System, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Passeig de la Vall d'Hebron, 129, 08035, Barcelona, Spain
- Department of Pediatric Orthopedics and Traumatology, Sant Joan de Déu Hospital, Passeig de Sant Joan de Déu, 2, 08950, Esplugues de Llobregat, Barcelona, Spain
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de Buck MHS, Hess AT, Jezzard P. Simulation-based optimization and experimental comparison of intracranial T2-weighted DANTE-SPACE vessel wall imaging at 3T and 7T. Magn Reson Med 2024. [PMID: 38970460 DOI: 10.1002/mrm.30203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 04/30/2024] [Accepted: 06/12/2024] [Indexed: 07/08/2024]
Abstract
PURPOSE T2-weighted DANTE-SPACE (Delay Alternating with Nutation for Tailored Excitation - Sampling Perfection with Application optimized Contrasts using different flip angle Evolution) sequences facilitate non-invasive intracranial vessel wall imaging at 7T through simultaneous suppression of blood and CSF. However, the achieved vessel wall delineation depends closely on the selected sequence parameters, and little information is available about the performance of the sequence using more widely available 3T MRI. Therefore, in this paper a comprehensive DANTE-SPACE simulation framework is used for the optimization and quantitative comparison of T2-weighted DANTE-SPACE at both 7T and 3T. METHODS Simulations are used to propose optimized sequence parameters at both 3T and 7T. At 7T, an additional protocol which uses a parallel transmission (pTx) shim during the DANTE preparation for improved suppression of inflowing blood is also proposed. Data at both field strengths using optimized and literature protocols are acquired and quantitatively compared in six healthy volunteers. RESULTS At 7T, more vessel wall signal can be retained while still achieving sufficient CSF suppression by using fewer DANTE pulses than described in previous implementations. The use of a pTx shim during DANTE at 7T provides a modest further improvement to the inner vessel wall delineation. At 3T, aggressive DANTE preparation is required to achieve CSF suppression, resulting in reduced vessel wall signal. As a result, the achievable vessel wall definition at 3T is around half that of 7T. CONCLUSION Simulation-based optimization of DANTE parameters facilitates improved T2-weighted DANTE-SPACE contrasts at 7T. The improved vessel definition of T2-weighted DANTE-SPACE at 7T makes DANTE preparation more suitable for T2-weighted VWI at 7T than at 3T.
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Affiliation(s)
- Matthijs H S de Buck
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Spinoza Centre for Neuroimaging, Netherlands Institute for Neuroscience, Royal Netherlands Academy for Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Aaron T Hess
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Peter Jezzard
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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de Buck MHS, Jezzard P, Hess AT. An extended phase graph-based framework for DANTE-SPACE simulations including physiological, temporal, and spatial variations. Magn Reson Med 2024; 92:332-345. [PMID: 38469983 DOI: 10.1002/mrm.30071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/18/2024] [Accepted: 02/09/2024] [Indexed: 03/13/2024]
Abstract
PURPOSE The delay alternating with nutation for tailored excitation (DANTE)-sampling perfection with application-optimized contrasts (SPACE) sequence facilitates 3D intracranial vessel wall imaging with simultaneous suppression of blood and CSF. However, the achieved image contrast depends closely on the selected sequence parameters, and the clinical use of the sequence is limited in vivo by observed signal variations in the vessel wall, CSF, and blood. This paper introduces a comprehensive DANTE-SPACE simulation framework, with the aim of providing a better understanding of the underlying contrast mechanisms and facilitating improved parameter selection and contrast optimization. METHODS An extended phase graph formalism was developed for efficient spin ensemble simulation of the DANTE-SPACE sequence. Physiological processes such as pulsatile flow velocity variation, varying flow directions, intravoxel velocity variation, diffusion, andB 1 + $$ {\mathrm{B}}_1^{+} $$ effects were included in the framework to represent the mechanisms behind the achieved signal levels accurately. RESULTS Intravoxel velocity variation improved temporal stability and robustness against small velocity changes. Time-varying pulsatile velocity variation affected CSF simulations, introducing periods of near-zero velocity and partial rephasing. Inclusion of diffusion effects was found to substantially reduce the CSF signal. Blood flow trajectory variations had minor effects, butB 1 + $$ {\mathrm{B}}_1^{+} $$ differences along the trajectory reduced DANTE efficiency in low-B 1 + $$ {\mathrm{B}}_1^{+} $$ areas. Introducing low-velocity pulsatility of both CSF and vessel wall helped explain the in vivo observed signal heterogeneity in both tissue types. CONCLUSION The presented simulation framework facilitates a more comprehensive optimization of DANTE-SPACE sequence parameters. Furthermore, the simulation framework helps to explain observed contrasts in acquired data.
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Affiliation(s)
- Matthijs H S de Buck
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Spinoza Centre for Neuroimaging, Amsterdam, The Netherlands
| | - Peter Jezzard
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Aaron T Hess
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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Sinha H, Raamana PR. Solving the Pervasive Problem of Protocol Non-Compliance in MRI using an Open-Source tool mrQA. Neuroinformatics 2024:10.1007/s12021-024-09668-4. [PMID: 38861098 DOI: 10.1007/s12021-024-09668-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2024] [Indexed: 06/12/2024]
Abstract
Pooling data across diverse sources acquired by multisite consortia requires compliance with a predefined reference protocol i.e., ensuring different sites and scanners for a given project have used identical or compatible MR physics parameter values. Traditionally, this has been an arduous and manual process due to difficulties in working with the complicated DICOM standard and lack of resources allocated towards protocol compliance. Moreover, issues of protocol compliance is often overlooked for lack of realization that parameter values are routinely improvised/modified locally at various sites. The inconsistencies in acquisition protocols can reduce SNR, statistical power, and in the worst case, may invalidate the results altogether. An open-source tool, mrQA was developed to automatically assess protocol compliance on standard dataset formats such as DICOM and BIDS, and to study the patterns of non-compliance in over 20 open neuroimaging datasets, including the large ABCD study. The results demonstrate that the lack of compliance is rather pervasive. The frequent sources of non-compliance include but are not limited to deviations in Repetition Time, Echo Time, Flip Angle, and Phase Encoding Direction. It was also observed that GE and Philips scanners exhibited higher rates of non-compliance relative to the Siemens scanners in the ABCD dataset. Continuous monitoring for protocol compliance is strongly recommended before any pre/post-processing, ideally right after the acquisition, to avoid the silent propagation of severe/subtle issues. Although, this study focuses on neuroimaging datasets, the proposed tool mrQA can work with any DICOM-based datasets.
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Affiliation(s)
- Harsh Sinha
- Intelligent Systems Program, School of Computing and Information, University of Pittsburgh, Pittsburgh, USA
| | - Pradeep Reddy Raamana
- Intelligent Systems Program, School of Computing and Information, University of Pittsburgh, Pittsburgh, USA.
- Department of Biomedical Informatics, University of Pittsburgh, Pittsburgh, USA.
- Department of Radiology, University of Pittsburgh, Pittsburgh, USA.
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Tunlayadechanont P, Chobaroon A, Chansakul T. Contrast-enhanced 3D black-blood magnetic resonance imaging for diagnosis of cerebral venous thrombosis. Neuroradiol J 2024:19714009241260798. [PMID: 38856687 DOI: 10.1177/19714009241260798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024] Open
Abstract
PURPOSE Cerebral venous thrombosis (CVT) is often under-recognized on routine magnetic resonance imaging (MRI) examinations without concomitant magnetic resonance venography (MRV). Contrast-enhanced black-blood MRI (BBMRI) based on a three-dimensional T1-weighted variable-flip-angle turbo spin echo sequence, one of the sequences used routinely in our practice, has the potential for detection of thrombi in patients with CVT. The aim of this study is to evaluate the diagnostic performance and enhancement patterns of contrast-enhanced three-dimensional BBMRI for the diagnosis of CVT. MATERIALS AND METHODS Contrast-enhanced BBMRI and contrast-enhanced MRV sequences of 64 patients, acquired from June 2018 to January 2021, were retrospectively reviewed by neuroradiologists for detection of CVT in each venous sinus segment. Diagnostic performance values were calculated for contrast-enhanced BBMRI based on enhancement patterns. RESULTS Of 749 venous segments from 64 patients analyzed, CVT was demonstrated in 41 venous segments from 12 patients on contrast-enhanced MRV (CE MRV). Thick wall enhancement and total enhancement patterns were dominantly demonstrated in thrombosed segments. Compared with contrast-enhanced MRV, contrast-enhanced BBMRI had a patient-based sensitivity and specificity of 100% and 98.1%, respectively, and a segment-based sensitivity and specificity of 87.8% and 96.2%, respectively. The positive predictive value of contrast-enhanced BBMRI in detecting CVT was 92.3% (patient-based) and 57.1% (segment-based), and the negative predictive value was 100% (patient-based) and 99.3% (segment-based). CONCLUSION Contrast-enhanced BBMRI has high diagnostic performance in detection and diagnosis of CVT. This sequence may be useful to recognize CVT when dedicated CE MRV was not performed in patients with nonspecific neurological symptoms.
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Affiliation(s)
- Padcha Tunlayadechanont
- Division of Neurological Radiology, Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Arin Chobaroon
- Division of Neurological Radiology, Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Thanissara Chansakul
- Division of Neurological Radiology, Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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Lemainque T, Pridöhl N, Zhang S, Huppertz M, Post M, Yüksel C, Yoneyama M, Prescher A, Kuhl C, Truhn D, Nebelung S. Time-efficient combined morphologic and quantitative joint MRI: an in situ study of standardized knee cartilage defects in human cadaveric specimens. Eur Radiol Exp 2024; 8:66. [PMID: 38834751 DOI: 10.1186/s41747-024-00462-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 03/27/2024] [Indexed: 06/06/2024] Open
Abstract
BACKGROUND Quantitative techniques such as T2 and T1ρ mapping allow evaluating the cartilage and meniscus. We evaluated multi-interleaved X-prepared turbo-spin echo with intuitive relaxometry (MIXTURE) sequences with turbo spin-echo (TSE) contrast and additional parameter maps versus reference TSE sequences in an in situ model of human cartilage defects. METHODS Standardized cartilage defects of 8, 5, and 3 mm in diameter were created in the lateral femora of ten human cadaveric knee specimens (81 ± 10 years old; nine males, one female). MIXTURE sequences providing proton density-weighted fat-saturated images and T2 maps or T1-weighted images and T1ρ maps as well as the corresponding two- and three-dimensional TSE reference sequences were acquired before and after defect creation (3-T scanner; knee coil). Defect delineability, bone texture, and cartilage relaxation times were quantified. Appropriate parametric or non-parametric tests were used. RESULTS Overall, defect delineability and texture features were not significantly different between the MIXTURE and reference sequences (p ≤ 0.47). After defect creation, relaxation times significantly increased in the central femur (T2pre = 51 ± 4 ms [mean ± standard deviation] versus T2post = 56 ± 4 ms; p = 0.002) and all regions combined (T1ρpre = 40 ± 4 ms versus T1ρpost = 43 ± 4 ms; p = 0.004). CONCLUSIONS MIXTURE permitted time-efficient simultaneous morphologic and quantitative joint assessment based on clinical image contrasts. While providing T2 or T1ρ maps in clinically feasible scan time, morphologic image features, i.e., cartilage defects and bone texture, were comparable between MIXTURE and reference sequences. RELEVANCE STATEMENT Equally time-efficient and versatile, the MIXTURE sequence platform combines morphologic imaging using familiar contrasts, excellent image correspondence versus corresponding reference sequences and quantitative mapping information, thereby increasing the diagnostic value beyond mere morphology. KEY POINTS • Combined morphologic and quantitative MIXTURE sequences are based on three-dimensional TSE contrasts. • MIXTURE sequences were studied in an in situ human cartilage defect model. • Morphologic image features, i.e., defect delineabilty and bone texture, were investigated. • Morphologic image features were similar between MIXTURE and reference sequences. • MIXTURE allowed time-efficient simultaneous morphologic and quantitative knee joint assessment.
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Affiliation(s)
- Teresa Lemainque
- Department of Diagnostic and Interventional Radiology, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, Aachen, 52074, Germany.
| | - Nicola Pridöhl
- Department of Diagnostic and Interventional Radiology, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, Aachen, 52074, Germany
| | - Shuo Zhang
- Philips GmbH Market DACH, Hamburg, Germany
| | - Marc Huppertz
- Department of Diagnostic and Interventional Radiology, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, Aachen, 52074, Germany
| | - Manuel Post
- Department of Diagnostic and Interventional Radiology, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, Aachen, 52074, Germany
| | - Can Yüksel
- Department of Diagnostic and Interventional Radiology, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, Aachen, 52074, Germany
| | | | - Andreas Prescher
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Aachen, 52074, Germany
| | - Christiane Kuhl
- Department of Diagnostic and Interventional Radiology, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, Aachen, 52074, Germany
| | - Daniel Truhn
- Department of Diagnostic and Interventional Radiology, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, Aachen, 52074, Germany
| | - Sven Nebelung
- Department of Diagnostic and Interventional Radiology, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, Aachen, 52074, Germany
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Liao L, Chen J, Liu Z, Liang S, Qin L, Lin X, Pan S, Tan M, Huang L, Ruan Q, Huang Z, Shi C, Xie G. Direct abdominal vein thrombus imaging (DATI): a contrast-free black-blood MR technique for the diagnosis of abdominal vein thrombosis. Abdom Radiol (NY) 2024:10.1007/s00261-024-04335-3. [PMID: 38780634 DOI: 10.1007/s00261-024-04335-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 04/08/2024] [Accepted: 04/08/2024] [Indexed: 05/25/2024]
Abstract
OBJECTIVES To develop and evaluate a direct abdominal vein thrombus imaging (DATI) technique, based on a respiratory navigating SPACE sequence with DANTE black-blood preparation, for diagnosing abdominal vein thrombosis (AVT) without the use of exogenous contrast agents. METHODS We prospectively enrolled 10 healthy subjects and 28 suspected AVT patients who underwent DATI scans on 3.0 T MRI. Contrast-enhanced CT venography (CTV) was also conducted on the suspected AVT patients for comparison. All images were analyzed by two blinded radiologists who independently evaluated randomized images and gave image quality and diagnostic confidence scores (1-poor, 4-excellent) for DATI and CTV. The accuracy (ACC), sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) of CTV were calculated using CTV as a standard reference. The diagnostic agreement between DATI and CTV as well as the interobserver agreement were conducted using Cohen κ test. RESULTS The patient study demonstrated that DATI can provide adequate thrombus signal intensity and the contrast between the thrombus to dark venous lumen for the diagnosis of AVT. It offers good to excellent image quality (reader1/reader2: 3.50 ± 0.64/3.42 ± 0.63, κ = 0.872) and diagnostic confidence (reader1/reader2: 3.71 ± 0.53/3.78 ± 0.42, κ = 0.804) for the diagnosis of AVT. Taking CTV as a reference, DATI has high accuracy (96.6%), SE (91.5%), SP (98.0%), PPV (92.3%), and NPV (97.8%). DATA CONCLUSION DATI can provide good to excellent image quality, effective venous blood signal suppression, and definitive thrombus detection for the diagnosis of AVT without the use of exogenous contrast agents.
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Affiliation(s)
- Liping Liao
- Department of Radiology, The First People's Hospital of Qinzhou, Qinnan District, Mingyang Road, Qinzhou, 535000, Guangxi, People's Republic of China
| | - Jiayuan Chen
- Department of Radiology, The First People's Hospital of Qinzhou, Qinnan District, Mingyang Road, Qinzhou, 535000, Guangxi, People's Republic of China
| | - Zeping Liu
- School of Biomedical Engineering, The Sixth Affiliated Hospital, #A2-607, Guangzhou Medical University, Xinzao, Panyu District, Guangzhou, 511436, Guangdong, People's Republic of China
| | - Shengyuan Liang
- Department of Radiology, The First People's Hospital of Qinzhou, Qinnan District, Mingyang Road, Qinzhou, 535000, Guangxi, People's Republic of China
| | - Lei Qin
- Department of Radiology, The First People's Hospital of Qinzhou, Qinnan District, Mingyang Road, Qinzhou, 535000, Guangxi, People's Republic of China
| | - Xinmei Lin
- Department of Radiology, The First People's Hospital of Qinzhou, Qinnan District, Mingyang Road, Qinzhou, 535000, Guangxi, People's Republic of China
| | - Shengzhang Pan
- Department of Radiology, The First People's Hospital of Qinzhou, Qinnan District, Mingyang Road, Qinzhou, 535000, Guangxi, People's Republic of China
| | - Mingxia Tan
- Department of Radiology, The First People's Hospital of Qinzhou, Qinnan District, Mingyang Road, Qinzhou, 535000, Guangxi, People's Republic of China
| | - Lanbin Huang
- Department of Radiology, The First People's Hospital of Qinzhou, Qinnan District, Mingyang Road, Qinzhou, 535000, Guangxi, People's Republic of China
| | - Qizeng Ruan
- Department of Radiology, The First People's Hospital of Qinzhou, Qinnan District, Mingyang Road, Qinzhou, 535000, Guangxi, People's Republic of China
| | - Zehe Huang
- Department of Radiology, The First People's Hospital of Qinzhou, Qinnan District, Mingyang Road, Qinzhou, 535000, Guangxi, People's Republic of China.
| | - Caiyun Shi
- School of Biomedical Engineering, The Fourth Affiliated Hospital, Guangzhou Medical University, Guangdong, People's Republic of China.
| | - Guoxi Xie
- School of Biomedical Engineering, The Fourth Affiliated Hospital, Guangzhou Medical University, Guangdong, People's Republic of China
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Hausmann D, Lerch A, Hitziger S, Farkas M, Weiland E, Lemke A, Grimm M, Kubik-Huch RA. AI-Supported Autonomous Uterus Reconstructions: First Application in MRI Using 3D SPACE with Iterative Denoising. Acad Radiol 2024; 31:1400-1409. [PMID: 37925344 DOI: 10.1016/j.acra.2023.09.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 09/19/2023] [Accepted: 09/22/2023] [Indexed: 11/06/2023]
Abstract
RATIONALE AND OBJECTIVES T2-weighted imaging in at least two orthogonal planes is recommended for assessment of the uterus. To determine whether a convolutional neural network-based algorithm could be used for the re-constructions of uterus axes derived from a 3D SPACE with iterative denoising. MATERIALS AND METHODS 50 patients aged 18-81 (mean: 42) years who underwent an MRI examination of the uterus participated voluntarily in this prospective study after informed consent. In addition to a standard MRI pelvis protocol, a 3D SPACE research application sequence was acquired in sagittal orientation. Reconstructions for both the cervix and the cavum in the short and long axes were performed by a research trainee (T), an experienced radiologist (E), and the prototype software (P). In the next step, the reconstructions were evaluated anonymously by two experienced readers according to 5-point-Likert-Scales. In addition, the length of the cervical canal, the length of the cavum and the distance between the tube angles were measured on all reconstructions. Interobserver agreement was assessed for all ratings. RESULTS For all axes, significant differences were found between the scores of the reconstructions by research T, E and P. P received higher scores and was preferred significantly more often with the exception of the comparison of the reconstruction Cervix short of E (Cervix short: P vs. T: p = 0.02; P vs. E: p = 0.26; Cervix long: P vs. T: p = 0.01; P vs. E: p < 0.01; Cavum short: P vs. T: p = 0.01; P vs. E: p = 0.02; Cavum long: P vs. T: p < 0.01; P vs. E: p < 0.01). Regarding the measured diameters, (length of cervical canal/cavum/distance between tube angles) significantly larger diameters were recorded for P compared to E and T (Cervix long (mm): T: 25.43; E: 25.65; P: 26.65; Cavum short (mm): T: 26.24; E: 25.04; P: 27.33; Cavum long (mm): T: 31.98; E: 32.91; P: 34.41; P vs. T: p < 0.01); P vs. E: p = 0.04). Moderate to substantial agreement was found between Reader 1 and Reader 2 (range: 0.39-0.67). CONCLUSION P was able to reconstruct the axes at least as well as or better than E and T. P could thereby lead to workflow facilitation and enable more efficient reporting of uterine MRI.
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Affiliation(s)
- Daniel Hausmann
- Department of Radiology, Kantonsspital Baden, Im Ergel 1, Baden, 5404, Switzerland (D.H., A.L., M.F., M.G., K.H.); Department of Radiology and Nuclear Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany (D.H.).
| | - Aline Lerch
- Department of Radiology, Kantonsspital Baden, Im Ergel 1, Baden, 5404, Switzerland (D.H., A.L., M.F., M.G., K.H.); Institute for Translational Medicine, ETH Zurich, Zurich, Switzerland (A.L); ETH, Department of Health Sciences and Technology (A.L.)
| | | | - Monika Farkas
- Department of Radiology, Kantonsspital Baden, Im Ergel 1, Baden, 5404, Switzerland (D.H., A.L., M.F., M.G., K.H.)
| | - Elisabeth Weiland
- MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany (E.W.)
| | | | - Maximilian Grimm
- Department of Radiology, Kantonsspital Baden, Im Ergel 1, Baden, 5404, Switzerland (D.H., A.L., M.F., M.G., K.H.)
| | - Rahel A Kubik-Huch
- Department of Radiology, Kantonsspital Baden, Im Ergel 1, Baden, 5404, Switzerland (D.H., A.L., M.F., M.G., K.H.)
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Riederer SJ, Borisch EA, Froemming AT, Kawashima A, Takahashi N. Comparison of model-based versus deep learning-based image reconstruction for thin-slice T2-weighted spin-echo prostate MRI. Abdom Radiol (NY) 2024:10.1007/s00261-024-04256-1. [PMID: 38520510 DOI: 10.1007/s00261-024-04256-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 03/25/2024]
Abstract
PURPOSE To compare a previous model-based image reconstruction (MBIR) with a newly developed deep learning (DL)-based image reconstruction for providing improved signal-to-noise ratio (SNR) in high through-plane resolution (1 mm) T2-weighted spin-echo (T2SE) prostate MRI. METHODS Large-area contrast and high-contrast spatial resolution of the reconstruction methods were assessed quantitatively in experimental phantom studies. The methods were next evaluated radiologically in 17 subjects at 3.0 Tesla for whom prostate MRI was clinically indicated. For each subject, the axial T2SE raw data were directed to MBIR and to the DL reconstruction at three vendor-provided levels: (L)ow, (M)edium, and (H)igh. Thin-slice images from the four reconstructions were compared using evaluation criteria related to SNR, sharpness, contrast fidelity, and reviewer preference. Results were compared using the Wilcoxon signed-rank test using Bonferroni correction, and inter-reader comparisons were done using the Cohen and Krippendorf tests. RESULTS Baseline contrast and resolution in phantom studies were equivalent for all four reconstruction pathways as desired. In vivo, all three DL levels (L, M, H) provided improved SNR versus MBIR. For virtually, all other evaluation criteria DL L and M were superior to MBIR. DL L and M were evaluated as superior to DL H in fidelity of contrast. For 44 of the 51 evaluations, the DL M reconstruction was preferred. CONCLUSION The deep learning reconstruction method provides significant SNR improvement in thin-slice (1 mm) T2SE images of the prostate while retaining image contrast. However, if taken to too high a level (DL High), both radiological sharpness and fidelity of contrast diminish.
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Affiliation(s)
| | - Eric A Borisch
- Department of Radiology, Mayo Clinic, Rochester, MN, 55905, USA
| | | | | | - Naoki Takahashi
- Department of Radiology, Mayo Clinic, Rochester, MN, 55905, USA
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Cho J, Gagoski B, Kim TH, Wang F, Manhard MK, Dean D, Kecskemeti S, Caprihan A, Lo WC, Splitthoff DN, Liu W, Polak D, Cauley S, Setsompop K, Grant PE, Bilgic B. Time-efficient, high-resolution 3T whole-brain relaxometry using 3D-QALAS with wave-CAIPI readouts. Magn Reson Med 2024; 91:630-639. [PMID: 37705496 DOI: 10.1002/mrm.29865] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 07/16/2023] [Accepted: 08/25/2023] [Indexed: 09/15/2023]
Abstract
PURPOSE Volumetric, high-resolution, quantitative mapping of brain-tissue relaxation properties is hindered by long acquisition times and SNR challenges. This study combines time-efficient wave-controlled aliasing in parallel imaging (wave-CAIPI) readouts with the 3D quantification using an interleaved Look-Locker acquisition sequence with a T2 preparation pulse (3D-QALAS), enabling full-brain quantitative T1 , T2 , and proton density (PD) maps at 1.15-mm3 isotropic voxels in 3 min. METHODS Wave-CAIPI readouts were embedded in the standard 3D-QALAS encoding scheme, enabling full-brain quantitative parameter maps (T1 , T2 , and PD) at acceleration factors of R = 3 × 2 with minimum SNR loss due to g-factor penalties. The quantitative parameter maps were estimated using a dictionary-based mapping algorithm incorporating inversion efficiency and B1 -field inhomogeneity effects. The parameter maps using the accelerated protocol were quantitatively compared with those obtained from the conventional 3D-QALAS sequence using GRAPPA acceleration of R = 2 in the ISMRM/NIST phantom, and in 10 healthy volunteers. RESULTS When tested in both the ISMRM/NIST phantom and 10 healthy volunteers, the quantitative maps using the accelerated protocol showed excellent agreement against those obtained from conventional 3D-QALAS at RGRAPPA = 2. CONCLUSION Three-dimensional QALAS enhanced with wave-CAIPI readouts enables time-efficient, full-brain quantitative T1 , T2 , and PD mapping at 1.15 mm3 in 3 min at R = 3 × 2 acceleration. The quantitative maps obtained from the accelerated wave-CAIPI 3D-QALAS protocol showed very similar values to those from the standard 3D-QALAS (R = 2) protocol, alluding to the robustness and reliability of the proposed method.
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Affiliation(s)
- Jaejin Cho
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Borjan Gagoski
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Tae Hyung Kim
- Department of Computer Engineering, Hongik University, Seoul, South Korea
| | - Fuyixue Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Mary Kate Manhard
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Douglas Dean
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Steven Kecskemeti
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | | | - Wei-Ching Lo
- Siemens Medical Solutions USA, Inc., Charlestown, Massachusetts, USA
| | | | - Wei Liu
- Siemens Healthcare GmbH, Erlangen, Germany
| | | | - Stephen Cauley
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Kawin Setsompop
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Patricia Ellen Grant
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Berkin Bilgic
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard/MIT Health Sciences and Technology, Cambridge, Massachusetts, USA
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KV A, Arunachalam VK, Sherene H, Ethiraju V, Ranganathan R, SM G, Rajasekaran S, Mehta P, Cherian M. Comparison of Contrast-Enhanced 3D Imaging with 2D Imaging in the Evaluation of Perianal Fistula at 3T: A Prospective Observational Study. Indian J Radiol Imaging 2024; 34:95-102. [PMID: 38106872 PMCID: PMC10723969 DOI: 10.1055/s-0043-1775738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023] Open
Abstract
Introduction Perianal fistula and its recurrence is a challenging entity for surgeons. It is a well-establi1shed fact that magnetic resonance imaging (MRI) findings influence surgical procedures and reduce the rate of recurrence. In this study, we assessed the contrast-enhanced (CE) three dimensional T1 sequences [sampling perfection with application optimized contrast using different flip angle evolution (SPACE) and volumetric interpolated breath-hold examination (VIBE)] in a 3T MRI system to evaluate perianal fistulas and compared them with two-dimensional (2D) sequences. Materials and Methods Forty-four patients (mean age, 38.8 ± 15.3 [standard deviation]; 32 males, 12 females) with perianal fistula were included in this prospective study. The patients underwent conventional noncontrast, 2D sequences, diffusion-weighted imaging, followed by postcontrast, 2D T1 images in both axial and coronal planes, and 3D sequences at 3T. Acquisition times were recorded for each sequence. Each postcontrast sequence was evaluated in terms of image quality, presence of artifacts, fistula type, presence of an abscess, visibility, and number of internal orifices. The surgical findings were considered the gold standard. The imaging findings were compared with the surgical findings. Results In all three sequences, the fistula type and abscess were identified correctly in all patients. The sensitivity value for identification of ramifications utilizing CE 3D T1 VIBE sequence, CE 3D T1 SPACE, and CE 2D T1 images was 100, 86, and 36%, respectively. The number of internal orifices was identified by the CE 3D T1 VIBE and CE 3D T1 SPACE sequences in 100 and 92% of patients, respectively. CE 2D T1 images correctly identified internal orifices in 80% of patients. The overall scan time for each 3D sequence was shorter than for the combined postcontrast 2D sequences. Conclusion CE 3D T1 SPACE and CE 3D T1 VIBE sequences outperformed conventional CE 2D sequences in the evaluation of perianal fistulas in terms of visibility and the number of internal orifices with a shorter scanning time. Among the 3D sequences, CE 3D T1 VIBE is slightly superior to CE 3D T1 SPACE sequence.
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Affiliation(s)
- Abdulla KV
- Department of Radiology, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
| | | | - Haleema Sherene
- Department of Radiology, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
| | - Vijayakumaran Ethiraju
- Department of Radiology, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
| | - Rupa Ranganathan
- Department of Radiology, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
| | - Gowtham SM
- Department of Radiology, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
| | - Sriman Rajasekaran
- Department of Radiology, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
| | - Pankaj Mehta
- Department of Radiology, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
| | - Mathew Cherian
- Department of Radiology, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
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12
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Mir N, Fransen SJ, Wolterink JM, Fütterer JJ, Simonis FFJ. Recent Developments in Speeding up Prostate MRI. J Magn Reson Imaging 2023. [PMID: 37982353 DOI: 10.1002/jmri.29108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 11/21/2023] Open
Abstract
The increasing incidence of prostate cancer cases worldwide has led to a tremendous demand for multiparametric MRI (mpMRI). In order to relieve the pressure on healthcare, reducing mpMRI scan time is necessary. This review focuses on recent techniques proposed for faster mpMRI acquisition, specifically shortening T2W and DWI sequences while adhering to the PI-RADS (Prostate Imaging Reporting and Data System) guidelines. Speeding up techniques in the reviewed studies rely on more efficient sampling of data, ranging from the acquisition of fewer averages or b-values to adjustment of the pulse sequence. Novel acquisition methods based on undersampling techniques are often followed by suitable reconstruction methods typically incorporating synthetic priori information. These reconstruction methods often use artificial intelligence for various tasks such as denoising, artifact correction, improvement of image quality, and in the case of DWI, for the generation of synthetic high b-value images or apparent diffusion coefficient maps. Reduction of mpMRI scan time is possible, but it is crucial to maintain diagnostic quality, confirmed through radiological evaluation, to integrate the proposed methods into the standard mpMRI protocol. Additionally, before clinical integration, prospective studies are recommended to validate undersampling techniques to avoid potentially inaccurate results demonstrated by retrospective analysis. This review provides an overview of recently proposed techniques, discussing their implementation, advantages, disadvantages, and diagnostic performance according to PI-RADS guidelines compared to conventional methods. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 3.
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Affiliation(s)
- Nida Mir
- Magnetic Detection and Imaging, Technical Medical Centre, University of Twente, Enschede, Netherlands
| | - Stefan J Fransen
- Department of Radiology, University Medical Center Groningen, Groningen, Netherlands
| | - Jelmer M Wolterink
- Department of Applied Mathematics, Technical Medical Centre, University of Twente, Enschede, Netherlands
| | - Jurgen J Fütterer
- Robotics and Mechatronics, Technical Medical Centre, University of Twente, Enschede, Netherlands
- Minimally Invasive Image-Guided Interventions Center, Department of Medical Imaging, Radboud University Medical Center, Nijmegen, Netherlands
| | - Frank F J Simonis
- Magnetic Detection and Imaging, Technical Medical Centre, University of Twente, Enschede, Netherlands
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Park EJ, Lee Y, Lee J. Impact of Deep-Learning Based Reconstruction on Single-Breath-Hold, Single-Shot Fast Spin-Echo in MR Enterography for Crohn's Disease. JOURNAL OF THE KOREAN SOCIETY OF RADIOLOGY 2023; 84:1309-1323. [PMID: 38107694 PMCID: PMC10721413 DOI: 10.3348/jksr.2023.0008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/18/2023] [Accepted: 05/06/2023] [Indexed: 12/19/2023]
Abstract
Purpose To assess the quality of four images obtained using single-breath-hold (SBH), single-shot fast spin-echo (SSFSE) and multiple-breath-hold (MBH) SSFSE with and without deep-learning based reconstruction (DLR) in patients with Crohn's disease. Materials and Methods This study included 61 patients who underwent MR enterography (MRE) for Crohn's disease. The following images were compared: SBH-SSFSE with (SBH-DLR) and without (SBH-conventional reconstruction [CR]) DLR and MBH-SSFSE with (MBH-DLR) and without (MBH-CR) DLR. Two radiologists independently reviewed the overall image quality, artifacts, sharpness, and motion-related signal loss using a 5-point scale. Three inflammatory parameters were evaluated in the ileum, the terminal ileum, and the colon. Moreover, the presence of a spatial misalignment was evaluated. Signal-to-noise ratio (SNR) was calculated at two locations for each sequence. Results DLR significantly improved the image quality, artifacts, and sharpness of the SBH images. No significant differences in scores between MBH-CR and SBH-DLR were detected. SBH-DLR had the highest SNR (p < 0.001). The inter-reader agreement for inflammatory parameters was good to excellent (κ = 0.76-0.95) and the inter-sequence agreement was nearly perfect (κ = 0.92-0.94). Misalignment artifacts were observed more frequently in the MBH images than in the SBH images (p < 0.001). Conclusion SBH-DLR demonstrated equivalent quality and performance compared to MBH-CR. Furthermore, it can be acquired in less than half the time, without multiple BHs and reduce slice misalignments.
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Shiraishi K, Nakaura T, Uetani H, Nagayama Y, Kidoh M, Kobayashi N, Morita K, Yamahita Y, Tanaka Y, Baba H, Hirai T. Deep learning-based reconstruction and 3D hybrid profile order technique for MRCP at 3T: evaluation of image quality and acquisition time. Eur Radiol 2023; 33:7585-7594. [PMID: 37178197 DOI: 10.1007/s00330-023-09703-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 03/06/2023] [Accepted: 03/20/2023] [Indexed: 05/15/2023]
Abstract
OBJECTIVES To evaluate the image quality of the 3D hybrid profile order technique and deep-learning-based reconstruction (DLR) for 3D magnetic resonance cholangiopancreatography (MRCP) within a single breath-hold (BH) at 3 T magnetic resonance imaging (MRI). METHODS This retrospective study included 32 patients with biliary and pancreatic disorders. BH images were reconstructed with and without DLR. The signal-to-noise ratio (SNR), contrast, contrast-to-noise ratio (CNR) between the common bile duct (CBD) and periductal tissues, and full width at half maximum (FWHM) of CBD on 3D-MRCP were evaluated quantitatively. Two radiologists scored image noise, contrast, artifacts, blur, and overall image quality of the three image types using a 4-point scale. Quantitative and qualitative scores were compared using the Friedman test and post hoc Nemenyi test. RESULTS The SNR and CNR were not significantly different when under respiratory gating- and BH-MRCP without DLR. However, they were significantly higher under BH with DLR than under respiratory gating (SNR, p = 0.013; CNR, p = 0.027). The contrast and FWHM of MRCP under BH with and without DLR were lower than those under respiratory gating (contrast, p < 0.001; FWHM, p = 0.015). Qualitative scores for noise, blur, and overall image quality were higher under BH with DLR than those under respiratory gating (blur, p = 0.003; overall, p = 0.008). CONCLUSIONS The combination of the 3D hybrid profile order technique and DLR is useful for MRCP within a single BH and does not lead to the deterioration of image quality and space resolution at 3 T MRI. CLINICAL RELEVANCE STATEMENT Considering its advantages, this sequence might become the standard protocol for MRCP in clinical practice, at least at 3.0 T. KEY POINTS • The 3D hybrid profile order can achieve MRCP within a single breath-hold without a decrease in spatial resolution. • The DLR significantly improved the CNR and SNR of BH-MRCP. • The 3D hybrid profile order technique with DLR reduces the deterioration of image quality in MRCP within a single breath-hold.
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Affiliation(s)
- Kaori Shiraishi
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto, 860-8556, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto, 860-8556, Japan.
| | - Hiroyuki Uetani
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto, 860-8556, Japan
| | - Yasunori Nagayama
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto, 860-8556, Japan
| | - Masafumi Kidoh
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto, 860-8556, Japan
| | - Naoki Kobayashi
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto, 860-8556, Japan
| | - Kosuke Morita
- Department of Radiology, Kumamoto University Hospital, Kumamoto, Japan, Honjo 1-1-1, Kumamoto, Japan
| | - Yuichi Yamahita
- Canon Medical Systems Corporation, 70-1, Yanagi-Cho, Saiwai-Ku, Kawasaki-Shi, Kanagawa, 212-0015, Japan
| | - Yasuhito Tanaka
- Department of Gastroenterology and Hepatology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Hideo Baba
- Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Toshinori Hirai
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto, 860-8556, Japan
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Quint R, Vaussy A, Stemmer A, Hautefort C, Houdart E, Eliezer M. Iterative Denoising Accelerated 3D FLAIR Sequence for Hydrops MR Imaging at 3T. AJNR Am J Neuroradiol 2023; 44:1064-1069. [PMID: 37536733 PMCID: PMC10494947 DOI: 10.3174/ajnr.a7953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/27/2023] [Indexed: 08/05/2023]
Abstract
BACKGROUND AND PURPOSE 3D FLAIR sequences have become the criterion standard for identifying endolymphatic hydrops, but scan time remains an important limitation to their widespread use. Our purpose was to evaluate the diagnostic performance and image quality of an accelerated 3D FLAIR sequence combined with an iterative denoising algorithm. MATERIALS AND METHODS This was a retrospective study performed on 30 patients with clinical suspicion of endolymphatic hydrops who underwent 3T MR imaging 4 hours after gadolinium injection using two 3D FLAIR sequences. The first (conventional FLAIR) was accelerated with a conventional turbo factor of 187. The second was accelerated with an increased turbo factor of 263, resulting in a 33% scan time reduction (5 minutes 36 seconds versus 8 minutes 15 seconds, respectively). A sequence was reconstructed in-line immediately after the accelerated 3D FLAIR acquisition from the same raw data with iterative denoising (accelerated-FLAIR iterative denoising). The signal intensity ratio image quality score and endolymphatic hydrops diagnosis were evaluated. RESULTS The mean signal intensity ratio for symptomatic and asymptomatic ears of accelerated-FLAIR iterative denoising was significantly higher than the mean SNR of conventional FLAIR (29.5 versus 19 and 25.9 versus 16.3, P < .001). Compared with the conventional FLAIR sequence, the image-quality score was higher with accelerated-FLAIR iterative denoising (mean image-quality score, 3.8 [SD, 0.4] versus 3.3 [SD, 0.6] for accelerated-FLAIR iterative denoising and conventional FLAIR, respectively, P = .003). There was no significant difference in the diagnosis of endolymphatic hydrops between the 2 sequences. Interreader agreement was good-to-excellent. CONCLUSIONS The iterative denoising algorithm applied to an accelerated 3D FLAIR sequence for exploration of endolymphatic hydrops enabled significantly reducing the scan time without compromising image quality and diagnostic performance.
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Affiliation(s)
- R Quint
- From the Department of Neuroradiology (R.Q., E.H., M.E.), Lariboisière University Hospital, Paris, France
| | - A Vaussy
- Siemens Healthineers France (A.V.), Saint-Denis, France
| | - A Stemmer
- Siemens Healthineers (A.S.), Erlangen, Germany
| | - C Hautefort
- Department of Head and Neck Surgery (C.H.), Lariboisière University Hospital, Paris, France
| | - E Houdart
- From the Department of Neuroradiology (R.Q., E.H., M.E.), Lariboisière University Hospital, Paris, France
- Faculté de Médecine (E.H.), Université de Paris, Paris, France
| | - M Eliezer
- From the Department of Neuroradiology (R.Q., E.H., M.E.), Lariboisière University Hospital, Paris, France
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Fritz B, de Cesar Netto C, Fritz J. Multiaxial 3D MRI of the Ankle: Advanced High-Resolution Visualization of Ligaments, Tendons, and Articular Cartilage. Foot Ankle Clin 2023; 28:529-550. [PMID: 37536817 DOI: 10.1016/j.fcl.2023.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
MRI is a valuable tool for diagnosing a broad spectrum of acute and chronic ankle disorders, including ligament tears, tendinopathy, and osteochondral lesions. Traditional two-dimensional (2D) MRI provides a high image signal and contrast of anatomic structures for accurately characterizing articular cartilage, bone marrow, synovium, ligaments, tendons, and nerves. However, 2D MRI limitations are thick slices and fixed slice orientations. In clinical practice, 2D MRI is limited to 2 to 3 mm slice thickness, which can cause blurred contours of oblique structures due to volume averaging effects within the image slice. In addition, image plane orientations are fixated and cannot be changed after the scan, resulting in 2D MRI lacking multiplanar and multiaxial reformation abilities for individualized image plane orientations along oblique and curved anatomic structures, such as ankle ligaments and tendons. In contrast, three-dimensional (3D) MRI is a newer, clinically available MRI technique capable of acquiring high-resolution ankle MRI data sets with isotropic voxel size. The inherently high spatial resolution of 3D MRI permits up to five times thinner (0.5 mm) image slices. In addition, 3D MRI can be acquired image voxel with the same edge length in all three space dimensions (isotropism), permitting unrestricted multiplanar and multiaxial image reformation and postprocessing after the MRI scan. Clinical 3D MRI of the ankle with 0.5 to 0.7 mm isotropic voxel size resolves the smallest anatomic ankle structures and abnormalities of ligament and tendon fibers, osteochondral lesions, and nerves. After acquiring the images, operators can align image planes individually along any anatomic structure of interest, such as ligaments and tendons segments. In addition, curved multiplanar image reformations can unfold the entire course of multiaxially curved structures, such as perimalleolar tendons, into one image plane. We recommend adding 3D MRI pulse sequences to traditional 2D MRI protocols to visualize small and curved ankle structures to better advantage. This article provides an overview of the clinical application of 3D MRI of the ankle, compares diagnostic performances of 2D and 3D MRI for diagnosing ankle abnormalities, and illustrates clinical 3D ankle MRI applications.
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Affiliation(s)
- Benjamin Fritz
- Department of Radiology, Balgrist University Hospital, Forchstrasse 340, Zurich 8008, Switzerland; Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Cesar de Cesar Netto
- Department of Orthopaedics and Rehabilitation, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, USA
| | - Jan Fritz
- Department of Radiology, Division of Musculoskeletal Radiology, NYU Grossman School of Medicine, 660 1st Avenue, New York, NY 10016, USA.
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Young T, Dowling J, Rai R, Liney G, Greer P, Thwaites D, Holloway L. Clinical validation of MR imaging time reduction for substitute/synthetic CT generation for prostate MRI-only treatment planning. Phys Eng Sci Med 2023; 46:1015-1021. [PMID: 37219797 PMCID: PMC10480277 DOI: 10.1007/s13246-023-01268-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 04/26/2023] [Indexed: 05/24/2023]
Abstract
Radiotherapy treatment planning based only on magnetic resonance imaging (MRI) has become clinically achievable. Though computed tomography (CT) is the gold standard for radiotherapy imaging, directly providing the electron density values needed for planning calculations, MRI has superior soft tissue visualisation to guide treatment planning decisions and optimisation. MRI-only planning removes the need for the CT scan, but requires generation of a substitute/synthetic/pseudo CT (sCT) for electron density information. Shortening the MRI imaging time would improve patient comfort and reduce the likelihood of motion artefacts. A volunteer study was previously carried out to investigate and optimise faster MRI sequences for a hybrid atlas-voxel conversion to sCT for prostate treatment planning. The aim of this follow-on study was to clinically validate the performance of the new optimised sequence for sCT generation in a treated MRI-only prostate patient cohort. 10 patients undergoing MRI-only treatment were scanned on a Siemens Skyra 3T MRI as part of the MRI-only sub-study of the NINJA clinical trial (ACTRN12618001806257). Two sequences were used, the standard 3D T2-weighted SPACE sequence used for sCT conversion which has been previously validated against CT, and a modified fast SPACE sequence, selected based on the volunteer study. Both were used to generate sCT scans. These were then compared to evaluate the fast sequence conversion for anatomical and dosimetric accuracy against the clinically approved treatment plans. The average Mean Absolute Error (MAE) for the body was 14.98 ± 2.35 HU, and for bone was 40.77 ± 5.51 HU. The external volume contour comparison produced a Dice Similarity Coefficient (DSC) of at least 0.976, and an average of 0.985 ± 0.004, and the bony anatomy contour comparison a DSC of at least 0.907, and an average of 0.950 ± 0.018. The fast SPACE sCT agreed with the gold standard sCT within an isocentre dose of -0.28% ± 0.16% and an average gamma pass rate of 99.66% ± 0.41% for a 1%/1 mm gamma tolerance. In this clinical validation study, the fast sequence, which reduced the required imaging time by approximately a factor of 4, produced an sCT with similar clinical dosimetric results compared to the standard sCT, demonstrating its potential for clinical use for treatment planning.
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Affiliation(s)
- Tony Young
- Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, Australia
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, Australia
| | - Jason Dowling
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, Australia
- CSIRO Health and Biosecurity, The Australian e-Health & Research Centre, Brisbane, QLD Australia
- South Western Sydney Clinical School, University of New South Wales, Sydney, NSW Australia
- School of Mathematical and Physical Sciences, University of Newcastle, Callaghan, NSW Australia
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW Australia
| | - Robba Rai
- Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, Australia
- South Western Sydney Clinical School, University of New South Wales, Sydney, NSW Australia
| | - Gary Liney
- Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, Australia
- South Western Sydney Clinical School, University of New South Wales, Sydney, NSW Australia
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW Australia
| | - Peter Greer
- School of Mathematical and Physical Sciences, University of Newcastle, Callaghan, NSW Australia
- Calvary Mater Newcastle Hospital, Newcastle, NSW Australia
| | - David Thwaites
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, Australia
| | - Lois Holloway
- Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, Australia
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, Australia
- South Western Sydney Clinical School, University of New South Wales, Sydney, NSW Australia
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW Australia
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Lespagnol M, Massire A, Megdiche I, Lespagnol F, Brugières P, Créange A, Stemmer A, Bapst B. Improved detection of juxtacortical lesions using highly accelerated double inversion-recovery MRI in patients with multiple sclerosis. Diagn Interv Imaging 2023; 104:401-409. [PMID: 37156721 DOI: 10.1016/j.diii.2023.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/13/2023] [Accepted: 04/27/2023] [Indexed: 05/10/2023]
Abstract
PURPOSE The purpose of this study was to compare a highly-accelerated double inversion recovery (fast-DIR) sequence using a recent parallel imaging technique (CAIPIRINHA) with a conventional DIR (conv-DIR) sequence for image quality and the detection of juxtacortical and infratentorial multiple sclerosis (MS) lesions. MATERIALS AND METHODS A total of 38 patients with MS who underwent brain MRI at 3 T between 2020 and 2021 were included. There were 27 women and 12 men with a mean age of 40 ± 12.8 (standard deviation) years (range: 20-59 years). All patients underwent conv-DIR sequence and fast-DIR sequence. Fast-DIR was obtained with a T2-preparation module to improve contrast and an iterative denoising algorithm to compensate noise enhancement. Two blinded readers reported the number of juxtacortical and infratentorial MS lesions for fast-DIR and conv-DIR, confirmed by further consensus reading that was used as the standard of reference. Image quality and contrast were evaluated for fast-DIR and conv-DIR sequences. Comparisons between fast-DIR and conv-DIR sequences were performed using Wilcoxon test and Lin concordance correlation coefficient. RESULTS Thirty-eight patients were analyzed. Fast-DIR imaging allowed detection of 289 juxtacortical lesions vs. 238 with conv-DIR, corresponding to a significant improved detection rate with fast-DIR (P < 0.001). Conversely, 117 infratentorial lesions were detected with conv-DIR sequence vs. 80 with fast-DIR sequence (P < 0.001). Inter-observer agreement for lesion detection with fast-DIR and conv-DIR was very high (Lin concordance correlation coefficient ranging between 0.86 and 0.96). CONCLUSION Fast-DIR improves the detection of juxtacortical MS lesions, but is limited for the detection of infratentorial MS lesions.
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Affiliation(s)
- Morgane Lespagnol
- Department of Neuroradiology, AP-HP, Henri Mondor University Hospital, 92010 Créteil, France
| | | | - Imen Megdiche
- Department of Neuroradiology, AP-HP, Henri Mondor University Hospital, 92010 Créteil, France
| | - Fabien Lespagnol
- MOX, Department of Mathematics, Politecnico di Milano, 20133 Milano, Italy; Research Center, INRIA, 75012 Paris, France
| | - Pierre Brugières
- Department of Neuroradiology, AP-HP, Henri Mondor University Hospital, 92010 Créteil, France
| | - Alain Créange
- Department of Neurology, AP-HP, Henri Mondor University Hospital, 92010 Créteil, France; Faculty of Medicine, Université Paris Est Créteil, 92010 Créteil, France
| | | | - Blanche Bapst
- Department of Neuroradiology, AP-HP, Henri Mondor University Hospital, 92010 Créteil, France; Faculty of Medicine, Université Paris Est Créteil, 92010 Créteil, France.
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Lin J, Miao QI, Surawech C, Raman SS, Zhao K, Wu HH, Sung K. High-Resolution 3D MRI With Deep Generative Networks via Novel Slice-Profile Transformation Super-Resolution. IEEE ACCESS : PRACTICAL INNOVATIONS, OPEN SOLUTIONS 2023; 11:95022-95036. [PMID: 37711392 PMCID: PMC10501177 DOI: 10.1109/access.2023.3307577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
High-resolution magnetic resonance imaging (MRI) sequences, such as 3D turbo or fast spin-echo (TSE/FSE) imaging, are clinically desirable but suffer from long scanning time-related blurring when reformatted into preferred orientations. Instead, multi-slice two-dimensional (2D) TSE imaging is commonly used because of its high in-plane resolution but is limited clinically by poor through-plane resolution due to elongated voxels and the inability to generate multi-planar reformations due to staircase artifacts. Therefore, multiple 2D TSE scans are acquired in various orthogonal imaging planes, increasing the overall MRI scan time. In this study, we propose a novel slice-profile transformation super-resolution (SPTSR) framework with deep generative learning for through-plane super-resolution (SR) of multi-slice 2D TSE imaging. The deep generative networks were trained by synthesized low-resolution training input via slice-profile downsampling (SP-DS), and the trained networks inferred on the slice profile convolved (SP-conv) testing input for 5.5x through-plane SR. The network output was further slice-profile deconvolved (SP-deconv) to achieve an isotropic super-resolution. Compared to SMORE SR method and the networks trained by conventional downsampling, our SPTSR framework demonstrated the best overall image quality from 50 testing cases, evaluated by two abdominal radiologists. The quantitative analysis cross-validated the expert reader study results. 3D simulation experiments confirmed the quantitative improvement of the proposed SPTSR and the effectiveness of the SP-deconv step, compared to 3D ground-truths. Ablation studies were conducted on the individual contributions of SP-DS and SP-conv, networks structure, training dataset size, and different slice profiles.
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Affiliation(s)
- Jiahao Lin
- Department of Radiological Sciences, University of California at Los Angeles, Los Angeles, CA 90095, USA
- Department of Electrical and Computer Engineering, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Q I Miao
- Department of Radiological Sciences, University of California at Los Angeles, Los Angeles, CA 90095, USA
- Department of Radiology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Chuthaporn Surawech
- Department of Radiological Sciences, University of California at Los Angeles, Los Angeles, CA 90095, USA
- Department of Radiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
- Division of Diagnostic Radiology, Department of Radiology, King Chulalongkorn Memorial Hospital, Bangkok 10330, Thailand
| | - Steven S Raman
- Department of Radiological Sciences, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Kai Zhao
- Department of Radiological Sciences, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Holden H Wu
- Department of Radiological Sciences, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Kyunghyun Sung
- Department of Radiological Sciences, University of California at Los Angeles, Los Angeles, CA 90095, USA
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20
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Wang Z, Ramasawmy R, Feng X, Campbell-Washburn AE, Mugler JP, Meyer CH. Concomitant magnetic-field compensation for 2D spiral-ring turbo spin-echo imaging at 0.55T and 1.5T. Magn Reson Med 2023; 90:552-568. [PMID: 37036033 PMCID: PMC10578525 DOI: 10.1002/mrm.29663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/08/2023] [Accepted: 03/21/2023] [Indexed: 04/11/2023]
Abstract
PURPOSE To develop 2D turbo spin-echo (TSE) imaging using annular spiral rings (abbreviated "SPRING-RIO TSE") with compensation of concomitant gradient fields and B0 inhomogeneity at both 0.55T and 1.5T for fast T2 -weighted imaging. METHODS Strategies of gradient waveform modifications were implemented in SPRING-RIO TSE for compensation of self-squared concomitant gradient terms at the TE and across echo spacings, along with reconstruction-based corrections to simultaneously compensate for the residual concomitant gradient and B0 field induced phase accruals along the readout. The signal pathway disturbance caused by time-varying and spatially dependent concomitant fields was simulated, and echo-to-echo phase variations before and after sequence-based compensation were compared. Images from SPRING-RIO TSE with no compensation, with compensation, and Cartesian TSE were also compared via phantom and in vivo acquisitions. RESULTS Simulation showed how concomitant fields affected the signal evolution with no compensation, and both simulation and phantom studies demonstrated the performance of the proposed sequence modifications, as well as the readout off-resonance corrections. Volunteer data showed that after full correction, the SPRING-RIO TSE sequence achieved high image quality with improved SNR efficiency (15%-20% increase), and reduced RF SAR (˜50% reduction), compared to the standard Cartesian TSE, presenting potential benefits, especially in regaining SNR at low-field (0.55T). CONCLUSION Implementation of SPRING-RIO TSE with concomitant field compensation was tested at 0.55T and 1.5T. The compensation principles can be extended to correct for other trajectory types that are time-varying along the echo train and temporally asymmetric in TSE-based imaging.
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Affiliation(s)
- Zhixing Wang
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - Rajiv Ramasawmy
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Xue Feng
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - Adrienne E. Campbell-Washburn
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - John P. Mugler
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
- Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, Virginia, USA
| | - Craig H. Meyer
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
- Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, Virginia, USA
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21
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Tian Y, Li X, Wang X, Su W, Li S, Wang W, Zhang Y, Li C, Chen M. CEST 2022-three-dimensional amide proton transfer (APT) imaging can identify the changes of cerebral cortex in Parkinson's disease. Magn Reson Imaging 2023:S0730-725X(23)00099-1. [PMID: 37356600 DOI: 10.1016/j.mri.2023.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 06/12/2023] [Indexed: 06/27/2023]
Abstract
PURPOSE Amide proton transfer (APT) imaging has shown its diagnostic and predictive superiority in PD in our previous studies using 2D APT imaging based on deep nuclei. We hypothesized that the pathophysiological abnormality of PD will change the APT-related parameters in the cerebral cortex, and the signal changes can contribute to accurate diagnosis of Parkinson's disease. METHODS 34 patients with sporadic Parkinson's disease (IPD) and 29 age- and sex-matched normal controls (NC) were enrolled in this prospective study. 3D-APT imaging and 3D-T1WI was performed in our participants. A volume-based morphometry algorithm was used and get automated cortical segmentations. Quantitative parameter maps of APT-related metrics were calculated by using SPM and MATLAB. The unpaired Student's t-test or Mann-Whitney U test was used for comparison of these values between IPD and NC groups. The associations between APT-related metrics and clinical assessments were investigated by Spearman correlation analysis. The receiver-operating characteristic (ROC) analysis was used to assess the diagnostic performances. The binary logistic regression model was used to combine the imaging parameters. RESULTS There wasn't any correlations between cortical APT-related signals and clinical assessment, including the H&Y scale, the disease duration, the UPDRS III scores and the MMSE scores. The MTRasym, CESTRnr and MTRRex had significantly higher values (p <0.001, corrected by Bonferroni methods) in the IPD group than NC groups in the region of bilateral and total temporal grey matter. The single parameters achieved the best diagnostic performance among all APT-related metrics was MTRRex on the right temporal grey matter, with an area under the ROC curve (AUC) of 0.865. The combined parameters achieved the highest diagnostic performance (AUC: 0.932). CONCLUSIONS 3D-APT imaging could identify the changes of the cerebral cortex in Parkinson's disease. The cortical changes of APT-related parameters could potentially serve as imaging biomarkers to aid in the non-invasive diagnosis of PD.
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Affiliation(s)
- Yaotian Tian
- Department of Radiology, National Center of Gerontology, Beijing Hospital, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, 100730 Beijing, China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, 100730 Beijing, China
| | - Xinyang Li
- Department of Radiology, National Center of Gerontology, Beijing Hospital, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, 100730 Beijing, China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, 100730 Beijing, China
| | - Xiaonan Wang
- Department of Radiology, National Center of Gerontology, Beijing Hospital, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, 100730 Beijing, China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, 100730 Beijing, China
| | - Wen Su
- Department of Neurology, National Center of Gerontology, Beijing Hospital, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, 100730 Beijing, China
| | - Shuhua Li
- Department of Neurology, National Center of Gerontology, Beijing Hospital, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, 100730 Beijing, China
| | - Wenqi Wang
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Yi Zhang
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Chunmei Li
- Department of Radiology, National Center of Gerontology, Beijing Hospital, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, 100730 Beijing, China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, 100730 Beijing, China.
| | - Min Chen
- Department of Radiology, National Center of Gerontology, Beijing Hospital, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, 100730 Beijing, China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, 100730 Beijing, China.
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22
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Barnden L, Thapaliya K, Eaton-Fitch N, Barth M, Marshall-Gradisnik S. Altered brain connectivity in Long Covid during cognitive exertion: a pilot study. Front Neurosci 2023; 17:1182607. [PMID: 37425014 PMCID: PMC10323677 DOI: 10.3389/fnins.2023.1182607] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 06/06/2023] [Indexed: 07/11/2023] Open
Abstract
Introduction Debilitating Long-Covid symptoms occur frequently after SARS-COVID-19 infection. Methods Functional MRI was acquired in 10 Long Covid (LCov) and 13 healthy controls (HC) with a 7 Tesla scanner during a cognitive (Stroop color-word) task. BOLD time series were computed for 7 salience and 4 default-mode network hubs, 2 hippocampus and 7 brainstem regions (ROIs). Connectivity was characterized by the correlation coefficient between each pair of ROI BOLD time series. We tested for HC versus LCov differences in connectivity between each pair of the 20 regions (ROI-to-ROI) and between each ROI and the rest of the brain (ROI-to-voxel). For LCov, we also performed regressions of ROI-to-ROI connectivity with clinical scores. Results Two ROI-to-ROI connectivities differed between HC and LCov. Both involved the brainstem rostral medulla, one connection to the midbrain, another to a DM network hub. Both were stronger in LCov than HC. ROI-to-voxel analysis detected multiple other regions where LCov connectivity differed from HC located in all major lobes. Most, but not all connections, were weaker in LCov than HC. LCov, but not HC connectivity, was correlated with clinical scores for disability and autonomic function and involved brainstem ROI. Discussion Multiple connectivity differences and clinical correlations involved brainstem ROIs. Stronger connectivity in LCov between the medulla and midbrain may reflect a compensatory response. This brainstem circuit regulates cortical arousal, autonomic function and the sleep-wake cycle. In contrast, this circuit exhibited weaker connectivity in ME/CFS. LCov connectivity regressions with disability and autonomic scores were consistent with altered brainstem connectivity in LCov.
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Affiliation(s)
- Leighton Barnden
- National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
| | - Kiran Thapaliya
- National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
- Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD, Australia
| | - Natalie Eaton-Fitch
- National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
| | - Markus Barth
- Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD, Australia
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD, Australia
| | - Sonya Marshall-Gradisnik
- National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
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23
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Fisher DG, Sharifi KA, Ulutas EZ, Kumar JS, Kalani MYS, Miller GW, Price RJ, Tvrdik P. Magnetic Resonance Imaging of Mouse Cerebral Cavernomas Reveal Differential Lesion Progression and Variable Permeability to Gadolinium. Arterioscler Thromb Vasc Biol 2023; 43:958-970. [PMID: 37078284 PMCID: PMC10257814 DOI: 10.1161/atvbaha.122.318938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/04/2023] [Indexed: 04/21/2023]
Abstract
BACKGROUND Cerebral cavernous malformations, also known as cavernous angiomas, are blood vessel abnormalities comprised of clusters of grossly enlarged and hemorrhage-prone capillaries. The prevalence in the general population, including asymptomatic cases, is estimated to be 0.5%. Some patients develop severe symptoms, including seizures and focal neurological deficits, whereas others remain asymptomatic. The causes of this remarkable presentation heterogeneity within a primarily monogenic disease remain poorly understood. METHODS We established a chronic mouse model of cerebral cavernous malformations, induced by postnatal ablation of Krit1 with Pdgfb-CreERT2, and examined lesion progression in these mice with T2-weighted 7T magnetic resonance imaging (MRI). We also established a modified protocol for dynamic contrast-enhanced MRI and produced quantitative maps of gadolinium tracer gadobenate dimeglumine. After terminal imaging, brain slices were stained with antibodies against microglia, astrocytes, and endothelial cells. RESULTS These mice develop cerebral cavernous malformations lesions gradually over 4 to 5 months of age throughout the brain. Precise volumetric analysis of individual lesions revealed nonmonotonous behavior, with some lesions temporarily growing smaller. However, the cumulative lesional volume invariably increased over time and after about 2 months followed a power trend. Using dynamic contrast-enhanced MRI, we produced quantitative maps of gadolinium in the lesions, indicating a high degree of heterogeneity in lesional permeability. MRI properties of the lesions were correlated with cellular markers for endothelial cells, astrocytes, and microglia. Multivariate comparisons of MRI properties of the lesions with cellular markers for endothelial and glial cells revealed that increased cell density surrounding lesions correlates with stability, whereas denser vasculature within and surrounding the lesions may correlate with high permeability. CONCLUSIONS Our results lay a foundation for better understanding individual lesion properties and provide a comprehensive preclinical platform for testing new drug and gene therapies for controlling cerebral cavernous malformations.
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Affiliation(s)
- Delaney G. Fisher
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Khadijeh A. Sharifi
- Department of Neuroscience, University of Virginia, Charlottesville, VA
- Department of Neurosurgery, University of Virginia Health System, Charlottesville, VA
| | - E. Zeynep Ulutas
- Department of Neuroscience, Georgia Institute of Technology, Atlanta, GA
| | - Jeyan S. Kumar
- Department of Neurosurgery, University of Virginia Health System, Charlottesville, VA
| | | | - G. Wilson Miller
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
- Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, VA
| | - Richard J. Price
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Petr Tvrdik
- Department of Neuroscience, University of Virginia, Charlottesville, VA
- Department of Neurosurgery, University of Virginia Health System, Charlottesville, VA
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24
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Zhang Y, Zu T, Liu R, Zhou J. Acquisition sequences and reconstruction methods for fast chemical exchange saturation transfer imaging. NMR IN BIOMEDICINE 2023; 36:e4699. [PMID: 35067987 DOI: 10.1002/nbm.4699] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/02/2022] [Accepted: 01/17/2022] [Indexed: 05/23/2023]
Abstract
Chemical exchange saturation transfer (CEST) imaging is an emerging molecular magnetic resonance imaging (MRI) technique that has been developed and employed in numerous diseases. Based on the unique saturation transfer principle, a family of CEST-detectable biomolecules in vivo have been found capable of providing valuable diagnostic information. However, CEST MRI needs a relatively long scan time due to the common long saturation labeling module and typical acquisition of multiple frequency offsets and signal averages, limiting its widespread clinical applications. So far, a plethora of imaging schemes and techniques has been developed to accelerate CEST MRI. In this review, the key acquisition and reconstruction methods for fast CEST imaging are summarized from a practical and systematic point of view. The first acquisition sequence section describes the major development of saturation schemes, readout patterns, ultrafast z-spectroscopy, and saturation-editing techniques for rapid CEST imaging. The second reconstruction method section lists the important advances of parallel imaging, compressed sensing, sparsity in the z-spectrum, and algorithms beyond the Fourier transform for speeding up CEST MRI.
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Affiliation(s)
- Yi Zhang
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China
| | - Tao Zu
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ruibin Liu
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jinyuan Zhou
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
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25
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Pollak C, Kügler D, Breteler MMB, Reuter M. Quantifying MR Head Motion in the Rhineland Study - A Robust Method for Population Cohorts. Neuroimage 2023; 275:120176. [PMID: 37209757 DOI: 10.1016/j.neuroimage.2023.120176] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/22/2023] [Accepted: 05/15/2023] [Indexed: 05/22/2023] Open
Abstract
Head motion during MR acquisition reduces image quality and has been shown to bias neuromorphometric analysis. The quantification of head motion, therefore, has both neuroscientific as well as clinical applications, for example, to control for motion in statistical analyses of brain morphology, or as a variable of interest in neurological studies. The accuracy of markerless optical head tracking, however, is largely unexplored. Furthermore, no quantitative analysis of head motion in a general, mostly healthy population cohort exists thus far. In this work, we present a robust registration method for the alignment of depth camera data that sensitively estimates even small head movements of compliant participants. Our method outperforms the vendor-supplied method in three validation experiments: 1. similarity to fMRI motion traces as a low-frequency reference, 2. recovery of the independently acquired breathing signal as a high-frequency reference, and 3. correlation with image-based quality metrics in structural T1-weighted MRI. In addition to the core algorithm, we establish an analysis pipeline that computes average motion scores per time interval or per sequence for inclusion in downstream analyses. We apply the pipeline in the Rhineland Study, a large population cohort study, where we replicate age and body mass index (BMI) as motion correlates and show that head motion significantly increases over the duration of the scan session. We observe weak, yet significant interactions between this within-session increase and age, BMI, and sex. High correlations between fMRI and camera-based motion scores of proceeding sequences further suggest that fMRI motion estimates can be used as a surrogate score in the absence of better measures to control for motion in statistical analyses.
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Affiliation(s)
- Clemens Pollak
- AI in Medical Imaging, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - David Kügler
- AI in Medical Imaging, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Monique M B Breteler
- Population Health Sciences, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany; Institute for Medical Biometry, Informatics and Epidemiology (IMBIE), Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Martin Reuter
- AI in Medical Imaging, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany; A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA; Department of Radiology, Harvard Medical School, Boston, MA, USA.
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26
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Mason KN, Black J. Incorporating Velopharyngeal MRI into the Clinical Decision-Making Process for a Patient Presenting with Velopharyngeal Dysfunction Following a Failed Palatoplasty. Cleft Palate Craniofac J 2023:10556656231173500. [PMID: 37143294 PMCID: PMC10624648 DOI: 10.1177/10556656231173500] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
This clinical report describes the implementation of magnetic resonance imaging (MRI) to evaluate a patient with long-standing velopharyngeal dysfunction. She was referred to the craniofacial clinic at age 10 with no prior surgical history and subsequently completed a Furlow palatoplasty due to a suspected submucous cleft palate. However, results were unfavorable with minimal improvement in speech or resonance. The clinical presentation, treatment, outcomes, and contributions from MRI for secondary surgical planning are described. Addition of MRI into the clinical workflow provided insights into the anatomy and physiology of the velopharyngeal mechanism that were unable to be obtained from nasendoscopy and speech evaluation alone.
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Affiliation(s)
- Kazlin N. Mason
- Department of Human Services, University of Virginia, Charlottesville, VA, 22903
| | - Jonathan Black
- University of Virginia Health System, Division of Plastic Surgery, Charlottesville, VA, 22903
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27
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Snyder J, Seres P, Wilman AH. Signal-to-noise ratio penalties from a loss of stimulated echoes when using slab-selective excitation in three-dimensional fast spin echo imaging with long echo trains. NMR IN BIOMEDICINE 2023; 36:e4881. [PMID: 36427186 DOI: 10.1002/nbm.4881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 11/18/2022] [Accepted: 11/19/2022] [Indexed: 06/16/2023]
Abstract
Three-dimensional fast spin echo imaging with long echo trains combines high resolution with reasonable acquisition times and reduced specific absorption rate due to low refocusing flip angles. Typically, an entire volume is encoded (nonselective excitation) or localization can be performed with slab select excitation, which uses a long 90° pulse for precise localization, followed by a preliminary nonselective 180° pulse bounded by spoiler gradients to destroy signal outside of the volume of interest. Subsequent flip angles in the train are nonselective and identical between the two methods. The inclusion of the initial selective pulse and spoiler gradients results in a signal-to-noise ratio (SNR) penalty for slab selection, beyond the slice-averaging dependence, arising from a loss of stimulated echoes. SNR differences are explored using Bloch equation simulations of a T2-weighted 96 echo train sequence with varying parameters including T2, T1, and B1+ and compared with phantom and in vivo brain, neck, and knee experiments. In vivo SNR measurements in the three regions showed a maximum decrease of selective SNR by 29% (gastrocnemius muscle), 25% (pons), and 22% (globus pallidus), despite similar experimental parameters to nonselective experiments. Decreased SNR was compounded by B1+ variation affecting prescribed flip angles with further smaller reductions with T2 and T1 times. In conclusion, the elimination of coherences via the preliminary nominal 180° pulse and spoiler gradients in addition to the extended echo timing from the long excitation pulse resulted in a reduction in SNR compared with the nonselective case. Consideration of the required SNR and chosen anatomy as well as sequence restrictions should be weighed before choosing slab-selective excitation.
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Affiliation(s)
- Jeff Snyder
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Peter Seres
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
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28
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Arefeen Y, Xu J, Zhang M, Dong Z, Wang F, White J, Bilgic B, Adalsteinsson E. Latent signal models: Learning compact representations of signal evolution for improved time-resolved, multi-contrast MRI. Magn Reson Med 2023; 90:483-501. [PMID: 37093775 DOI: 10.1002/mrm.29657] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/09/2023] [Accepted: 03/16/2023] [Indexed: 04/25/2023]
Abstract
PURPOSE To improve time-resolved reconstructions by training auto-encoders to learn compact representations of Bloch-simulated signal evolution and inserting the decoder into the forward model. METHODS Building on model-based nonlinear and linear subspace techniques, we train auto-encoders on dictionaries of simulated signal evolution to learn compact, nonlinear, latent representations. The proposed latent signal model framework inserts the decoder portion of the auto-encoder into the forward model and directly reconstructs the latent representation. Latent signal models essentially serve as a proxy for fast and feasible differentiation through the Bloch equations used to simulate signal. This work performs experiments in the context of T2 -shuffling, gradient echo EPTI, and MPRAGE-shuffling. We compare how efficiently auto-encoders represent signal evolution in comparison to linear subspaces. Simulation and in vivo experiments then evaluate if reducing degrees of freedom by incorporating our proxy for the Bloch equations, the decoder portion of the auto-encoder, into the forward model improves reconstructions in comparison to subspace constraints. RESULTS An auto-encoder with 1 real latent variable represents single-tissue fast spin echo, EPTI, and MPRAGE signal evolution to within 0.15% normalized RMS error, enabling reconstruction problems with 3 degrees of freedom per voxel (real latent variable + complex scaling) in comparison to linear models with 4-8 degrees of freedom per voxel. In simulated/in vivo T2 -shuffling and in vivo EPTI experiments, the proposed framework achieves consistent quantitative normalized RMS error improvement over linear approaches. From qualitative evaluation, the proposed approach yields images with reduced blurring and noise amplification in MPRAGE-shuffling experiments. CONCLUSION Directly solving for nonlinear latent representations of signal evolution improves time-resolved MRI reconstructions.
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Affiliation(s)
- Yamin Arefeen
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Junshen Xu
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Molin Zhang
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Zijing Dong
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA
| | - Fuyixue Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA
| | - Jacob White
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Berkin Bilgic
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Elfar Adalsteinsson
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Harvard-MIT Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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Rahbek S, Schakel T, Mahmood F, Madsen KH, Philippens MEP, Hanson LG. Optimized flip angle schemes for the split acquisition of fast spin-echo signals (SPLICE) sequence and application to diffusion-weighted imaging. Magn Reson Med 2023; 89:1469-1480. [PMID: 36420920 PMCID: PMC10099388 DOI: 10.1002/mrm.29545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 10/21/2022] [Accepted: 11/14/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE The diffusion-weighted SPLICE (split acquisition of fast spin-echo signals) sequence employs split-echo rapid acquisition with relaxation enhancement (RARE) readout to provide images almost free of geometric distortions. However, due to the varying T 2 $$ {}_2 $$ -weighting during k-space traversal, SPLICE suffers from blurring. This work extends a method for controlling the spatial point spread function (PSF) while optimizing the signal-to-noise ratio (SNR) achieved by adjusting the flip angles in the refocusing pulse train of SPLICE. METHODS An algorithm based on extended phase graph (EPG) simulations optimizes the flip angles by maximizing SNR for a flexibly chosen predefined target PSF that describes the desired k-space density weighting and spatial resolution. An optimized flip angle scheme and a corresponding post-processing correction filter which together achieve the target PSF was tested by healthy subject brain imaging using a clinical 1.5 T scanner. RESULTS Brain images showed a clear and consistent improvement over those obtained with a standard constant flip angle scheme. SNR was increased and apparent diffusion coefficient estimates were more accurate. For a modified Hann k-space weighting example, considerable benefits resulted from acquisition weighting by flip angle control. CONCLUSION The presented flexible method for optimizing SPLICE flip angle schemes offers improved MR image quality of geometrically accurate diffusion-weighted images that makes the sequence a strong candidate for radiotherapy planning or stereotactic surgery.
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Affiliation(s)
- Sofie Rahbek
- Department of Health Technology, Technical University of Denmark, Lyngby, Denmark
| | - Tim Schakel
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands
| | - Faisal Mahmood
- Laboratory of Radiation Physics, Department of Oncology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Kristoffer H Madsen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark.,Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark
| | | | - Lars G Hanson
- Department of Health Technology, Technical University of Denmark, Lyngby, Denmark.,Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark
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Park J, Jang M, Heier L, Limperopoulos C, Zun Z. Rapid anatomical imaging of the neonatal brain using T 2 -prepared 3D balanced steady-state free precession. Magn Reson Med 2023; 89:1456-1468. [PMID: 36420869 PMCID: PMC10208121 DOI: 10.1002/mrm.29537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/18/2022] [Accepted: 11/03/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE To develop a new approach to 3D gradient echo-based anatomical imaging of the neonatal brain with a substantially shorter scan time than standard 3D fast spin echo (FSE) methods, while maintaining a high SNR. METHODS T2 -prepration was employed immediately prior to image acquisition of 3D balanced steady-state free precession (bSSFP) with a single trajectory of center-out k-space view ordering, which requires no magnetization recovery time between imaging segments during the scan. This approach was compared with 3D FSE, 2D single-shot FSE, and product 3D bSSFP imaging in numerical simulations, plus phantom and in vivo experiments. RESULTS T2 -prepared 3D bSSFP generated image contrast of gray matter, white matter, and CSF very similar to that of reference T2 -weighted imaging methods, without major image artifacts. Scan time of T2 -prepared 3D bSSFP was remarkably shorter compared to 3D FSE, whereas SNR was comparable to that of 3D FSE and higher than that of 2D single-shot FSE. Specific absorption rate of T2 -prepared 3D bSSFP remained within the safety limit. Determining an optimal imaging flip angle of T2 -prepared 3D bSSFP was critical to minimizing blurring of images. CONCLUSION T2 -prepared 3D bSSFP offers an alternative method for anatomical imaging of the neonatal brain with dramatically reduced scan time compared to standard 3D FSE and higher SNR than 2D single-shot FSE.
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Affiliation(s)
- Jinho Park
- Department of Cardiology, Yonsei University, Seoul, Korea
| | - MinJung Jang
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - Linda Heier
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Catherine Limperopoulos
- Developing Brain Institute, Division of Diagnostic Imaging and Radiology, Children’s National Hospital, Washington, DC, USA
- Division of Fetal and Transitional Medicine, Children’s National Hospital, Washington, DC, USA
- Department of Pediatrics, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA
- Department of Radiology, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA
| | - Zungho Zun
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
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Yoshida R, Machida Y. Modulation transfer function measurement of three-dimensional T 1-weighted turbo spin echo sequence with low refocusing flip angles using single-plate method. Radiol Phys Technol 2023; 16:346-353. [PMID: 36966438 DOI: 10.1007/s12194-023-00711-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 03/27/2023]
Abstract
This study aimed to demonstrate the usefulness of modulation transfer function (MTF) measurements using the single-plate method to evaluate changes in resolution properties that are dependent on three parameters: echo train length (ETL), low refocusing flip angle (RFA), and start-up echo in three-dimensional T1-weighted turbo spin echoes (TSE) with a low RFA and to optimize these parameters. Although the MTFs were slightly degraded with an RFA of 120°, they were considerably degraded with an RFA of ≤ 90°. On the other hand, the MTF of low RFA was greatly improved by setting the start-up echo, allowing setting a long ETL. The single-plate method provided a clear and easy evaluation of the resolution properties of low RFA TSE. Furthermore, this method allows us to visualize changes in the signal intensity of each echo in k-space, depending on the sequence variation. These results suggest that the MTF measurement using the single-plate method is useful for evaluating the resolution properties of TSE sequences and optimizing the measured parameters.
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Affiliation(s)
- Rei Yoshida
- Department of Radiology, Kurihara Central Hospital, 3-1-1 Miyano Chuo, Tsukidate, Kurihara, Miyagi, 987-2205, Japan.
- Health Sciences, Tohoku University Graduate School of Medicine, 2‑1 Seiryo‑machi, Aoba‑ku, Sendai, Miyagi, 980‑8575, Japan.
| | - Yoshio Machida
- Health Sciences, Tohoku University Graduate School of Medicine, 2‑1 Seiryo‑machi, Aoba‑ku, Sendai, Miyagi, 980‑8575, Japan
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Tao S, Zhou X, Lin C, Patel V, Westerhold EM, Middlebrooks EH. Optimization of MP2RAGE T1 mapping with radial view-ordering for deep brain stimulation targeting at 7 T MRI. Magn Reson Imaging 2023; 100:55-63. [PMID: 36924805 DOI: 10.1016/j.mri.2023.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/28/2023] [Accepted: 03/12/2023] [Indexed: 03/15/2023]
Abstract
PURPOSE Deep brain stimulation (DBS) is an effective treatment of various neurological disorders. Due to higher intrinsic signal, 7 T MRI can potentially improve delineation of DBS targets. However, the severe RF transmit field (B1+) inhomogeneity at 7 T can compromise the image contrast of traditional single-contrast sequences for DBS targeting, leading to sub-optimal target visualization. The Magnetization Prepared 2 Rapid Acquisition Gradient Echo (MP2RAGE)-based T1 mapping provides an alternative to the traditional single-contrast techniques by allowing retrospective synthesis of images at arbitrary inversion times to aid in visualization of various DBS targets. With this approach, optimization of sequence parameters to create T1 maps with low noise and low quantification bias is critical, as these characteristics directly affect the noise and uniformity of the synthetic images. In this work, we perform sequence optimization for MP2RAGE-based T1 mapping using a radial view-ordering technique to improve image quality, and demonstrate the clinical utility of T1 mapping approach for DBS targeting. METHODS We first introduce a systematic sequence optimization framework for 7 T MP2RAGE T1 mapping by formulating it into a constrained, multi-dimensional optimization process considering the effect of B1+ inhomogeneity on image noise, T1 quantification bias, and image blurring. With this framework, we investigate the use of radial view-order approach for T1 mapping, in lieu of the conventional linear view-ordering. Bloch's equation-based simulations were performed to compare the T1 maps generated using different approaches. Images of healthy volunteer and patients were acquired on a clinical 7 T MRI scanner for validation and to demonstrate the utility of T1 mapping for DBS targeting. RESULTS Numerical experiments demonstrated that the proposed framework allowed optimization of image SNR in T1 maps while controlling the quantification bias and image blurring, therefore facilitating the selection of optimal sequence parameters for visualizing DBS targets. The optimized sequence using radial view-ordering offered 40-60% noise reduction compared to the linear view-ordering. The improvement of SNR was confirmed in the in vivo examples. Clinical images showed that the synthetic images generated from the optimized T1 maps allowed clear visualization of DBS targets. CONCLUSION We demonstrated the optimization of MP2RAGE T1 mapping with radial view-ordering technique for DBS targeting at 7 T and showed that the optimized sequence allows retrospective generation of synthetic inversion time images commonly utilized in DBS targeting, such as fast gray matter acquisition T1 inversion recovery (FGATIR) and edge-enhancing gradient echo (EDGE) sequences.
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Affiliation(s)
- Shengzhen Tao
- Department of Radiology, Mayo Clinic, Jacksonville, FL, USA.
| | - Xiangzhi Zhou
- Department of Radiology, Mayo Clinic, Jacksonville, FL, USA
| | - Chen Lin
- Department of Radiology, Mayo Clinic, Jacksonville, FL, USA
| | - Vishal Patel
- Department of Radiology, Mayo Clinic, Jacksonville, FL, USA
| | | | - Erik H Middlebrooks
- Department of Radiology, Mayo Clinic, Jacksonville, FL, USA; Department of Neurosurgery, Mayo Clinic, Jacksonville, FL, USA
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Varghese J, Jin N, Giese D, Chen C, Liu Y, Pan Y, Nair N, Shalaan MT, Khan M, Tong MS, Ahmad R, Han Y, Simonetti OP. Building a comprehensive cardiovascular magnetic resonance exam on a commercial 0.55 T system: A pictorial essay on potential applications. Front Cardiovasc Med 2023; 10:1120982. [PMID: 36937932 PMCID: PMC10014600 DOI: 10.3389/fcvm.2023.1120982] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 02/06/2023] [Indexed: 03/05/2023] Open
Abstract
Background Contemporary advances in low-field magnetic resonance imaging systems can potentially widen access to cardiovascular magnetic resonance (CMR) imaging. We present our initial experience in building a comprehensive CMR protocol on a commercial 0.55 T system with a gradient performance of 26 mT/m amplitude and 45 T/m/s slew rate. To achieve sufficient image quality, we adapted standard imaging techniques when possible, and implemented compressed-sensing (CS) based techniques when needed in an effort to compensate for the inherently low signal-to-noise ratio at lower field strength. Methods A prototype CMR exam was built on an 80 cm, ultra-wide bore commercial 0.55 T MR system. Implementation of all components aimed to overcome the inherently lower signal of low-field and the relatively longer echo and repetition times owing to the slower gradients. CS-based breath-held and real-time cine imaging was built utilizing high acceleration rates to meet nominal spatial and temporal resolution recommendations. Similarly, CS 2D phase-contrast cine was implemented for flow. Dark-blood turbo spin echo sequences with deep learning based denoising were implemented for morphology assessment. Magnetization-prepared single-shot myocardial mapping techniques incorporated additional source images. CS-based dynamic contrast-enhanced imaging was implemented for myocardial perfusion and 3D MR angiography. Non-contrast 3D MR angiography was built with electrocardiogram-triggered, navigator-gated magnetization-prepared methods. Late gadolinium enhanced (LGE) tissue characterization methods included breath-held segmented and free-breathing single-shot imaging with motion correction and averaging using an increased number of source images. Proof-of-concept was demonstrated through porcine infarct model, healthy volunteer, and patient scans. Results Reasonable image quality was demonstrated for cardiovascular structure, function, flow, and LGE assessment. Low-field afforded utilization of higher flip angles for cine and MR angiography. CS-based techniques were able to overcome gradient speed limitations and meet spatial and temporal resolution recommendations with imaging times comparable to higher performance scanners. Tissue mapping and perfusion imaging require further development. Conclusion We implemented cardiac applications demonstrating the potential for comprehensive CMR on a novel commercial 0.55 T system. Further development and validation studies are needed before this technology can be applied clinically.
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Affiliation(s)
- Juliet Varghese
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Ning Jin
- Cardiovascular MR R&D, Siemens Medical Solutions USA, Malvern, PA, United States
| | - Daniel Giese
- Magnetic Resonance, Siemens Healthcare, Erlangen, Germany
- Institute of Radiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), University Hospital Erlangen, Erlangen, Germany
| | - Chong Chen
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Yingmin Liu
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Yue Pan
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Nikita Nair
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Mahmoud T. Shalaan
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Mahmood Khan
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
- Department of Emergency Medicine, The Ohio State University, Columbus, OH, United States
| | - Matthew S. Tong
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - Rizwan Ahmad
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Yuchi Han
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - Orlando P. Simonetti
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
- Department of Radiology, The Ohio State University, Columbus, OH, United States
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Mechó S, Lisbona Ortega R, Pruna R, Nescolarde Selva L, Morillas Pérez J, Rodríguez-Baeza A, Martínez Agea J, Pérez-Andrés R. Measuring direct and indirect tendon parameters to characterize the proximal tendinous complex of the rectus femoris in football and futsal players. Front Physiol 2023; 14:986872. [PMID: 36824472 PMCID: PMC9941635 DOI: 10.3389/fphys.2023.986872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 01/13/2023] [Indexed: 02/09/2023] Open
Abstract
Objective: To present unprecedented radiological parameters that characterize the angle between the direct and indirect tendons of the proximal rectus femoris (RF) and its inclinations and to evaluate the population variability according to demographic variables. Materials and methods: From September 2019 to July 2021, using MRI multiplanar reconstructions of the proximal thigh/hip, two blinded radiologists measured the direct and indirect tendon angle and the inclination of each tendon in different planes. The intra- and inter-observer agreements were assessed with Bland-Altman analysis and intraclass correlation coefficient (ICC). The correlations between radiological parameters and demographic variables were evaluated using linear regression, Student's t-test, and analysis of variance. Results: We performed 112 thigh/hip MRI scans on 91 football players of different age, gender, and disciplines (football and futsal). For observer 1 (the reference), the mean direct and indirect tendon angle was 56.74° ± 9.37, the mean indirect tendon slope was -7.90° ± 7.49, and the mean direct tendon slope was 22.16° ± 5.88. The three measurements showed inter- and intra-observer agreement (mean differences ∼0). No correlation was observed between age and the parameters. Likewise, no statistically significant differences were found for gender, dominant limb, examined limb, and sport. Conclusion: There is an inter- and intra-observer agreement in the measurements of the direct and indirect tendon angle and the inclination of each tendon. There is population variability in the proximal tendinous complex unrelated to demographic factors. These results allow further detection of morphological patterns that represent a risk factor for lesions in the RF in professional football and futsal players and other sports.
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Affiliation(s)
- Sandra Mechó
- Autonomous University of Barcelona, Barcelona, Spain,Department of Radiology Hospital de Barcelona, SCIAS, Barcelona, Spain,*Correspondence: Sandra Mechó,
| | | | - Ricard Pruna
- FC Barcelona Medical Services, Sant Joan Despí, Spain
| | - Lexa Nescolarde Selva
- Department of Electronic Engineering, Universitat Politècnica de Catalunya, Barcelona, Spain
| | | | - Alfonso Rodríguez-Baeza
- Department of Morphological Sciences (Human Anatomy and Embryology Unit), Faculty of Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
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Ryan P, Huins CT, O'Brien KJ, Misra S, Birman CS. Cochlear nerve dysplasia in unilateral severe to profound congenital sensorineural hearing loss - Prevalence in Australian children and the impact of socioeconomic disadvantage on its management. Int J Pediatr Otorhinolaryngol 2023; 165:111445. [PMID: 36630865 DOI: 10.1016/j.ijporl.2023.111445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 12/21/2022] [Accepted: 01/06/2023] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Congenital unilateral sensorineural hearing loss (cuSNHL) carries potentially significant social, educational, and developmental consequences. Early diagnosis enables investigation, and consideration of options for management and early intervention, helping to mitigate the effects of hearing loss. Cochlear nerve dysplasia (CND) is a prominent cause of cuSNHL and may affect candidacy for cochlear implantation. Socioeconomic disadvantage may impact on a patient's family's capacity to participate in necessary intervention and follow-up. METHODS Infants with severe-profound cuSNHL referred to a large Australian quaternary pediatric center between October 2004 and December 2020 were retrospectively included. Audiometric and clinical data, and the presence of hearing loss risk factors were obtained from a prospectively collated database. In Australia MRI scans are provided free-of-charge to citizens and residents. MRI scans were reviewed to determine the status of the nerves within the internal acoustic meatus (IAM grade) along with attendance rates. Travel distance to the hospital was also calculated. Reasons for non-attendance at MRI were obtained from patient medical records and correspondence. Socioeconomic, educational, and occupational indices, and travel distances were obtained using patient residential postcodes with reference to Australian Bureau of Statistics data. RESULTS A total of 98 patients were reviewed, 64.3% (n = 63) of whom underwent MRI. The median age at diagnosis was 40 days (IQR 27). The prevalence of CND was 75% (n = 47). Importantly, there was no significant difference in the degree of hearing loss between IAM grades (F(4,57) = 1.029, p = 0.405). Socioeconomic indices were significantly lower in patients not attending MRI investigations compared with patients who did attend. Travel distance was not significantly different between the two groups. CONCLUSION CND is a prominent cause of cuSNHL in Australian infants. MRI at a young age allows parent education regarding management options and timely intervention where indicated. Socioeconomic disadvantage significantly impacts on participation in further routine assessment of cuSNHL, potentially limiting management options for these children long term.
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Affiliation(s)
- P Ryan
- Department of Otolaryngology and Head & Neck Surgery, The Children's Hospital at Westmead, NSW, Australia.
| | - C T Huins
- Department of Otolaryngology and Head & Neck Surgery, The Children's Hospital at Westmead, NSW, Australia; Queen Elizabeth Hospital, Birmingham, UK
| | - K J O'Brien
- Department of Audiology, The Children's Hospital at Westmead, NSW, Australia
| | - S Misra
- Department of Otolaryngology and Head & Neck Surgery, The Children's Hospital at Westmead, NSW, Australia
| | - C S Birman
- Department of Otolaryngology and Head & Neck Surgery, The Children's Hospital at Westmead, NSW, Australia; Sydney Medical School, Faculty of Medicine and Health, Sydney University, Australia; Faculty of Medicine and Health Sciences, Macquarie University, Australia
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Taso M, Munsch F, Girard OM, Duhamel G, Alsop DC, Varma G. Fast-spin-echo versus rapid gradient-echo for 3D magnetization-prepared acquisitions: Application to inhomogeneous magnetization transfer. Magn Reson Med 2023; 89:550-564. [PMID: 36306334 PMCID: PMC10848167 DOI: 10.1002/mrm.29461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 08/23/2022] [Accepted: 08/26/2022] [Indexed: 12/13/2022]
Abstract
PURPOSE To evaluate the benefits of fast spin echo (FSE) imaging over rapid gradient-echo (RAGE) for magnetization-prepared inhomogeneous magnetization transfer (ihMT) imaging. METHODS A 3D FSE sequence was modified to include an ihMT preparation (ihMT-FSE) with an optional CSF suppression based on an inversion-recovery (ihMT-FLAIR). After numeric simulations assessing SNR benefits of FSE and the potential impact of an additional inversion-recovery, ihMT-RAGE, ihMT-FSE, and ihMT-FLAIR sequences were compared in a group of six healthy volunteers, evaluating image quality, thermal, and physiological noise as well as quantification using an ihMT saturation (ihMTsat) approach. A preliminary exploration in the cervical spinal cord was also conducted in a group of three healthy volunteers. RESULTS Several fold improvements in thermal SNR were observed with ihMT-FSE in agreement with numerical simulations. However, we observed significantly higher physiological noise in ihMT-FSE compared to ihMT-RAGE that was mitigated in ihMT-FLAIR, which provided the best total SNR (+74% and +49% compared to ihMT-RAGE in the white and gray matter, P ≤ 0.004). IhMTsat quantification was successful in all cases with strong correlation between all sequences (r2 > 0.75). Early experiments showed potential for spinal cord imaging. CONCLUSIONS FSE generally offers higher SNR compared to gradient-echo based acquisitions for magnetization-prepared contrasts as illustrated here in the case of ihMT. However, physiological noise has a significant effect, but an inversion-recovery-based CSF suppression was shown to be efficient in mitigating effects of CSF motion.
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Affiliation(s)
- Manuel Taso
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - Fanny Munsch
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | | | | | - David C. Alsop
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - Gopal Varma
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
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Juvekar P, Torio E, Bi WL, Bastos DCDA, Golby AJ, Frisken SF. Mapping Resection Progress by Tool-Tip Tracking during Brain Tumor Surgery for Real-Time Estimation of Residual Tumor. Cancers (Basel) 2023; 15:cancers15030825. [PMID: 36765783 PMCID: PMC9913508 DOI: 10.3390/cancers15030825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/21/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
Surgical resection continues to be the primary initial therapeutic strategy in the treatment of patients with brain tumors. Computerized cranial neuronavigation based on preoperative imaging offers precision guidance during craniotomy and early tumor resection but progressively loses validity with brain shift. Intraoperative MRI (iMRI) and intraoperative ultrasound (iUS) can update the imaging used for guidance and navigation but are limited in terms of temporal and spatial resolution, respectively. We present a system that uses time-stamped tool-tip positions of surgical instruments to generate a map of resection progress with high spatial and temporal accuracy. We evaluate this system and present results from 80 cranial tumor resections. Regions of the preoperative tumor segmentation that are covered by the resection map (True Positive Tracking) and regions of the preoperative tumor segmentation not covered by the resection map (True Negative Tracking) are determined for each case. We compare True Negative Tracking, which estimates the residual tumor, with the actual residual tumor identified using iMRI. We discuss factors that can cause False Positive Tracking and False Negative Tracking, which underestimate and overestimate the residual tumor, respectively. Our method provides good estimates of the residual tumor when there is minimal brain shift, and line-of-sight is maintained. When these conditions are not met, surgeons report that it is still useful for identifying regions of potential residual.
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Affiliation(s)
- Parikshit Juvekar
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
- Correspondence: or (P.J.); (S.F.F.)
| | - Erickson Torio
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Wenya Linda Bi
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Dhiego Chaves De Almeida Bastos
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Alexandra J. Golby
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
- Department of Radiology, Brigham and Women’s Hospital, Boston, MA 02115, USA
| | - Sarah F. Frisken
- Harvard Medical School, Boston, MA 02115, USA
- Department of Radiology, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Correspondence: or (P.J.); (S.F.F.)
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Williams SN, McElhinney P, Gunamony S. Ultra-high field MRI: parallel-transmit arrays and RF pulse design. Phys Med Biol 2023; 68. [PMID: 36410046 DOI: 10.1088/1361-6560/aca4b7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 11/21/2022] [Indexed: 11/22/2022]
Abstract
This paper reviews the field of multiple or parallel radiofrequency (RF) transmission for magnetic resonance imaging (MRI). Currently the use of ultra-high field (UHF) MRI at 7 tesla and above is gaining popularity, yet faces challenges with non-uniformity of the RF field and higher RF power deposition. Since its introduction in the early 2000s, parallel transmission (pTx) has been recognized as a powerful tool for accelerating spatially selective RF pulses and combating the challenges associated with RF inhomogeneity at UHF. We provide a survey of the types of dedicated RF coils used commonly for pTx and the important modeling of the coil behavior by electromagnetic (EM) field simulations. We also discuss the additional safety considerations involved with pTx such as the specific absorption rate (SAR) and how to manage them. We then describe the application of pTx with RF pulse design, including a practical guide to popular methods. Finally, we conclude with a description of the current and future prospects for pTx, particularly its potential for routine clinical use.
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Affiliation(s)
- Sydney N Williams
- Imaging Centre of Excellence, University of Glasgow, Glasgow, United Kingdom
| | - Paul McElhinney
- Imaging Centre of Excellence, University of Glasgow, Glasgow, United Kingdom
| | - Shajan Gunamony
- Imaging Centre of Excellence, University of Glasgow, Glasgow, United Kingdom.,MR CoilTech Limited, Glasgow, United Kingdom
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Towards functional spin-echo BOLD line-scanning in humans at 7T. MAGMA (NEW YORK, N.Y.) 2023; 36:317-327. [PMID: 36625959 PMCID: PMC10140128 DOI: 10.1007/s10334-022-01059-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Neurons cluster into sub-millimeter spatial structures and neural activity occurs at millisecond resolutions; hence, ultimately, high spatial and high temporal resolutions are required for functional MRI. In this work, we implemented a spin-echo line-scanning (SELINE) sequence to use in high spatial and temporal resolution fMRI. MATERIALS AND METHODS A line is formed by simply rotating the spin-echo refocusing gradient to a plane perpendicular to the excited slice and by removing the phase-encoding gradient. This technique promises a combination of high spatial and temporal resolution (250 μm, 500 ms) and microvascular specificity of functional responses. We compared SELINE data to a corresponding gradient-echo version (GELINE). RESULTS We demonstrate that SELINE showed much-improved line selection (i.e. a sharper line profile) compared to GELINE, albeit at the cost of a significant drop in functional sensitivity. DISCUSSION This low functional sensitivity needs to be addressed before SELINE can be applied for neuroscientific purposes.
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Zhao M, Jiang H, Zhang S, Liu Z, Li Q, Wen X, Hu J, Zeng M, Xie X, Lin J. Comparison of an optimized 3D-real IR and a 3D-FLAIR with a constant flip angle in the evaluation of endolymphatic hydrops. Eur J Radiol 2023; 158:110614. [PMID: 36423365 DOI: 10.1016/j.ejrad.2022.110614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 10/09/2022] [Accepted: 11/14/2022] [Indexed: 11/21/2022]
Abstract
PURPOSE To evaluate an optimized 3D-real IR sequence with a longer TR (16,000 ms) based on the modulated flip angle technique in refocused imaging with extended echo train (MATRIX) for the endolymphatic hydrops (EH) after intravenous (IV) single-dose gadolinium (Gd) administration, and compare it with a heavily T2-weighted 3D-FLAIR sequence with a constant flip angle. METHOD The 3D-FLAIR and 3D-real IR sequences were performed in forty patients with definite Meniere's disease (MD) four hours after IV Gd administration. Image qualities of the two sequences were rated and compared. Contrast-to-noise ratios (CNRs) and signal-to-noise ratios (SNRs) of the two sequences were measured for quantitative comparison. EH was graded on the images of the two sequences by two radiologists. RESULTS Scores and CNRs of the 3D-real IR were significantly higher than those of the 3D-FLAIR (P < 0.05). SNRs of the two sequences were comparable between the two groups. 3D-real IR had a higher inter- and intra-observer reliability for the grading of cochlear and vestibular EH than 3D-FLAIR. Using 3D-real IR sequence, the detection rate of EH of the whole labyrinth was higher than using 3D-FLAIR (86.6 % vs 73.3 %, p = 0.031). In the patients with unilateral MD, SNRs in the affected sides were significantly higher than the unaffected sides (P < 0.05). CONCLUSIONS The optimized 3D-real IR with a longer TR is a robust sequence with an improved depiction of EH after IV administration of single-dose Gd. Compared with 3D-FLAIR, it may allow a more precise evaluation and grading of EH.
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Affiliation(s)
- Menglong Zhao
- Department of Radiology, Zhongshan Hospital, Fudan University, and Shanghai Institute of Medical Imaging, Shanghai 200032, China
| | - Huaili Jiang
- Otolaryngology Head and Neck Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Shujie Zhang
- Department of Radiology, Zhongshan Hospital, Fudan University, and Shanghai Institute of Medical Imaging, Shanghai 200032, China
| | - Zhuang Liu
- Department of Radiology, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Qin Li
- Department of Radiology, Zhongshan Hospital, Fudan University, and Shanghai Institute of Medical Imaging, Shanghai 200032, China
| | - Xixi Wen
- United Imaging Healthcare, Shanghai 201807, China
| | - Junpu Hu
- United Imaging Healthcare, Shanghai 201807, China
| | - Mengsu Zeng
- Department of Radiology, Zhongshan Hospital, Fudan University, and Shanghai Institute of Medical Imaging, Shanghai 200032, China
| | - Xiaofeng Xie
- Otolaryngology Head and Neck Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
| | - Jiang Lin
- Department of Radiology, Zhongshan Hospital, Fudan University, and Shanghai Institute of Medical Imaging, Shanghai 200032, China.
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Borisch EA, Froemming AT, Grimm RC, Kawashima A, Trzasko JD, Riederer SJ. Model-based image reconstruction with wavelet sparsity regularization for through-plane resolution restoration in T 2 -weighted spin-echo prostate MRI. Magn Reson Med 2023; 89:454-468. [PMID: 36093998 PMCID: PMC9617775 DOI: 10.1002/mrm.29447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 11/06/2022]
Abstract
PURPOSE The purpose is to develop a model-based image-reconstruction method using wavelet sparsity regularization for maintaining restoration of through-plane resolution but with improved retention of SNR versus linear reconstruction using Tikhonov (TK) regularization in high through-plane resolution (1 mm) T2 -weighted spin-echo (T2SE) images of the prostate. METHODS A wavelet sparsity (WS)-regularized image reconstruction was developed that takes as input a set of ≈80 overlapped 3-mm-thick slices acquired using a T2SE multislice scan and typically 30 coil elements. After testing in contrast and resolution phantoms and calibration in 6 subjects, the WS reconstruction was evaluated in 16 consecutive prostate T2SE MRI exams. Results reconstructed with nominal 1-mm thickness were compared with those from the TK reconstruction with the same raw data. Results were evaluated radiologically. The ratio of magnitude of prostate signal to periprostatic muscle signal was used to assess the presence of noise reduction. Technical performance was also compared with a commercial 3D-T2SE sequence. RESULTS The new WS reconstruction was assessed as superior statistically to TK for overall SNR, contrast, and multiple evaluation criteria related to sharpness while retaining the high (1 mm) through-plane resolution. Wavelet sparsity tended to provide improved overall diagnostic quality versus TK, but not significantly so. In all 16 studies, the prostate-to-muscle signal ratio increased. CONCLUSIONS Model-based WS-regularized reconstruction consistently provides improved SNR in high (1 mm) through-plane resolution images of prostate T2SE MRI versus linear reconstruction using TK regularization.
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Anti-Correlated Myelin-Sensitive MRI Levels in Humans Consistent with a Subcortical to Sensorimotor Regulatory Process-Multi-Cohort Multi-Modal Evidence. Brain Sci 2022; 12:brainsci12121693. [PMID: 36552153 PMCID: PMC9776387 DOI: 10.3390/brainsci12121693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/07/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
Differential axonal myelination synchronises signalling over different axon lengths. The consequences of myelination processes described at the cellular level for the regulation of myelination at the macroscopic level are unknown. We analysed multiple cohorts of myelin-sensitive brain MRI. Our aim was to (i) confirm a previous report of anti-correlation between myelination in subcortical and sensorimotor areas in healthy subjects, (ii) and thereby test our hypothesis for a regulatory interaction between them. We analysed nine image-sets across three different human cohorts using six MRI modalities. Each image-set contained healthy controls (HC) and ME/CFS subjects. Subcortical and Sensorimotor regions of interest (ROI) were optimised for the detection of anti-correlations and the same ROIs were used to test the HC in all image-sets. For each cohort, median MRI values were computed in both regions for each subject and their correlation across the cohort was computed. We confirmed negative correlations in healthy controls between subcortical and sensorimotor regions in six image-sets: three T1wSE (p = 5 × 10-8, 5 × 10-7, 0.002), T2wSE (p =2 × 10-6), MTC (p = 0.01), and WM volume (p = 0.02). T1/T2 was the exception with a positive correlation (p = 0.01). This myelin regulation study is novel in several aspects: human subjects, cross-sectional design, ROI optimization, spin-echo MRI and reproducible across multiple independent image-sets. In multiple independent image-sets we confirmed an anti-correlation between subcortical and sensorimotor myelination which supports a previously unreported regulatory interaction. The subcortical region contained the brain's primary regulatory nuclei. We suggest a mechanism has evolved whereby relatively low subcortical myelination in an individual is compensated by upregulated sensorimotor myelination to maintain adequate sensorimotor performance.
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Guo H, Liu J, Hu J, Zhang H, Zhao W, Gao M, Zhang Y, Yang G, Cui Y. Diagnostic performance of gliomas grading and IDH status decoding A comparison between 3D amide proton transfer APT and four diffusion-weighted MRI models. J Magn Reson Imaging 2022; 56:1834-1844. [PMID: 35488516 PMCID: PMC9790544 DOI: 10.1002/jmri.28211] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/13/2022] [Accepted: 04/14/2022] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND The focus of neuro-oncology research has changed from histopathologic grading to molecular characteristics, and medical imaging routinely follows this change. PURPOSE To compare the diagnostic performance of amide proton transfer (APT) and four diffusion models in gliomas grading and isocitrate dehydrogenase (IDH) genotype. STUDY TYPE Prospective. POPULATION A total of 62 participants (37 males, 25 females; mean age, 52 ± 13 years) whose IDH genotypes were mutant in 6 of 14 grade II gliomas, 8 of 20 of grade III gliomas, and 4 of 28 grade IV gliomas. FIELD STRENGTH/SEQUENCE APT imaging using sampling perfection with application optimized contrasts by using different flip angle evolutions (SPACE) and DWI with q-space Cartesian grid sampling were acquired at 3 T. ASSESSMENT The ability of diffusion kurtosis imaging, diffusion kurtosis imaging, neurite orientation dispersion and density imaging (NODDI), mean apparent propagator (MAP), and APT imaging for glioma grade and IDH status were assessed, with histopathological grade and genetic testing used as a reference standard. Regions of interest (ROIs) were drawn by two neuroradiologists after consensus. STATISTICAL TESTS T-test and Mann-Whitney U test; one-way analysis of variance (ANOVA); receiver operating curve (ROC) and area under the curve (AUC); DeLong test. P value < 0.05 was considered statistically significant. RESULTS Compared with IDH-mutant gliomas, IDH-wildtype gliomas showed a significantly higher mean, 5th-percentile (APT5 ), and 95th-percentile from APTw, the 95th-percentile value of axial, mean, and radial diffusivity from DKI, and 95th-percentile value of isotropic volume fraction from NODDI, and no significantly different parameters from DTI and MAP (P = 0.075-0.998). The combined APT model showed a significantly wider area under the curve (AUC 0.870) for IDH status, when compared with DKI and NODDI. APT5 was significantly different between two of the three groups (glioma II vs. glioma III vs. glioma IV: 1.35 ± 0.75 vs. 2.09 ± 0.93 vs. 2.71 ± 0.81). DATA CONCLUSION APT has higher diagnostic accuracy than DTI, DKI, MAP, and NODDI in glioma IDH genotype. APT5 can effectively identify both tumor grading and IDH genotyping, making it a promising biomarker for glioma classification. EVIDENCE LEVEL 1 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Hu Guo
- Department of RadiologyThe Second Xiangya Hospital, Central South UniversityNo. 139 Middle Renmin Road, ChangshaHunan410011China
| | - Jun Liu
- Department of RadiologyThe Second Xiangya Hospital, Central South UniversityNo. 139 Middle Renmin Road, ChangshaHunan410011China,Department of Radiology Quality Control CenterHunan ProvinceChangsha410011China
| | - JunJiao Hu
- Department of RadiologyThe Second Xiangya Hospital, Central South UniversityNo. 139 Middle Renmin Road, ChangshaHunan410011China
| | - HuiTing Zhang
- MR Scientific Marketing, Siemens Healthineers Ltd.Wuhan430071China
| | - Wei Zhao
- Department of RadiologyThe Second Xiangya Hospital, Central South UniversityNo. 139 Middle Renmin Road, ChangshaHunan410011China
| | - Min Gao
- Department of RadiologyThe Second Xiangya Hospital, Central South UniversityNo. 139 Middle Renmin Road, ChangshaHunan410011China
| | - Yi Zhang
- Department of Biomedical EngineeringCollege of Biomedical Engineering & Instrument Science, Zhejiang UniversityHangzhouZhejiangChina
| | - Guang Yang
- Shanghai Key Laboratory of Magnetic ResonanceSchool of Physics and Electronic, East China Normal UniversityShanghaiChina
| | - Yan Cui
- Department of NeurosurgeryThe Second Xiangya Hospital, Central South UniversityNo. 139 Middle Renmin Rd, ChangshaHunan Province410011P.R. China
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Yoshida T, Naganawa S, Kobayashi M, Sugimoto S, Katayama N, Nakashima T, Kato Y, Ichikawa K, Yamaguchi H, Nishida K, Sone M. 17O-labeled water distribution in the human inner ear: Insights into lymphatic dynamics and vestibular function. Front Neurol 2022; 13:1016577. [DOI: 10.3389/fneur.2022.1016577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 09/26/2022] [Indexed: 11/06/2022] Open
Abstract
We evaluated the inner ear distribution of 17O-labeled saline administered to the human tympanic cavity. Magnetic resonance imaging was performed after intratympanic administration in five healthy volunteers and one patient with cochlear endolymphatic hydrops. In all volunteers, 17O-labeled water permeated the cochlear basal turn and vestibule at 30 min and disappeared gradually within 2–4 h. All participants experienced positional vertigo lasting a few hours to a few days. Visualization of 17O-labeled water distribution in the endolymphatic space of the posterior ampulla showed indistinct separation of endolymph and perilymph in the cochlea and most of the vestibule in all participants. Intralabyrinthine distribution of 17O-labeled water differed from that in previous reports of intratympanically administered gadolinium-based contrast agent. 17O-labeled water in the endolymphatic space may cause heavier endolymph and positional vertigo. These results of this study may add new insights for investigating the distribution and the effects of molecules in the inner ear after the intratympanic administration in living humans.
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Evaluation of Inferior Intercavernous Sinus in Patients With Pituitary Microadenoma by Contrast-Enhanced SPACE Imaging. J Comput Assist Tomogr 2022; 46:961-967. [DOI: 10.1097/rct.0000000000001371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Almansour H, Weiland E, Kuehn B, Kannengiesser S, Gassenmaier S, Herrmann J, Hoffmann R, Othman AE, Afat S. Accelerated Three-dimensional T2-Weighted Turbo-Spin-Echo Sequences with Inner-Volume Excitation and Iterative Denoising in the Setting of Pelvis MRI at 1.5T: Impact on Image Quality and Lesion Detection. Acad Radiol 2022; 29:e248-e259. [PMID: 35144868 DOI: 10.1016/j.acra.2022.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/25/2021] [Accepted: 01/05/2022] [Indexed: 11/01/2022]
Abstract
RATIONALE AND OBJECTIVES To investigate image quality and rate of lesion detection in a novel three-dimensional T2-weighted turbo-spin-echo sequence with inner-volume excitation (zoomed imaging) and iterative denoising processing in pelvic MRI at 1.5T. Two-dimensional T2-weighted turbo-spin-echo sequences were used as the clinical reference standard (2D-T2-TSE). MATERIALS AND METHODS This is a prospective study of patients with various pelvic pathologies. Each patient underwent standard 2D-T2-TSE in three planes with two-fold acceleration as well as a single three-dimensional T2-TSE in the sagittal plane with four-fold acceleration known as Sampling-Perfection-with-Application-optimized-Contrast-using-different-flip-angle-Evolutions (3D-T2-SPACE). The 3D-T2-SPACE images were reconstructed in three orthogonal planes at a slice thickness of 2 mm (vs. 2D-T2-TSE at 4 mm). Two radiologists conducted a qualitative image analysis on standard 2D-T2-TSE and multiplanar reconstructed 3D-T2-SPACE images. These parameters were compared and inter-reader agreement was computed. Furthermore, each reader documented the observed lesions of various pelvic organs. The rate of lesion detection was compared between readers and sequences. Inter-reader and inter-sequence agreement were computed. RESULTS Forty patients (25 females) were included. Mean patient age was 58 ± 13 years. 3D-T2-SPACE enabled an approximate 22% reduction of acquisition time and 50% of reconstructed slice thickness. 3D-T2-SPACE showed fewer artifacts than 2D-T2-TSE (p < 0.001). However, 2D-T2-TSE was rated to have significantly higher signal intensity than 3D-T2-SPACE (p < 0.001). There were no significant differences between the two sequences regarding all other parameters. Inter-reader agreement regarding image quality parameters was substantial (Kappa = 0.772). For all analyzed pelvic anatomic structures, inter-reader and inter-sequence agreement for lesion detection was excellent (Kappa > 0.80). CONCLUSION 3D-T2-SPACE with the inner-volume excitation and iterative denoising is clinically feasible at 1.5 T, enabling faster imaging, thinner slices, and significant reduction of artifacts. Despite that signal intensity was inferior in the SPACE images, overall image quality, diagnostic confidence and lesion detection were not compromised. This prospective study sets the stage for further clinical implementation and future investigations tailored to specific indications in pelvis MRI.
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Affiliation(s)
- Haidara Almansour
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tuebingen University Hospital, Tuebingen, Germany
| | - Elisabeth Weiland
- MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany
| | - Bernd Kuehn
- MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany
| | | | - Sebastian Gassenmaier
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tuebingen University Hospital, Tuebingen, Germany
| | - Judith Herrmann
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tuebingen University Hospital, Tuebingen, Germany
| | - Rüdiger Hoffmann
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tuebingen University Hospital, Tuebingen, Germany
| | - Ahmed E Othman
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tuebingen University Hospital, Tuebingen, Germany; Department of Neuroradiology, University Medical Center Mainz, Mainz, Germany.
| | - Saif Afat
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tuebingen University Hospital, Tuebingen, Germany
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State-of-the-art magnetic resonance imaging sequences for pediatric body imaging. Pediatr Radiol 2022:10.1007/s00247-022-05528-y. [PMID: 36255456 DOI: 10.1007/s00247-022-05528-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/17/2022] [Accepted: 10/03/2022] [Indexed: 10/24/2022]
Abstract
Longer examination time, need for anesthesia in smaller children and the inability of most children to hold their breath are major limitations of MRI in pediatric body imaging. Fortunately, with technical advances, many new and upcoming MRI sequences are overcoming these limitations. Advances in data acquisition and k-space sampling methods have enabled sequences with improved temporal and spatial resolution, and minimal artifacts. Sequences to minimize movement artifacts mainly utilize radial k-space filling, and examples include the stack-of-stars method for T1-weighted imaging and the periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER)/BLADE method for T2-weighted imaging. Similarly, the sequences with improved temporal resolution and the ability to obtain multiple phases in a single breath-hold in dynamic imaging mainly use some form of partial k-space filling method. New sequences use a variable combination of data sampling methods like compressed sensing, golden-angle radial k-space filling, parallel imaging and partial k-space filling to achieve free-breathing, faster sequences that could be useful for pediatric abdominal and thoracic imaging. Simultaneous multi-slice method has improved diffusion-weighted imaging (DWI) with reduction in scan time and artifacts. In this review, we provide an overview of data sampling methods like parallel imaging, compressed sensing, radial k-space sampling, partial k-space sampling and simultaneous multi-slice. This is followed by newer available and upcoming sequences for T1-, T2- and DWI based on these other advances. We also discuss the Dixon method and newer approaches to reducing metal artifacts.
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Phantom Study on the Robustness of MR Radiomics Features: Comparing the Applicability of 3D Printed and Biological Phantoms. Diagnostics (Basel) 2022; 12:diagnostics12092196. [PMID: 36140598 PMCID: PMC9497898 DOI: 10.3390/diagnostics12092196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/24/2022] [Accepted: 08/29/2022] [Indexed: 11/17/2022] Open
Abstract
The objectives of our study were to (a) evaluate the feasibility of using 3D printed phantoms in magnetic resonance imaging (MR) in assessing the robustness and repeatability of radiomic parameters and (b) to compare the results obtained from the 3D printed phantoms to metrics obtained in biological phantoms. To this end, three different 3D phantoms were printed: a Hilbert cube (5 × 5 × 5 cm3) and two cubic quick response (QR) code phantoms (a large phantom (large QR) (5 × 5 × 4 cm3) and a small phantom (small QR) (4 × 4 × 3 cm3)). All 3D printed and biological phantoms (kiwis, tomatoes, and onions) were scanned thrice on clinical 1.5 T and 3 T MR with 1 mm and 2 mm isotropic resolution. Subsequent analyses included analyses of several radiomics indices (RI), their repeatability and reliability were calculated using the coefficient of variation (CV), the relative percentage difference (RPD), and the interclass coefficient (ICC) parameters. Additionally, the readability of QR codes obtained from the MR images was examined with several mobile phones and algorithms. The best repeatability (CV ≤ 10%) is reported for the acquisition protocols with the highest spatial resolution. In general, the repeatability and reliability of RI were better in data obtained at 1.5 T (CV = 1.9) than at 3 T (CV = 2.11). Furthermore, we report good agreements between results obtained for the 3D phantoms and biological phantoms. Finally, analyses of the read-out rate of the QR code revealed better texture analyses for images with a spatial resolution of 1 mm than 2 mm. In conclusion, 3D printing techniques offer a unique solution to create textures for analyzing the reliability of radiomic data from MR scans.
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Omodaka S, Endo H, Niizuma K, Endo T, Sato K, Saito A, Uchida H, Matsumoto Y, Tominaga T. Wall enhancement in unruptured posterior communicating aneurysms with oculomotor nerve palsy on magnetic resonance vessel wall imaging. J Neurosurg 2022; 137:668-674. [PMID: 35061982 DOI: 10.3171/2021.11.jns212249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 11/15/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Recent MR vessel wall imaging studies of unruptured intracranial aneurysms (UIAs) have revealed that aneurysm wall enhancement (AWE) can be an indicator for aneurysm evolution; however, the degree of AWE among different types of evolving UIAs has yet to be clarified. The authors assessed the degree of AWE in unruptured posterior communicating artery (PcomA) aneurysms with oculomotor nerve palsy (ONP), which may be a subgroup of evolving UIAs with rapid enlargement and high rupture risk. METHODS The degree of AWE was analyzed in 35 consecutive evolving PcomA aneurysms (19 with and 16 without ONP). UIAs were considered to be evolving when showing growth or ONP. A 3D T1-weighted fast spin echo sequence was obtained after contrast media injection, and the contrast ratio of the aneurysm wall against the pituitary stalk (CRstalk) was calculated as the indicator of AWE. The CRstalk in evolving UIAs with ONP was compared with that in UIAs without ONP. RESULTS The CRstalk was significantly higher in evolving UIAs with ONP than in those without ONP (0.85 vs 0.57; p = 0.006). In multivariable analysis, the CRstalk remained a significant indicator for ONP presentation in evolving UIAs (OR 6.13, 95% CI 1.21-31.06). CONCLUSIONS AWE was stronger in evolving PcomA aneurysms with ONP than in those without ONP, suggesting the potential utility of AWE for risk stratification in evolving UIAs. The degree of AWE can be a promising indicator of a rupture-prone UIA, which can be useful information for the decision-making process in the treatment of UIAs.
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Affiliation(s)
- Shunsuke Omodaka
- Departments of1Neurosurgery and
- 2Neuroendovascular Therapy, Kohnan Hospital, Sendai
| | - Hidenori Endo
- Departments of1Neurosurgery and
- 3Division of Advanced Cerebrovascular Surgery and
| | - Kuniyasu Niizuma
- 4Department of Neurosurgical Engineering and Translational Neuroscience, Tohoku University, Sendai
- 5Department of Neurosurgical Engineering and Translational Neuroscience, Graduate School of Biomedical Engineering, Tohoku University, Sendai
| | - Toshiki Endo
- 6Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai
| | - Kenichi Sato
- 7Department of Neurosurgery, Tohoku Medical and Pharmaceutical University, Sendai; and
| | - Atsushi Saito
- 8Department of Neurosurgery, Sendai Medical Center, Sendai, Japan
| | | | | | - Teiji Tominaga
- 6Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai
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Glasser MF, Coalson TS, Harms MP, Xu J, Baum GL, Autio JA, Auerbach EJ, Greve DN, Yacoub E, Van Essen DC, Bock NA, Hayashi T. Empirical transmit field bias correction of T1w/T2w myelin maps. Neuroimage 2022; 258:119360. [PMID: 35697132 PMCID: PMC9483036 DOI: 10.1016/j.neuroimage.2022.119360] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 06/01/2022] [Accepted: 06/04/2022] [Indexed: 12/30/2022] Open
Abstract
T1-weighted divided by T2-weighted (T1w/T2w) myelin maps were initially developed for neuroanatomical analyses such as identifying cortical areas, but they are increasingly used in statistical comparisons across individuals and groups with other variables of interest. Existing T1w/T2w myelin maps contain radiofrequency transmit field (B1+) biases, which may be correlated with these variables of interest, leading to potentially spurious results. Here we propose two empirical methods for correcting these transmit field biases using either explicit measures of the transmit field or alternatively a 'pseudo-transmit' approach that is highly correlated with the transmit field at 3T. We find that the resulting corrected T1w/T2w myelin maps are both better neuroanatomical measures (e.g., for use in cross-species comparisons), and more appropriate for statistical comparisons of relative T1w/T2w differences across individuals and groups (e.g., sex, age, or body-mass-index) within a consistently acquired study at 3T. We recommend that investigators who use the T1w/T2w approach for mapping cortical myelin use these B1+ transmit field corrected myelin maps going forward.
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Affiliation(s)
| | | | - Michael P Harms
- Psychiatry, Washington University Medical School, St. Louis, MO, United States
| | - Junqian Xu
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States; Departments of Radiology and Psychiatry, Baylor College of Medicine, Houston, TX, United States
| | - Graham L Baum
- Department of Psychology, Harvard University, Cambridge, MA, United States
| | - Joonas A Autio
- RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Edward J Auerbach
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States
| | - Douglas N Greve
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Essa Yacoub
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States
| | | | - Nicholas A Bock
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, ON, Canada
| | - Takuya Hayashi
- RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
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