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Ensle F, Abel F, Lohezic M, Obermüller C, Guggenberger R. Deep learning reconstruction for optimized bone assessment in zero echo time MR imaging of the knee. Eur J Radiol 2024; 179:111663. [PMID: 39142010 DOI: 10.1016/j.ejrad.2024.111663] [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: 03/20/2024] [Revised: 06/29/2024] [Accepted: 08/02/2024] [Indexed: 08/16/2024]
Abstract
PURPOSE To evaluate the impact of deep learning-based reconstruction (DLRecon) on bone assessment in zero echo-time (ZTE) MRI of the knee at 1.5 Tesla. METHODS This retrospective study included 48 consecutive exams of 46 patients (23 females) who underwent clinically indicated knee MRI at 1.5 Tesla. Standard imaging protocol comprised a sagittal prescribed, isotropic ZTE sequence. ZTE image reconstruction was performed with a standard-of-care (non-DL) and prototype DLRecon method. Exams were divided into subsets with and without osseous pathology based on the radiology report. Using a 4-point scale, two blinded readers qualitatively graded features of bone depiction including artifacts and conspicuity of pathology including diagnostic certainty in the respective subsets. Quantitatively, one reader measured signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of bone. Comparative analyses were conducted to assess the differences between the reconstruction methods. In addition, interreader agreement was calculated for the qualitative gradings. RESULTS DLRecon significantly improved gradings for bone depiction relative to non-DL reconstruction (all, p < 0.05), while there was no significant difference with regards to artifacts (both, median score of 0; p = 0.058). In the subset with pathologies, conspicuity of pathology and diagnostic confidence were also scored significantly higher in DLRecon compared to non-DL (median 3 vs 2; p ≤ 0.03). Interreader agreement ranged from moderate to almost-perfect (κ = 0.54-0.88). Quantitatively, DLRecon demonstrated significantly enhanced CNR and SNR of bone compared to non-DL (p < 0.001). CONCLUSION ZTE MRI with DLRecon improved bone depiction in the knee, compared to non-DL. Additionally, DLRecon increased conspicuity of osseous findings together with diagnostic certainty.
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Affiliation(s)
- Falko Ensle
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
| | - Frederik Abel
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | | | - Carina Obermüller
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Roman Guggenberger
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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Vu BTD, Kamona N, Kim Y, Ng JJ, Jones BC, Wehrli FW, Song HK, Bartlett SP, Lee H, Rajapakse CS. Three contrasts in 3 min: Rapid, high-resolution, and bone-selective UTE MRI for craniofacial imaging with automated deep-learning skull segmentation. Magn Reson Med 2024. [PMID: 39219299 DOI: 10.1002/mrm.30275] [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: 05/28/2024] [Revised: 07/17/2024] [Accepted: 08/12/2024] [Indexed: 09/04/2024]
Abstract
PURPOSE Ultrashort echo time (UTE) MRI can be a radiation-free alternative to CT for craniofacial imaging of pediatric patients. However, unlike CT, bone-specific MR imaging is limited by long scan times, relatively low spatial resolution, and a time-consuming bone segmentation workflow. METHODS A rapid, high-resolution UTE technique for brain and skull imaging in conjunction with an automatic segmentation pipeline was developed. A dual-RF, dual-echo UTE sequence was optimized for rapid scan time (3 min) and smaller voxel size (0.65 mm3). A weighted least-squares conjugate gradient method for computing the bone-selective image improves bone specificity while retaining bone sensitivity. Additionally, a deep-learning U-Net model was trained to automatically segment the skull from the bone-selective images. Ten healthy adult volunteers (six male, age 31.5 ± 10 years) and three pediatric patients (two male, ages 12 to 15 years) were scanned at 3 T. Clinical CT for the three patients were obtained for validation. Similarities in 3D skull reconstructions relative to clinical standard CT were evaluated based on the Dice similarity coefficient and Hausdorff distance. Craniometric measurements were used to assess geometric accuracy of the 3D skull renderings. RESULTS The weighted least-squares method produces images with enhanced bone specificity, suppression of soft tissue, and separation from air at the sinuses when validated against CT in pediatric patients. Dice similarity coefficient overlap was 0.86 ± 0.05, and the 95th percentile Hausdorff distance was 1.77 ± 0.49 mm between the full-skull binary masks of the optimized UTE and CT in the testing dataset. CONCLUSION An optimized MRI acquisition, reconstruction, and segmentation workflow for craniofacial imaging was developed.
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Affiliation(s)
- Brian-Tinh Duc Vu
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nada Kamona
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yohan Kim
- Division of Plastic, Reconstructive and Oral Surgery, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jinggang J Ng
- Division of Plastic, Reconstructive and Oral Surgery, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Brandon C Jones
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Felix W Wehrli
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hee Kwon Song
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Scott P Bartlett
- Division of Plastic, Reconstructive and Oral Surgery, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Hyunyeol Lee
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- School of Electronics Engineering, Kyungpook National University, Daegu, Republic of Korea
| | - Chamith S Rajapakse
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Ilbey S, Jung M, Emir U, Bock M, Özen AC. Characterizing Off-center MRI with ZTE. Z Med Phys 2024; 34:446-455. [PMID: 36328861 DOI: 10.1016/j.zemedi.2022.09.002] [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: 07/18/2022] [Revised: 09/29/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
PURPOSE To maximize acquisition bandwidth in zero echo time (ZTE) sequences, readout gradients are already switched on during the RF pulse, creating unwanted slice selectivity. The resulting image distortions are amplified especially when the anatomy of interest is not located at the isocenter. We aim to characterize off-center ZTE MRI of extremities such as the shoulder, knee, and hip, adjusting the carrier frequency of the RF pulse excitation for each TR. METHODS In ZTE MRI, radial encoding schemes are used, where the distorted slice profile due to the finite RF pulse length rotates with the k-space trajectory. To overcome these modulations for objects far away from the magnet isocenter, the frequency of the RF pulse is shifted for each gradient setting so that artifacts do not occur at a given off-center target position. The sharpness of the edges in the images were calculated and the ZTE acquisition with off-center excitation was compared to an acquisition with isocenter excitation both in phantom and in vivo off-center MRI of the shoulder, knee, and hip at 1.5 and 3T MRI systems. RESULTS Distortion and blurriness artifacts on the off-center MRI images of the phantom, in vivo shoulder, knee, and hip images were mitigated with off-center excitation without time or noise penalty, at no additional computational cost. CONCLUSION The off-center excitation allows ZTE MRI of the shoulder, knee, and hip for high-bandwidth image acquisitions for clinical settings, where positioning at the isocenter is not possible.
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Affiliation(s)
- Serhat Ilbey
- Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Matthias Jung
- Department of Diagnostic and Interventional Radiology, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Uzay Emir
- Weldon School of Biomedical Engineering, Purdue University, USA; School of Health Science Department, Purdue University, USA
| | - Michael Bock
- Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ali Caglar Özen
- Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Linkugel AD, Wang T, Boroojeni PE, Eldeniz C, Chen Y, Skolnick GB, Commean PK, Merrill CM, Strahle JM, Goyal MS, An H, Patel KB. MR Cranial Bone Imaging: Evaluation of Both Motion-Corrected and Automated Deep Learning Pseudo-CT Estimated MR Images. AJNR Am J Neuroradiol 2024:ajnr.A8335. [PMID: 38991771 DOI: 10.3174/ajnr.a8335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 04/19/2024] [Indexed: 07/13/2024]
Abstract
BACKGROUND AND PURPOSE CT imaging exposes patients to ionizing radiation. MR imaging is radiation free but previously has not been able to produce diagnostic-quality images of bone on a timeline suitable for clinical use. We developed automated motion correction and use deep learning to generate pseudo-CT images from MR images. We aim to evaluate whether motion-corrected pseudo-CT produces cranial images that have potential to be acceptable for clinical use. MATERIALS AND METHODS Patients younger than age 18 who underwent CT imaging of the head for either trauma or evaluation of cranial suture patency were recruited. Subjects underwent a 5-minute golden-angle stack-of-stars radial volumetric interpolated breath-hold MR image. Motion correction was applied to the MR imaging followed by a deep learning-based method to generate pseudo-CT images. CT and pseudo-CT images were evaluated and, based on indication for imaging, either presence of skull fracture or cranial suture patency was first recorded while viewing the MR imaging-based pseudo-CT and then recorded while viewing the clinical CT. RESULTS A total of 12 patients underwent CT and MR imaging to evaluate suture patency, and 60 patients underwent CT and MR imaging for evaluation of head trauma. For cranial suture patency, pseudo-CT had 100% specificity and 100% sensitivity for the identification of suture closure. For identification of skull fractures, pseudo-CT had 100% specificity and 90% sensitivity. CONCLUSIONS Our early results show that automated motion-corrected and deep learning-generated pseudo-CT images of the pediatric skull have potential for clinical use and offer a high level of diagnostic accuracy when compared with standard CT scans.
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Affiliation(s)
- Andrew D Linkugel
- From the Division of Plastic and Reconstructive Surgery (A.D.L., G.B.S., C.M.M., K.B.P.), Washington University in St. Louis, St. Louis, Missouri
| | - Tongyao Wang
- Mallinckrodt Institute of Radiology (T.W., P.E.B., C.E., P.K.C., M.S.G., H.A.), Washington University in St. Louis, St. Louis, Missouri
| | - Parna Eshraghi Boroojeni
- Mallinckrodt Institute of Radiology (T.W., P.E.B., C.E., P.K.C., M.S.G., H.A.), Washington University in St. Louis, St. Louis, Missouri
| | - Cihat Eldeniz
- Mallinckrodt Institute of Radiology (T.W., P.E.B., C.E., P.K.C., M.S.G., H.A.), Washington University in St. Louis, St. Louis, Missouri
| | - Yasheng Chen
- Department of Neurology (Y.C., H.A.), Washington University in St. Louis, St. Louis, Missouri
| | - Gary B Skolnick
- From the Division of Plastic and Reconstructive Surgery (A.D.L., G.B.S., C.M.M., K.B.P.), Washington University in St. Louis, St. Louis, Missouri
| | - Paul K Commean
- Mallinckrodt Institute of Radiology (T.W., P.E.B., C.E., P.K.C., M.S.G., H.A.), Washington University in St. Louis, St. Louis, Missouri
| | - Corinne M Merrill
- From the Division of Plastic and Reconstructive Surgery (A.D.L., G.B.S., C.M.M., K.B.P.), Washington University in St. Louis, St. Louis, Missouri
| | - Jennifer M Strahle
- Department of Neurosurgery (J.M.S.), Washington University in St. Louis, St. Louis, Missouri
| | - Manu S Goyal
- Mallinckrodt Institute of Radiology (T.W., P.E.B., C.E., P.K.C., M.S.G., H.A.), Washington University in St. Louis, St. Louis, Missouri
| | - Hongyu An
- Mallinckrodt Institute of Radiology (T.W., P.E.B., C.E., P.K.C., M.S.G., H.A.), Washington University in St. Louis, St. Louis, Missouri
- Department of Neurology (Y.C., H.A.), Washington University in St. Louis, St. Louis, Missouri
| | - Kamlesh B Patel
- From the Division of Plastic and Reconstructive Surgery (A.D.L., G.B.S., C.M.M., K.B.P.), Washington University in St. Louis, St. Louis, Missouri
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Oishi T, Tasaki A, Mashimo S, Moriya M, Yamashita D, Nozaki T, Kitamura N, Inaba Y. Evaluation of glenoid morphology and bony Bankart lesion in shoulders with traumatic anterior instability using zero echo time magnetic resonance imaging. JSES Int 2024; 8:714-718. [PMID: 39035642 PMCID: PMC11258840 DOI: 10.1016/j.jseint.2024.03.003] [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: 07/23/2024] Open
Abstract
Background Preoperative computed tomography (CT) evaluation of bone morphometry aids in determining treatment strategies for shoulder instability. The use of zero echo time (ZTE) sequence in magnetic resonance imaging (MRI), a new bone cortex imaging technique, may help reduce radiation exposure and medical costs. Therefore, this study aimed to evaluate the glenoid morphology and detect the presence of bony Bankart lesion using ZTE MRI in shoulders with anterior instability and compare its diagnostic accuracy with that of CT. Methods Thirty-six patients (36 shoulders) with anterior instability who underwent preoperative CT and MRI examinations between April 2019 and October 2021 were retrospectively analyzed. The percentages of glenoid bone defects on 3-dimensional (3D) CT and ZTE images were determined, and the correlation between these percentages was evaluated. The number of cases with bony Bankart lesion on CT and 2 types of ZTE (3D and CT-like) images was determined, and the diagnostic accuracy of ZTE for detecting bony Bankart lesion was assessed, with CT as the gold standard. Patients with bony Bankart lesion on CT images were divided into 2 groups based on whether the lesion was detectable on 3D ZTE or CT-like images. The longer diameters of bony Bankart lesion were compared between the groups. Results The median percentage of glenoid bone loss was 12.1% (range, 1.3%-45.9%) and 12.3% (range, 0%-46.6%) on 3D CT and 3D ZTE images, respectively. The Spearman's rank correlation coefficient was 0.89. Bony Bankart lesion was detected in 18, 13, and 8 shoulders of the 36 patients on CT, 3D ZTE, and CT-like images, respectively. The overall diagnostic accuracy of the CT-like and 3D ZTE images for detecting bony Bankart lesion was 86.1% and 72.2%, respectively. A significant difference was observed between the groups with and without bony Bankart lesion on CT-like images in terms of the long diameter of the bone fragments on CT (P < .01). Conclusion ZTE MRI demonstrated high reproducibility for the evaluation of glenoid bone defect in shoulders with anterior instability. Although no significant difference in the measurement was observed compared with that on CT, the ability of ZTE MRI to delineate bone Bankart lesion remains limited.
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Affiliation(s)
- Takayuki Oishi
- Department of Orthopedic Surgery, St. Luke’s International Hospital, Tokyo, Japan
| | - Atsushi Tasaki
- Department of Orthopedic Surgery, St. Luke’s International Hospital, Tokyo, Japan
| | - Shota Mashimo
- Department of Rehabilitation, St. Luke’s International Hospital, Tokyo, Japan
| | - Michiru Moriya
- Department of Orthopedic Surgery, St. Luke’s International Hospital, Tokyo, Japan
| | - Daisuke Yamashita
- Department of Orthopedic Surgery, St. Luke’s International Hospital, Tokyo, Japan
| | - Taiki Nozaki
- Department of Radiology, Keio University School of Medicine, Tokyo, Japan
| | - Nobuto Kitamura
- Department of Orthopedic Surgery, St. Luke’s International Hospital, Tokyo, Japan
| | - Yutaka Inaba
- Department of Orthopedic Surgery, Yokohama City University, Yokohama, Japan
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Lo YW, Lin KH, Lee CY, Li CW, Lin CY, Chen YW, Wang LW, Wu YH, Huang WS. The impact of ZTE-based MR attenuation correction compared to CT-AC in 18F-FBPA PET before boron neutron capture therapy. Sci Rep 2024; 14:13950. [PMID: 38886395 PMCID: PMC11183148 DOI: 10.1038/s41598-024-63248-9] [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: 09/12/2023] [Accepted: 05/27/2024] [Indexed: 06/20/2024] Open
Abstract
Tumor-to-normal ratio (T/N) measurement of 18F-FBPA is crucial for patient eligibility to receive boron neutron capture therapy. This study aims to compare the difference in standard uptake value ratios on brain tumors and normal brains using PET/MR ZTE and atlas-based attenuation correction with the current standard PET/CT attenuation correction. Regarding the normal brain uptake, the difference was not significant between PET/CT and PET/MR attenuation correction methods. The T/N ratio of PET/CT-AC, PET/MR ZTE-AC and PET/MR AB-AC were 2.34 ± 0.95, 2.29 ± 0.88, and 2.19 ± 0.80, respectively. The T/N ratio comparison showed no significance using PET/CT-AC and PET/MR ZTE-AC. As for the PET/MRI AB-AC, significantly lower T/N ratio was observed (- 5.18 ± 9.52%; p < 0.05). The T/N difference between ZTE-AC and AB-AC was also significant (4.71 ± 5.80%; p < 0.01). Our findings suggested PET/MRI imaging using ZTE-AC provided superior quantification on 18F-FBPA-PET compared to atlas-based AC. Using ZTE-AC on 18F-FBPA-PET /MRI might be crucial for BNCT pre-treatment planning.
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Affiliation(s)
- Yi-Wen Lo
- Integrated PET/MR Imaging Center, Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan ROC
- Clinical Imaging Research Center (CIRC), Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Ko-Han Lin
- Integrated PET/MR Imaging Center, Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan ROC.
| | - Chien-Ying Lee
- Integrated PET/MR Imaging Center, Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan ROC
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming Chiao Tung University, Taipei, Taiwan ROC
| | | | | | - Yi-Wei Chen
- Division of Radiotherapy, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan ROC
| | - Ling-Wei Wang
- Division of Radiotherapy, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan ROC
| | - Yuan-Hung Wu
- Division of Radiotherapy, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan ROC
| | - Wen-Sheng Huang
- Department of Nuclear Medicine, Chang Bing Show Chwan Memorial Hospital, Taipei, Taiwan ROC.
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Okazawa H, Nogami M, Ishida S, Makino A, Mori T, Kiyono Y, Ikawa M. PET/MRI multimodality imaging to evaluate changes in glymphatic system function and biomarkers of Alzheimer's disease. Sci Rep 2024; 14:12310. [PMID: 38811627 PMCID: PMC11137097 DOI: 10.1038/s41598-024-62806-5] [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: 01/25/2024] [Accepted: 05/20/2024] [Indexed: 05/31/2024] Open
Abstract
The glymphatic system is considered to play a pivotal role in the clearance of disease-causing proteins in neurodegenerative diseases. This study employed MR diffusion tensor imaging (DTI) to evaluate glymphatic system function and its correlation with brain amyloid accumulation levels measured using [11C]Pittsburgh compound-B (PiB) PET/MRI. Fifty-six patients with mild cognitive impairment and early Alzheimer's disease (AD: 70 ± 11 y) underwent [11C]PiB PET/MRI to assess amyloid deposition and were compared with 27 age-matched cognitively normal volunteers (CN: 69 ± 10y). All participants were evaluated for cognitive function using the Mini Mental State Examination (MMSE) before [11C]PiB PET/MRI. DTI images were acquired during the PET/MRI scan with several other MR sequences. The DTI analysis along the perivascular space index (DTI-ALPS index) was calculated to estimate the functional activity of the glymphatic system. Centiloid scale was applied to quantify amyloid deposition levels from [11C]PiB PET images. All patients in the AD group showed positive [11C]PiB accumulation, whereas all CN participants were negative. ALPS-index for all subjects linearly correlated with PiB centiloid, MMSE scores, and hippocampal volume. The correlation between the ALPS-index and PiB accumulation was more pronounced than with any other biomarkers. These findings suggest that glymphatic system dysfunction is a significant factor in the early stages of Alzheimer's disease.
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Affiliation(s)
- Hidehiko Okazawa
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan.
| | - Munenobu Nogami
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
- Department of Radiology, Kobe University Hospital, Kobe, Japan
| | | | - Akira Makino
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
| | - Tetsuya Mori
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
| | - Yasushi Kiyono
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
| | - Masamichi Ikawa
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
- Department of Community Health Science, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
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Kaster MA, Caldwell MA, Meade TJ. Development of Ln(III) Derivatives as 19F Parashift Probes. Inorg Chem 2024; 63:9877-9887. [PMID: 38748735 DOI: 10.1021/acs.inorgchem.4c00652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2024]
Abstract
19F parashift probes with paramagnetically shifted reporter nuclei provide attractive platforms to develop molecular imaging probes. These probes enable ratiometric detection of molecular disease markers using a direct detection technique. Here, we describe a series of trivalent lanthanide (Ln(III)) complexes that are structural analogues of the clinically approved MR contrast agent (CA) ProHance to obtain LnL 19F parashift probes. We evaluated trans-gadolinium paramagnetic lanthanides compared to diamagnetic YL for 19F chemical shift and relaxation rate enhancement. The paramagnetic contribution to chemical shift (δPCS) for paramagnetic LnL exhibited either shifts to lower frequency (δPCS < 0 for TbL, DyL, and HoL) or shifts to higher frequency (δPCS > 0 for ErL, TmL, and YbL) compared to YL 19F spectroscopic signal. Zero-echo time pulse sequences achieved 56-fold sensitivity enhancement for DyL over YL, while developing probe-specific pulse sequences with fast delay times and acquisition times achieved 0.6-fold enhancement in limit of detection for DyL. DyL provides an attractive platform to develop 19F parashift probes for ratiometric detection of enzymatic activity.
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Affiliation(s)
- Megan A Kaster
- Departments of Chemistry, Molecular Biosciences, Neurobiology and Radiology, Northwestern University, 2145 N. Sheridan Road, Evanston, Illinois 60208, United States
| | - Michael A Caldwell
- Departments of Chemistry, Molecular Biosciences, Neurobiology and Radiology, Northwestern University, 2145 N. Sheridan Road, Evanston, Illinois 60208, United States
| | - Thomas J Meade
- Departments of Chemistry, Molecular Biosciences, Neurobiology and Radiology, Northwestern University, 2145 N. Sheridan Road, Evanston, Illinois 60208, United States
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Kong D, Liu G, Cheng B, Qi X, Zhu J, He Q, Xing H, Gong Q. A novel transcranial MR Guided focused ultrasound method based on the ultrashort echo time skull acoustic model and phase retrieval techniques. Sci Rep 2024; 14:11876. [PMID: 38789537 DOI: 10.1038/s41598-024-62500-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 05/17/2024] [Indexed: 05/26/2024] Open
Abstract
Transcranial ultrasound stimulation (TUS) has been clinically applied as a neuromodulation tool. Particularly, the phase array ultrasound can be applied in TUS to non-invasively focus on the cortex or deep brain. However, the vital phase distortion of the ultrasound induced by the skull limits its clinical application. In the current study, we aimed to develop a hybrid method that combines the ultrashort echo time (UTE) magnetic resonance imaging (MRI) sequences with the prDeep technique to achieve focusing ventral intermediate thalamic nucleus (VIM). The time-reversal (TR) approach of the UTE numerical acoustic model of the skull combined with the prDeep algorithm was used to reduce the number of iterations. The skull acoustic model simulation therapy process was establish to valid this method's prediction and focus performance, and the classical TR method were considered as the gold standard (GS). Our approach could restore 75% of the GS intensity in 25 iteration steps, with a superior the noise immunity. Our findings demonstrate that the phase aberration caused by the skull can be estimated using phase retrieval techniques to achieve a fast and accurate transcranial focus. The method has excellent adaptability and anti-noise capacity for satisfying complex and changeable scenarios.
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Affiliation(s)
- Dechen Kong
- College Of Physics, Sichuan University, Chengdu, China
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Gaojie Liu
- Department of Radiation Oncology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Bochao Cheng
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Department of Radiology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China
| | - Xu Qi
- Radiotherapy Physics & Technology Center, Cancer Center, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Jiayu Zhu
- Central Research Institute, United Imaging Healthcare Group, Shanghai, China
| | - Qiang He
- Central Research Institute, United Imaging Healthcare Group, Shanghai, China
| | - Haoyang Xing
- College Of Physics, Sichuan University, Chengdu, China.
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China.
- Xiamen West China Hospital, Sichuan University, Xiamen, China.
| | - Qiyong Gong
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Xiamen West China Hospital, Sichuan University, Xiamen, China
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Cornfeld D, Condron P, Newburn G, McGeown J, Scadeng M, Bydder M, Griffin M, Handsfield G, Perera MR, Melzer T, Holdsworth S, Kwon E, Bydder G. Ultra-High Contrast MRI: Using Divided Subtracted Inversion Recovery (dSIR) and Divided Echo Subtraction (dES) Sequences to Study the Brain and Musculoskeletal System. Bioengineering (Basel) 2024; 11:441. [PMID: 38790308 PMCID: PMC11118255 DOI: 10.3390/bioengineering11050441] [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: 04/01/2024] [Revised: 04/26/2024] [Accepted: 04/28/2024] [Indexed: 05/26/2024] Open
Abstract
Divided and subtracted MRI is a novel imaging processing technique, where the difference of two images is divided by their sum. When the sequence parameters are chosen properly, this results in images with a high T1 or T2 weighting over a small range of tissues with specific T1 and T2 values. In the T1 domain, we describe the implementation of the divided Subtracted Inversion Recovery Sequence (dSIR), which is used to image very small changes in T1 from normal in white matter. dSIR has shown widespread changes in otherwise normal-appearing white matter in patients suffering from mild traumatic brain injury (mTBI), substance abuse, and ischemic leukoencephalopathy. It can also be targeted to measure small changes in T1 from normal in other tissues. In the T2 domain, we describe the divided echo subtraction (dES) sequence that is used to image musculoskeletal tissues with a very short T2*. These tissues include fascia, tendons, and aponeuroses. In this manuscript, we explain how this contrast is generated, review how these techniques are used in our research, and discuss the current challenges and limitations of this technique.
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Affiliation(s)
- Daniel Cornfeld
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Department of Anatomy and Medical Imaging—Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
- Te Whatu Ora Tairawhiti, Gisborne 4010, New Zealand
| | - Paul Condron
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Department of Anatomy and Medical Imaging—Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
| | - Gil Newburn
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
| | - Josh McGeown
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
| | - Miriam Scadeng
- Department of Anatomy and Medical Imaging—Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
| | - Mark Bydder
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
| | - Mark Griffin
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Insight Research Services Associated, Gold Coast 4215, Australia
| | - Geoffrey Handsfield
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
| | | | - Tracy Melzer
- Department of Medicine, University of Otago, Christchurch 8011, New Zealand
- New Zealand Brain Research Institute, Christchurch 8011, New Zealand
| | - Samantha Holdsworth
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Department of Anatomy and Medical Imaging—Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
| | - Eryn Kwon
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
| | - Graeme Bydder
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Department of Radiology, University of California, San Diego, CA 92093, USA
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11
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Ensle F, Kaniewska M, Lohezic M, Guggenberger R. Enhanced bone assessment of the shoulder using zero-echo time MRI with deep-learning image reconstruction. Skeletal Radiol 2024:10.1007/s00256-024-04690-8. [PMID: 38658419 DOI: 10.1007/s00256-024-04690-8] [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: 01/22/2024] [Revised: 04/07/2024] [Accepted: 04/18/2024] [Indexed: 04/26/2024]
Abstract
OBJECTIVES To assess a deep learning-based reconstruction algorithm (DLRecon) in zero echo-time (ZTE) MRI of the shoulder at 1.5 Tesla for improved delineation of osseous findings. METHODS In this retrospective study, 63 consecutive exams of 52 patients (28 female) undergoing shoulder MRI at 1.5 Tesla in clinical routine were included. Coronal 3D isotropic radial ZTE pulse sequences were acquired in the standard MR shoulder protocol. In addition to standard-of-care (SOC) image reconstruction, the same raw data was reconstructed with a vendor-supplied prototype DLRecon algorithm. Exams were classified into three subgroups: no pathological findings, degenerative changes, and posttraumatic changes, respectively. Two blinded readers performed bone assessment on a 4-point scale (0-poor, 3-perfect) by qualitatively grading image quality features and delineation of osseous pathologies including diagnostic confidence in the respective subgroups. Quantitatively, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of bone were measured. Qualitative variables were compared using the Wilcoxon signed-rank test for ordinal data and the McNemar test for dichotomous variables; quantitative measures were compared with Student's t-testing. RESULTS DLRecon scored significantly higher than SOC in all visual metrics of image quality (all, p < 0.03), except in the artifact category (p = 0.37). DLRecon also received superior qualitative scores for delineation of osseous pathologies and diagnostic confidence (p ≤ 0.03). Quantitatively, DLRecon achieved superior CNR (95 CI [1.4-3.1]) and SNR (95 CI [15.3-21.5]) of bone than SOC (p < 0.001). CONCLUSION DLRecon enhanced image quality in ZTE MRI and improved delineation of osseous pathologies, allowing for increased diagnostic confidence in bone assessment.
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Affiliation(s)
- Falko Ensle
- Diagnostic and Interventional Radiology, University Hospital Zurich, University Zurich, Zurich, Switzerland.
- University of Zurich (UZH), Raemistrasse 100, CH-8091, Zurich, Switzerland.
| | - Malwina Kaniewska
- Diagnostic and Interventional Radiology, University Hospital Zurich, University Zurich, Zurich, Switzerland
- University of Zurich (UZH), Raemistrasse 100, CH-8091, Zurich, Switzerland
| | | | - Roman Guggenberger
- Diagnostic and Interventional Radiology, University Hospital Zurich, University Zurich, Zurich, Switzerland
- University of Zurich (UZH), Raemistrasse 100, CH-8091, Zurich, Switzerland
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12
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Florkow MC, Nguyen CH, Sakkers RJB, Weinans H, Jansen MP, Custers RJH, van Stralen M, Seevinck PR. Magnetic resonance imaging-based bone imaging of the lower limb: Strategies for generating high-resolution synthetic computed tomography. J Orthop Res 2024; 42:843-854. [PMID: 37807082 DOI: 10.1002/jor.25707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 09/13/2023] [Accepted: 10/05/2023] [Indexed: 10/10/2023]
Abstract
This study aims at assessing approaches for generating high-resolution magnetic resonance imaging- (MRI-) based synthetic computed tomography (sCT) images suitable for orthopedic care using a deep learning model trained on low-resolution computed tomography (CT) data. To that end, paired MRI and CT data of three anatomical regions were used: high-resolution knee and ankle data, and low-resolution hip data. Four experiments were conducted to investigate the impact of low-resolution training CT data on sCT generation and to find ways to train models on low-resolution data while providing high-resolution sCT images. Experiments included resampling of the training data or augmentation of the low-resolution data with high-resolution data. Training sCT generation models using low-resolution CT data resulted in blurry sCT images. By resampling the MRI/CT pairs before the training, models generated sharper images, presumably through an increase in the MRI/CT mutual information. Alternatively, augmenting the low-resolution with high-resolution data improved sCT in terms of mean absolute error proportionally to the amount of high-resolution data. Overall, the morphological accuracy was satisfactory as assessed by an average intermodal distance between joint centers ranging from 0.7 to 1.2 mm and by an average intermodal root-mean-squared distances between bone surfaces under 0.7 mm. Average dice scores ranged from 79.8% to 87.3% for bony structures. To conclude, this paper proposed approaches to generate high-resolution sCT suitable for orthopedic care using low-resolution data. This can generalize the use of sCT for imaging the musculoskeletal system, paving the way for an MR-only imaging with simplified logistics and no ionizing radiation.
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Affiliation(s)
- Mateusz C Florkow
- Image Sciences Institute, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Chien H Nguyen
- Department of Orthopaedics, University Medical Centre Utrecht, Utrecht, The Netherlands
- 3D Lab, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Ralph J B Sakkers
- Department of Orthopaedics, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Harrie Weinans
- Department of Orthopaedics, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Mylene P Jansen
- Department of Rheumatology & Clinical Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Roel J H Custers
- Department of Orthopaedics, University Medical Centre Utrecht, Utrecht, The Netherlands
| | | | - Peter R Seevinck
- Image Sciences Institute, University Medical Centre Utrecht, Utrecht, The Netherlands
- MRIguidance B.V., Utrecht, The Netherlands
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Lee D, Kim E, Woo H, Jeon CY, Yoon J, Choi J. Fast field echo resembling CT using restricted echo-spacing (FRACTURE) MR sequence can provide craniocervical region images comparable to a CT in dogs. Front Bioeng Biotechnol 2024; 12:1297675. [PMID: 38476967 PMCID: PMC10927716 DOI: 10.3389/fbioe.2024.1297675] [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: 09/20/2023] [Accepted: 02/09/2024] [Indexed: 03/14/2024] Open
Abstract
Magnetic resonance imaging (MRI) is essential for evaluating cerebellar compression in patients with craniocervical junction abnormalities (CJA). However, it is limited in depicting cortical bone because of its short T2 relaxation times, low proton density, and organized structure. Fast field echo resembling a computed tomography (CT) scan using restricted echo-spacing (FRACTURE) MRI, is a new technique that offers CT-like bone contrast without radiation. This study aimed to assess the feasibility of using FRACTURE MRI for craniocervical junction (CCJ) assessment compared with CT and conventional MRI, potentially reducing the need for multiple scans and radiation exposure, and simplifying procedures in veterinary medicine. CT and MRI of the CCJ were obtained from five healthy beagles. MRI was performed using three-dimensional (3D) T1-weighted, T2-weighted, proton density-weighted (PDW), single echo-FRACTURE (sFRACTURE), and multiple echo-FRACTURE (mFRACTURE) sequences. For qualitative assessment, cortical delineation, trabecular bone visibility, joint space visibility, vertebral canal definition, overall quality, and artifacts were evaluated for each sequence. The geometrical accuracy, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were quantified. Both sFRACTURE and CT images provided significantly higher scores for cortical delineation and trabecular bone visibility than conventional MRI. Joint space visibility and vertebral canal definition were similar to those observed on CT images, regardless of the MR sequence. In the quantitative assessment, the distances measured on T2-weighted images differed significantly from those measured on CT. There were no significant differences between the distances taken using T1-weighted, PD-weighted, sFRACTURE, mFRACTURE and those taken using CT. T1-weighted and sFRACTURE had a higher SNR for trabecular bone than CT. The CNR between the cortical bone and muscle was high on CT and FRACTURE images. However, the CNR between the cortical and trabecular bones was low in mFRACTURE. Similar to CT, FRACTURE sequences showed higher cortical delineation and trabecular bone visibility than T2-weighted, T1-weighted, and PDW CCJ sequences. In particular, sFRACTURE provided a high signal-to-noise ratio (SNR) of the trabecular bone and a high CNR between the cortical bone and muscle and between the cortical and trabecular bones. FRACTURE sequences can complement conventional MR sequences for bone assessment of the CCJ in dogs.
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Affiliation(s)
- Dongjae Lee
- Department of Veterinary Medical Imaging, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Eunjee Kim
- Department of Veterinary Medical Imaging, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Hyeonjae Woo
- Department of Veterinary Medical Imaging, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Chang-Yeop Jeon
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Republic of Korea
| | - Junghee Yoon
- Department of Veterinary Medical Imaging, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Jihye Choi
- Department of Veterinary Medical Imaging, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
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14
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Kamona N, Jones BC, Lee H, Song HK, Rajapakse CS, Wagner CS, Bartlett SP, Wehrli FW. Cranial bone imaging using ultrashort echo-time bone-selective MRI as an alternative to gradient-echo based "black-bone" techniques. MAGMA (NEW YORK, N.Y.) 2024; 37:83-92. [PMID: 37934295 PMCID: PMC10923077 DOI: 10.1007/s10334-023-01125-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 11/08/2023]
Abstract
OBJECTIVES CT is the clinical standard for surgical planning of craniofacial abnormalities in pediatric patients. This study evaluated three MRI cranial bone imaging techniques for their strengths and limitations as a radiation-free alternative to CT. METHODS Ten healthy adults were scanned at 3 T with three MRI sequences: dual-radiofrequency and dual-echo ultrashort echo time sequence (DURANDE), zero echo time (ZTE), and gradient-echo (GRE). DURANDE bright-bone images were generated by exploiting bone signal intensity dependence on RF pulse duration and echo time, while ZTE bright-bone images were obtained via logarithmic inversion. Three skull segmentations were derived, and the overlap of the binary masks was quantified using dice similarity coefficient. Craniometric distances were measured, and their agreement was quantified. RESULTS There was good overlap of the three masks and excellent agreement among craniometric distances. DURANDE and ZTE showed superior air-bone contrast (i.e., sinuses) and soft-tissue suppression compared to GRE. DISCUSSIONS ZTE has low levels of acoustic noise, however, ZTE images had lower contrast near facial bones (e.g., zygomatic) and require effective bias-field correction to separate bone from air and soft-tissue. DURANDE utilizes a dual-echo subtraction post-processing approach to yield bone-specific images, but the sequence is not currently manufacturer-supported and requires scanner-specific gradient-delay corrections.
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Affiliation(s)
- Nada Kamona
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Brandon C Jones
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Hyunyeol Lee
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- School of Electronics Engineering, Kyungpook National University, Daegu, South Korea
| | - Hee Kwon Song
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Chamith S Rajapakse
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Connor S Wagner
- Division of Plastic, Reconstructive, and Oral Surgery, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Scott P Bartlett
- Division of Plastic, Reconstructive, and Oral Surgery, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Felix W Wehrli
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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15
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Fujisaki A, Tsukamoto J, Narimatsu H, Hayashida Y, Todoroki Y, Hirano N, Takeda K, Shin S, Ota S, Anai K, Fukumitsu S, Yoshimatsu Y, Kono Y, Ueno M, Ide S, Murakami Y, Aoki T. Zero Echo Time Magnetic Resonance Imaging; Techniques and Clinical Utility in Musculoskeletal System. J Magn Reson Imaging 2024; 59:32-42. [PMID: 37288953 DOI: 10.1002/jmri.28843] [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: 03/21/2023] [Revised: 05/23/2023] [Accepted: 05/23/2023] [Indexed: 06/09/2023] Open
Abstract
Zero echo time (ZTE) sequence is recent advanced magnetic resonance technique that utilizes ultrafast readouts to capture signals from short-T2 tissues. This sequence enables T2- and T2* weighted imaging of tissues with short intrinsic relaxation times by using an extremely short TE, and are increasingly used in the musculoskeletal system. We review the imaging physics of these sequences, practical limitations, and image reconstruction, and then discuss the clinical utilities in various disorders of the musculoskeletal system. ZTE can be readily incorporated into the clinical workflow, and is a promising technique to avoid unnecessary radiation exposure, cost, and time-consuming by computed tomography in some cases. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Akitaka Fujisaki
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Jun Tsukamoto
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Hidekuni Narimatsu
- Department of Radiology, Hospital of University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Yoshiko Hayashida
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Yo Todoroki
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Natsumi Hirano
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Kazuki Takeda
- Department of Radiology, Hospital of University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Sho Shin
- Department of Radiology, Hospital of University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Satoru Ota
- Department of Radiology, Hospital of University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Kenta Anai
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Satoshi Fukumitsu
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Yuta Yoshimatsu
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Yuichiro Kono
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Midori Ueno
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Satoru Ide
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Yu Murakami
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
| | - Takatoshi Aoki
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan
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Sousa JM, Appel L, Engström M, Nyholm D, Ahlström H, Lubberink M. Comparison of quantitative [ 11C]PE2I brain PET studies between an integrated PET/MR and a stand-alone PET system. Phys Med 2024; 117:103185. [PMID: 38042064 DOI: 10.1016/j.ejmp.2023.103185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 11/03/2023] [Accepted: 11/20/2023] [Indexed: 12/04/2023] Open
Abstract
PET/MR systems demanded great efforts for accurate attenuation correction (AC) but differences in technology, geometry and hardware attenuation may also affect quantitative results. Dedicated PET systems using transmission-based AC are regarded as the gold standard for quantitative brain PET. The study aim was to investigate the agreement between quantitative PET outcomes from a PET/MR scanner against a stand-alone PET system. Nine patients with Parkinsonism underwent two 80-min dynamic PET scans with the dopamine transporter ligand [11C]PE2I. Images were reconstructed with resolution-matched settings using 68Ge-transmission (stand-alone PET), and zero-echo-time MR (PET/MR) scans for AC. Non-displaceable binding potential (BPND) and relative delivery (R1) were evaluated using volumes of interest and voxel-wise analysis. Correlations between systems were high (r ≥ 0.85) for both quantitative outcome parameters in all brain regions. Striatal BPND was significantly lower on PET/MR than on stand-alone PET (-7%). R1 was significantly overestimated in posterior cortical regions (9%) and underestimated in striatal (-9%) and limbic areas (-6%). The voxel-wise evaluation revealed that the MR-safe headphones caused a negative bias in both parametric BPND and R1 images. Additionally, a significant positive bias of R1 was found in the auditory cortex, most likely due to the acoustic background noise during MR imaging. The relative bias of the quantitative [11C]PE2I PET data acquired from a SIGNA PET/MR system was in the same order as the expected test-retest reproducibility of [11C]PE2I BPND and R1, compared to a stand-alone ECAT PET scanner. MR headphones and background noise are potential sources of error in functional PET/MR studies.
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Affiliation(s)
- João M Sousa
- Nuclear Medicine & PET, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; Medical Physics, Uppsala University Hospital, Uppsala, Sweden.
| | - Lieuwe Appel
- Nuclear Medicine & PET, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; Medical Imaging Centre, Uppsala University Hospital, Uppsala, Sweden
| | | | - Dag Nyholm
- Department of Neurology, Uppsala University Hospital, Uppsala, Sweden; Department of Medical Sciences, Neurology, Uppsala University, Uppsala, Sweden
| | - Håkan Ahlström
- Nuclear Medicine & PET, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; Medical Imaging Centre, Uppsala University Hospital, Uppsala, Sweden; Antaros Medical AB, BioVenture Hub, Mölndal, Sweden
| | - Mark Lubberink
- Nuclear Medicine & PET, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; Medical Physics, Uppsala University Hospital, Uppsala, Sweden
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Tsuchiya K, Gomyo M, Katase S, Hiraoka S, Tateishi H. Magnetic resonance bone imaging: applications to vertebral lesions. Jpn J Radiol 2023; 41:1173-1185. [PMID: 37209299 PMCID: PMC10613598 DOI: 10.1007/s11604-023-01449-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/12/2023] [Indexed: 05/22/2023]
Abstract
MR bone imaging is a recently introduced technique, that allows visualization of bony structures in good contrast against adjacent structures, like CT. Although CT has long been considered the modality of choice for bone imaging, MR bone imaging allows visualization of the bone without radiation exposure while simultaneously allowing conventional MR images to be obtained. Accordingly, MR bone imaging is expected as a new imaging technique for the diagnosis of miscellaneous spinal diseases. This review presents several sequences used in MR bone imaging including black bone imaging, ultrashort/zero echo time (UTE/ZTE) sequences, and T1-weighted 3D gradient-echo sequence. We also illustrate clinical cases in which spinal lesions could be effectively demonstrated on MR bone imaging, performed in most cases using a 3D gradient-echo sequence at our institution. The lesions presented herein include degenerative diseases, tumors and similar diseases, fractures, infectious diseases, and hemangioma. Finally, we discuss the differences between MR bone imaging and previously reported techniques, and the limitations and future perspectives of MR bone imaging.
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Affiliation(s)
- Kazuhiro Tsuchiya
- Department of Radiology, JR Tokyo General Hospital, 2-1-3 Yoyogi, Shibuya-ku, Tokyo, 151-8528, Japan.
- Department of Radiology, Faculty of Medicine, Kyorin University, 6-20-2 Shinkawa, Mitaka City, Tokyo, 181-8611, Japan.
| | - Miho Gomyo
- Department of Radiology, Faculty of Medicine, Kyorin University, 6-20-2 Shinkawa, Mitaka City, Tokyo, 181-8611, Japan
| | - Shichiro Katase
- Department of Radiology, Faculty of Medicine, Kyorin University, 6-20-2 Shinkawa, Mitaka City, Tokyo, 181-8611, Japan
| | - Sayuki Hiraoka
- Department of Radiology, JR Tokyo General Hospital, 2-1-3 Yoyogi, Shibuya-ku, Tokyo, 151-8528, Japan
| | - Hidekatsu Tateishi
- Department of Radiology, JR Tokyo General Hospital, 2-1-3 Yoyogi, Shibuya-ku, Tokyo, 151-8528, Japan
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18
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Zhou J, Hagberg GE, Aghaeifar A, Bause J, Zaitsev M, Scheffler K. Prediction of motion induced magnetic fields for human brain MRI at 3 T. MAGMA (NEW YORK, N.Y.) 2023; 36:797-813. [PMID: 36964797 PMCID: PMC10504152 DOI: 10.1007/s10334-023-01076-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 03/08/2023] [Accepted: 03/13/2023] [Indexed: 03/26/2023]
Abstract
OBJECTIVE Maps of B0 field inhomogeneities are often used to improve MRI image quality, even in a retrospective fashion. These field inhomogeneities depend on the exact head position within the static field but acquiring field maps (FM) at every position is time consuming. Here we propose a forward simulation strategy to obtain B0 predictions at different head-positions. METHODS FM were predicted by combining (1) a multi-class tissue model for estimation of tissue-induced fields, (2) a linear k-space model for capturing gradient imperfections, (3) a dipole estimation for quantifying lower-body perturbing fields (4) and a position-dependent tissue mask to model FM alterations caused by large motion effects. The performance of the combined simulation strategy was compared with an approach based on a rigid body transformation of the FM measured in the reference position to the new position. RESULTS The transformed FM provided inconsistent results for large head movements (> 5° rotation, approximately), while the simulation strategy had a superior prediction accuracy for all positions. The simulated FM was used to optimize B0 shims with up to 22.2% improvement with respect to the transformed FM approach. CONCLUSION The proposed simulation strategy is able to predict movement-induced B0 field inhomogeneities yielding more precise estimates of the ground truth field homogeneity than the transformed FM.
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Affiliation(s)
- Jiazheng Zhou
- Max Planck Institute for Biological Cybernetics, High-Field Magnetic Resonance Center, Max-Planck-Ring 11, 72076, Tübingen, Germany.
- IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany.
| | - Gisela E Hagberg
- Max Planck Institute for Biological Cybernetics, High-Field Magnetic Resonance Center, Max-Planck-Ring 11, 72076, Tübingen, Germany
- Department of Biomedical Magnetic Resonance, University Hospital Tübingen, Tübingen, Germany
| | - Ali Aghaeifar
- Max Planck Institute for Biological Cybernetics, High-Field Magnetic Resonance Center, Max-Planck-Ring 11, 72076, Tübingen, Germany
- Department of Biomedical Magnetic Resonance, University Hospital Tübingen, Tübingen, Germany
| | - Jonas Bause
- Max Planck Institute for Biological Cybernetics, High-Field Magnetic Resonance Center, Max-Planck-Ring 11, 72076, Tübingen, Germany
| | - Maxim Zaitsev
- Department of Radiology, Medical Physics, Faculty of Medicine, Medical Center University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Klaus Scheffler
- Max Planck Institute for Biological Cybernetics, High-Field Magnetic Resonance Center, Max-Planck-Ring 11, 72076, Tübingen, Germany
- Department of Biomedical Magnetic Resonance, University Hospital Tübingen, Tübingen, Germany
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Kaushik SS, Bylund M, Cozzini C, Shanbhag D, Petit SF, Wyatt JJ, Menzel MI, Pirkl C, Mehta B, Chauhan V, Chandrasekharan K, Jonsson J, Nyholm T, Wiesinger F, Menze B. Region of interest focused MRI to synthetic CT translation using regression and segmentation multi-task network. Phys Med Biol 2023; 68:195003. [PMID: 37567235 DOI: 10.1088/1361-6560/acefa3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 08/10/2023] [Indexed: 08/13/2023]
Abstract
Objective. In MR-only clinical workflow, replacing CT with MR image is of advantage for workflow efficiency and reduces radiation to the patient. An important step required to eliminate CT scan from the workflow is to generate the information provided by CT via an MR image. In this work, we aim to demonstrate a method to generate accurate synthetic CT (sCT) from an MR image to suit the radiation therapy (RT) treatment planning workflow. We show the feasibility of the method and make way for a broader clinical evaluation.Approach. We present a machine learning method for sCT generation from zero-echo-time (ZTE) MRI aimed at structural and quantitative accuracies of the image, with a particular focus on the accurate bone density value prediction. The misestimation of bone density in the radiation path could lead to unintended dose delivery to the target volume and results in suboptimal treatment outcome. We propose a loss function that favors a spatially sparse bone region in the image. We harness the ability of the multi-task network to produce correlated outputs as a framework to enable localization of region of interest (RoI) via segmentation, emphasize regression of values within RoI and still retain the overall accuracy via global regression. The network is optimized by a composite loss function that combines a dedicated loss from each task.Main results. We have included 54 brain patient images in this study and tested the sCT images against reference CT on a subset of 20 cases. A pilot dose evaluation was performed on 9 of the 20 test cases to demonstrate the viability of the generated sCT in RT planning. The average quantitative metrics produced by the proposed method over the test set were-(a) mean absolute error (MAE) of 70 ± 8.6 HU; (b) peak signal-to-noise ratio (PSNR) of 29.4 ± 2.8 dB; structural similarity metric (SSIM) of 0.95 ± 0.02; and (d) Dice coefficient of the body region of 0.984 ± 0.Significance. We demonstrate that the proposed method generates sCT images that resemble visual characteristics of a real CT image and has a quantitative accuracy that suits RT dose planning application. We compare the dose calculation from the proposed sCT and the real CT in a radiation therapy treatment planning setup and show that sCT based planning falls within 0.5% target dose error. The method presented here with an initial dose evaluation makes an encouraging precursor to a broader clinical evaluation of sCT based RT planning on different anatomical regions.
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Affiliation(s)
- Sandeep S Kaushik
- GE Healthcare, Munich, Germany
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Mikael Bylund
- Department of Radiation Sciences, UmeåUniversity, Umea, Sweden
| | | | | | - Steven F Petit
- Department of Radiotherapy, Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | - Jonathan J Wyatt
- Translational and Clinical Research Institute, Newcastle University and Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, United Kingdom
| | - Marion I Menzel
- GE Healthcare, Munich, Germany
- Dept. of Physics, Technical University of Munich, Munich, Germany
| | | | | | - Vikas Chauhan
- Sree Chitra Tirunal Institute of Medical Sciences and Technology (SCTIMST), Trivandrum, India
| | | | - Joakim Jonsson
- Department of Radiation Sciences, UmeåUniversity, Umea, Sweden
| | - Tufve Nyholm
- Department of Radiation Sciences, UmeåUniversity, Umea, Sweden
| | | | - Bjoern Menze
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
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DE Luca F, Bolin M, Blomqvist L, Wassberg C, Martin H, Falk Delgado A. 11C-methionine PET/MRI in postoperative patients after craniotomy: zero echo time and head atlas versus CT-based attenuation correction. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF... 2023; 67:215-222. [PMID: 35119249 DOI: 10.23736/s1824-4785.22.03389-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
BACKGROUND Attenuation correction (AC) is an important topic in PET/MRI and particularly challenging after brain tumor surgery, near metal implants, adjacent bone and burr holes. In this study, we evaluated the performance of two MR-driven AC methods, zero-echo-time AC (ZTE-AC) and atlas-AC, in comparison to reference standard CT-AC in patients with surgically treated brain tumors at 11C-methionine PET/MRI. METHODS This retrospective study investigated seven postoperative patients with neuropathologically confirmed brain tumor at 11C-methionine PET/MRI. Three AC maps - ZTE-AC, atlas-AC and reference standard CT-AC - were generated for each patient. Standardized uptake values (SUV) were obtained at the metal implant, adjacent bone and burr hole. Standard uptake ratio (SUR) SURmetal/mirror, SURbone/mirror and SURburrhole/mirror were then calculated and analyzed with Bland-Altman, Pearson correlation and intraclass correlation reliability. RESULTS Smaller mean percent bias range (Bland-Altman) was found for ZTE-AC than atlas-AC in all analyses (metal ZTE -0.46 to -0.02, metal atlas -3.57 to -3.26; bone ZTE -4.60 to -2.16, bone atlas -5.25 to -3.81; burr hole ZTE -0.95 to -0.52, burr hole atlas 7.86 to 8.87). Percent SD range (Bland-Altman) was large for both methods in all analyses, with lower absolute values for ZTE-AC (ZTE 7.02-8.49; atlas 11.47-14.83). A very strong correlation (Pearson correlation) was demonstrated for both methods compared to CT-AC (ZTE ρ 0.97-0.99, P<0.001; atlas ρ 0.88-0.91, P≤0.009) with higher absolute values for ZTE. An excellent intraclass correlation coefficient was found across all analyses for ZTE, atlas and CT maps (ICC ≥0.88). CONCLUSIONS ZTE for MR-driven PET attenuation correction presented a more comparable performance to reference standard CT-AC at the postoperative site. ZTE-AC may serve as a useful diagnostic tool for MR-driven AC in patients with surgically treated brain tumors.
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Affiliation(s)
- Francesca DE Luca
- Department of Clinical Neuroscience, Karolinska Institute, Solna, Sweden -
- Department of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden -
| | - Martin Bolin
- Department of Clinical Neuroscience, Karolinska Institute, Solna, Sweden
- Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Lennart Blomqvist
- Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden
- Department of Molecular Medicine and Surgery Karolinska Institute, Solna, Sweden
| | - Cecilia Wassberg
- Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Heather Martin
- Department of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden
| | - Anna Falk Delgado
- Department of Clinical Neuroscience, Karolinska Institute, Solna, Sweden
- Department of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden
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Gillett D, MacFarlane J, Bashari W, Crawford R, Harper I, Mendichovszky IA, Aloj L, Cheow H, Gurnell M. Molecular Imaging of Pituitary Tumors. Semin Nucl Med 2023; 53:530-538. [PMID: 36966020 DOI: 10.1053/j.semnuclmed.2023.02.005] [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: 02/03/2023] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 03/27/2023]
Abstract
Tumors of the pituitary gland, although mostly benign adenomas, are a cause of significant morbidity and even excess mortality due to local compressive effects (eg visual loss, hypopituitarism) and unregulated hormone secretion (eg acromegaly or Cushing Disease). Surgery, radiotherapy, and medical management (sometimes in combination) may be needed to mitigate the effects of tumor expansion and endocrine dysfunction. Magnetic resonance imaging (MRI) plays a central role in treatment planning for most patients. However, it does not always reliably identify the site(s) of primary or recurrent disease, especially where post-treatment remodeling results in indeterminate anatomical appearances. In these contexts, molecular imaging is a potential game-changer, allowing precise localization of sites of active disease and enabling safe and effective targeted intervention when patients would otherwise be consigned to expensive life-long medication. For pituitary and parasellar imaging, PET is the preferred modality due to its superior spatial resolution and sensitivity compared with SPECT, and an array of PET radioligands have been studied in different pituitary adenoma (PA) subtypes. While 18F-fluorodeoxyglucose (18F-FDG) is widely available, significant heterogeneity in tumoral uptake has limited its use. Instead, ligands targeting specific molecular pathways relevant to PA biology (eg somatostatin or dopamine receptor expression, amino acid uptake) are increasingly preferred and are beginning to find application in routine clinical practice. In addition, novel approaches to distinguish adenomatous tissue from normal gland (eg through comparison of images obtained with different radiotracers) and increase confidence that a suspected abnormal focus is indeed pathological (eg through subtraction imaging) have been proposed. It is likely therefore that molecular imaging will continue to find increasing application in the management of pituitary tumors just as it already does in other endocrine disorders.
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Affiliation(s)
- Daniel Gillett
- Department of Nuclear Medicine, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK; Cambridge Endocrine Molecular Imaging Group, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK.
| | - James MacFarlane
- Cambridge Endocrine Molecular Imaging Group, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK
| | - Waiel Bashari
- Cambridge Endocrine Molecular Imaging Group, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK
| | - Rosy Crawford
- Department of Nuclear Medicine, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK
| | - Ines Harper
- Department of Nuclear Medicine, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK
| | - Iosif A Mendichovszky
- Department of Nuclear Medicine, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK; Department of Radiology, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK
| | - Luigi Aloj
- Department of Nuclear Medicine, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK; Department of Radiology, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK
| | - Heok Cheow
- Department of Nuclear Medicine, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK
| | - Mark Gurnell
- Cambridge Endocrine Molecular Imaging Group, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK; Metabolic Research Laboratories, Wellcome-MRC Institute of Metabolic Science, University of Cambridge, and National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK.
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Inoue A, Watanabe H, Suehiro S, Nishida N, Shiraishi Y, Furumochi T, Takimoto Y, Ohnishi T, Shigekawa S, Kunieda T. Clinical utility of new bone imaging using zero-echo-time sequence in neurosurgical procedures: Can zero-echo-time be used in clinical practice in neurosurgery? Neuroradiol J 2023; 36:289-296. [PMID: 37259240 PMCID: PMC10268098 DOI: 10.1177/19714009221114447] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2024] Open
Abstract
PURPOSE The purpose of this study was to evaluate the clinical usefulness of zero-echo-time (ZTE)-based magnetic resonance imaging (MRI) in planning the optimum surgical approach and applying ZTE for anatomical guidance during transcranial surgery. METHODS Eleven of 26 patients who underwent transcranial surgery and carotid endarterectomy and in whom ZTE-based MRI and magnetic resonance angiography (MRA) data were obtained were analyzed by creating ZTE/MRA fusion images and 3D ZTE-based MRI models. We examined whether these images and models can be substituted for computed tomography imaging for neurosurgical procedures. Furthermore, the clinical usability of the 3D ZTE-based MRI models was evaluated by comparing them with actual surgical views. RESULTS Zero-echo-time/MRA fusion images and 3D ZTE-based MRI models clearly illustrated the cranial and intracranial morphology without radiation exposure or the use of iodinated contrast medium. The models allowed determination of the optimum surgical approach to cerebral aneurysms, brain tumors near the brain surface, and cervical internal carotid artery stenosis by visualizing the relationship of lesions with adjacent bone structures. However, ZTE-based MRI did not provide useful information for surgery for skull base lesions such as vestibular schwannoma because bone structures of the skull base often include air components, which cause signal disturbance in MRI. CONCLUSIONS Zero-echo-time sequences on MRI allowed distinct visualization of not only bone but also vital structures around the lesion. This technology has low invasiveness for patients and was useful for preoperative planning and guidance of the optimum approach during surgery in a subset of neurosurgical diseases.
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Affiliation(s)
- Akihiro Inoue
- Department of Neurosurgery, Ehime University School of
Medicine, Japan
| | - Hideaki Watanabe
- Department of Neurosurgery, Ehime University School of
Medicine, Japan
| | - Satoshi Suehiro
- Department of Neurosurgery, Ehime University School of
Medicine, Japan
| | - Naoya Nishida
- Department of Otolaryngology, Ehime University School of
Medicine, Japan
| | | | | | | | | | - Seiji Shigekawa
- Department of Neurosurgery, Ehime University School of
Medicine, Japan
| | - Takeharu Kunieda
- Department of Neurosurgery, Ehime University School of
Medicine, Japan
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Jungmann PM, Lange T, Wenning M, Baumann FA, Bamberg F, Jung M. Ankle Sprains in Athletes: Current Epidemiological, Clinical and Imaging Trends. Open Access J Sports Med 2023; 14:29-46. [PMID: 37252646 PMCID: PMC10216848 DOI: 10.2147/oajsm.s397634] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 05/06/2023] [Indexed: 05/31/2023] Open
Abstract
Purpose Ankle injuries are frequent sports injuries. Despite optimizing treatment strategies during recent years, the percentage of chronification following an ankle sprain remains high. The purpose of this review article is, to highlight current epidemiological, clinical and novel advanced cross-sectional imaging trends that may help to evaluate ankle sprain injuries. Methods Systematic PubMed literature research. Identification and review of studies (i) analyzing and describing ankle sprain and (ii) focusing on advanced cross-sectional imaging techniques at the ankle. Results The ankle is one of the most frequently injured body parts in sports. During the COVID-19 pandemic, there was a change in sporting behavior and sports injuries. Ankle sprains account for about 16-40% of the sports-related injuries. Novel cross-sectional imaging techniques, including Compressed Sensing MRI, 3D MRI, ankle MRI with traction or plantarflexion-supination, quantitative MRI, CT-like MRI, CT arthrography, weight-bearing cone beam CT, dual-energy CT, photon-counting CT, and projection-based metal artifact reduction CT may be introduced for detection and evaluation of specific pathologies after ankle injury. While simple ankle sprains are generally treated conservatively, unstable syndesmotic injuries may undergo stabilization using suture-button-fixation. Minced cartilage implantation is a novel cartilage repair technique for osteochondral defects at the ankle. Conclusion Applications and advantages of different cross-sectional imaging techniques at the ankle are highlighted. In a personalized approach, optimal imaging techniques may be chosen that best detect and delineate structural ankle injuries in athletes.
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Affiliation(s)
- Pia M Jungmann
- Department of Diagnostic and Interventional Radiology, Medical Center–University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Radiology, Kantonsspital Graubünden, Chur, Switzerland
| | - Thomas Lange
- Department of Radiology, Medical Physics, Medical Center – University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Markus Wenning
- Department of Orthopedic and Trauma Surgery, Medical Center – University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Frédéric A Baumann
- Department of Vascular Medicine, Hospital of Schiers, Schiers, Switzerland
| | - Fabian Bamberg
- Department of Diagnostic and Interventional Radiology, Medical Center–University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Matthias Jung
- Department of Diagnostic and Interventional Radiology, Medical Center–University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Wyatt JJ, Kaushik S, Cozzini C, Pearson RA, Petit S, Capala M, Hernandez-Tamames JA, Hideghéty K, Maxwell RJ, Wiesinger F, McCallum HM. Comprehensive dose evaluation of a Deep Learning based synthetic Computed Tomography algorithm for pelvic Magnetic Resonance-only radiotherapy. Radiother Oncol 2023; 184:109692. [PMID: 37150446 DOI: 10.1016/j.radonc.2023.109692] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 04/19/2023] [Accepted: 04/24/2023] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND PURPOSE Magnetic Resonance (MR)-only radiotherapy enables the use of MR without the uncertainty of MR-Computed Tomography (CT) registration. This requires a synthetic CT (sCT) for dose calculations, which can be facilitated by a novel Zero Echo Time (ZTE) sequence where bones are visible and images are acquired in 65 seconds. This study evaluated the dose calculation accuracy for pelvic sites of a ZTE-based Deep Learning sCT algorithm developed by GE Healthcare. MATERIALS AND METHODS ZTE and CT images were acquired in 56 pelvic radiotherapy patients in the radiotherapy position. A 2D U-net convolutional neural network was trained using pairs of deformably registered CT and ZTE images from 36 patients. In the remaining 20 patients the dosimetric accuracy of the sCT was assessed using cylindrical dummy Planning Target Volumes (PTVs) positioned at four different central axial locations, as well as the clinical treatment plans (for prostate (n=10), rectum (n=4) and anus (n=6) cancers). The sCT was rigidly and deformably registered, the plan recalculated and the doses compared using mean differences and gamma analysis. RESULTS Mean dose differences to the PTV D98% were ≤ 0.5% for all dummy PTVs and clinical plans (rigid registration). Mean gamma pass rates at 1%/1 mm were 98.0 ± 0.4% (rigid) and 100.0 ± 0.0% (deformable), 96.5 ± 0.8% and 99.8 ± 0.1%, and 95.4 ± 0.6% and 99.4 ± 0.4% for the clinical prostate, rectum and anus plans respectively. CONCLUSIONS A ZTE-based sCT algorithm with high dose accuracy throughout the pelvis has been developed. This suggests the algorithm is sufficiently accurate for MR-only radiotherapy for all pelvic sites.
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Affiliation(s)
- Jonathan J Wyatt
- Translational and Clinical Research Institute, Newcastle University, Newcastle, UK; Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - Sandeep Kaushik
- GE Healthcare, Munich, Germany; Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | | | - Rachel A Pearson
- Translational and Clinical Research Institute, Newcastle University, Newcastle, UK; Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - Steven Petit
- Department of Radiotherapy, Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | - Marta Capala
- Department of Radiotherapy, Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | | | | | - Ross J Maxwell
- Translational and Clinical Research Institute, Newcastle University, Newcastle, UK
| | | | - Hazel M McCallum
- Translational and Clinical Research Institute, Newcastle University, Newcastle, UK; Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
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Baba A, Kurokawa R, Kurokawa M, Reifeiss S, Policeni BA, Ota Y, Srinivasan A. Advanced imaging of head and neck infections. J Neuroimaging 2023. [PMID: 36922159 DOI: 10.1111/jon.13099] [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: 12/29/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/17/2023] Open
Abstract
When head and neck infection is suspected, appropriate imaging contributes to treatment decisions and prognosis. While contrast-enhanced CT is the standard imaging modality for evaluating head and neck infections, MRI can better characterize the skull base, intracranial involvement, and osteomyelitis, implying that these are complementary techniques for a comprehensive assessment. Both CT and MRI are useful in the evaluation of abscesses and thrombophlebitis, while MRI is especially useful in the evaluation of intracranial inflammatory spread/abscess formation, differentiation of abscess from other conditions, evaluation of the presence and activity of inflammation and osteomyelitis, evaluation of mastoid extension in middle ear cholesteatoma, and evaluation of facial neuritis and labyrinthitis. Apparent diffusion coefficient derived from diffusion-weighted imaging is useful for differential diagnosis and treatment response of head and neck infections in various anatomical sites. Dynamic contrast-enhanced MRI perfusion may be useful in assessing the activity of skull base osteomyelitis. MR bone imaging may be of additional value in evaluating bony structures of the skull base and jaw. Dual-energy CT is helpful in reducing metal artifacts, evaluating deep neck abscess, and detecting salivary stones. Subtraction CT techniques are used to detect progressive bone-destructive changes and to reduce dental amalgam artifacts. This article provides a region-based approach to the imaging evaluation of head and neck infections, using both conventional and advanced imaging techniques.
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Affiliation(s)
- Akira Baba
- Division of Neuroradiology, Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Ryo Kurokawa
- Division of Neuroradiology, Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Mariko Kurokawa
- Division of Neuroradiology, Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Scott Reifeiss
- Department of Radiology, Roy Caver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Bruno A Policeni
- Department of Radiology, Roy Caver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Yoshiaki Ota
- Division of Neuroradiology, Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Ashok Srinivasan
- Division of Neuroradiology, Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
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Zhang J, Treyer V, Sun J, Zhang C, Gietl A, Hock C, Razansky D, Nitsch RM, Ni R. Automatic analysis of skull thickness, scalp-to-cortex distance and association with age and sex in cognitively normal elderly. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.19.524484. [PMID: 36711717 PMCID: PMC9882276 DOI: 10.1101/2023.01.19.524484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Personalized neurostimulation has been a potential treatment for many brain diseases, which requires insights into brain/skull geometry. Here, we developed an open source efficient pipeline BrainCalculator for automatically computing the skull thickness map, scalp-to-cortex distance (SCD), and brain volume based on T 1 -weighted magnetic resonance imaging (MRI) data. We examined the influence of age and sex cross-sectionally in 407 cognitively normal older adults (71.9±8.0 years, 60.2% female) from the ADNI. We demonstrated the compatibility of our pipeline with commonly used preprocessing packages and found that BrainSuite Skullfinder was better suited for such automatic analysis compared to FSL Brain Extraction Tool 2 and SPM12- based unified segmentation using ground truth. We found that the sphenoid bone and temporal bone were thinnest among the skull regions in both females and males. There was no increase in regional minimum skull thickness with age except in the female sphenoid bone. No sex difference in minimum skull thickness or SCD was observed. Positive correlations between age and SCD were observed, faster in females (0.307%/y) than males (0.216%/y) in temporal SCD. A negative correlation was observed between age and whole brain volume computed based on brain surface (females -1.031%/y, males -0.998%/y). In conclusion, we developed an automatic pipeline for MR-based skull thickness map, SCD, and brain volume analysis and demonstrated the sex-dependent association between minimum regional skull thickness, SCD and brain volume with age. This pipeline might be useful for personalized neurostimulation planning.
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Affiliation(s)
- Junhao Zhang
- Institute for Regenerative Medicine, University of Zurich, 8952 Zurich, Switzerland
- Institute for Biomedical Engineering, ETH Zurich & University of Zurich, 8093 Zurich, Switzerland
| | - Valerie Treyer
- Institute for Regenerative Medicine, University of Zurich, 8952 Zurich, Switzerland
- Department of Nuclear Medicine, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Junfeng Sun
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Chencheng Zhang
- Department of Neurosurgery, Center for Functional Neurosurgery, Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Anton Gietl
- Institute for Regenerative Medicine, University of Zurich, 8952 Zurich, Switzerland
| | - Christoph Hock
- Institute for Regenerative Medicine, University of Zurich, 8952 Zurich, Switzerland
- Neurimmune, Schlieren, Switzerland
| | - Daniel Razansky
- Institute for Biomedical Engineering, ETH Zurich & University of Zurich, 8093 Zurich, Switzerland
| | - Roger M Nitsch
- Institute for Regenerative Medicine, University of Zurich, 8952 Zurich, Switzerland
- Neurimmune, Schlieren, Switzerland
| | - Ruiqing Ni
- Institute for Regenerative Medicine, University of Zurich, 8952 Zurich, Switzerland
- Institute for Biomedical Engineering, ETH Zurich & University of Zurich, 8093 Zurich, Switzerland
- Zentrum für Neurowissenschaften Zurich, Zurich, Switzerland
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Ladefoged CN, Andersen FL, Andersen TL, Anderberg L, Engkebølle C, Madsen K, Højgaard L, Henriksen OM, Law I. DeepDixon synthetic CT for [ 18F]FET PET/MRI attenuation correction of post-surgery glioma patients with metal implants. Front Neurosci 2023; 17:1142383. [PMID: 37090806 PMCID: PMC10115992 DOI: 10.3389/fnins.2023.1142383] [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: 01/11/2023] [Accepted: 03/08/2023] [Indexed: 04/25/2023] Open
Abstract
Purpose Conventional magnetic resonance imaging (MRI) can for glioma assessment be supplemented by positron emission tomography (PET) imaging with radiolabeled amino acids such as O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET), which provides additional information on metabolic properties. In neuro-oncology, patients often undergo brain and skull altering treatment, which is known to challenge MRI-based attenuation correction (MR-AC) methods and thereby impact the simplified semi-quantitative measures such as tumor-to-brain ratio (TBR) used in clinical routine. The aim of the present study was to examine the applicability of our deep learning method, DeepDixon, for MR-AC in [18F]FET PET/MRI scans of a post-surgery glioma cohort with metal implants. Methods The MR-AC maps were assessed for all 194 included post-surgery glioma patients (318 studies). The subgroup of 147 patients (222 studies, 200 MBq [18F]FET PET/MRI) with tracer uptake above 1 ml were subsequently reconstructed with DeepDixon, vendor-default atlas-based method, and a low-dose computed tomography (CT) used as reference. The biological tumor volume (BTV) was delineated on each patient by isocontouring tracer uptake above a TBR threshold of 1.6. We evaluated the MR-AC methods using the recommended clinical metrics BTV and mean and maximum TBR on a patient-by-patient basis against the reference with CT-AC. Results Ninety-seven percent of the studies (310/318) did not have any major artifacts using DeepDixon, which resulted in a Dice coefficient of 0.89/0.83 for tissue/bone, respectively, compared to 0.84/0.57 when using atlas. The average difference between DeepDixon and CT-AC was within 0.2% across all clinical metrics, and no statistically significant difference was found. When using DeepDixon, only 3 out of 222 studies (1%) exceeded our acceptance criteria compared to 72 of the 222 studies (32%) with the atlas method. Conclusion We evaluated the performance of a state-of-the-art MR-AC method on the largest post-surgical glioma patient cohort to date. We found that DeepDixon could overcome most of the issues arising from irregular anatomy and metal artifacts present in the cohort resulting in clinical metrics within acceptable limits of the reference CT-AC in almost all cases. This is a significant improvement over the vendor-provided atlas method and of particular importance in response assessment.
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Miscouridou M, Pineda-Pardo JA, Stagg CJ, Treeby BE, Stanziola A. Classical and Learned MR to Pseudo-CT Mappings for Accurate Transcranial Ultrasound Simulation. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:2896-2905. [PMID: 35984788 DOI: 10.1109/tuffc.2022.3198522] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Model-based treatment planning for transcranial ultrasound therapy typically involves mapping the acoustic properties of the skull from an X-ray computed tomography (CT) image of the head. Here, three methods for generating pseudo-CT (pCT) images from magnetic resonance (MR) images were compared as an alternative to CT. A convolutional neural network (U-Net) was trained on paired MR-CT images to generate pCT T images from either T1-weighted or zero-echo time (ZTE) MR images (denoted tCT and zCT, respectively). A direct mapping from ZTE to pCT was also implemented (denoted cCT). When comparing the pCT and ground-truth CT images for the test set, the mean absolute error was 133, 83, and 145 Hounsfield units (HU) across the whole head, and 398, 222, and 336 HU within the skull for the tCT, zCT, and cCT images, respectively. Ultrasound simulations were also performed using the generated pCT images and compared to simulations based on CT. An annular array transducer was used targeting the visual or motor cortex. The mean differences in the simulated focal pressure, focal position, and focal volume were 9.9%, 1.5 mm, and 15.1% for simulations based on the tCT images; 5.7%, 0.6 mm, and 5.7% for the zCT; and 6.7%, 0.9 mm, and 12.1% for the cCT. The improved results for images mapped from ZTE highlight the advantage of using imaging sequences, which improves the contrast of the skull bone. Overall, these results demonstrate that acoustic simulations based on MR images can give comparable accuracy to those based on CT.
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Webb TD, Fu F, Leung SA, Ghanouni P, Dahl JJ, Does MD, Pauly KB. Improving Transcranial Acoustic Targeting: The Limits of CT-Based Velocity Estimates and the Role of MR. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:2630-2637. [PMID: 35853046 PMCID: PMC9519088 DOI: 10.1109/tuffc.2022.3192224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Transcranial magnetic resonance-guided focused ultrasound (tcMRgFUS) enables the noninvasive treatment of the deep brain. This capacity relies on the ability to focus acoustic energy through the in-tact skull, a feat that requires accurate estimates of the acoustic velocity in individual patient skulls. In current practice, these estimates are generated using a pretreatment computed tomography (CT) scan and then registered to a magnetic resonance (MR) dataset on the day of the treatment. Treatment safety and efficacy can be improved by eliminating the need to register the CT data to the MR images and by improving the accuracy of acoustic velocity measurements. In this study, we examine the capacity of MR to supplement or replace CT as a means of estimating velocity in the skull. We find that MR can predict velocity with less but comparable accuracy to CT. We then use micro-CT imaging to better understand the limitations of Hounsfield unit (HU)-based estimates of velocity, demonstrating that the macrostructure of pores in the skull contributes to the acoustic velocity of the bone. We find evidence that detailed T2 measurements provide information about pore macrostructure similar to the information obtained with micro-CT, offering a potential clinical mechanism for improving patient-specific estimates of acoustic velocity in the human skull.
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Comparison between MR and CT imaging used to correct for skull-induced phase aberrations during transcranial focused ultrasound. Sci Rep 2022; 12:13407. [PMID: 35927449 PMCID: PMC9352781 DOI: 10.1038/s41598-022-17319-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 07/25/2022] [Indexed: 11/08/2022] Open
Abstract
Transcranial focused ultrasound with the InSightec Exablate system uses thermal ablation for the treatment of movement and mood disorders and blood brain barrier disruption for tumor therapy. The system uses computed tomography (CT) images to calculate phase corrections that account for aberrations caused by the human skull. This work investigates whether magnetic resonance (MR) images can be used as an alternative to CT images to calculate phase corrections. Phase corrections were calculated using the gold standard hydrophone method and the standard of care InSightec ray tracing method. MR binary image mask, MR-simulated-CT (MRsimCT), and CT images of three ex vivo human skulls were supplied as inputs to the InSightec ray tracing method. The degassed ex vivo human skulls were sonicated with a 670 kHz hemispherical phased array transducer (InSightec Exablate 4000). 3D raster scans of the beam profiles were acquired using a hydrophone mounted on a 3-axis positioner system. Focal spots were evaluated using six metrics: pressure at the target, peak pressure, intensity at the target, peak intensity, positioning error, and focal spot volume. Targets at the geometric focus and 5 mm lateral to the geometric focus were investigated. There was no statistical difference between any of the metrics at either target using either MRsimCT or CT for phase aberration correction. As opposed to the MRsimCT, the use of CT images for aberration correction requires registration to the treatment day MR images; CT misregistration within a range of ± 2 degrees of rotation error along three dimensions was shown to reduce focal spot intensity by up to 9.4%. MRsimCT images used for phase aberration correction for the skull produce similar results as CT-based correction, while avoiding both CT to MR registration errors and unnecessary patient exposure to ionizing radiation.
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Wiesinger F, Ho ML. Zero-TE MRI: principles and applications in the head and neck. Br J Radiol 2022; 95:20220059. [PMID: 35616709 PMCID: PMC10162052 DOI: 10.1259/bjr.20220059] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Zero echo-time (ZTE) MRI is a novel imaging technique that utilizes ultrafast readouts to capture signal from short-T2 tissues. Additional sequence advantages include rapid imaging times, silent scanning, and artifact resistance. A robust application of this technology is imaging of cortical bone without the use of ionizing radiation, thus representing a viable alternative to CT for both rapid screening and "one-stop-shop" MRI. Although ZTE is increasingly used in musculoskeletal and body imaging, neuroimaging applications have historically been limited by complex anatomy and pathology. In this article, we review the imaging physics of ZTE including pulse sequence options, practical limitations, and image reconstruction. We then discuss optimization of settings for ZTE bone neuroimaging including acquisition, processing, segmentation, synthetic CT generation, and artifacts. Finally, we examine clinical utility of ZTE in the head and neck with imaging examples including malformations, trauma, tumors, and interventional procedures.
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Affiliation(s)
- Florian Wiesinger
- Department for Neuroimaging, Institute of Psychiatry & Neuroscience, King's College London, London, UK.,Principal Scientist at GE Healthcare, Munich, Germany
| | - Mai-Lan Ho
- Nationwide Children's Hospital and The Ohio State University, Columbus, USA
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Chen J, Pal P, Ahrens ET. Enhanced detection of paramagnetic fluorine-19 magnetic resonance imaging agents using zero echo time sequence and compressed sensing. NMR IN BIOMEDICINE 2022; 35:e4725. [PMID: 35262991 PMCID: PMC10655826 DOI: 10.1002/nbm.4725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 02/25/2022] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Fluorine-19 (19 F) magnetic resonance imaging (MRI) is an emerging technique offering specific detection of labeled cells in vivo. Lengthy acquisition times and modest signal-to-noise ratio (SNR) makes three-dimensional spin-density-weighted 19 F imaging challenging. Recent advances in tracer paramagnetic metallo-perfluorocarbon (MPFC) nanoemulsion probes have shown multifold SNR improvements due to an accelerated 19 F T1 relaxation rate and a commensurate gain in imaging speed and averages. However, 19 F T2 -reduction and increased linewidth limit the amount of metal additive in MPFC probes, thus constraining the ultimate SNR. To overcome these barriers, we describe a compressed sampling (CS) scheme, implemented using a "zero" echo time (ZTE) sequence, with data reconstructed via a sparsity-promoting algorithm. Our CS-ZTE scheme acquires k-space data using an undersampled spherical radial pattern and signal averaging. Image reconstruction employs off-the-shelf sparse solvers to solve a joint total variation and l 1 -norm regularized least square problem. To evaluate CS-ZTE, we performed simulations and acquired 19 F MRI data at 11.7 T in phantoms and mice receiving MPFC-labeled dendritic cells. For MPFC-labeled cells in vivo, we show SNR gains of ~6.3 × with 8-fold undersampling. We show that this enhancement is due to three mechanisms including undersampling and commensurate increase in signal averaging in a fixed scan time, denoising attributes from the CS algorithm, and paramagnetic reduction of T1 . Importantly, 19 F image intensity analyses yield accurate estimates of absolute quantification of 19 F spins. Overall, the CS-ZTE method using MPFC probes achieves ultrafast imaging, a substantial boost in detection sensitivity, accurate 19 F spin quantification, and minimal image artifacts.
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Affiliation(s)
- Jiawen Chen
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, California, USA
| | - Piya Pal
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, California, USA
| | - Eric T. Ahrens
- Department of Radiology, University of California San Diego, La Jolla, California, USA
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Aydıngöz Ü, Yıldız AE, Ergen FB. Zero Echo Time Musculoskeletal MRI: Technique, Optimization, Applications, and Pitfalls. Radiographics 2022; 42:1398-1414. [PMID: 35904982 DOI: 10.1148/rg.220029] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Zero echo time (ZTE) imaging is an MRI technique that produces images similar to those obtained with radiography or CT. In ZTE MRI, the very short T2 signal from the mineralized trabecular bone matrix and especially cortical bone-both of which have a low proton density (PD)-is sampled in a unique sequence setup. Additionally, the PD weighting of the ZTE sequence results in less contrast between soft tissues. Therefore, along with gray-scale inversion from black to white and vice versa, ZTE imaging provides excellent contrast between cortical bone and soft tissues similar to that of radiography and CT. However, despite isotropic or near-isotropic three-dimensional (3D) imaging capabilities of the ZTE sequence, spatial resolution in this technique is still inferior to that of radiography and CT, and 3D volume renderings are currently time-consuming and require postprocessing software that features segmentation and manual contouring. Optimization of ZTE MRI mostly entails adjustments of bandwidth, flip angle, field of view, and image matrix. A wide range of structural abnormalities and disease or healing processes in the musculoskeletal system are well delineated with ZTE MRI, including conditions that involve bone-based morphometric analyses (which aid diagnosis, help prognostication, and guide surgery), impaction, avulsion and stress fractures, loose bodies or erosions in and around joints, soft-tissue calcifications and ossifications, and bone tumors (including treatment response). The pitfalls of ZTE imaging include mimics of foci of calcification or ossification such as intra-articular gas and susceptibility artifacts from surgical materials and hemosiderin deposition, which can be avoided in many instances by cross-referencing images obtained with other MRI sequences. Online supplemental material is available for this article. ©RSNA, 2022.
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Affiliation(s)
- Üstün Aydıngöz
- From the Department of Radiology, Hacettepe University School of Medicine, 06230 Ankara, Turkey
| | - Adalet Elçin Yıldız
- From the Department of Radiology, Hacettepe University School of Medicine, 06230 Ankara, Turkey
| | - F Bilge Ergen
- From the Department of Radiology, Hacettepe University School of Medicine, 06230 Ankara, Turkey
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Matsuo H, Nishio M, Nogami M, Zeng F, Kurimoto T, Kaushik S, Wiesinger F, Kono AK, Murakami T. Unsupervised-learning-based method for chest MRI-CT transformation using structure constrained unsupervised generative attention networks. Sci Rep 2022; 12:11090. [PMID: 35773366 PMCID: PMC9247083 DOI: 10.1038/s41598-022-14677-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 06/10/2022] [Indexed: 01/04/2023] Open
Abstract
The integrated positron emission tomography/magnetic resonance imaging (PET/MRI) scanner simultaneously acquires metabolic information via PET and morphological information using MRI. However, attenuation correction, which is necessary for quantitative PET evaluation, is difficult as it requires the generation of attenuation-correction maps from MRI, which has no direct relationship with the gamma-ray attenuation information. MRI-based bone tissue segmentation is potentially available for attenuation correction in relatively rigid and fixed organs such as the head and pelvis regions. However, this is challenging for the chest region because of respiratory and cardiac motions in the chest, its anatomically complicated structure, and the thin bone cortex. We propose a new method using unsupervised generative attentional networks with adaptive layer-instance normalisation for image-to-image translation (U-GAT-IT), which specialised in unpaired image transformation based on attention maps for image transformation. We added the modality-independent neighbourhood descriptor (MIND) to the loss of U-GAT-IT to guarantee anatomical consistency in the image transformation between different domains. Our proposed method obtained a synthesised computed tomography of the chest. Experimental results showed that our method outperforms current approaches. The study findings suggest the possibility of synthesising clinically acceptable computed tomography images from chest MRI with minimal changes in anatomical structures without human annotation.
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Affiliation(s)
- Hidetoshi Matsuo
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Mizuho Nishio
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Munenobu Nogami
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Feibi Zeng
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | | | | | | | - Atsushi K Kono
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takamichi Murakami
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
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35
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Okazawa H, Ikawa M, Tsujikawa T, Mori T, Makino A, Kiyono Y, Nakamoto Y, Kosaka H, Yoneda M. Cerebral Oxidative Stress in Early Alzheimer's Disease Evaluated by 64Cu-ATSM PET/MRI: A Preliminary Study. Antioxidants (Basel) 2022; 11:1022. [PMID: 35624886 PMCID: PMC9138060 DOI: 10.3390/antiox11051022] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/16/2022] [Accepted: 05/20/2022] [Indexed: 12/17/2022] Open
Abstract
Oxidative stress imaging using diacetyl-bis (N4-methylthiosemicarbazone) (Cu-ATSM) was applied to the evaluation of patients with early Alzheimer's disease (eAD). Ten eAD patients (72 ± 9 years) and 10 age-matched healthy controls (HCs) (73 ± 9 years) participated in this study. They underwent dynamic PET/MRI using 11C-PiB and 64Cu-ATSM with multiple MRI sequences. To evaluate cerebral oxidative stress, three parameters of 64Cu-ATSM PET were compared: standardized uptake value (SUV), tracer influx rate (Kin), and a rate constant k3. The input functions were estimated by the image-derived input function method. The relative differences were analyzed by statistical parametric mapping (SPM) using SUV and Kin images. All eAD patients had positive and HC subjects had negative PiB accumulation, and MMSE scores were significantly different between them. The 64Cu-ATSM accumulation tended to be higher in eAD than in HCs for both SUV and Kin. When comparing absolute values, eAD patients had a greater Kin in the posterior cingulate cortex and a greater k3 in the hippocampus compared with lobar cortical values of HCs. In SPM analysis, eAD had an increased left operculum and decreased bilateral hippocampus and anterior cingulate cortex compared to HCs. 64Cu-ATSM PET/MRI and tracer kinetic analysis elucidated cerebral oxidative stress in the eAD patients, particularly in the cingulate cortex and hippocampus.
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Affiliation(s)
- Hidehiko Okazawa
- Biomedical Imaging Research Center, University of Fukui, Fukui 910-1193, Japan; (M.I.); (T.T.); (T.M.); (A.M.); (Y.K.); (M.Y.)
| | - Masamichi Ikawa
- Biomedical Imaging Research Center, University of Fukui, Fukui 910-1193, Japan; (M.I.); (T.T.); (T.M.); (A.M.); (Y.K.); (M.Y.)
- Second Department of Internal Medicine, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan;
| | - Tetsuya Tsujikawa
- Biomedical Imaging Research Center, University of Fukui, Fukui 910-1193, Japan; (M.I.); (T.T.); (T.M.); (A.M.); (Y.K.); (M.Y.)
| | - Tetsuya Mori
- Biomedical Imaging Research Center, University of Fukui, Fukui 910-1193, Japan; (M.I.); (T.T.); (T.M.); (A.M.); (Y.K.); (M.Y.)
| | - Akira Makino
- Biomedical Imaging Research Center, University of Fukui, Fukui 910-1193, Japan; (M.I.); (T.T.); (T.M.); (A.M.); (Y.K.); (M.Y.)
| | - Yasushi Kiyono
- Biomedical Imaging Research Center, University of Fukui, Fukui 910-1193, Japan; (M.I.); (T.T.); (T.M.); (A.M.); (Y.K.); (M.Y.)
| | - Yasunari Nakamoto
- Second Department of Internal Medicine, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan;
| | - Hirotaka Kosaka
- Department of Neuropsychiatry, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan;
| | - Makoto Yoneda
- Biomedical Imaging Research Center, University of Fukui, Fukui 910-1193, Japan; (M.I.); (T.T.); (T.M.); (A.M.); (Y.K.); (M.Y.)
- Faculty of Nursing and Social Welfare Science, Fukui Prefectural University, Fukui 910-1195, Japan
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Preliminary experience with black bone magnetic resonance imaging for morphometry of the mandible and visualisation of the facial skeleton. Pediatr Radiol 2022; 52:951-958. [PMID: 35076727 DOI: 10.1007/s00247-021-05257-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 09/21/2021] [Accepted: 11/30/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND Children with orofacial deformity may require repeated imaging of the facial skeleton. OBJECTIVE To test the feasibility and accuracy of "black bone" magnetic resonance imaging (MRI) for assessing facial deformity in children. MATERIALS AND METHODS Three-dimensional (3-D) black bone gradient echo sequences (flip angle 5°, submillimetre spatial resolution) from 10 children (median age: 13 years, range: 2-16 years), who underwent MRI of the temporomandibular joints, were evaluated with multiplanar reconstruction and 3-D rendering tools. Intra- and inter-reader agreement was investigated for measuring the height of the mandibular ramus and condyle, basal length of the mandible, gonion angle and mandibular inclination angle by intraclass correlation coefficient (ICC) and Bland-Altman analysis. Absolute percentage error was calculated with the average of all measurements serving as reference. RESULTS Sixty linear and 40 angle measurements were obtained on reformatted multiplanar black bone images with excellent inter-reader agreement (ICC > 0.99, agreement bias < 1.4 mm/ < 1.5°) and small error (median absolute error < 3%). The black bone images required inversion of the signal intensity and removal of air before they could be processed with standard volume rendering tools. The diagnostic utility of 3-D views for assessing the facial skeleton was sufficient except for assessing dental relationship. CONCLUSION Morphometric measurements of the mandible can be obtained from black bone MRI with comparable inter-rater agreement to that reported for cone beam computed tomography (CT). With improvements of 3-D rendering techniques and software, black bone MRI may become a radiation-free alternative to CT in children with facial deformities.
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Eley KA, Delso G. Imaging of Bone in the Head and Neck Region, is There More Than CT? CURRENT RADIOLOGY REPORTS 2022; 10:69-82. [PMID: 35463479 PMCID: PMC9013214 DOI: 10.1007/s40134-022-00396-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2022] [Indexed: 01/22/2023]
Abstract
Purpose of Review The objective of this review is to document the advances in non-ionising imaging alternatives to CT for the head and neck. Recent Findings The main alternative to CT for imaging bone of the head and neck region is MRI, particularly techniques which incorporate gradient echo imaging (Black Bone technique) and ultra-short or zero-echo time imaging. Since these techniques can provide high resolution isometric voxels, they can be used to provide multi-planar reformats and, following post processing, 3D reconstructed images of the craniofacial skeleton. As expected, the greatest advancements in recent years have been focused on enhanced image processing techniques and attempts to address the difficulties encountered at air-bone interfaces. Summary This article will review the imaging techniques and recent advancements which are bringing non-ionising alternatives to CT imaging of the bone of the head and neck region into the realm of routine clinical application.
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Affiliation(s)
- Karen A. Eley
- Department of Radiology, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Box 218, Cambridge, CB2 0QQ UK
| | - Gaspar Delso
- MR Applications & Workflow, GE Healthcare, Barcelona, Spain
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Ljungberg E, Wood TC, Solana AB, Williams SCR, Barker GJ, Wiesinger F. Motion corrected silent ZTE neuroimaging. Magn Reson Med 2022; 88:195-210. [PMID: 35381110 PMCID: PMC9321117 DOI: 10.1002/mrm.29201] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 01/16/2022] [Accepted: 01/28/2022] [Indexed: 11/11/2022]
Abstract
Purpose To develop self‐navigated motion correction for 3D silent zero echo time (ZTE) based neuroimaging and characterize its performance for different types of head motion. Methods The proposed method termed MERLIN (Motion Estimation & Retrospective correction Leveraging Interleaved Navigators) achieves self‐navigation by using interleaved 3D phyllotaxis k‐space sampling. Low resolution navigator images are reconstructed continuously throughout the ZTE acquisition using a sliding window and co‐registered in image space relative to a fixed reference position. Rigid body motion corrections are then applied retrospectively to the k‐space trajectory and raw data and reconstructed into a final, high‐resolution ZTE image. Results MERLIN demonstrated successful and consistent motion correction for magnetization prepared ZTE images for a range of different instructed motion paradigms. The acoustic noise response of the self‐navigated phyllotaxis trajectory was found to be only slightly above ambient noise levels (<4 dBA). Conclusion Silent ZTE imaging combined with MERLIN addresses two major challenges intrinsic to MRI (i.e., subject motion and acoustic noise) in a synergistic and integrated manner without increase in scan time and thereby forms a versatile and powerful framework for clinical and research MR neuroimaging applications.
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Affiliation(s)
- Emil Ljungberg
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.,Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Tobias C Wood
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | | | - Steven C R Williams
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Gareth J Barker
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Florian Wiesinger
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.,GE Healthcare, Munich, Germany
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Composite attenuation correction method using a 68Ge-transmission multi-atlas for quantitative brain PET/MR. Phys Med 2022; 97:36-43. [PMID: 35339864 DOI: 10.1016/j.ejmp.2022.03.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 02/18/2022] [Accepted: 03/14/2022] [Indexed: 01/06/2023] Open
Abstract
In positron emission tomography (PET), 68Ge-transmission scanning is considered the gold standard in attenuation correction (AC) though not available in current dual imaging systems. In this experimental study we evaluated a novel AC method for PET/magnetic resonance (MR) imaging which is essentially based on a composite database of multiple 68Ge-transmission maps and T1-weighted (T1w) MR image-pairs (composite transmission, CTR-AC). This proof-of-concept study used retrospectively a database with 125 pairs of co-registered 68Ge-AC maps and T1w MR images from anatomical normal subjects and a validation dataset comprising dynamic [11C]PE2I PET data from nine patients with Parkinsonism. CTR-AC maps were generated by non-rigid image registration of all database T1w MRI to each subject's T1w, applying the same transformation to every 68Ge-AC map, and averaging the resulting 68Ge-AC maps. [11C]PE2I PET images were reconstructed using CTR-AC and a patient-specific 68Ge-AC map as the reference standard. Standardized uptake values (SUV) and quantitative parameters of kinetic analysis were compared, i.e., relative delivery (R1) and non-displaceable binding potential (BPND). CTR-AC showed high accuracy for whole-brain SUV (mean %bias ± SD: 0.5 ± 3.5%), whole-brain R1 (-0.1 ± 3.2%), and putamen BPND (3.7 ± 8.1%). SUV and R1 precision (SD of %bias) were modest and lowest in the anterior cortex, with an R1 %bias of -1.1 ± 6.4%). The prototype CTR-AC is capable of providing accurate MRAC-maps with continuous linear attenuation coefficients though still experimental. The method's accuracy is comparable to the best MRAC methods published so far, both in SUV and as found for ZTE-AC in quantitative parameters of kinetic modelling.
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40
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Epelbaum S, Burgos N, Canney M, Matthews D, Houot M, Santin MD, Desseaux C, Bouchoux G, Stroer S, Martin C, Habert MO, Levy M, Bah A, Martin K, Delatour B, Riche M, Dubois B, Belin L, Carpentier A. Pilot study of repeated blood-brain barrier disruption in patients with mild Alzheimer's disease with an implantable ultrasound device. Alzheimers Res Ther 2022; 14:40. [PMID: 35260178 PMCID: PMC8905724 DOI: 10.1186/s13195-022-00981-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/22/2022] [Indexed: 12/11/2022]
Abstract
Background Temporary disruption of the blood-brain barrier (BBB) using pulsed ultrasound leads to the clearance of both amyloid and tau from the brain, increased neurogenesis, and mitigation of cognitive decline in pre-clinical models of Alzheimer’s disease (AD) while also increasing BBB penetration of therapeutic antibodies. The goal of this pilot clinical trial was to investigate the safety and efficacy of this approach in patients with mild AD using an implantable ultrasound device. Methods An implantable, 1-MHz ultrasound device (SonoCloud-1) was implanted under local anesthesia in the skull (extradural) of 10 mild AD patients to target the left supra-marginal gyrus. Over 3.5 months, seven ultrasound sessions in combination with intravenous infusion of microbubbles were performed twice per month to temporarily disrupt the BBB. 18F-florbetapir and 18F-fluorodeoxyglucose positron emission tomography (PET) imaging were performed on a combined PET/MRI scanner at inclusion and at 4 and 8 months after the initiation of sonications to monitor the brain metabolism and amyloid levels along with cognitive evaluations. The evolution of cognitive and neuroimaging features was compared to that of a matched sample of control participants taken from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Results A total of 63 BBB opening procedures were performed in nine subjects. The procedure was well-tolerated. A non-significant decrease in amyloid accumulation at 4 months of − 6.6% (SD = 7.2%) on 18F-florbetapir PET imaging in the sonicated gray matter targeted by the ultrasound transducer was observed compared to baseline in six subjects that completed treatments and who had evaluable imaging scans. No differences in the longitudinal change in the glucose metabolism were observed compared to the neighboring or contralateral regions or to the change observed in the same region in ADNI participants. No significant effect on cognition evolution was observed in comparison with the ADNI participants as expected due to the small sample size and duration of the trial. Conclusions These results demonstrate the safety of ultrasound-based BBB disruption and the potential of this technology to be used as a therapy for AD patients. Research of this technique in a larger clinical trial with a device designed to sonicate larger volumes of tissue and in combination with disease-modifying drugs may further enhance the effects observed. Trial registration ClinicalTrials.gov, NCT03119961 Supplementary Information The online version contains supplementary material available at 10.1186/s13195-022-00981-1.
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Affiliation(s)
- Stéphane Epelbaum
- Sorbonne Université, Paris, France.,Institut du Cerveau - Paris Brain Institute - ICM, Paris, France.,Inserm, Paris, France.,CNRS, Paris, France.,Department of Neurology, Institute of Memory and Alzheimer's Disease (IM2A), Pitié-Salpêtrière Hospital, AP-HP, Paris, France.,Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | - Ninon Burgos
- Sorbonne Université, Paris, France.,Institut du Cerveau - Paris Brain Institute - ICM, Paris, France.,Inserm, Paris, France.,CNRS, Paris, France.,Pitié-Salpêtrière Hospital, AP-HP, Paris, France.,Aramis Project-Team, Inria-APHP Collaboration, Inria, Paris, France
| | | | | | - Marion Houot
- Sorbonne Université, Paris, France.,Institut du Cerveau - Paris Brain Institute - ICM, Paris, France.,Inserm, Paris, France.,CNRS, Paris, France.,Department of Neurology, Institute of Memory and Alzheimer's Disease (IM2A), Pitié-Salpêtrière Hospital, AP-HP, Paris, France.,Centre of Excellence of Neurodegenerative Disease (CoEN), Pitié-Salpêtrière Hospital, AP-HP, Paris, France.,Clinical Investigation Centre, Institut du Cerveau - Paris Brain Institute - ICM, Paris, France
| | - Mathieu D Santin
- Sorbonne Université, Paris, France.,Institut du Cerveau - Paris Brain Institute - ICM, Paris, France.,Inserm, Paris, France.,CNRS, Paris, France.,Pitié-Salpêtrière Hospital, AP-HP, Paris, France.,Center for NeuroImaging Research (CENIR), Institut du Cerveau - Paris Brain Institute - ICM, Paris, France
| | | | | | - Sebastian Stroer
- Department of Neuroradiology, Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | | | - Marie-Odile Habert
- Department of Nuclear Medicine, Pitié-Salpêtrière Hospital, AP-HP, Paris, France.,Laboratoire d'Imagerie Biomédicale, Sorbonne Université, Inserm U 1146, CNRS UMR 7371, Pitié-Salpêtrière Hospital, Paris, France.,Centre Acquisition et Traitement des Images, Pitié-Salpêtrière Hospital, Paris, France
| | - Marcel Levy
- Department of Neurology, Institute of Memory and Alzheimer's Disease (IM2A), Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | - Aicha Bah
- Clinical Research Unit, Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | - Karine Martin
- Clinical Research Unit, Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | - Benoît Delatour
- Sorbonne Université, Paris, France.,Institut du Cerveau - Paris Brain Institute - ICM, Paris, France.,Inserm, Paris, France.,CNRS, Paris, France.,Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | - Maximilien Riche
- Sorbonne Université, Paris, France.,Institut du Cerveau - Paris Brain Institute - ICM, Paris, France.,Inserm, Paris, France.,CNRS, Paris, France.,Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | - Bruno Dubois
- Sorbonne Université, Paris, France.,Institut du Cerveau - Paris Brain Institute - ICM, Paris, France.,Inserm, Paris, France.,CNRS, Paris, France.,Department of Neurology, Institute of Memory and Alzheimer's Disease (IM2A), Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | - Lisa Belin
- Sorbonne Université, Paris, France.,Department of Biostatistics, Public Health and Medical Informatics, Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | - Alexandre Carpentier
- Sorbonne Université, Paris, France. .,Department of Neurosurgery, Pitié-Salpêtrière Hospital, AP-HP, Paris, France.
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van den Wyngaert T, de Schepper S, Elvas F, Seyedinia SS, Beheshti M. Positron emission tomography-magnetic resonance imaging as a research tool in musculoskeletal conditions. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF... 2022; 66:15-30. [PMID: 35005878 DOI: 10.23736/s1824-4785.22.03434-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Compared to positron emission tomography/computed tomography (PET/CT), the uptake of PET- magnetic resonance imaging (MRI) has been slow, even more so in clinical practice compared to the (pre-)clinical research setting. However, for applications in musculoskeletal (MSK) research, the combination of PET and MRI into a single modality offers attractive advantages over other imaging modalities. Most importantly, MRI has exquisite soft-tissue detail without the use of contrast agents or ionizing radiation, superior bone marrow visualization, and an extensive spectrum of distinct multiparametric assessment methods. In the preclinical setting, the introduction of PET inserts for small-animal MRI machines has proven to be a successful concept in bringing this technology to the lab. Initial hurdles in quantification have been mainly overcome in this setting. In parallel, a promising range of radiochemistry techniques has been developed to create multimodality probes that offer the possibility of simultaneously querying different metabolic pathways. Not only will these applications help in elucidating disease mechanisms, but they can also facilitate drug development. The clinical applications of PET/MRI in MSK are still limited, but encouraging initial results with novel radiotracers suggest a high potential for use in various MSK conditions, including osteoarthritis, rheumatoid arthritis, ankylosing spondylitis and inflammation and infection. Further innovations will be required to bring down the cost of PET/MRI to justify a broader clinical implementation, and remaining issues with quality control and standardization also need to be addressed. Nevertheless, PET/MRI is a powerful platform for MSK research with distinct qualities that are not offered by other techniques.
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Affiliation(s)
- Tim van den Wyngaert
- Department of Nuclear Medicine, Antwerp University Hospital, Edegem, Belgium -
- Faculty of Medicine and Health Sciences (MICA), University of Antwerp, Wilrijk, Belgium -
- Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Wilrijk, Belgium -
| | - Stijn de Schepper
- Department of Nuclear Medicine, Antwerp University Hospital, Edegem, Belgium
- Faculty of Medicine and Health Sciences (MICA), University of Antwerp, Wilrijk, Belgium
| | - Filipe Elvas
- Department of Nuclear Medicine, Antwerp University Hospital, Edegem, Belgium
- Faculty of Medicine and Health Sciences (MICA), University of Antwerp, Wilrijk, Belgium
| | - Seyedeh S Seyedinia
- Division of Molecular Imaging and Theranostics, Department of Nuclear Medicine and Endocrinology, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Mohsen Beheshti
- Division of Molecular Imaging and Theranostics, Department of Nuclear Medicine and Endocrinology, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
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42
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Comparison of zero echo time MRI with T1-weighted fast spin echo for the recognition of sacroiliac joint structural lesions using CT as the reference standard. Eur Radiol 2022; 32:3963-3973. [DOI: 10.1007/s00330-021-08513-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 11/04/2021] [Accepted: 12/10/2021] [Indexed: 02/07/2023]
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43
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Florkow MC, Willemsen K, Mascarenhas VV, Oei EHG, van Stralen M, Seevinck PR. Magnetic Resonance Imaging Versus Computed Tomography for Three-Dimensional Bone Imaging of Musculoskeletal Pathologies: A Review. J Magn Reson Imaging 2022; 56:11-34. [PMID: 35044717 PMCID: PMC9305220 DOI: 10.1002/jmri.28067] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 12/31/2021] [Accepted: 01/05/2022] [Indexed: 12/18/2022] Open
Abstract
Magnetic resonance imaging (MRI) is increasingly utilized as a radiation‐free alternative to computed tomography (CT) for the diagnosis and treatment planning of musculoskeletal pathologies. MR imaging of hard tissues such as cortical bone remains challenging due to their low proton density and short transverse relaxation times, rendering bone tissues as nonspecific low signal structures on MR images obtained from most sequences. Developments in MR image acquisition and post‐processing have opened the path for enhanced MR‐based bone visualization aiming to provide a CT‐like contrast and, as such, ease clinical interpretation. The purpose of this review is to provide an overview of studies comparing MR and CT imaging for diagnostic and treatment planning purposes in orthopedic care, with a special focus on selective bone visualization, bone segmentation, and three‐dimensional (3D) modeling. This review discusses conventional gradient‐echo derived techniques as well as dedicated short echo time acquisition techniques and post‐processing techniques, including the generation of synthetic CT, in the context of 3D and specific bone visualization. Based on the reviewed literature, it may be concluded that the recent developments in MRI‐based bone visualization are promising. MRI alone provides valuable information on both bone and soft tissues for a broad range of applications including diagnostics, 3D modeling, and treatment planning in multiple anatomical regions, including the skull, spine, shoulder, pelvis, and long bones.
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Affiliation(s)
- Mateusz C Florkow
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Koen Willemsen
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Vasco V Mascarenhas
- Musculoskeletal Imaging Unit, Imaging Center, Hospital da Luz, Lisbon, Portugal
| | - Edwin H G Oei
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Marijn van Stralen
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands.,MRIguidance BV, Utrecht, The Netherlands
| | - Peter R Seevinck
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands.,MRIguidance BV, Utrecht, The Netherlands
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Magdum S, Ganau M, Syrmos N. Imaging in craniofacial disorders with special emphasis on gradient echo Black-Bone and Zero Time Echo MRI sequences. J Pediatr Neurosci 2022; 17:S14-S20. [PMID: 36388002 PMCID: PMC9648653 DOI: 10.4103/jpn.jpn_46_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 04/04/2022] [Indexed: 11/25/2022] Open
Abstract
Context: The well-known effects of ionizing radiation on brain cells have been a major driving force toward the use of non-ionizing methods of imaging in both elective and emergency settings. Pediatric neurosurgery has certainly leveraged on this shift in clinical practice, however patients with craniofacial disorders could not fully benefit from the adoption of magnetic resonance imaging (MRI) because computed tomography (CT) scans still retain superior imaging power on bone tissue. Aims: To explore the knowledge available on the use of MRI as surrogate for CT scan in the assessment of craniosynostosis. Settings and Design: A scoping review was designed to identify landmark studies and ongoing clinical trials exploring the accuracy of MRI-based bone imaging in the preoperative planning of pediatric patients with craniosynostosis. Materials and Methods: A total of 492 records were screened from Pubmed, Ovid Medline, Scopus, and Cochrane Library databases; while 55 records were retrieved from ClinicalTrials.gov register. Only clinical studies revolving around the use of Gradient Echo Black-Bone (BB) and Zero Time Echo (ZTE) MRI sequences for the preoperative planning of pediatric craniosynostosis were retained for inclusion. Results and Conclusions: This review identified only five clinical studies reporting a high accuracy of MRI-based 3D bone reconstruction in 47 pediatric candidates to surgical correction of craniosynostosis. Although promising, limited evidence (Level IV) exist that BB and ZTE MRI could help in the surgical planning for craniosynostosis management. The results of two ongoing randomized clinical trials, which are actively enrolling patients, will hopefully help answering this research question.
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45
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Sandberg JK, Young VA, Yuan J, Hargreaves BA, Wishah F, Vasanawala SS. Zero echo time pediatric musculoskeletal magnetic resonance imaging: initial experience. Pediatr Radiol 2021; 51:2549-2560. [PMID: 34156504 DOI: 10.1007/s00247-021-05125-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/24/2021] [Accepted: 06/10/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Projection radiography (XR) is often supplemented by both CT (to evaluate osseous structures with ionizing radiation) and MRI (for marrow and soft-tissue assessment). Zero echo time (ZTE) MR imaging produces a "CT-like" osseous contrast that might obviate CT. OBJECTIVE This study investigated our institution's initial experience in implementing an isotropic ZTE MR imaging sequence for pediatric musculoskeletal examinations. MATERIALS AND METHODS Pediatric patients referred for extremity MRI at 3 tesla (T) underwent ZTE MR imaging to yield images with contrast similar to that of CT. A radiograph-like image was also created with ray-sum image processing. We assessed ZTE-CT/XR anatomical image quality (Sanat) from 0 (nondiagnostic) to 5 (outstanding). Further, we made image comparisons on a 5-point scale (Scomp) (range of -2 = conventional CT/XR greater anatomical delineation to +2 = ZTE-CT/XR greater anatomical delineation; 0=same) for three cohorts: (1) ZTE-XR to conventional radiography, (2) ZTE-CT to conventional CT and (3) pathological lesion assessment on ZTE-XR to conventional radiography. We measured cortical thickness of ZTE-XR and ZTE-CT and compared these with conventional imaging. We calculated confidence interval of proportions, Wilcoxon rank sum test and intraclass correlation coefficients for inter-reader agreement. RESULTS Cohorts 1, 2 and 3 consisted of 40, 20 and 35 cases, respectively (age range 0.6-23.0 years). ZTE-CT versus CT and ZTE-XR versus radiography of cortical thicknesses were not significantly different (P=0.55 and P=0.31, respectively). Cortical delineation was rated diagnostic or better (score of 3, 4 or 5) in all cases (confidence interval of proportions = 100%) for ZTE-CT/XR. Similarly, intramedullary cavity delineation was rated diagnostic or better in all cases for ZTE-CT, and ZTE-XR was at least diagnostic in 58-63% of cases. For cohort 2, cortex and intramedullary cavity Scomp for ZTE-CT was comparable to those of conventional CT, with confidence interval of proportion (sum of score of -1 to +2) of 93-100% and 95%, respectively. Pathology visualized on ZTE-CT/XR was comparable; Scomp confidence interval of proportions was 95%/97-100%, with improved delineation of non-displaced fractures on ZTE-XR. Readers had moderate to near-perfect intraclass correlation coefficient (range=0.60-0.93). CONCLUSION Implementation of a diagnostic-quality ZTE MRI sequence in the pediatric population is feasible and can be performed as a complementary pulse sequence to enhance musculoskeletal MRI studies. Compared to conventional CT, ZTE has comparable cortical delineation, intramedullary cavity and pathology visualization. While not intended as a replacement for conventional radiography, ZTE-XR provides similar visualization of pathology.
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Affiliation(s)
- Jesse K Sandberg
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA.
| | - Victoria A Young
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA
| | - Jianmin Yuan
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA
| | - Brian A Hargreaves
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA
| | - Fidaa Wishah
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA
| | - Shreyas S Vasanawala
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA
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46
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Lei Y, Wang T, Dong X, Tian S, Liu Y, Mao H, Curran WJ, Shu HK, Liu T, Yang X. MRI classification using semantic random forest with auto-context model. Quant Imaging Med Surg 2021; 11:4753-4766. [PMID: 34888187 PMCID: PMC8611460 DOI: 10.21037/qims-20-1114] [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: 10/03/2020] [Accepted: 04/28/2021] [Indexed: 11/06/2022]
Abstract
BACKGROUND It is challenging to differentiate air and bone on MR images of conventional sequences due to their low contrast. We propose to combine semantic feature extraction under auto-context manner into random forest to improve reasonability of the MRI segmentation for MRI-based radiotherapy treatment planning or PET attention correction. METHODS We applied a semantic classification random forest (SCRF) method which consists of a training stage and a segmentation stage. In the training stage, patch-based MRI features were extracted from registered MRI-CT training images, and the most informative elements were selected via feature selection to train an initial random forest. The rest sequence of random forests was trained by a combination of MRI feature and semantic feature under an auto-context manner. During segmentation, the MRI patches were first fed into these random forests to derive patch-based segmentation. By using patch fusion, the final end-to-end segmentation was obtained. RESULTS The Dice similarity coefficient (DSC) for air, bone and soft tissue classes obtained via proposed method were 0.976±0.007, 0.819±0.050 and 0.932±0.031, compared to 0.916±0.099, 0.673±0.151 and 0.830±0.083 with random forest (RF), and 0.942±0.086, 0.791±0.046 and 0.917±0.033 with U-Net. SCRF also outperformed the competing methods in sensitivity and specificity for all three structure types. CONCLUSIONS The proposed method accurately segmented bone, air and soft tissue. It is promising in facilitating advanced MR application in diagnosis and therapy.
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Affiliation(s)
- Yang Lei
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Tonghe Wang
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Xue Dong
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Sibo Tian
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Yingzi Liu
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Hui Mao
- Department of Radiology and Imaging Sciences and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Walter J. Curran
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Hui-Kuo Shu
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Tian Liu
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Xiaofeng Yang
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
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47
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Kronthaler S, Boehm C, Feuerriegel G, Börnert P, Katscher U, Weiss K, Makowski MR, Schwaiger BJ, Gersing AS, Karampinos DC. Assessment of vertebral fractures and edema of the thoracolumbar spine based on water-fat and susceptibility-weighted images derived from a single ultra-short echo time scan. Magn Reson Med 2021; 87:1771-1783. [PMID: 34752650 DOI: 10.1002/mrm.29078] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 12/22/2022]
Abstract
PURPOSE To develop a methodology to simultaneously perform single echo Dixon water-fat imaging and susceptibility-weighted imaging (SWI) based on a single echo time (TE) ultra-short echo time (UTE) (sUTE) scan to assess vertebral fractures and degenerative bone changes in the thoracolumbar spine. METHODS A methodology was developed to solve the smoothness-constrained inverse water-fat problem to separate water and fat while removing unwanted low-frequency phase terms. Additionally, the corrected UTE phase was used for SWI. UTE imaging (TE: 0.14 ms, 3T MRI) was performed in the lumbar spine of nine patients with vertebral fractures and bone marrow edema (BME). All images were reviewed by two radiologists. Water- and fat-separated images were analyzed in comparison with short-tau inversion recovery (STIR) and with respect to BME visibility. The visibility of fracture lines and cortical outlining of the UTE magnitude images were analyzed in comparison with computed tomography. RESULTS Unwanted phase components, dominated by the B1 phase, were removed from the UTE phase images. The rating of the diagnostic quality of BME visualization showed a high preference for the sUTE-Dixon water- and fat-separated images in comparison with STIR. The UTE magnitude images enabled better visualizing fracture lines compared with STIR and slightly better visibility of cortical outlining. With increasing SWI weighting osseous structures and fatty tissues were enhanced. CONCLUSION The proposed sUTE-Dixon-SWI methodology allows the removal of unwanted low-frequency phases and enables water-fat separation and SWI processing from a single complex UTE image. The methodology can be used for the simultaneous assessment of vertebral fractures and BME of the thoracolumbar spine.
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Affiliation(s)
- Sophia Kronthaler
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany
| | - Christof Boehm
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany
| | - Georg Feuerriegel
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany
| | | | | | | | - Marcus R Makowski
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany
| | - Benedikt J Schwaiger
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Technical University of Munich, Munich, Germany
| | - Alexandra S Gersing
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany
| | - Dimitrios C Karampinos
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany
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48
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Kobayashi N, Bambach S, Ho ML. Ultrashort Echo-Time MR Imaging of the Pediatric Head and Neck. Magn Reson Imaging Clin N Am 2021; 29:583-593. [PMID: 34717846 DOI: 10.1016/j.mric.2021.06.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Bone MR imaging techniques use extremely rapid echo times to maximize detection of short-T2 tissues with low water concentrations. The major approaches used in clinical practice are ultrashort echo-time and zero echo-time. Synthetic CT generation is feasible using atlas-based, voxel-based, and deep learning approaches. Major clinical applications in the pediatric head and neck include evaluation for craniosynostosis, sinonasal and jaw imaging, trauma, interventional planning, and postoperative follow-up. In this article, we review the technical background and practical usefulness of bone MR imaging with key imaging examples.
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Affiliation(s)
- Naoharu Kobayashi
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, 2021 6th Street SE, Minneapolis, MN 55455, USA
| | - Sven Bambach
- Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH 43215, USA
| | - Mai-Lan Ho
- Department of Radiology, Nationwide Children's Hospital, 700 Children's Dr - ED4, Columbus, OH 43205, USA.
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49
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Abstract
Three-dimensional (3D) magnetic resonance imaging of the spine is now clinically feasible due to technological advancements. Its advantages over two-dimensional imaging include higher in-plane spatial resolution and the ability for reformation in any plane that enables time savings in image acquisition and aids more accurate interpretation. Multispectral 3D techniques for imaging around metal are sometimes useful for evaluating anatomy adjacent to spinal fixation hardware. 3D gradient-recalled echo sequences, including ultrashort or zero time to echo sequences, can provide osseous detail similar to conventional computed tomography.
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Affiliation(s)
- Meghan Sahr
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York
| | - Ek Tsoon Tan
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York
| | - Darryl B Sneag
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York
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50
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Chong LR, Lee K, Sim FY. 3D MRI with CT-like bone contrast - An overview of current approaches and practical clinical implementation. Eur J Radiol 2021; 143:109915. [PMID: 34461599 DOI: 10.1016/j.ejrad.2021.109915] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 08/13/2021] [Accepted: 08/15/2021] [Indexed: 12/24/2022]
Abstract
CT is the imaging modality of choice for assessment of 3D bony morphology but incurs the penalty of ionizing radiation. Improving the ability of 3D MRI to provide high-resolution images of cortical bone with CT-like bone contrast has been a focus of recent research. The ability of 3D MRI to deliver cortical bone information with similar diagnostic performance to CT would complement assessment of soft tissues and medullary bone from a single MRI examination, simplifying evaluation and obviating radiation exposure from additional CT. This article presents an overview of current 3D MRI approaches for imaging cortical bone with CT-like bone contrast including ultrashort echo time, zero echo time, T1-weighted gradient recalled echo, susceptibility-weighted imaging and deep learning techniques. We also discuss clinical implementation of an optimized stack-of-stars 3D gradient recalled echo pulse sequence (3D-Bone) on commercially available MRI scanners for rendering 3D MRI with CT-like bone contrast in our institutional practice.
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Affiliation(s)
- Le Roy Chong
- Department of Radiology, Changi General Hospital, 2 Simei Street 3, Singapore 529889, Republic of Singapore.
| | - Kathy Lee
- Department of Radiology, Changi General Hospital, 2 Simei Street 3, Singapore 529889, Republic of Singapore.
| | - Fang Yang Sim
- Department of Radiology, Changi General Hospital, 2 Simei Street 3, Singapore 529889, Republic of Singapore.
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