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Meng T, Liu H, Liu J, Wang F, Xie C, Ke L, He H. The investigation of reduced field-of-view diffusion-weighted imaging (DWI) in patients with nasopharyngeal carcinoma: comparison with conventional DWI. Acta Radiol 2023; 64:2118-2125. [PMID: 36912041 DOI: 10.1177/02841851231159389] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
BACKGROUND Field-of-view optimized and constrained undistorted single-shot imaging (FOCUS) is a new sequence that shows enhanced anatomical details, improving the diffusion-weighted (DW) images. PURPOSE To investigate the value of FOCUS diffusion-weighted imaging (DWI) in the evaluation of nasopharyngeal carcinoma (NPC) and compare it with the single-shot echo planner imaging (SS-EPI) DWI approach. MATERIAL AND METHODS A total of 87 patients with NPC underwent magnetic resonance imaging, including FOCUS and SS-EPI DWI sequences. The signal-to-noise ratio (SNR), signal-intensity ratio (SIR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC) values of the nasopharyngeal lesions were measured and compared. According to the clinical stages of patients, T and N were divided into early and advanced stage groups, respectively. The mean ADC values of the two techniques were computed, and the area under the curve (AUC) was estimated to calculate the diagnostic efficiency. RESULTS Subjective and objective image qualitative values of FOCUS were significantly higher than those of SS-EPI. The ADC values for FOCUS of early T and N stages were significantly lower than those of the advanced stages. CONCLUSION FOCUS provides significantly better image quality in NPC compared to SS-EPI, with lower ADC values for early-stage disease than late-stage disease.
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Affiliation(s)
- Tiebao Meng
- Department of Radiology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, 71067Sun Yat-sen University Cancer Center, Guangzhou, PR China
| | - Huiming Liu
- Department of Radiology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, 71067Sun Yat-sen University Cancer Center, Guangzhou, PR China
| | - Jinbo Liu
- Department of Radiology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, 71067Sun Yat-sen University Cancer Center, Guangzhou, PR China
| | - Feixiang Wang
- Department of Thoracic Oncology, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, PR China
| | - Chuanmiao Xie
- Department of Radiology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, 71067Sun Yat-sen University Cancer Center, Guangzhou, PR China
| | - Liangru Ke
- Department of Radiology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, 71067Sun Yat-sen University Cancer Center, Guangzhou, PR China
| | - Haoqiang He
- Department of Radiology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, 71067Sun Yat-sen University Cancer Center, Guangzhou, PR China
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Barlas BA, Bahadir CD, Kafali SG, Yilmaz U, Saritas EU. Sheared two-dimensional radiofrequency excitation for off-resonance robustness and fat suppression in reduced field-of-view imaging. Magn Reson Med 2022; 88:2504-2519. [PMID: 36000548 DOI: 10.1002/mrm.29416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/16/2022] [Accepted: 07/27/2022] [Indexed: 11/09/2022]
Abstract
PURPOSE Two-dimensional (2D) echo-planar radiofrequency (RF) pulses are widely used for reduced field-of-view (FOV) imaging in applications such as diffusion-weighted imaging. However, long pulse durations render the 2D RF pulses sensitive to off-resonance effects, causing local signal losses in reduced-FOV images. This work aims to achieve off-resonance robustness for 2D RF pulses via a sheared trajectory design. THEORY AND METHODS A sheared 2D RF pulse design is proposed to reduce pulse durations while covering identical excitation k-space extent as a standard 2D RF pulse. For a given shear angle, the number of sheared trajectory lines is minimized to obtain the shortest pulse duration, such that the excitation replicas are repositioned outside the slice stack to guarantee unlimited slice coverage. A target fat/water signal ratio of 5% is chosen to achieve robust fat suppression. RESULTS Simulations, imaging experiments on a custom head and neck phantom, and in vivo imaging experiments in the spinal cord at 3 T demonstrate that the sheared 2D RF design provides significant improvement in image quality while preserving profile sharpnesses. In regions with high off-resonance effects, the sheared 2D RF pulse improves the signal by more than 50% when compared to the standard 2D RF pulse. CONCLUSION The proposed sheared 2D RF design successfully reduces pulse durations, exhibiting significantly improved through-plane off-resonance robustness, while providing unlimited slice coverage and high fidelity fat suppression. This method will be especially beneficial in regions suffering from a variety of off-resonance effects, such as spinal cord and breast.
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Affiliation(s)
- Bahadir Alp Barlas
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.,National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Cagla Deniz Bahadir
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.,National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey.,Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Sevgi Gokce Kafali
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.,National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey.,Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA
| | - Ugur Yilmaz
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Emine Ulku Saritas
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.,National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey.,Neuroscience Graduate Program, Bilkent University, Ankara, Turkey
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Eren OC, Barlas BA, Saritas EU. 2D RF pulse design for optimized reduced field-of-view imaging at 1.5T and 3T. Magn Reson Imaging 2021; 85:210-216. [PMID: 34688847 DOI: 10.1016/j.mri.2021.10.021] [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: 07/15/2021] [Revised: 10/15/2021] [Accepted: 10/16/2021] [Indexed: 10/20/2022]
Abstract
Two-dimensional spatially selective radiofrequency (2DRF) excitation pulses are widely used for reduced field-of-view (FOV) targeted high-resolution diffusion weighted imaging (DWI), especially for anatomically small regions such as the spinal cord and prostate. The reduction in FOV achieved by 2DRF pulses significantly improve the in-plane off-resonance artifacts in single-shot echo planar imaging (ss-EPI). However, long durations of 2DRF pulses create a sensitivity to through-plane off-resonance effects, especially at 3T where the off-resonance field doubles with respect to 1.5T. This work proposes a parameter-based optimization approach to design 2DRF pulses with blips along the slice-select axis, with the goal of maximizing slab sharpness while minimizing off-resonance effects on 1.5T and 3T MRI scanners, separately. Extensive Bloch simulations are performed to evaluate the off-resonance robustness of 2DRF pulses. Three different metrics are proposed to quantify the similarity between the actual and ideal 2D excitation profiles, based on the signals within and outside the targeted reduced-FOV region. In addition, simulations on a digital brain phantom are performed for visual comparison purposes. The results show that maintaining a sharp profile is the primary design requirement at 1.5T, necessitating the usage of relatively high slab sharpness with a time-bandwidth product (TBW) around 8-10. In contrast, off-resonance robustness is the primary design requirement at 3T, requiring the usage of a moderate slap sharpness with TBW around 5-7.
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Affiliation(s)
- Orhun Caner Eren
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey; Institute of Neuroinformatics, ETH Zurich, Zurich, Switzerland; Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland.
| | - Bahadir Alp Barlas
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey; National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey.
| | - Emine Ulku Saritas
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey; National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey; Neuroscience Graduate Program, Bilkent University, Ankara, Turkey.
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High-fidelity diffusion tensor imaging of the cervical spinal cord using point-spread-function encoded EPI. Neuroimage 2021; 236:118043. [PMID: 33857617 DOI: 10.1016/j.neuroimage.2021.118043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/16/2021] [Accepted: 03/31/2021] [Indexed: 01/21/2023] Open
Abstract
Diffusion tensor imaging (DTI) of the spinal cord is technically challenging due to the size of its structure and susceptibility-induced field inhomogeneity, which impedes clinical applications. This study aimed to achieve high-fidelity spinal cord DTI with reasonable SNR and practical acquisition efficiency. Particularly, a distortion-free multi-shot EPI technique, namely point-spread-function encoded EPI (PSF-EPI), was adopted for diffusion imaging of the cervical spinal cord (CSC). The shot number can be reduced to six for sagittal scans through titled-CAIPI acceleration and partial Fourier undersampling, consequently rendering this technique beneficial in clinics. Fifteen healthy volunteers and seven patients with metallic implants underwent sagittal scans using tilted-CAIPI PSF-EPI at 3T. Unsuppressed fat signals were further removed by retrospective water/fat separation using the intrinsic chemical-shift encoded signals. Compared with multi-shot interleaved EPI method, highly accelerated PSF-EPI method provided evidently improved distortion reduction and higher consistency with anatomical references even with metallic implants. Additionally, axial DTI scans using PSF-EPI were also evaluated quantitatively, and the measured DTI metrics are similar to those obtained from the zonal oblique multi-slice EPI (ZOOM-EPI) method and reported values. The high anatomical consistency, practical scan time and quantitative reliability indicate PSF-EPI's clinical potential for CSC diffusion imaging.
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Zhang Y, Jiang K, Jiang W, Wang N, Wright AJ, Liu A, Wang J. Multi-task convolutional neural network-based design of radio frequency pulse and the accompanying gradients for magnetic resonance imaging. NMR IN BIOMEDICINE 2021; 34:e4443. [PMID: 33200468 DOI: 10.1002/nbm.4443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 10/21/2020] [Accepted: 10/21/2020] [Indexed: 06/11/2023]
Abstract
Modern MRI systems usually load the predesigned RFs and the accompanying gradients during clinical scans, with minimal adaption to the specific requirements of each scan. Here, we describe a neural network-based method for real-time design of excitation RF pulses and the accompanying gradients' waveforms to achieve spatially two-dimensional selectivity. Nine thousand sets of radio frequency (RF) and gradient waveforms with two-dimensional spatial selectivity were generated as the training dataset using the Shinnar-Le Roux (SLR) method. Neural networks were created and trained with five strategies (TS-1 to TS-5). The neural network-designed RF and gradients were compared with their SLR-designed counterparts and underwent Bloch simulation and phantom imaging to investigate their performances in spin manipulations. We demonstrate a convolutional neural network (TS-5) with multi-task learning to yield both the RF pulses and the accompanying two channels of gradient waveforms that comply with the SLR design, and these design results also provide excitation spatial profiles comparable with SLR pulses in both simulation (normalized root mean square error [NRMSE] of 0.0075 ± 0.0038 over the 400 sets of testing data between TS-5 and SLR) and phantom imaging. The output RF and gradient waveforms between the neural network and SLR methods were also compared, and the joint NRMSE, with both RF and the two channels of gradient waveforms considered, was 0.0098 ± 0.0024 between TS-5 and SLR. The RF and gradients were generated on a commercially available workstation, which took ~130 ms for TS-5. In conclusion, we present a convolutional neural network with multi-task learning, trained with SLR transformation pairs, that is capable of simultaneously generating RF and two channels of gradient waveforms, given the desired spatially two-dimensional excitation profiles.
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Affiliation(s)
- Yajing Zhang
- MR Clinical Science, Philips Healthcare (Suzhou), Suzhou, China
| | - Ke Jiang
- MSC Clinical & Technical Solutions, Philips Healthcare, Beijing, China
| | - Weiwei Jiang
- MR Clinical Science, Philips Healthcare (Suzhou), Suzhou, China
| | - Nan Wang
- Department of Radiology, the First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Alan J Wright
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, UK
| | - Ailian Liu
- Department of Radiology, the First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Jiazheng Wang
- MSC Clinical & Technical Solutions, Philips Healthcare, Beijing, China
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Comparison of Field-of-view Optimized and Constrained Undistorted Single Shot With Conventional Intravoxel Incoherent Motion Diffusion-Weighted Imaging for Measurements of Diffusion and Perfusion in Vertebral Bone Marrow. J Comput Assist Tomogr 2021; 45:98-102. [PMID: 33186175 DOI: 10.1097/rct.0000000000001111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND AND PURPOSE A limited number of studies have used the intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) approach on bone marrow. The purpose of this study was to qualitatively and quantitatively compare the clinical value of IVIM based on field-of-view optimized and constrained undistorted single shot (FOCUS) with the standard single-shot echo-planar imaging (ss-EPI) in the vertebral bone marrow. MATERIALS AND METHODS Twenty healthy volunteers underwent ss-EPI and FOCUS IVIM-DWI of the lumbar spine. Intravoxel incoherent motion parameters (the apparent diffusion coefficient [ADC], true diffusion coefficient [D], pseudodiffusion coefficient [D*], and perfusion fraction [f]) were calculated. RESULTS The FOCUS IVIM protocol allowed for measurement of ADC, D, D*, and f in all volunteers: ADC, 0.28 ± 1.33 ×10-3 mm2/s; D = 0.25 ± 3.98 ×10-3 mm2/s, f = 0.36 ± 4.01; and D* = 102.16 ± 71.21 ×10-3 mm2/s. There were no significant differences between the values of ADC, D, and f obtained with ss-EPI and FOCUS. The D* was significantly different (P < 0.05) between ss-EPI and FOCUS IVIM. Image quality assessments showed that the image qualities of FOCUS were superior to ss-EPI (P < 0.001). CONCLUSIONS As a high-resolution IVIM-DWI technique, the FOCUS technique has potential clinical utility in evaluating the diffusion and perfusion in the vertebral bone marrow.
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Alizadeh M, Poplawski MM, Fisher J, Gorniak RJT, Dresner A, Mohamed FB, Flanders AE. Zonally Magnified Oblique Multislice and Non-Zonally Magnified Oblique Multislice DWI of the Cervical Spinal Cord. AJNR Am J Neuroradiol 2018; 39:1555-1561. [PMID: 29903926 DOI: 10.3174/ajnr.a5703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 04/26/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The zonally magnified oblique multislice EPI (ZOOM-EPI) diffusion-weighted sequence has been visually shown to provide superior MR diffusion image quality compared with the full-FOV single-shot EPI sequence (non-ZOOM-EPI) in the adult cervical spinal cord. The purpose of this study was to examine the diffusion tensor imaging indices in the normal human cervical spinal cord between ZOOMED and non-ZOOMED DTI acquisitions and determine whether DTI values are comparable between direct and indirect age-matched groups. MATERIALS AND METHODS Fifty-four subjects 23-58 years of age (9 direct age-matched and 45 indirect age-matched) were scanned using a 1.5T scanner. Diffusion tensor indices including fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity were generated from the DTI dataset. These DTI values were calculated for both ZOOM and non-ZOOM acquisitions and compared at each intervertebral disc level. The variability of the DTI values for ZOOM and non-ZOOM sequences was measured using a coefficient of variation within direct and indirect age-matched controls. RESULTS The mean diffusivity, axial diffusivity, and radial diffusivity values obtained along the cervical spinal cord in the age-matched controls showed a significant decrease using the ZOOM sequence (P = .05, P = .002, and P < .001). Mean fractional anisotropy showed a significant increase (P = .04) using the ZOOM sequence. The indirect age-matched controls showed a statistically significant increase in fractional anisotropy (P = .03) and a decrease in mean diffusivity (P = .002), axial diffusivity (P < .001), and radial diffusivity (P = .002) using the ZOOM sequence. Less variability has been shown in DTI using the ZOOM sequence compared with the non-ZOOM sequence in both direct and indirect age groups. The ZOOM sequence exhibited higher SNR (SNRZOOM = 22.84 ± 7.59) compared with the non-ZOOM sequence (SNRnon-ZOOM = 19.7 ± 7.05). However, when we used a 2-tailed t test assuming unequal variances, the ZOOM sequence did not demonstrate a statistically significant increase. CONCLUSIONS ZOOM DTI acquisition methods provide superior image quality and precision over non-ZOOM techniques and are recommended over conventional full-FOV single-shot EPI DTI for clinical applications in cervical spinal cord imaging.
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Affiliation(s)
- M Alizadeh
- From the Department of Radiology (M.A., M.M.P., J.F., R.J.T.G., A.D., F.B.M., A.E.F.), Jefferson Integrated Magnetic Resonance Imaging Center
- Department of Neurosurgery (M.A.), Thomas Jefferson University, Philadelphia, Pennsylvania
| | - M M Poplawski
- From the Department of Radiology (M.A., M.M.P., J.F., R.J.T.G., A.D., F.B.M., A.E.F.), Jefferson Integrated Magnetic Resonance Imaging Center
| | - J Fisher
- From the Department of Radiology (M.A., M.M.P., J.F., R.J.T.G., A.D., F.B.M., A.E.F.), Jefferson Integrated Magnetic Resonance Imaging Center
| | - R J T Gorniak
- From the Department of Radiology (M.A., M.M.P., J.F., R.J.T.G., A.D., F.B.M., A.E.F.), Jefferson Integrated Magnetic Resonance Imaging Center
| | - A Dresner
- From the Department of Radiology (M.A., M.M.P., J.F., R.J.T.G., A.D., F.B.M., A.E.F.), Jefferson Integrated Magnetic Resonance Imaging Center
| | - F B Mohamed
- From the Department of Radiology (M.A., M.M.P., J.F., R.J.T.G., A.D., F.B.M., A.E.F.), Jefferson Integrated Magnetic Resonance Imaging Center
| | - A E Flanders
- From the Department of Radiology (M.A., M.M.P., J.F., R.J.T.G., A.D., F.B.M., A.E.F.), Jefferson Integrated Magnetic Resonance Imaging Center
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Budde MD, Skinner NP. Diffusion MRI in acute nervous system injury. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 292:137-148. [PMID: 29773299 DOI: 10.1016/j.jmr.2018.04.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/06/2018] [Accepted: 04/27/2018] [Indexed: 06/08/2023]
Abstract
Diffusion weighted magnetic resonance imaging (DWI) and related techniques such as diffusion tensor imaging (DTI) are uniquely sensitive to the microstructure of the brain and spinal cord. In the acute aftermath of nervous system injury, for example, DWI reveals changes caused by injury that remains invisible on other MRI contrasts such as T2-weighted imaging. This ability has led to a demonstrated clinical utility in cerebral ischemia. However, despite strong promise in preclinical models and research settings, DWI has not been as readily adopted for other acute injuries such as traumatic spinal cord, brain, or peripheral nerve injury. Furthermore, the precise biophysical mechanisms that underlie DWI and DTI changes are not fully understood. In this report, we review the DWI and DTI changes that occur in acute neurological injury of cerebral ischemia, spinal cord injury, traumatic brain injury, and peripheral nerve injury. Their associations with the underlying biology are examined with an emphasis on the role of acute axon and dendrite beading. Lastly, emerging DWI techniques to overcome the limitations of DTI are discussed as these may offer the needed improvements to translate to clinical settings.
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Affiliation(s)
- Matthew D Budde
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States.
| | - Nathan P Skinner
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States; Medical Scientist Training Program, Medical College of Wisconsin, Milwaukee, WI, United States
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Hu J, Li M, Dai Y, Geng C, Tong B, Zhou Z, Liang X, Yang W, Zhang B. Combining SENSE and reduced field-of-view for high-resolution diffusion weighted magnetic resonance imaging. Biomed Eng Online 2018; 17:77. [PMID: 29903023 PMCID: PMC6003092 DOI: 10.1186/s12938-018-0511-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 06/05/2018] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND In diffusion-weighted magnetic resonance imaging (DWI) using single-shot echo planar imaging (ss-EPI), both reduced field-of-view (FOV) excitation and sensitivity encoding (SENSE) alone can increase in-plane resolution to some degree. However, when the two techniques are combined to further increase resolution without pronounced geometric distortion, the resulted images are often corrupted by high level of noise and artifact due to the numerical restriction in SENSE. Hence, this study is aimed to provide a reconstruction method to deal with this problem. METHODS The proposed reconstruction method was developed and implemented to deal with the high level of noise and artifact in the combination of reduced FOV imaging and traditional SENSE, in which all the imaging data were considered jointly by incorporating the motion induced phase variations among excitations. The in vivo human spine diffusion images from ten subjects were acquired at 1.5 T and reconstructed using the proposed method, and compared with SENSE magnitude average results for a range of reduction factors in reduced FOV. These images were evaluated by two radiologists using visual scores (considering distortion, noise and artifact levels) from 1 to 10. RESULTS The proposed method was able to reconstruct images with greatly reduced noise and artifact compared to SENSE magnitude average. The mean g-factors were maintained close to 1 along with enhanced signal-to-noise ratio efficiency. The image quality scores of the proposed method were significantly higher (P < 0.01) than SENSE magnitude average for all the evaluated reduction factors. CONCLUSION The proposed method can improve the combination of SENSE and reduced FOV for high-resolution ss-EPI DWI with reduced noise and artifact.
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Affiliation(s)
- Jisu Hu
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu, China
| | - Ming Li
- Department of Radiology, Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, Jiangsu, China
| | - Yakang Dai
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu, China
| | - Chen Geng
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu, China
| | - Baotong Tong
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu, China
| | - Zhiyong Zhou
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu, China
| | - Xue Liang
- Department of Radiology, Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, Jiangsu, China
| | - Wen Yang
- Department of Radiology, Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, Jiangsu, China
| | - Bing Zhang
- Department of Radiology, Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, Jiangsu, China.
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Hwang J, Hong SS, Kim HJ, Chang YW, Nam BD, Oh E, Lee E, Cha H. Reduced field-of-view diffusion-weighted MRI in patients with cervical cancer. Br J Radiol 2018; 91:20170864. [PMID: 29630391 DOI: 10.1259/bjr.20170864] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE Diffusion-weighted imaging (DWI) with reduced field-of-view (FOV) has been shown to provide high spatial resolution with reduced distorsion in the spinal cord, breast, pancreas, and prostate gland. Therefore, we performed this study to evaluate the qualitative image quality and quantitative ADC value of reduced FOV DWI in patients with cervical cancer in comparison with conventional DWI. METHODS This study retrospectively included 22 patients (mean age, 53.9 years) with biopsy-proven cervical cancer who underwent pelvic MR imaging including conventional DWI and reduced FOV DWI before therapy. Two observers independently rated image quality for reduced FOV DWI and conventional DWI regarding anatomic detail, lesion conspicuity, presence of artifacts, and overall image quality using the following 4-point scale. Quantitative analysis was performed by measuring the ADC value of the tumor. The Wilcoxon signed-rank test was used to compare qualitative scores and mean ADC value between two DWI sequences. RESULTS Reduced FOV DWI achieved significantly better anatomic detail, lesion conspicuity, presence of artifacts, and overall image quality compared to conventional DWI (p < 0.05). There was no significant difference in mean tumor ADC value between the two DWI sequences (0.990 × 10-3 mm2 s-1 ± 0.364 at reduced FOV DWI vs 1.253 × 10-3 mm2 s-1 ± 0.387 at conventional DWI) (p = 0.067). CONCLUSION Reduced FOV DWI shows better image quality in terms of anatomic detail and lesion conspicuity with fewer artifacts compared to conventional DWI. Advance in knowledge: Reduced FOV DWI may enhance diagnostic performance for evaluation of cervical cancer.
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Affiliation(s)
- Jiyoung Hwang
- 1 Department of Radiology, Soonchunhyang University College of Medicine, Seoul Hospital , Seoul , Republic of Korea
| | - Seong Sook Hong
- 1 Department of Radiology, Soonchunhyang University College of Medicine, Seoul Hospital , Seoul , Republic of Korea
| | - Hyun-Joo Kim
- 1 Department of Radiology, Soonchunhyang University College of Medicine, Seoul Hospital , Seoul , Republic of Korea
| | - Yun-Woo Chang
- 1 Department of Radiology, Soonchunhyang University College of Medicine, Seoul Hospital , Seoul , Republic of Korea
| | - Bo Da Nam
- 1 Department of Radiology, Soonchunhyang University College of Medicine, Seoul Hospital , Seoul , Republic of Korea
| | - Eunsun Oh
- 1 Department of Radiology, Soonchunhyang University College of Medicine, Seoul Hospital , Seoul , Republic of Korea
| | - EunJi Lee
- 1 Department of Radiology, Soonchunhyang University College of Medicine, Seoul Hospital , Seoul , Republic of Korea
| | - Hwajin Cha
- 1 Department of Radiology, Soonchunhyang University College of Medicine, Seoul Hospital , Seoul , Republic of Korea
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Guan L, Chen X, Hai Y, Ma X, He L, Wang G, Yuan C, Guo H. High-resolution diffusion tensor imaging in cervical spondylotic myelopathy: a preliminary follow-up study. NMR IN BIOMEDICINE 2017; 30:e3769. [PMID: 28703331 DOI: 10.1002/nbm.3769] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 06/01/2017] [Accepted: 06/01/2017] [Indexed: 06/07/2023]
Abstract
Diffusion imaging is a promising technique as it can provide microstructural tissue information and thus potentially show viable changes in spinal cord. However, the traditional single-shot imaging method is limited as a result of various image artifacts. In order to improve measurement accuracy, we used a newly developed, multi-shot, high-resolution, diffusion tensor imaging (DTI) method to investigate diffusion metric changes and compare them with T2 -weighted (T2W) images before and after decompressive surgery for cervical spondylotic myelopathy (CSM). T2W imaging, single-shot DTI and multi-shot DTI were employed to scan seven patients with CSM before and 3 months after decompressive surgery. High signal intensities were scored using the T2 W images. DTI metrics, including fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD), were quantified and compared pre- and post-surgery. In addition, the relationship between imaging metrics and neurological assessments was examined. The reproducibility of multi-shot DTI was also assessed in 10 healthy volunteers. Post-surgery, the mean grade of cervical canal stenosis was reduced from grade 3 to normal after 3 months. Compared with single-shot DTI, multi-shot DTI provided better images with lower artifact levels, especially following surgery, as a result of reduced artifacts from metal implants. The new method also showed acceptable reproducibility. Both FA and RD values from the new acquisition showed significant differences post-surgery (FA, p = 0.026; RD, p = 0.048). These changes were consistent with neurological assessments. In contrast, T2W images did not show significant changes before and after surgery. Multi-shot diffusion imaging showed improved image quality over single-shot DWI, and presented superior performance in diagnosis and recovery monitoring for patients with CSM compared with T2W imaging. DTI metrics can reflect the pathological conditions of spondylotic spinal cord quantitatively and may serve as a sensitive biomarker for potential CSM management.
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Affiliation(s)
- Li Guan
- Department of Orthopedics, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Xiaolong Chen
- Department of Orthopedics, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Yong Hai
- Department of Orthopedics, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Xiaodong Ma
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China
| | - Le He
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China
| | - Guangzhi Wang
- Department of Biomedical Engineering, Tsinghua University, Beijing, China
| | - Chun Yuan
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China
- Department of Radiology, University of Washington, Seattle, WA, USA
| | - Hua Guo
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China
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12
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Wu W, Miller KL. Image formation in diffusion MRI: A review of recent technical developments. J Magn Reson Imaging 2017; 46:646-662. [PMID: 28194821 PMCID: PMC5574024 DOI: 10.1002/jmri.25664] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 01/25/2017] [Indexed: 12/13/2022] Open
Abstract
Diffusion magnetic resonance imaging (MRI) is a standard imaging tool in clinical neurology, and is becoming increasingly important for neuroscience studies due to its ability to depict complex neuroanatomy (eg, white matter connectivity). Single-shot echo-planar imaging is currently the predominant formation method for diffusion MRI, but suffers from blurring, distortion, and low spatial resolution. A number of methods have been proposed to address these limitations and improve diffusion MRI acquisition. Here, the recent technical developments for image formation in diffusion MRI are reviewed. We discuss three areas of advance in diffusion MRI: improving image fidelity, accelerating acquisition, and increasing the signal-to-noise ratio. LEVEL OF EVIDENCE 5 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:646-662.
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Affiliation(s)
- Wenchuan Wu
- FMRIB Centre, Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Karla L. Miller
- FMRIB Centre, Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
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Peng Y, Li Z, Tang H, Wang Y, Hu X, Shen Y, Hu D. Comparison of reduced field‐of‐view diffusion‐weighted imaging (DWI) and conventional DWI techniques in the assessment of rectal carcinoma at 3.0T: Image quality and histological T staging. J Magn Reson Imaging 2017; 47:967-975. [PMID: 28691219 DOI: 10.1002/jmri.25814] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 06/24/2017] [Indexed: 01/02/2023] Open
Affiliation(s)
- Yang Peng
- Department of RadiologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan Hubei P.R. China
| | - Zhen Li
- Department of RadiologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan Hubei P.R. China
| | - Hao Tang
- Department of RadiologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan Hubei P.R. China
| | - Yanchun Wang
- Department of RadiologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan Hubei P.R. China
| | - Xuemei Hu
- Department of RadiologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan Hubei P.R. China
| | - Yaqi Shen
- Department of RadiologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan Hubei P.R. China
| | - Daoyu Hu
- Department of RadiologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan Hubei P.R. China
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14
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Vidiri A, Minosse S, Piludu F, Curione D, Pichi B, Spriano G, Marzi S. Feasibility study of reduced field of view diffusion-weighted magnetic resonance imaging in head and neck tumors. Acta Radiol 2017; 58:292-300. [PMID: 27287402 DOI: 10.1177/0284185116652014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Background Reduced field of view (rFOV) imaging may be used to improve the quality of diffusion-weighted imaging (DWI) in the head and neck (HN) region. Purpose To evaluate the feasibility of rFOV-DWI in patients affected by HN tumors, through a comparison with conventional full FOV (fFOV) DWI. Material and Methods Twenty-two patients with histologically-proven malignant or benign tumors of the head and neck were included in a retrospective study. All patients underwent pre-treatment magnetic resonance imaging (MRI) studies including rFOV-DWI and fFOV-DWI. The apparent diffusion coefficient (ADC) value distributions inside tumor and muscle were derived and the mean, standard deviation (SD), and kurtosis were calculated. Image distortion was quantitatively and qualitatively evaluated, as well as the capability of lesion identification. The Wilcoxon test was used to compare all variables. Agreements between the ADC estimations were assessed by Bland-Altman plots. Results Image distortion and lesion identification scores were both higher for rFOV-DWI compared to fFOV-DWI. A reduction in ADC values with rFOV-DWI emerged for both lesion and muscle, with a mean percentage difference in ADC of 6.2% in the lesions and 24.9% in the muscle. The difference in SD of ADC was statistically significant in the lesions, indicating a higher ADC homogeneity for rFOV DWI ( P = 0.005). Conclusion The application of rFOV DWI in patients affected by HN tumors is feasible and promising, based on both qualitative and quantitative analyses. This technique has potential for improving the diagnostic accuracy of fFOV-DWI for the study of specific tumoral areas.
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Affiliation(s)
- Antonello Vidiri
- Radiology and Diagnostic Imaging Department, Regina Elena National Cancer Institute, Rome, Italy
| | - Silvia Minosse
- Medical Physics Laboratory, Regina Elena National Cancer Institute, Rome, Italy
| | | | - Davide Curione
- Radiology Department, Catholic University of Rome, Rome, Italy
| | - Barbara Pichi
- Department of Otolaryngology Head and Neck Surgery, Regina Elena National Cancer Institute, Rome, Italy
| | - Giuseppe Spriano
- Department of Otolaryngology Head and Neck Surgery, Regina Elena National Cancer Institute, Rome, Italy
| | - Simona Marzi
- Medical Physics Laboratory, Regina Elena National Cancer Institute, Rome, Italy
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15
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Banerjee S, Nishimura DG, Shankaranarayanan A, Saritas EU. Reduced field-of-view DWI with robust fat suppression and unrestricted slice coverage using tilted 2D RF excitation. Magn Reson Med 2016; 76:1668-1676. [PMID: 27654126 DOI: 10.1002/mrm.26405] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 07/11/2016] [Accepted: 08/11/2016] [Indexed: 12/21/2022]
Abstract
PURPOSE Reduced field-of-view (rFOV) diffusion-weighted imaging (DWI) using 2D echo-planar radiofrequency (2DRF) excitation has been widely and successfully applied in clinical settings. The purpose of this work is to further improve its clinical utility by overcoming slice coverage limitations without any scan time penalty while providing robust fat suppression. THEORY AND METHODS During multislice imaging with 2DRF pulses, periodic sidelobes in the slice direction cause partial saturation, limiting the slice coverage. In this work, a tilting of the excitation plane is proposed to push the sidelobes out of the imaging section while preserving robust fat suppression. The 2DRF pulse is designed using Shinnar-Le Roux algorithm on a rotated excitation k-space. The performance of the method is validated via simulations, phantom experiments, and high in-plane resolution in vivo DWI of the spinal cord. RESULTS Results show that rFOV DWI using the tilted 2DRF pulse provides increased signal-to-noise ratio, extended coverage, and robust fat suppression, without any scan time penalty. CONCLUSION Using a tilted 2DRF excitation, a high-resolution rFOV DWI method with robust fat suppression and unrestricted slice coverage is presented. This method will be beneficial in clinical applications needing large slice coverage, for example, axial imaging of the spine, prostate, or breast. Magn Reson Med 76:1668-1676, 2016. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
| | - Dwight G Nishimura
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | | | - Emine Ulku Saritas
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.,National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
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Talbott JF, Narvid J, Chazen JL, Chin CT, Shah V. An Imaging-Based Approach to Spinal Cord Infection. Semin Ultrasound CT MR 2016; 37:411-30. [PMID: 27616314 DOI: 10.1053/j.sult.2016.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Infections of the spinal cord, nerve roots, and surrounding meninges are uncommon, but highly significant given their potential for severe morbidity and even mortality. Prompt diagnosis can be lifesaving, as many spinal infections are treatable. Advances in imaging technology have now firmly established magnetic resonance imaging (MRI) as the gold standard for spinal cord imaging evaluation, enabling the depiction of infectious myelopathies with exquisite detail and contrast. In this article, we aim to provide an overview of MRI findings for spinal cord infections with special focus on imaging patterns of infection that are primarily confined to the spinal cord, spinal meninges, and spinal nerve roots. In this context, we describe and organize this review around 5 distinct patterns of transverse spinal abnormality that may be detected with MRI as follows: (1) extramedullary, (2) centromedullary, (3) eccentric, (4) frontal horn, and (5) irregular. We seek to classify the most common presentations for a wide variety of infectious agents within this image-based framework while realizing that significant overlap and variation exists, including some infections that remain occult with conventional imaging techniques.
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Affiliation(s)
- Jason F Talbott
- Department of Radiology, San Francisco General Hospital, San Francisco, CA; Brain and Spinal Injury Center, San Francisco General Hospital, San Francisco, CA.
| | - Jared Narvid
- Department of Radiology, San Francisco General Hospital, San Francisco, CA
| | - J Levi Chazen
- Department of Radiology, Weill Cornell Medical School, New York, NY
| | - Cynthia T Chin
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA; Department of Radiology, San Francisco General Hospital, San Francisco, CA; Brain and Spinal Injury Center, San Francisco General Hospital, San Francisco, CA; Department of Radiology, Weill Cornell Medical School, New York, NY
| | - Vinil Shah
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA; Department of Radiology, San Francisco General Hospital, San Francisco, CA
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Koh DM, Lee JM, Bittencourt LK, Blackledge M, Collins DJ. Body Diffusion-weighted MR Imaging in Oncology: Imaging at 3 T. Magn Reson Imaging Clin N Am 2016; 24:31-44. [PMID: 26613874 DOI: 10.1016/j.mric.2015.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Advances in hardware and software enable high-quality body diffusion-weighted images to be acquired for oncologic assessment. 3.0 T affords improved signal/noise for higher spatial resolution and smaller field-of-view diffusion-weighted imaging (DWI). DWI at 3.0 T can be applied as at 1.5 T to improve tumor detection, disease characterization, and the assessment of treatment response. DWI at 3.0 T can be acquired on a hybrid PET-MR imaging system, to allow functional MR information to be combined with molecular imaging.
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Affiliation(s)
- Dow-Mu Koh
- Department of Radiology, Royal Marsden Hospital, Downs Road, Sutton, SM2 5PT, UK.
| | - Jeong-Min Lee
- Department of Radiology, Seoul National University Hospital, Seoul, South Korea
| | - Leonardo Kayat Bittencourt
- Department of Radiology, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil; CDPI and Multi-Imagem Clinics, Rio de Janeiro, Brazil
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18
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Kim H, Lee JM, Yoon JH, Jang JY, Kim SW, Ryu JK, Kannengiesser S, Han JK, Choi BI. Reduced Field-of-View Diffusion-Weighted Magnetic Resonance Imaging of the Pancreas: Comparison with Conventional Single-Shot Echo-Planar Imaging. Korean J Radiol 2015; 16:1216-25. [PMID: 26576110 PMCID: PMC4644742 DOI: 10.3348/kjr.2015.16.6.1216] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 07/21/2015] [Indexed: 02/01/2023] Open
Abstract
Objective To investigate the image quality (IQ) and apparent diffusion coefficient (ADC) of reduced field-of-view (FOV) di-ffusion-weighted imaging (DWI) of pancreas in comparison with full FOV DWI. Materials and Methods In this retrospective study, 2 readers independently performed qualitative analysis of full FOV DWI (FOV, 38 × 38 cm; b-value, 0 and 500 s/mm2) and reduced FOV DWI (FOV, 28 × 8.5 cm; b-value, 0 and 400 s/mm2). Both procedures were conducted with a two-dimensional spatially selective radiofrequency excitation pulse, in 102 patients with benign or malignant pancreatic diseases (mean size, 27.5 ± 14.4 mm). The study parameters included 1) anatomic structure visualization, 2) lesion conspicuity, 3) artifacts, 4) IQ score, and 5) subjective clinical utility for confirming or excluding initially considered differential diagnosis on conventional imaging. Another reader performed quantitative ADC measurements of focal pancreatic lesions and parenchyma. Wilcoxon signed-rank test was used to compare qualitative scores and ADCs between DWI sequences. Mann Whitney U-test was used to compare ADCs between the lesions and parenchyma. Results On qualitative analysis, reduced FOV DWI showed better anatomic structure visualization (2.76 ± 0.79 at b = 0 s/mm2 and 2.81 ± 0.64 at b = 400 s/mm2), lesion conspicuity (3.11 ± 0.99 at b = 0 s/mm2 and 3.15 ± 0.79 at b = 400 s/mm2), IQ score (8.51 ± 2.05 at b = 0 s/mm2 and 8.79 ± 1.60 at b = 400 s/mm2), and higher clinical utility (3.41 ± 0.64), as compared to full FOV DWI (anatomic structure, 2.18 ± 0.59 at b = 0 s/mm2 and 2.56 ± 0.47 at b = 500 s/mm2; lesion conspicuity, 2.55 ± 1.07 at b = 0 s/mm2 and 2.89 ± 0.86 at b = 500 s/mm2; IQ score, 7.13 ± 1.83 at b = 0 s/mm2 and 8.17 ± 1.31 at b = 500 s/mm2; clinical utility, 3.14 ± 0.70) (p < 0.05). Artifacts were significantly improved on reduced FOV DWI (2.65 ± 0.68) at b = 0 s/mm2 (full FOV DWI, 2.41 ± 0.63) (p < 0.001). On quantitative analysis, there were no significant differences between the 2 DWI sequences in ADCs of various pancreatic lesions and parenchyma (p > 0.05). ADCs of adenocarcinomas (1.061 × 10-3 mm2/s ± 0.133 at reduced FOV and 1.079 × 10-3 mm2/s ± 0.135 at full FOV) and neuroendocrine tumors (0.983 × 10-3 mm2/s ± 0.152 at reduced FOV and 1.004 × 10-3 mm2/s ± 0.153 at full FOV) were significantly lower than those of parenchyma (1.191 × 10-3 mm2/s ± 0.125 at reduced FOV and 1.218 × 10-3 mm2/s ± 0.103 at full FOV) (p < 0.05). Conclusion Reduced FOV DWI of the pancreas provides better overall IQ including better anatomic detail, lesion conspicuity and subjective clinical utility.
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Affiliation(s)
- Hyungjin Kim
- Department of Radiology, Seoul National University Hospital, Seoul 03080, Korea. ; Aerospace Medical Group, Air Force Education and Training Command, Jinju 52634, Korea
| | - Jeong Min Lee
- Department of Radiology, Seoul National University Hospital, Seoul 03080, Korea. ; Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Jeong Hee Yoon
- Department of Radiology, Seoul National University Hospital, Seoul 03080, Korea
| | - Jin-Young Jang
- Department of Surgery, Seoul National University Hospital, Seoul 03080, Korea
| | - Sun-Whe Kim
- Department of Surgery, Seoul National University Hospital, Seoul 03080, Korea
| | - Ji Kon Ryu
- Division of Gastroenterology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Korea
| | | | - Joon Koo Han
- Department of Radiology, Seoul National University Hospital, Seoul 03080, Korea. ; Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Byung Ihn Choi
- Department of Radiology, Seoul National University Hospital, Seoul 03080, Korea. ; Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 03080, Korea
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Barakat N, Shah P, Faro SH, Gaughan JP, Middleton D, Mulcahey MJ, Mohamed FB. Inter- and intra-rater reliability of diffusion tensor imaging parameters in the normal pediatric spinal cord. World J Radiol 2015; 7:279-85. [PMID: 26435778 PMCID: PMC4585951 DOI: 10.4329/wjr.v7.i9.279] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 06/24/2015] [Accepted: 07/29/2015] [Indexed: 02/06/2023] Open
Abstract
AIM To assess inter- and intra-rater reliability (agreement) between two region of interest (ROI) methods in pediatric spinal cord diffusion tensor imaging (DTI). METHODS Inner-Field-of-View DTI data previously acquired from ten pediatric healthy subjects (mean age = 12.10 years) was used to assess for reliability. ROIs were drawn by two neuroradiologists on each subject data twice within a 3-mo interval. ROIs were placed on axial B0 maps along the cervical spine using free-hand and fixed-size ROIs. Agreement analyses for fractional anisotropy (FA), axial diffusivity, radial diffusivity and mean diffusivity were performed using intra-class-correlation (ICC) and Cronbach's alpha statistical methods. RESULTS Inter- and intra-rater agreement between the two ROI methods showed moderate (ICC = 0.5) to strong (ICC = 0.84). There were significant differences between raters in the number of pixels selected using free-hand ROIs (P < 0.05). However, no significant differences were observed in DTI parameter values. FA showed highest variability in ICC values (0.10-0.87). Cronbach's alpha showed moderate-high values for raters and ROI methods. CONCLUSION The study showed that high reproducibility in spinal cord DTI can be achieved, and demonstrated the importance of setting detailed methodology for post-processing DTI data, specifically the placement of ROIs.
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20
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Barakat N, Gorman MP, Benson L, Becerra L, Borsook D. Pain and spinal cord imaging measures in children with demyelinating disease. NEUROIMAGE-CLINICAL 2015; 9:338-47. [PMID: 26509120 PMCID: PMC4588416 DOI: 10.1016/j.nicl.2015.08.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 08/19/2015] [Accepted: 08/28/2015] [Indexed: 12/15/2022]
Abstract
Pain is a significant problem in diseases affecting the spinal cord, including demyelinating disease. To date, studies have examined the reliability of clinical measures for assessing and classifying the severity of spinal cord injury (SCI) and also to evaluate SCI-related pain. Most of this research has focused on adult populations and patients with traumatic injuries. Little research exists regarding pediatric spinal cord demyelinating disease. One reason for this is the lack of reliable and useful approaches to measuring spinal cord changes since currently used diagnostic imaging has limited specificity for quantitative measures of demyelination. No single imaging technique demonstrates sufficiently high sensitivity or specificity to myelin, and strong correlation with clinical measures. However, recent advances in diffusion tensor imaging (DTI) and magnetization transfer imaging (MTI) measures are considered promising in providing increasingly useful and specific information on spinal cord damage. Findings from these quantitative imaging modalities correlate with the extent of demyelination and remyelination. These techniques may be of potential use for defining the evolution of the disease state, how it may affect specific spinal cord pathways, and contribute to the management of pediatric demyelination syndromes. Since pain is a major presenting symptom in patients with transverse myelitis, the disease is an ideal model to evaluate imaging methods to define these regional changes within the spinal cord. In this review we summarize (1) pediatric demyelinating conditions affecting the spinal cord; (2) their distinguishing features; and (3) current diagnostic and classification methods with particular focus on pain pathways. We also focus on concepts that are essential in developing strategies for the detection, monitoring, treatment and repair of pediatric myelitis. Pain is a major presenting symptom in children with myelitis. Currently used imaging has limited sensitivity to myelin content. We provide a summary on pediatric demyelinating conditions. We review pain involvement and pathways affected by demyelination. We review imaging modalities for the diagnosis and monitoring of myelitis.
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Affiliation(s)
- Nadia Barakat
- Center for Pain and the Brain, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Mark P Gorman
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Leslie Benson
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Lino Becerra
- Center for Pain and the Brain, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, USA ; Department of Radiology, Boston Children's Hospital, Boston, MA, USA
| | - David Borsook
- Center for Pain and the Brain, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, USA ; Department of Radiology, Boston Children's Hospital, Boston, MA, USA
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Palasis S, Hayes LL. Acquired pathology of the pediatric spine and spinal cord. Pediatr Radiol 2015; 45 Suppl 3:S420-32. [PMID: 26346148 DOI: 10.1007/s00247-015-3328-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 12/21/2014] [Accepted: 02/24/2015] [Indexed: 12/13/2022]
Abstract
Pediatric spine pathology poses a diagnostic challenge for radiologists. Acquired spine pathology often yields nonspecific signs and symptoms in children, especially in the younger age groups, and diagnostic delay can carry significant morbidity. This review is focused on some of the more common diagnostic dilemmas we face when attempting to evaluate and diagnose acquired pediatric spine anomalies in daily practice. An understanding of some of the key differentiating features of these disease processes in conjunction with pertinent history, physical exam, and advanced imaging techniques can indicate the correct diagnosis.
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Affiliation(s)
- Susan Palasis
- Department of Radiology at Scottish Rite, Children's Healthcare of Atlanta, 1001 Johnson Ferry Road, Atlanta, GA, 30342, USA,
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22
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Feng Z, Min X, Sah VK, Li L, Cai J, Deng M, Wang L. Comparison of field-of-view (FOV) optimized and constrained undistorted single shot (FOCUS) with conventional DWI for the evaluation of prostate cancer. Clin Imaging 2015; 39:851-5. [DOI: 10.1016/j.clinimag.2015.03.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 02/28/2015] [Accepted: 03/10/2015] [Indexed: 01/01/2023]
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Nocardia farcinica Meningitis Masquerading as Central Nervous System Metastasis in a Child With Cerebellar Pilocytic Astrocytoma. J Pediatr Hematol Oncol 2015; 37:482-5. [PMID: 26181420 DOI: 10.1097/mph.0000000000000360] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Juvenile pilocytic astrocytoma, the most common pediatric central nervous system (CNS) neoplasm, characteristically displays an indolent growth pattern and rarely demonstrates metastatic dissemination. Reports of infections mimicking CNS metastatic disease are also rare and can impact treatment. We report the youngest known case of a child with a CNS Nocardia farcinica infection who had a known cerebellar pilocytic astrocytoma, review other infections that may masquerade as CNS neoplasms, and discuss N. farcinica CNS infections.
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Repeatability Investigation of Reduced Field-of-View Diffusion-Weighted Magnetic Resonance Imaging on Thyroid Glands. J Comput Assist Tomogr 2015; 39:334-9. [PMID: 25700226 DOI: 10.1097/rct.0000000000000227] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To investigate the repeatability of the quantitative magnetic resonance imaging (MRI) metric (apparent diffusion coefficient [ADC]) derived from reduced field-of-view diffusion-weighted (rFOV DWI) on thyroid glands in a clinical setting. MATERIALS AND METHODS Ten healthy human volunteers were enrolled in MRI studies performed on a 3-T MRI scanner. Each volunteer was designed to undergo 3 longitudinal examinations (2 weeks apart) with 2 repetitive sessions within each examination, which included rFOV and conventional full field-of-view (fFOV) DWI scans. Diffusion-weighted images were assessed and scored based on image characteristics. Apparent diffusion coefficient values of thyroid glands from all participants were calculated based on regions of interest. Repeatability analysis was performed based on the framework proposed by the Quantitative Imaging Biomarker Alliance, generating 4 repeatability metrics: within-participant variance ((Equation is included in full-text article.)), repeatability coefficients, intraclass correlation coefficient, and within-participant coefficient of variation. Student t test was used to compare the performance difference between rFOV and fFOV DWI. RESULTS The overall image quality from rFOV DWI was significantly higher than that from fFOV DWI (P = 0.04). The ADC values calculated from rFOV DWI were significantly lower than corresponding values from fFOV DWI (P < 0.001). There was no significant difference in ADC values across sessions and examinations in either rFOV or fFOV DWI (P > 0.05). Reduced field-of-view DWI had lower values of (Equation is included in full-text article.), repeatability coefficient, and within-participant coefficient of variation and had a higher value of intraclass correlation coefficient compared with fFOV DWI across either sessions or examinations. CONCLUSIONS This study demonstrated that rFOV DWI produced more superior-quality DWI images and more repeatable ADC measurements compared with fFOV DWI, thus providing a feasible quantitative imaging tool for investigating thyroid glands in clinical settings.
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25
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Weidauer S, Nichtweiß M, Hattingen E, Berkefeld J. Spinal cord ischemia: aetiology, clinical syndromes and imaging features. Neuroradiology 2014; 57:241-57. [PMID: 25398656 DOI: 10.1007/s00234-014-1464-6] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/03/2014] [Indexed: 10/24/2022]
Abstract
INTRODUCTION The purpose of this study was to analyse MR imaging features and lesion patterns as defined by compromised vascular territories, correlating them to different clinical syndromes and aetiological aspects. METHODS In a 19.8-year period, clinical records and magnetic resonance imaging (MRI) features of 55 consecutive patients suffering from spinal cord ischemia were evaluated. RESULTS Aetiologies of infarcts were arteriosclerosis of the aorta and vertebral arteries (23.6%), aortic surgery or interventional aneurysm repair (11%) and aortic and vertebral artery dissection (11%), and in 23.6%, aetiology remained unclear. Infarcts occurred in 38.2% at the cervical and thoracic level, respectively, and 49% of patients suffered from centromedullar syndrome caused by anterior spinal artery ischemia. MRI disclosed hyperintense pencil-like lesion pattern on T2WI in 98.2%, cord swelling in 40%, enhancement on post-contrast T1WI in 42.9% and always hyperintense signal on diffusion-weighted imaging (DWI) when acquired. CONCLUSION The most common clinical feature in spinal cord ischemia is a centromedullar syndrome, and in contrast to anterior spinal artery ischemia, infarcts in the posterior spinal artery territory are rare. The exclusively cervical location of the spinal sulcal artery syndrome seems to be a likely consequence of anterior spinal artery duplication which is observed preferentially here.
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Affiliation(s)
- Stefan Weidauer
- Department of Neurology, Sankt Katharinen Hospital, Teaching Hospital of the Goethe - University, Frankfurt / Main, Seckbacher Landstraße 65, D 60389, Frankfurt / Main, Germany,
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Seeger A, Klose U, Bischof F, Strobel J, Ernemann U, Hauser TK. Zoomed EPI DWI of Acute Spinal Ischemia Using a Parallel Transmission System. Clin Neuroradiol 2014; 26:177-82. [PMID: 25168248 DOI: 10.1007/s00062-014-0342-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 08/14/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE A new method for diffusion-weighted imaging (DWI) using independent parallel transmission technique resulting in zoomed DWI was applied in four patients suffering from acute spinal cord ischemia. METHODS Four patients with clinical symptoms of acute spinal cord ischemia were examined on a 3 T MR-system equipped with a two-channel transmit array. Scans included T2-weighted turbo spin echo, conventional DWI, and zoomed DWI. Image evaluation was performed with regard to overall image quality, anatomic delineation of the spinal cord, and the level of confidence to establish the diagnosis of spinal cord ischemia. RESULTS Through spatially selective excitation, zoomed DWI allows for acquisition of high-resolution images with reduced scan time due to a reduced field of view in phase-encoding direction, resulting in zoomed images. In all cases the ischemia was demonstrated in conventional DWI as well as zoomed DWI. CONCLUSIONS Compared to conventional DWI, zoomed DWI enables a faster image acquisition and allowed a more detailed analysis of the spinal lesion which may be critical to attribute the lesion to a particular vessel territory.
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Affiliation(s)
- A Seeger
- Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany.
| | - U Klose
- Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany
| | - F Bischof
- Department of Neurology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany
| | - J Strobel
- Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany
| | - U Ernemann
- Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany
| | - T-K Hauser
- Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany
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Neuroimaging to investigate multisystem involvement and provide biomarkers in amyotrophic lateral sclerosis. BIOMED RESEARCH INTERNATIONAL 2014; 2014:467560. [PMID: 24949452 PMCID: PMC4052676 DOI: 10.1155/2014/467560] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 03/25/2014] [Indexed: 12/11/2022]
Abstract
Neuroimaging allows investigating the extent of neurological systems degeneration in amyotrophic lateral sclerosis (ALS). Advanced MRI methods can detect changes related to the degeneration of upper motor neurons but have also demonstrated the participation of other systems such as the sensory system or basal ganglia, demonstrating in vivo that ALS is a multisystem disorder. Structural and functional imaging also allows studying dysfunction of brain areas associated with cognitive signs. From a biomarker perspective, numerous studies using diffusion tensor imaging showed a decrease of fractional anisotropy in the intracranial portion of the corticospinal tract but its diagnostic value at the individual level remains limited. A multiparametric approach will be required to use MRI in the diagnostic workup of ALS. A promising avenue is the new methodological developments of spinal cord imaging that has the advantage to investigate the two motor system components that are involved in ALS, that is, the lower and upper motor neuron. For all neuroimaging modalities, due to the intrinsic heterogeneity of ALS, larger pooled banks of images with standardized image acquisition and analysis procedures are needed. In this paper, we will review the main findings obtained with MRI, PET, SPECT, and nuclear magnetic resonance spectroscopy in ALS.
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Goh C, Desmond PM, Phal PM. MRI in transverse myelitis. J Magn Reson Imaging 2014; 40:1267-79. [PMID: 24752988 DOI: 10.1002/jmri.24563] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 12/19/2013] [Indexed: 12/22/2022] Open
Abstract
Transverse myelitis is an acute inflammatory disease of the spinal cord, characterized by rapid onset of bilateral neurological symptoms. Weakness, sensory disturbance, and autonomic dysfunction evolve over hours or days, most progressing to maximal clinical severity within 10 days of onset. At maximal clinical severity, half will have a paraparesis, and almost all patients have sensory disturbance and bladder dysfunction. Residual disability is divided equally between severe, moderate and minimal or none. The causes of transverse myelitis are diverse; etiologies implicated include demyelinating conditions, collagen vascular disease, and parainfectious causes, however, despite extensive diagnostic work-up many cases are considered idiopathic. Due to heterogeneity in pathogenesis, and the similarity of its clinical presentation with those of various noninflammatory myelopathies, transverse myelitis has frequently been viewed as a diagnostic dilemma. However, as targeted therapies to optimize patient outcome develop, timely identification of the underlying etiology is becoming increasingly important. In this review, we describe the imaging and clinical features of idiopathic and disease-associated transverse myelitis and its major differentials, with discussion of how MR imaging features assist in the identification of various sub-types of transverse myelitis. We will also discuss the potential for advanced MR techniques to contribute to diagnosis and prognostication.
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Affiliation(s)
- Christine Goh
- Department of Radiology, Royal Melbourne Hospital, Parkville, Melbourne, Australia
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Saritas EU, Lee D, Çukur T, Shankaranarayanan A, Nishimura DG. Hadamard slice encoding for reduced-FOV diffusion-weighted imaging. Magn Reson Med 2013; 72:1277-90. [DOI: 10.1002/mrm.25044] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 10/22/2013] [Accepted: 10/24/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Emine Ulku Saritas
- Department of Electrical Engineering; Stanford University; Stanford California USA
- Department of Electrical and Electronics Engineering; Bilkent University; Bilkent Ankara Turkey
- National Magnetic Resonance Research Center (UMRAM); Bilkent University; Bilkent Ankara Turkey
| | - Daeho Lee
- Department of Electrical Engineering; Stanford University; Stanford California USA
| | - Tolga Çukur
- Department of Electrical Engineering; Stanford University; Stanford California USA
- Department of Electrical and Electronics Engineering; Bilkent University; Bilkent Ankara Turkey
- National Magnetic Resonance Research Center (UMRAM); Bilkent University; Bilkent Ankara Turkey
| | | | - Dwight G. Nishimura
- Department of Electrical Engineering; Stanford University; Stanford California USA
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