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Takemura H, Kruper JA, Miyata T, Rokem A. Tractometry of Human Visual White Matter Pathways in Health and Disease. Magn Reson Med Sci 2024; 23:316-340. [PMID: 38866532 PMCID: PMC11234945 DOI: 10.2463/mrms.rev.2024-0007] [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] [Indexed: 06/14/2024] Open
Abstract
Diffusion-weighted MRI (dMRI) provides a unique non-invasive view of human brain tissue properties. The present review article focuses on tractometry analysis methods that use dMRI to assess the properties of brain tissue within the long-range connections comprising brain networks. We focus specifically on the major white matter tracts that convey visual information. These connections are particularly important because vision provides rich information from the environment that supports a large range of daily life activities. Many of the diseases of the visual system are associated with advanced aging, and tractometry of the visual system is particularly important in the modern aging society. We provide an overview of the tractometry analysis pipeline, which includes a primer on dMRI data acquisition, voxelwise model fitting, tractography, recognition of white matter tracts, and calculation of tract tissue property profiles. We then review dMRI-based methods for analyzing visual white matter tracts: the optic nerve, optic tract, optic radiation, forceps major, and vertical occipital fasciculus. For each tract, we review background anatomical knowledge together with recent findings in tractometry studies on these tracts and their properties in relation to visual function and disease. Overall, we find that measurements of the brain's visual white matter are sensitive to a range of disorders and correlate with perceptual abilities. We highlight new and promising analysis methods, as well as some of the current barriers to progress toward integration of these methods into clinical practice. These barriers, such as variability in measurements between protocols and instruments, are targets for future development.
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Affiliation(s)
- Hiromasa Takemura
- Division of Sensory and Cognitive Brain Mapping, Department of System Neuroscience, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Hayama, Kanagawa, Japan
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology, Suita, Osaka, Japan
| | - John A Kruper
- Department of Psychology and eScience Institute, University of Washington, Seattle, WA, USA
| | - Toshikazu Miyata
- Division of Sensory and Cognitive Brain Mapping, Department of System Neuroscience, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology, Suita, Osaka, Japan
| | - Ariel Rokem
- Department of Psychology and eScience Institute, University of Washington, Seattle, WA, USA
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Zöllner FG. Editorial for "Comparison of Reduced and Full Field of View in Diffusion-Weighted MRI on Image Quality: A Meta-Analysis". J Magn Reson Imaging 2024. [PMID: 38924186 DOI: 10.1002/jmri.29488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 04/26/2024] [Indexed: 06/28/2024] Open
Affiliation(s)
- Frank G Zöllner
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Mannheim Institute for Intelligent Systems in Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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Tur C, Battiston M, Yiannakas MC, Collorone S, Calvi A, Prados F, Kanber B, Grussu F, Ricciardi A, Pajak P, Martinelli D, Schneider T, Ciccarelli O, Samson RS, Wheeler-Kingshott CAG. What contributes to disability in progressive MS? A brain and cervical cord-matched quantitative MRI study. Mult Scler 2024; 30:516-534. [PMID: 38372019 DOI: 10.1177/13524585241229969] [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] [Indexed: 02/20/2024]
Abstract
BACKGROUND We assessed the ability of a brain-and-cord-matched quantitative magnetic resonance imaging (qMRI) protocol to differentiate patients with progressive multiple sclerosis (PMS) from controls, in terms of normal-appearing (NA) tissue abnormalities, and explain disability. METHODS A total of 27 patients and 16 controls were assessed on the Expanded Disability Status Scale (EDSS), 25-foot timed walk (TWT), 9-hole peg (9HPT) and symbol digit modalities (SDMT) tests. All underwent 3T brain and (C2-C3) cord structural imaging and qMRI (relaxometry, quantitative magnetisation transfer, multi-shell diffusion-weighted imaging), using a fast brain-and-cord-matched protocol with brain-and-cord-unified imaging readouts. Lesion and NA-tissue volumes and qMRI metrics reflecting demyelination and axonal loss were obtained. Random forest analyses identified the most relevant volumetric/qMRI measures to clinical outcomes. Confounder-adjusted linear regression estimated the actual MRI-clinical associations. RESULTS Several qMRI/volumetric differences between patients and controls were observed (p < 0.01). Higher NA-deep grey matter quantitative-T1 (EDSS: beta = 7.96, p = 0.006; 9HPT: beta = -0.09, p = 0.004), higher NA-white matter orientation dispersion index (TWT: beta = -3.21, p = 0.005; SDMT: beta = -847.10, p < 0.001), lower whole-cord bound pool fraction (9HPT: beta = 0.79, p = 0.001) and higher NA-cortical grey matter quantitative-T1 (SDMT = -94.31, p < 0.001) emerged as particularly relevant predictors of greater disability. CONCLUSION Fast brain-and-cord-matched qMRI protocols are feasible and identify demyelination - combined with other mechanisms - as key for disability accumulation in PMS.
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Affiliation(s)
- Carmen Tur
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
- Multiple Sclerosis Centre of Catalonia (Cemcat). Vall d'Hebron Institute of Research. Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Marco Battiston
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Marios C Yiannakas
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Sara Collorone
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Alberto Calvi
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
- Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomèdiques August Pi i Sunyer, Hospital Clinic, Barcelona, Spain
| | - Ferran Prados
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, UK
- eHealth Center, Universitat Oberta de Catalunya, Barcelona, Spain
| | - Baris Kanber
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Francesco Grussu
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
- Radiomics Group, Vall d'Hebron Institute of Oncology, Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Antonio Ricciardi
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Patrizia Pajak
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Daniele Martinelli
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
| | | | - Olga Ciccarelli
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
- NIHR UCLH Biomedical Research Centre, London, UK
| | - Rebecca S Samson
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Claudia Am Gandini Wheeler-Kingshott
- NMR Research Unit, Queen Square Multiple Sclerosis Centre, UCL (University College London) Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy; Brain Connectivity Research Center, IRCCS Mondino Foundation, Pavia, Italy
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Takemura H, Liu W, Kuribayashi H, Miyata T, Kida I. Evaluation of simultaneous multi-slice readout-segmented diffusion-weighted MRI acquisition in human optic nerve measurements. Magn Reson Imaging 2023; 102:103-114. [PMID: 37149064 DOI: 10.1016/j.mri.2023.05.001] [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: 03/31/2022] [Revised: 05/02/2023] [Accepted: 05/02/2023] [Indexed: 05/08/2023]
Abstract
Diffusion-weighted magnetic resonance imaging (dMRI) is the only available method to measure the tissue properties of white matter tracts in living human brains and has opened avenues for neuroscientific and clinical studies on human white matter. However, dMRI using conventional simultaneous multi-slice (SMS) single-shot echo planar imaging (ssEPI) still presents challenges in the analyses of some specific white matter tracts, such as the optic nerve, which are heavily affected by susceptibility-induced artifacts. In this study, we evaluated dMRI data acquired by using SMS readout-segmented EPI (rsEPI), which aims to reduce susceptibility-induced artifacts by dividing the acquisition space into multiple segments along the readout direction to reduce echo spacing. To this end, we acquired dMRI data from 11 healthy volunteers by using SMS ssEPI and SMS rsEPI, and then compared the dMRI data of the human optic nerve between the SMS ssEPI and SMS rsEPI datasets by visual inspection of the datasets and statistical comparisons of fractional anisotropy (FA) values. In comparison with the SMS ssEPI data, the SMS rsEPI data showed smaller susceptibility-induced distortion and exhibited a significantly higher FA along the optic nerve. In summary, this study demonstrates that despite its prolonged acquisition time, SMS rsEPI is a promising approach for measuring the tissue properties of the optic nerve in living humans and will be useful for future neuroscientific and clinical investigations of this pathway.
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Affiliation(s)
- Hiromasa Takemura
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology, Suita, Japan; Division of Sensory and Cognitive Brain Mapping, Department of System Neuroscience, National Institute for Physiological Sciences, Okazaki, Japan; Graduate Institute for Advanced Studies, SOKENDAI, Hayama, Japan.
| | - Wei Liu
- Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China
| | | | - Toshikazu Miyata
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology, Suita, Japan; Division of Sensory and Cognitive Brain Mapping, Department of System Neuroscience, National Institute for Physiological Sciences, Okazaki, Japan; Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Ikuhiro Kida
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology, Suita, Japan; Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
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Johansson J, Lagerstrand K, Ivarsson L, Svensson PA, Hebelka H, Maier SE. Brain diffusion MRI with multiplexed sensitivity encoding for reduced distortion in a pediatric patient population. Magn Reson Imaging 2022; 87:97-103. [PMID: 34999160 DOI: 10.1016/j.mri.2022.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/30/2021] [Accepted: 01/04/2022] [Indexed: 10/19/2022]
Abstract
BACKGROUND Diffusion-weighted imaging (DWI) is a valuable tool for routine imaging of the pediatric brain. However, the commonly used single-shot (ss) echo-planar imaging (EPI) DWI sequence is prone to geometric distortions and T2*-blurring. This study aimed to investigate in a pediatric population the benefits of using multiplexed sensitivity-encoding (MUSE) without and with reversed polarity gradients (RPG) instead. METHODS This retrospective study compared image quality, geometric distortions, and diffusion values between three different approaches for DWI (ssEPI, MUSE, and RPG-MUSE) in 14 patients (median age = 4 (0.6-15) years, 11 males). Distortion levels were quantified and compared in two brain regions, i.e., the brain stem and the temporal lobes, using the Dice Coefficient and the Hausdorff Distance, with T2-weighted images as reference. Expected geometrical distortion was further evaluated by comparing the effective echo spacing between the DWI sequences. Apparent diffusion coefficient (ADC) values were determined in the genu of the corpus callosum and the optic nerves. Two raters graded overall image quality and image distortions on a Likert scale. RESULTS Distortion levels assessed with Dice coefficient and Hausdorff distance were significantly lower for MUSE (p < 0.05) and RPG-MUSE (p < 0.01) compared to ssEPI. No significant difference in ADC values was observed between methods. The RPG-MUSE method was graded by one rater as significantly higher in overall image quality than ssEPI (p < 0.05) and by both raters as significantly lower in levels of image distortions than both MUSE (p < 0.05) and ssEPI (p < 0.05). These results were in agreement with the reduced effective echo spacing was that was attained with MUSE and RPG-MUSE. CONCLUSION For imaging of the pediatric brain, MUSE and even more so RPG-MUSE offers both improved geometric fidelity and image quality compared to ssEPI.
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Affiliation(s)
- Jens Johansson
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
| | - Kerstin Lagerstrand
- Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Liz Ivarsson
- Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Pär-Arne Svensson
- Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Hanna Hebelka
- Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden; Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Stephan E Maier
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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Mournet S, Sené T, Charbonneau F, Poillon G, Vignal C, Clavel G, Guillaume J, Savatovsky J, Lecler A. Early diffusion-weighted MRI at 3 Tesla detects ischemic changes of the optic nerve in anterior ischemic optic neuropathy. Eur Radiol 2021; 32:3588-3596. [PMID: 34851430 DOI: 10.1007/s00330-021-08417-4] [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: 05/21/2021] [Revised: 09/21/2021] [Accepted: 10/15/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To assess the impact of timing from visual symptoms' onset to diffusion-weighted (DW) 3 T MRI completion to detect ischemic changes of the optic disc and optic nerve in AION patients. METHODS This IRB-approved retrospective single-center study included 3 T MRI data from 126 patients with AION and 111 controls with optic neuritis treated between January 2015 and May 2020. Two radiologists blinded to all data individually analyzed imaging. A senior neuroradiologist resolved any discrepancies by consensus. The primary judgment criterion was the restricted diffusion of the optic disc and/or the optic nerve assessed subjectively on the ADC maps. ADC values were also measured. Spearman rank correlations were used to examine the relationships between timing from visual symptoms' onset to MRI completion and both the restricted diffusion and the ADC values. RESULTS One hundred twenty-six patients (47/126 [37.3%] women and 79/126 [62.7%] men, mean age 69.1 ± 13.7 years) with AION were included. Restricted diffusion of the optic disc in AION eyes was more frequent in the early MRI group than in the late MRI group: 35/49 (71.4%) eyes versus 3/83 (3.6%) eyes, p < 0.001. ADC values of the pathological optic discs and optic nerves were lower in the early MRI group than in the late MRI group: 0.61 [0.52-0.94] × 10-3 mm2/s versus 1.28 [1.01-1.44] × 10-3 mm2/s, p < 0.001, and 0.74 [0.61-0.88] × 10-3 mm2/s versus 0.89 [0.72-1.10] × 10-3 mm2/s, p < 0.001, respectively. CONCLUSIONS DWI MRI showed good diagnostic performance to detect AION when performed early after the onset of visual symptoms. KEY POINTS • Restricted diffusion of the optic disc in eyes affected by AION was significantly more likely to be observed in patients who had undergone MRI within 5 days after onset of visual symptoms. • ADC values of the pathological optic discs and optic nerves were significantly lower in patients who had undergone MRI within 5 days after onset of visual symptoms of AION: 0.61 × 10-3 mm2/s versus 1.28 × 10-3 mm2/s, p < 0.001, and 0.74 × 10-3 mm2/s versus 0.89 × 10-3 mm2/s, p < 0.001, respectively. • The optimal threshold for timing from visual symptoms' onset to MRI completion to detect restricted diffusion of the optic disc and/or optic nerve was 5 days, with an AUC of 0.88 (CI95%: 0.82-0.94).
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Affiliation(s)
- Sandy Mournet
- Department of Neuroradiology, Foundation Adolphe de Rothschild Hospital, 29 rue Manin, 75019, Paris, France.
| | - Thomas Sené
- Department of Internal Medicine, Foundation Adolphe de Rothschild Hospital, Paris, France
| | - Frédérique Charbonneau
- Department of Neuroradiology, Foundation Adolphe de Rothschild Hospital, 29 rue Manin, 75019, Paris, France
| | - Guillaume Poillon
- Department of Neuroradiology, Foundation Adolphe de Rothschild Hospital, 29 rue Manin, 75019, Paris, France
| | - Catherine Vignal
- Department of Neuro-Ophthalmology, Foundation Adolphe de Rothschild Hospital, Paris, France
| | - Gaëlle Clavel
- Department of Internal Medicine, Foundation Adolphe de Rothschild Hospital, Paris, France
| | - Jessica Guillaume
- Department of Clinical Research, Foundation Adolphe de Rothschild Hospital, Paris, France
| | - Julien Savatovsky
- Department of Neuroradiology, Foundation Adolphe de Rothschild Hospital, 29 rue Manin, 75019, Paris, France
| | - Augustin Lecler
- Department of Neuroradiology, Foundation Adolphe de Rothschild Hospital, 29 rue Manin, 75019, Paris, France
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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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Deng F, Reinshagen KL, Li MD, Juliano AF. Motion degradation in optic nerve MRI: A randomized intraindividual comparison study of eye states. Eur J Radiol 2021; 142:109865. [PMID: 34298389 DOI: 10.1016/j.ejrad.2021.109865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 02/02/2023]
Abstract
PURPOSE MRI is a powerful tool for optic nerve assessment, but image quality can be degraded by artifacts related to ocular motion. The purpose of this investigation was to evaluate the effect of undergoing MRI with eyes open versus closed on the degree of motion degradation affecting the optic nerves. METHOD Patients undergoing 3 Tesla orbital MRI were randomized to undergo the coronal STIR sequence with eyes open and focused on a standardized fixation point, blinking as needed, or with eyes closed. The sequence was then performed again with the other instruction set. Two neuroradiologists rated the intraorbital optic nerves for motion artifact on a 5-point scale (higher numbers reflecting greater motion artifact) in 2 locations of each nerve. Differences were evaluated by the clustered Wilcoxon signed rank test. RESULTS Seventy-seven orbits were included. Interrater reliability was high (weighted kappa = 0.78). The anterior intraorbital optic nerves were rated with less motion artifact when eyes were open and focused during acquisition than when closed (p = 0.006), but this was not the case for the posterior intraorbital optic nerve (p = 0.69). For example, at the anterior intraorbital optic nerve, motion artifact of mean grade better than 2 was seen in 60% of eyes-open vs. 32% of eyes-closed acquisitions, while mean grade 4 or worse was seen in 4% of eyes-open vs. 12% of eyes-closed acquisitions. CONCLUSION Undergoing orbital MRI with eyes open and focused rather than closed reduces motion artifact at the anterior intraorbital segment of the optic nerve.
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Affiliation(s)
- Francis Deng
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
| | - Katherine L Reinshagen
- Department of Radiology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA.
| | - Matthew D Li
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
| | - Amy F Juliano
- Department of Radiology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA.
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Danyluk H, Sankar T, Beaulieu C. High spatial resolution nerve-specific DTI protocol outperforms whole-brain DTI protocol for imaging the trigeminal nerve in healthy individuals. NMR IN BIOMEDICINE 2021; 34:e4427. [PMID: 33038059 DOI: 10.1002/nbm.4427] [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: 04/13/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
Diffusion tensor imaging (DTI) can provide markers of axonal micro-structure of the trigeminal nerve (cranial nerve five [CNV]), which may be affected in trigeminal neuralgia (TN) and other disorders. Previous attempts to image CNV have used low spatial resolution DTI protocols designed for whole-brain acquisition that are susceptible to errors from partial volume effects, particularly with adjacent cerebrospinal fluid (CSF). The purpose of this study was to develop a nerve-specific DTI protocol in healthy subjects that provides more accurate CNV tractography and diffusion quantification than whole-brain protocols. Four DTI protocols were compared in five healthy individuals (age 22-45 years, three males) on a 3 T Siemens Prisma MRI scanner: two newly developed nerve-specific high resolution (1.2 x 1.2 x 1.2 = 1.7 mm3 ) DTI protocols without (3.5 minutes) and with CSF suppression (fluid-attenuated inversion recovery [FLAIR]; 7.5 minutes) with limited slice-coverage, and two typical whole-brain protocols with either isotropic (2 x 2 x 2 = 8 mm3 ) or thicker slice anisotropic (1.9 x 1.9 x 3 = 10.8 mm3 ) voxels. Deterministic tractography was used to identify the CNV and quantify bilateral fractional anisotropy (FA), and mean (MD), axial (AD) and radial diffusivity (RD). CNV volume was determined by manual tracing on T1-weighted images. High spatial resolution nerve-specific protocols yielded better delineation of CNV, with less distortions and blurring, and markedly different diffusion parameters (42% higher FA, 35% lower MD, 27% lower RD and 43% lower AD) compared with the two lower resolution whole-brain protocols. The anisotropic whole-brain protocol showed a positive correlation between CNV FA and volume. The high resolution nerve-specific protocol with FLAIR yielded additional reductions in CNV AD and MD with a value of 1.0 x 10-3 mm2 /s, approaching that expected for healthy young adult white matter. In conclusion, high resolution nerve-specific DTI with FLAIR enhances the identification of CNV and provides more accurate quantification of diffusion compared with lower resolution whole-brain approaches.
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Affiliation(s)
- Hayden Danyluk
- Department of Surgery, Division of Surgical Research, University of Alberta, Edmonton, Canada
- Department of Surgery, Division of Neurosurgery, University of Alberta, Edmonton, Canada
| | - Tejas Sankar
- Department of Surgery, Division of Neurosurgery, University of Alberta, Edmonton, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
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Yon M, Bao Q, Chitrit OJ, Henriques RN, Shemesh N, Frydman L. High-Resolution 3D in vivo Brain Diffusion Tensor Imaging at Ultrahigh Fields: Following Maturation on Juvenile and Adult Mice. Front Neurosci 2020; 14:590900. [PMID: 33328861 PMCID: PMC7714913 DOI: 10.3389/fnins.2020.590900] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/22/2020] [Indexed: 12/20/2022] Open
Abstract
Diffusion tensor imaging (DTI) is a well-established technique for mapping brain microstructure and white matter tracts in vivo. High resolution DTI, however, is usually associated with low intrinsic sensitivity and therefore long acquisition times. By increasing sensitivity, high magnetic fields can alleviate these demands, yet high fields are also typically associated with significant susceptibility-induced image distortions. This study explores the potential arising from employing new pulse sequences and emerging hardware at ultrahigh fields, to overcome these limitations. To this end, a 15.2 T MRI instrument equipped with a cryocooled surface transceiver coil was employed, and DTI experiments were compared between SPatiotemporal ENcoding (SPEN), a technique that tolerates well susceptibility-induced image distortions, and double-sampled Spin-Echo Echo-Planar Imaging (SE-EPI) methods. Following optimization, SE-EPI afforded whole brain DTI maps at 135 μm isotropic resolution that possessed higher signal-to-noise ratios (SNRs) than SPEN counterparts. SPEN, however, was a better alternative to SE-EPI when focusing on challenging regions of the mouse brain -including the olfactory bulb and the cerebellum. In these instances, the higher robustness of fully refocused SPEN acquisitions coupled to its built-in zooming abilities, provided in vivo DTI maps with 75 μm nominal isotropic spatial resolution. These DTI maps, and in particular the mean diffusion direction (MDD) details, exhibited variations that matched very well the anatomical features known from histological brain Atlases. Using these capabilities, the development of the olfactory bulb (OB) in live mice was followed from week 1 post-partum, until adulthood. The diffusivity of this organ showed a systematic decrease in its overall isotropic value and increase in its fractional anisotropy with age; this maturation was observed for all regions used in the OB's segmentation but was most evident for the lobules' centers, in particular for the granular cell layer. The complexity of the OB neuronal connections also increased during maturation, as evidenced by the growth in directionalities arising in the mean diffusivity direction maps.
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Affiliation(s)
- Maxime Yon
- Department of Chemical and Biological Physics, Weizmann Institute, Rehovot, Israel
| | - Qingjia Bao
- Department of Chemical and Biological Physics, Weizmann Institute, Rehovot, Israel
| | | | | | - Noam Shemesh
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Lucio Frydman
- Department of Chemical and Biological Physics, Weizmann Institute, Rehovot, Israel
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11
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Haykal S, Jansonius NM, Cornelissen FW. Investigating changes in axonal density and morphology of glaucomatous optic nerves using fixel-based analysis. Eur J Radiol 2020; 133:109356. [DOI: 10.1016/j.ejrad.2020.109356] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 09/18/2020] [Accepted: 10/11/2020] [Indexed: 12/13/2022]
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Grussu F, Battiston M, Veraart J, Schneider T, Cohen-Adad J, Shepherd TM, Alexander DC, Fieremans E, Novikov DS, Gandini Wheeler-Kingshott CAM. Multi-parametric quantitative in vivo spinal cord MRI with unified signal readout and image denoising. Neuroimage 2020; 217:116884. [PMID: 32360689 PMCID: PMC7378937 DOI: 10.1016/j.neuroimage.2020.116884] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/18/2020] [Accepted: 04/23/2020] [Indexed: 12/11/2022] Open
Abstract
Multi-parametric quantitative MRI (qMRI) of the spinal cord is a promising non-invasive tool to probe early microstructural damage in neurological disorders. It is usually performed in vivo by combining acquisitions with multiple signal readouts, which exhibit different thermal noise levels, geometrical distortions and susceptibility to physiological noise. This ultimately hinders joint multi-contrast modelling and makes the geometric correspondence of parametric maps challenging. We propose an approach to overcome these limitations, by implementing state-of-the-art microstructural MRI of the spinal cord with a unified signal readout in vivo (i.e. with matched spatial encoding parameters across a range of imaging contrasts). We base our acquisition on single-shot echo planar imaging with reduced field-of-view, and obtain data from two different vendors (vendor 1: Philips Achieva; vendor 2: Siemens Prisma). Importantly, the unified acquisition allows us to compare signal and noise across contrasts, thus enabling overall quality enhancement via multi-contrast image denoising methods. As a proof-of-concept, here we provide a demonstration with one such method, known as Marchenko-Pastur (MP) Principal Component Analysis (PCA) denoising. MP-PCA is a singular value (SV) decomposition truncation approach that relies on redundant acquisitions, i.e. such that the number of measurements is large compared to the number of components that are maintained in the truncated SV decomposition. Here we used in vivo and synthetic data to test whether a unified readout enables more efficient MP-PCA denoising of less redundant acquisitions, since these can be denoised jointly with more redundant ones. We demonstrate that a unified readout provides robust multi-parametric maps, including diffusion and kurtosis tensors from diffusion MRI, myelin metrics from two-pool magnetisation transfer, and T1 and T2 from relaxometry. Moreover, we show that MP-PCA improves the quality of our multi-contrast acquisitions, since it reduces the coefficient of variation (i.e. variability) by up to 17% for mean kurtosis, 8% for bound pool fraction (myelin-sensitive), and 13% for T1, while enabling more efficient denoising of modalities limited in redundancy (e.g. relaxometry). In conclusion, multi-parametric spinal cord qMRI with unified readout is feasible and provides robust microstructural metrics with matched resolution and distortions, whose quality benefits from multi-contrast denoising methods such as MP-PCA.
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Affiliation(s)
- Francesco Grussu
- Queen Square MS Centre, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK; Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK.
| | - Marco Battiston
- Queen Square MS Centre, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Jelle Veraart
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, USA
| | | | - Julien Cohen-Adad
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, Canada; Functional Neuroimaging Unit, CRIUGM, Université de Montréal, Montreal, Canada
| | - Timothy M Shepherd
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, USA
| | - Daniel C Alexander
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK
| | - Els Fieremans
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, USA
| | - Dmitry S Novikov
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, USA
| | - Claudia A M Gandini Wheeler-Kingshott
- Queen Square MS Centre, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK; Brain MRI 3T Research Centre, IRCCS Mondino Foundation, Pavia, Italy; Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
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Kyriakopoulos M, Bargiotas T, Barker GJ, Frangou S. Diffusion tensor imaging in schizophrenia. Eur Psychiatry 2020; 23:255-73. [DOI: 10.1016/j.eurpsy.2007.12.004] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Revised: 11/19/2007] [Accepted: 12/03/2007] [Indexed: 12/12/2022] Open
Abstract
AbstractDiffusion tensor imaging (DTI) is a magnetic resonance imaging technique that is increasingly being used for the non-invasive evaluation of brain white matter abnormalities. In this review, we discuss the basic principles of DTI, its roots and the contribution of European centres in its development, and we review the findings from DTI studies in schizophrenia. We searched EMBASE, PubMed, PsychInfo, and Medline from February 1998 to December 2006 using as keywords ‘schizophrenia’, ‘diffusion’, ‘tensor’, and ‘DTI’. Forty studies fulfilling the inclusion criteria of this review were included and systematically reviewed. White matter abnormalities in many diverse brain regions were identified in schizophrenia. Although the findings are not completely consistent, frontal and temporal white matter seems to be more commonly affected. Limitations and future directions of this method are discussed.
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Accelerated Segmented Diffusion-Weighted Prostate Imaging for Higher Resolution, Higher Geometric Fidelity, and Multi-b Perfusion Estimation. Invest Radiol 2019; 54:238-246. [PMID: 30601292 DOI: 10.1097/rli.0000000000000536] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
PURPOSE The aim of this study was to improve the geometric fidelity and spatial resolution of multi-b diffusion-weighted magnetic resonance imaging of the prostate. MATERIALS AND METHODS An accelerated segmented diffusion imaging sequence was developed and evaluated in 25 patients undergoing multiparametric magnetic resonance imaging examinations of the prostate. A reduced field of view was acquired using an endorectal coil. The number of sampled diffusion weightings, or b-factors, was increased to allow estimation of tissue perfusion based on the intravoxel incoherent motion (IVIM) model. Apparent diffusion coefficients measured with the proposed segmented method were compared with those obtained with conventional single-shot echo-planar imaging (EPI). RESULTS Compared with single-shot EPI, the segmented method resulted in faster acquisition with 2-fold improvement in spatial resolution and a greater than 3-fold improvement in geometric fidelity. Apparent diffusion coefficient values measured with the novel sequence demonstrated excellent agreement with those obtained from the conventional scan (R = 0.91 for bmax = 500 s/mm and R = 0.89 for bmax = 1400 s/mm). The IVIM perfusion fraction was 4.0% ± 2.7% for normal peripheral zone, 6.6% ± 3.6% for normal transition zone, and 4.4% ± 2.9% for suspected tumor lesions. CONCLUSIONS The proposed accelerated segmented prostate diffusion imaging sequence achieved improvements in both spatial resolution and geometric fidelity, along with concurrent quantification of IVIM perfusion.
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15
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Kim LH, Lee EH, Galvez M, Aksoy M, Skare S, O’Halloran R, Edwards MSB, Holdsworth SJ, Yeom KW. Reduced field of view echo-planar imaging diffusion tensor MRI for pediatric spinal tumors. J Neurosurg Spine 2019; 31:607-615. [PMID: 31277060 PMCID: PMC6942637 DOI: 10.3171/2019.4.spine19178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/01/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Spine MRI is a diagnostic modality for evaluating pediatric CNS tumors. Applying diffusion-weighted MRI (DWI) or diffusion tensor imaging (DTI) to the spine poses challenges due to intrinsic spinal anatomy that exacerbates various image-related artifacts, such as signal dropouts or pileups, geometrical distortions, and incomplete fat suppression. The zonal oblique multislice (ZOOM)-echo-planar imaging (EPI) technique reduces geometric distortion and image blurring by reducing the field of view (FOV) without signal aliasing into the FOV. The authors hypothesized that the ZOOM-EPI method for spine DTI in concert with conventional spinal MRI is an efficient method for augmenting the evaluation of pediatric spinal tumors. METHODS Thirty-eight consecutive patients (mean age 8 years) who underwent ZOOM-EPI spine DTI for CNS tumor workup were retrospectively identified. Patients underwent conventional spine MRI and ZOOM-EPI DTI spine MRI. Two blinded radiologists independently reviewed two sets of randomized images: conventional spine MRI without ZOOM-EPI DTI, and conventional spine MRI with ZOOM-EPI DTI. For both image sets, the reviewers scored the findings based on lesion conspicuity and diagnostic confidence using a 5-point Likert scale. The reviewers also recorded presence of tumors. Quantitative apparent diffusion coefficient (ADC) measurements of various spinal tumors were extracted. Tractography was performed in a subset of patients undergoing presurgical evaluation. RESULTS Sixteen patients demonstrated spinal tumor lesions. The readers were in moderate agreement (kappa = 0.61, 95% CI 0.30-0.91). The mean scores for conventional MRI and combined conventional MRI and DTI were as follows, respectively: 3.0 and 4.0 for lesion conspicuity (p = 0.0039), and 2.8 and 3.9 for diagnostic confidence (p < 0.001). ZOOM-EPI DTI identified new lesions in 3 patients. In 3 patients, tractography used for neurosurgical planning showed characteristic fiber tract projections. The mean weighted ADCs of low- and high-grade tumors were 1201 × 10-6 and 865 × 10-6 mm2/sec (p = 0.002), respectively; the mean minimum weighted ADCs were 823 × 10-6 and 474 × 10-6 mm2/sec (p = 0.0003), respectively. CONCLUSIONS Diffusion MRI with ZOOM-EPI can improve the detection of spinal lesions while providing quantitative diffusion information that helps distinguish low- from high-grade tumors. By adding a 2-minute DTI scan, quantitative diffusion information and tract profiles can reliably be obtained and serve as a useful adjunct to presurgical planning for pediatric spinal tumors.
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Affiliation(s)
- Lily H. Kim
- Department of Neurosurgery, Stanford University School of Medicine, Stanford
| | - Edward H. Lee
- Department of Electrical Engineering, Stanford University, Stanford, California
| | - Michelle Galvez
- Department of Radiology, Stanford University School of Medicine, Stanford
| | - Murat Aksoy
- Department of Radiology, Stanford University School of Medicine, Stanford
| | - Stefan Skare
- Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Rafael O’Halloran
- Hyperfine Research Inc., Guilford, Connecticut; University of Auckland, New Zealand
| | | | - Samantha J. Holdsworth
- Department of Anatomy and Medical Imaging & Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, New Zealand
| | - Kristen W. Yeom
- Department of Radiology, Stanford University School of Medicine, Stanford
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Holdsworth SJ, O'Halloran R, Setsompop K. The quest for high spatial resolution diffusion-weighted imaging of the human brain in vivo. NMR IN BIOMEDICINE 2019; 32:e4056. [PMID: 30730591 DOI: 10.1002/nbm.4056] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 09/11/2018] [Accepted: 11/08/2018] [Indexed: 06/09/2023]
Abstract
Diffusion-weighted imaging, a contrast unique to MRI, is used for assessment of tissue microstructure in vivo. However, this exquisite sensitivity to finer scales far above imaging resolution comes at the cost of vulnerability to errors caused by sources of motion other than diffusion motion. Addressing the issue of motion has traditionally limited diffusion-weighted imaging to a few acquisition techniques and, as a consequence, to poorer spatial resolution than other MRI applications. Advances in MRI imaging methodology have allowed diffusion-weighted MRI to push to ever higher spatial resolution. In this review we focus on the pulse sequences and associated techniques under development that have pushed the limits of image quality and spatial resolution in diffusion-weighted MRI.
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Affiliation(s)
- Samantha J Holdsworth
- Department of Anatomy Medical Imaging & Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | | | - Kawin Setsompop
- Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
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17
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Kim JW, Andersson JL, Seifert AC, Sun P, Song SK, Dula C, Naismith RT, Xu J. Incorporating non-linear alignment and multi-compartmental modeling for improved human optic nerve diffusion imaging. Neuroimage 2019; 196:102-113. [PMID: 30930313 DOI: 10.1016/j.neuroimage.2019.03.058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 03/22/2019] [Accepted: 03/25/2019] [Indexed: 12/19/2022] Open
Abstract
In vivo human optic nerve diffusion magnetic resonance imaging (dMRI) is technically challenging with two outstanding issues not yet well addressed: (i) non-linear optic nerve movement, independent of head motion, and (ii) effect from partial-volumed cerebrospinal fluid or interstitial fluid such as in edema. In this work, we developed a non-linear optic nerve registration algorithm for improved volume alignment in axial high resolution optic nerve dMRI. During eyes-closed dMRI data acquisition, optic nerve dMRI measurements by diffusion tensor imaging (DTI) with and without free water elimination (FWE), and by diffusion basis spectrum imaging (DBSI), as well as optic nerve motion, were characterized in healthy adults at various locations along the posterior-to-anterior dimension. Optic nerve DTI results showed consistent trends in microstructural parametric measurements along the posterior-to-anterior direction of the entire intraorbital optic nerve, while the anterior portion of the intraorbital optic nerve exhibited the largest spatial displacement. Multi-compartmental dMRI modeling, such as DTI with FWE or DBSI, was less subject to spatially dependent biases in diffusivity and anisotropy measurements in the optic nerve which corresponded to similar spatial distributions of the estimated fraction of isotropic diffusion components. DBSI results derived from our clinically feasible (∼10 min) optic nerve dMRI protocol in this study are consistent with those from small animal studies, which provides the basis for evaluating the utility of multi-compartmental dMRI modeling in characterizing coexisting pathophysiology in human optic neuropathies.
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Affiliation(s)
- Joo-Won Kim
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Jesper Lr Andersson
- Wellcome Center for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - Alan C Seifert
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Peng Sun
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Sheng-Kwei Song
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Courtney Dula
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Robert T Naismith
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Junqian Xu
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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18
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Gaspar AS, Nunes RG, Ferrazzi G, Hughes EJ, Hutter J, Malik SJ, McCabe L, Baruteau KP, Rutherford MA, Hajnal JV, Price AN. Optimizing maternal fat suppression with constrained image-based shimming in fetal MR. Magn Reson Med 2019; 81:477-485. [PMID: 30058204 PMCID: PMC6282825 DOI: 10.1002/mrm.27375] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 05/02/2018] [Accepted: 05/03/2018] [Indexed: 12/21/2022]
Abstract
PURPOSE Echo planar imaging (EPI) is the primary sequence for functional and diffusion MRI. In fetal applications, the large field of view needed to encode the maternal abdomen leads to prolonged EPI readouts, which may be further extended due to safety considerations that limit gradient performance. The resulting images become very sensitive to water-fat shift and susceptibility artefacts. The purpose of this study was to reduce artefacts and increase stability of EPI in fetal brain imaging, balancing local field homogeneity across the fetal brain with longer range variations to ensure compatibility with fat suppression of the maternal abdomen. METHODS Spectral Pre-saturation with Inversion-Recovery (SPIR) fat suppression was optimized by investigating SPIR pulse frequency offsets. Subsequently, fetal brain EPI data were acquired using image-based (IB) shimming on 6 pregnant women by (1) minimizing B0 field variations within the fetal brain (localized IB shimming) and (2) with added constraint to limit B0 variation in maternal fat (fat constrained IB shimming). RESULTS The optimal offset for the SPIR pulse at 3 Tesla was 550 Hz. Both shimming approaches had similar performances in terms of B0 homogeneity within the brain, but constrained IB shimming enabled higher fat suppression efficiency. CONCLUSION Optimized SPIR in combination with constrained IB shimming can improve maternal fat suppression while minimizing EPI distortions in the fetal brain.
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Affiliation(s)
- Andreia S. Gaspar
- Centre for the Developing Brain, School of Biomedical Engineering & Imaging SciencesKing's College London, St Thomas' HospitalLondonUnited Kingdom
- Institute for Systems and Robotics/Department of Bioengineering, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal
- Instituto de Biofísica e Engenharia BiomédicaFaculdade de Ciências da Universidade de LisboaCampo GrandeLisbonPortugal
| | - Rita G. Nunes
- Centre for the Developing Brain, School of Biomedical Engineering & Imaging SciencesKing's College London, St Thomas' HospitalLondonUnited Kingdom
- Institute for Systems and Robotics/Department of Bioengineering, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal
- Instituto de Biofísica e Engenharia BiomédicaFaculdade de Ciências da Universidade de LisboaCampo GrandeLisbonPortugal
| | - Giulio Ferrazzi
- Centre for the Developing Brain, School of Biomedical Engineering & Imaging SciencesKing's College London, St Thomas' HospitalLondonUnited Kingdom
| | - Emer J. Hughes
- Centre for the Developing Brain, School of Biomedical Engineering & Imaging SciencesKing's College London, St Thomas' HospitalLondonUnited Kingdom
| | - Jana Hutter
- Centre for the Developing Brain, School of Biomedical Engineering & Imaging SciencesKing's College London, St Thomas' HospitalLondonUnited Kingdom
| | - Shaihan J. Malik
- Centre for the Developing Brain, School of Biomedical Engineering & Imaging SciencesKing's College London, St Thomas' HospitalLondonUnited Kingdom
| | - Laura McCabe
- Centre for the Developing Brain, School of Biomedical Engineering & Imaging SciencesKing's College London, St Thomas' HospitalLondonUnited Kingdom
| | - Kelly P. Baruteau
- Centre for the Developing Brain, School of Biomedical Engineering & Imaging SciencesKing's College London, St Thomas' HospitalLondonUnited Kingdom
- Lysholm Department of Neuroradiology, National Hospital for Neurology and NeurosurgeryUniversity College London Hospitals NHS Foundation TrustLondonUnited Kingdom
| | - Mary A. Rutherford
- Centre for the Developing Brain, School of Biomedical Engineering & Imaging SciencesKing's College London, St Thomas' HospitalLondonUnited Kingdom
| | - Joseph V. Hajnal
- Centre for the Developing Brain, School of Biomedical Engineering & Imaging SciencesKing's College London, St Thomas' HospitalLondonUnited Kingdom
| | - Anthony N. Price
- Centre for the Developing Brain, School of Biomedical Engineering & Imaging SciencesKing's College London, St Thomas' HospitalLondonUnited Kingdom
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19
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Grussu F, Ianuş A, Tur C, Prados F, Schneider T, Kaden E, Ourselin S, Drobnjak I, Zhang H, Alexander DC, Gandini Wheeler-Kingshott CAM. Relevance of time-dependence for clinically viable diffusion imaging of the spinal cord. Magn Reson Med 2018; 81:1247-1264. [PMID: 30229564 PMCID: PMC6586052 DOI: 10.1002/mrm.27463] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 06/28/2018] [Accepted: 06/29/2018] [Indexed: 12/17/2022]
Abstract
Purpose Time‐dependence is a key feature of the diffusion‐weighted (DW) signal, knowledge of which informs biophysical modelling. Here, we study time‐dependence in the human spinal cord, as its axonal structure is specific and different from the brain. Methods We run Monte Carlo simulations using a synthetic model of spinal cord white matter (WM) (large axons), and of brain WM (smaller axons). Furthermore, we study clinically feasible multi‐shell DW scans of the cervical spinal cord (b = 0; b = 711 s mm−2; b = 2855 s mm−2), obtained using three diffusion times (Δ of 29, 52 and 76 ms) from three volunteers. Results Both intra‐/extra‐axonal perpendicular diffusivities and kurtosis excess show time‐dependence in our synthetic spinal cord model. This time‐dependence is reflected mostly in the intra‐axonal perpendicular DW signal, which also exhibits strong decay, unlike our brain model. Time‐dependence of the total DW signal appears detectable in the presence of noise in our synthetic spinal cord model, but not in the brain. In WM in vivo, we observe time‐dependent macroscopic and microscopic diffusivities and diffusion kurtosis, NODDI and two‐compartment SMT metrics. Accounting for large axon calibers improves fitting of multi‐compartment models to a minor extent. Conclusions Time‐dependence of clinically viable DW MRI metrics can be detected in vivo in spinal cord WM, thus providing new opportunities for the non‐invasive estimation of microstructural properties. The time‐dependence of the perpendicular DW signal may feature strong intra‐axonal contributions due to large spinal axon caliber. Hence, a popular model known as “stick” (zero‐radius cylinder) may be sub‐optimal to describe signals from the largest spinal axons.
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Affiliation(s)
- Francesco Grussu
- Queen Square MS Centre, UCL Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom.,Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
| | - Andrada Ianuş
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom.,Champalimaud Centre for the Unknown, Champalimaud Foundation, Lisbon, Portugal
| | - Carmen Tur
- Queen Square MS Centre, UCL Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom
| | - Ferran Prados
- Queen Square MS Centre, UCL Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom.,Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | | | - Enrico Kaden
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
| | - Sébastien Ourselin
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Ivana Drobnjak
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
| | - Hui Zhang
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
| | - Daniel C Alexander
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom.,Clinical Imaging Research Centre, National University of Singapore, Singapore, Singapore
| | - Claudia A M Gandini Wheeler-Kingshott
- Queen Square MS Centre, UCL Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom.,Brain MRI 3T Research Centre, C. Mondino National Neurological Institute, Pavia, Italy.,Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
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20
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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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21
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Comparison of field-of-view optimized and constrained undistorted single-shot diffusion-weighted imaging and conventional diffusion-weighted imaging of optic nerve and chiasma at 3T. Neuroradiology 2018; 60:903-912. [DOI: 10.1007/s00234-018-2058-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/10/2018] [Indexed: 10/28/2022]
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Sartoretti T, Sartoretti E, Binkert C, Gutzeit A, Reischauer C, Czell D, Wyss M, Brüllmann E, Sartoretti-Schefer S. Diffusion-Weighted Zonal Oblique Multislice-EPI Enhances the Detection of Small Lesions with Diffusion Restriction in the Brain Stem and Hippocampus: A Clinical Report of Selected Cases. AJNR Am J Neuroradiol 2018; 39:1255-1259. [PMID: 29700045 DOI: 10.3174/ajnr.a5635] [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: 10/19/2017] [Accepted: 03/05/2018] [Indexed: 12/30/2022]
Abstract
Diffusion restriction is the morphologic hallmark of acute ischemic infarcts and excitotoxic brain injury in various cerebral pathologies. Diffusion restriction is visible as hyperintensity on DWI and as hypointensity on ADC maps. Due to the vicinity of multiple anatomic structures in the brain stem and hippocampus, very small lesions with diffusion restriction may result in severe clinical symptomatology, but these small lesions easily go undetected on standard cerebral DWI due to insufficient spatial resolution, T2* blurring, and image artifacts caused by susceptibility-related image distortions. Diffusion-weighted zonal oblique multislice-EPI with reduced FOV acquisition permits a considerable increase in spatial resolution and enhances the visualization of very small pathologic lesions in the brain stem and hippocampus. Improved performance in the depiction of different pathologic lesions with diffusion restriction in the brain stem and hippocampus using this sequence compared with standard DWI in selected cases is presented.
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Affiliation(s)
- T Sartoretti
- From the Institut für Radiologie (T.S., E.S., C.B., M.W., S.S.-S.), Kantonsspital Winterthur, Winterthur, Switzerland
| | - E Sartoretti
- From the Institut für Radiologie (T.S., E.S., C.B., M.W., S.S.-S.), Kantonsspital Winterthur, Winterthur, Switzerland
| | - C Binkert
- From the Institut für Radiologie (T.S., E.S., C.B., M.W., S.S.-S.), Kantonsspital Winterthur, Winterthur, Switzerland
| | - A Gutzeit
- Institut für Radiologie und Nuklearmedizin (A.G., C.R.), Hirslanden Klinik St. Anna, Luzern, Switzerland
| | - C Reischauer
- Institut für Radiologie und Nuklearmedizin (A.G., C.R.), Hirslanden Klinik St. Anna, Luzern, Switzerland
| | - D Czell
- Medizinische Klinik (D.C.), Abteilung für Neurologie, Uznach, Switzerland
| | - M Wyss
- From the Institut für Radiologie (T.S., E.S., C.B., M.W., S.S.-S.), Kantonsspital Winterthur, Winterthur, Switzerland
- Philips HealthSystems (M.W., E.B.), Zürich, Switzerland
| | - E Brüllmann
- Philips HealthSystems (M.W., E.B.), Zürich, Switzerland
| | - S Sartoretti-Schefer
- From the Institut für Radiologie (T.S., E.S., C.B., M.W., S.S.-S.), Kantonsspital Winterthur, Winterthur, Switzerland
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Paul K, Huelnhagen T, Oberacker E, Wenz D, Kuehne A, Waiczies H, Schmitter S, Stachs O, Niendorf T. Multiband diffusion-weighted MRI of the eye and orbit free of geometric distortions using a RARE-EPI hybrid. NMR IN BIOMEDICINE 2018; 31:e3872. [PMID: 29315932 DOI: 10.1002/nbm.3872] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 10/19/2017] [Accepted: 11/02/2017] [Indexed: 06/07/2023]
Abstract
Diffusion-weighted imaging (DWI) provides information on tissue microstructure. Single-shot echo planar imaging (EPI) is the most common technique for DWI applications in the brain, but is prone to geometric distortions and signal voids. Rapid acquisition with relaxation enhancement [RARE, also known as fast spin echo (FSE)] imaging presents a valuable alternative to DWI with high anatomical accuracy. This work proposes a multi-shot diffusion-weighted RARE-EPI hybrid pulse sequence, combining the anatomical integrity of RARE with the imaging speed and radiofrequency (RF) power deposition advantage of EPI. The anatomical integrity of RARE-EPI was demonstrated and quantified by center of gravity analysis for both morphological images and diffusion-weighted acquisitions in phantom and in vivo experiments at 3.0 T and 7.0 T. The results indicate that half of the RARE echoes in the echo train can be replaced by EPI echoes whilst maintaining anatomical accuracy. The reduced RF power deposition of RARE-EPI enabled multiband RF pulses facilitating simultaneous multi-slice imaging. This study shows that diffusion-weighted RARE-EPI has the capability to acquire high fidelity, distortion-free images of the eye and the orbit. It is shown that RARE-EPI maintains the immunity to B0 inhomogeneities reported for RARE imaging. This benefit can be exploited for the assessment of ocular masses and pathological changes of the eye and the orbit.
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Affiliation(s)
- Katharina Paul
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Till Huelnhagen
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Eva Oberacker
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Daniel Wenz
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | | | | | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Oliver Stachs
- Department of Ophthalmology, University of Rostock, Rostock, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
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24
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Seeger A, Schulze M, Schuettauf F, Ernemann U, Hauser TK. Advanced diffusion-weighted imaging in patients with optic neuritis deficit - value of reduced field of view DWI and readout-segmented DWI. Neuroradiol J 2018; 31:126-132. [PMID: 29417865 DOI: 10.1177/1971400918757711] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Objective The objective of this article is to evaluate advanced techniques of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) measurements of the optic nerve in patients with optic neuritis. Methods In this prospective and institutional review board-approved trial, we examined 15 patients with acute visual loss and clinical signs of optic neuritis including thin-slice multi-shot segmented readout of long variable echo trains (rs-EPI, RESOLVE) DWI and reduced field-of view DWI using a parallel transmit system (rFOV-EPI). Conventional single-shot echo-planar DWI (ss-EPI) of the whole brain was available in 13 patients. Subjective image quality was compared using a four-point scale and objective ADC measurements were performed in comparison with the non-affected side. Results In the intraorbital segment, subjective image quality was significantly higher in rFOV-EPI (score 3.3 ± 0.8) compared with rs-EPI (score 2.1 ± 0.8) and ss-EPI (score 0.9 ± 0.8). Diagnosis was hampered in the canalicular segment ( n = 3) and the intracranial segment ( n = 1) in all applied DWI techniques. ADC measurements of the affected side differed significantly in all DWI sequences ss-EPI (sensitivity 54%, accuracy 77%), rs-EPI (sensitivity 71%, accuracy 86%), and rFOV-EPI (sensitivity 73%, accuracy 87%). Conclusion Optic neuritis in the intraorbital segment can be detected with high sensitivity without the need for contrast application. Using rFOV-EPI improves subjective image quality compared with rs-EPI and ss-EPI. Due to its higher spatial resolution, rFOV-EPI was the preferred technique in our study and can ensure the diagnosis in the intraorbital segment. However, artefacts occur in the canalicular and intracranial segment of the optic nerve, therefore contrast-enhanced T1-weighted images must still be considered as the gold standard.
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Affiliation(s)
- Achim Seeger
- 1 Diagnostic and Interventional Neuroradiology, University Hospital of Tübingen, Germany.,2 Radiologiepraxis Tübingen, Germany
| | - Maximilian Schulze
- 1 Diagnostic and Interventional Neuroradiology, University Hospital of Tübingen, Germany
| | - Frank Schuettauf
- 3 Department of Ophthalmology, University Hospital Hamburg-Eppendorf, Germany
| | - Ulrike Ernemann
- 1 Diagnostic and Interventional Neuroradiology, University Hospital of Tübingen, Germany
| | - Till-Karsten Hauser
- 1 Diagnostic and Interventional Neuroradiology, University Hospital of Tübingen, Germany
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Massire A, Rasoanandrianina H, Taso M, Guye M, Ranjeva JP, Feiweier T, Callot V. Feasibility of single-shot multi-level multi-angle diffusion tensor imaging of the human cervical spinal cord at 7T. Magn Reson Med 2018; 80:947-957. [DOI: 10.1002/mrm.27087] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/07/2017] [Accepted: 12/26/2017] [Indexed: 01/11/2023]
Affiliation(s)
- Aurélien Massire
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
- iLab-Spine - Laboratoire international associé - Imagerie et Biomécanique du rachis, France; Canada
| | - Henitsoa Rasoanandrianina
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
- iLab-Spine - Laboratoire international associé - Imagerie et Biomécanique du rachis, France; Canada
| | - Manuel Taso
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
- iLab-Spine - Laboratoire international associé - Imagerie et Biomécanique du rachis, France; Canada
- Division of MRI Research, Department of Radiology; Beth Israel Deaconess Medical Center & Harvard Medical School; Boston Massachusetts USA
| | - Maxime Guye
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
| | - Jean-Philippe Ranjeva
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
- iLab-Spine - Laboratoire international associé - Imagerie et Biomécanique du rachis, France; Canada
| | | | - Virginie Callot
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
- iLab-Spine - Laboratoire international associé - Imagerie et Biomécanique du rachis, France; Canada
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26
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Battiston M, Grussu F, Ianus A, Schneider T, Prados F, Fairney J, Ourselin S, Alexander DC, Cercignani M, Gandini Wheeler-Kingshott CAM, Samson RS. An optimized framework for quantitative magnetization transfer imaging of the cervical spinal cord in vivo. Magn Reson Med 2017; 79:2576-2588. [PMID: 28921614 PMCID: PMC5836910 DOI: 10.1002/mrm.26909] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 08/15/2017] [Accepted: 08/16/2017] [Indexed: 11/06/2022]
Abstract
PURPOSE To develop a framework to fully characterize quantitative magnetization transfer indices in the human cervical cord in vivo within a clinically feasible time. METHODS A dedicated spinal cord imaging protocol for quantitative magnetization transfer was developed using a reduced field-of-view approach with echo planar imaging (EPI) readout. Sequence parameters were optimized based in the Cramer-Rao-lower bound. Quantitative model parameters (i.e., bound pool fraction, free and bound pool transverse relaxation times [ T2F, T2B], and forward exchange rate [kFB ]) were estimated implementing a numerical model capable of dealing with the novelties of the sequence adopted. The framework was tested on five healthy subjects. RESULTS Cramer-Rao-lower bound minimization produces optimal sampling schemes without requiring the establishment of a steady-state MT effect. The proposed framework allows quantitative voxel-wise estimation of model parameters at the resolution typically used for spinal cord imaging (i.e. 0.75 × 0.75 × 5 mm3 ), with a protocol duration of ∼35 min. Quantitative magnetization transfer parametric maps agree with literature values. Whole-cord mean values are: bound pool fraction = 0.11(±0.01), T2F = 46.5(±1.6) ms, T2B = 11.0(±0.2) µs, and kFB = 1.95(±0.06) Hz. Protocol optimization has a beneficial effect on reproducibility, especially for T2B and kFB . CONCLUSION The framework developed enables robust characterization of spinal cord microstructure in vivo using qMT. Magn Reson Med 79:2576-2588, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- Marco Battiston
- Queen Square MS Centre, UCL Institute of Neurology, University College London, London, United Kingdom
| | - Francesco Grussu
- Queen Square MS Centre, UCL Institute of Neurology, University College London, London, United Kingdom
| | - Andrada Ianus
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom.,Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | | | - Ferran Prados
- Queen Square MS Centre, UCL Institute of Neurology, University College London, London, United Kingdom.,Translational Imaging Group, Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - James Fairney
- Queen Square MS Centre, UCL Institute of Neurology, University College London, London, United Kingdom.,UCL Department of Medical Physics and Bioengineering, University College London, London, United Kingdom
| | - Sebastien Ourselin
- Translational Imaging Group, Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Daniel C Alexander
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
| | - Mara Cercignani
- CISC, Department of Neuroscience, Brighton & Sussex Medical School, Brighton, Sussex, United Kingdom
| | - Claudia A M Gandini Wheeler-Kingshott
- Queen Square MS Centre, UCL Institute of Neurology, University College London, London, United Kingdom.,Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy.,Brain MRI 3T Mondino Research Center, C. Mondino National Neurological Institute, Pavia, Italy
| | - Rebecca S Samson
- Queen Square MS Centre, UCL Institute of Neurology, University College London, London, United Kingdom
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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: 83] [Impact Index Per Article: 11.9] [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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Quantitative assessment of optic nerve in patients with Leber’s hereditary optic neuropathy using reduced field-of-view diffusion tensor imaging. Eur J Radiol 2017; 93:24-29. [DOI: 10.1016/j.ejrad.2017.05.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 05/21/2017] [Indexed: 11/22/2022]
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Battiston M, Schneider T, Prados F, Grussu F, Yiannakas MC, Ourselin S, Gandini Wheeler-Kingshott CAM, Samson RS. Fast and reproducible in vivo T 1 mapping of the human cervical spinal cord. Magn Reson Med 2017; 79:2142-2148. [PMID: 28736946 DOI: 10.1002/mrm.26852] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 07/04/2017] [Accepted: 07/05/2017] [Indexed: 12/16/2022]
Abstract
PURPOSE To develop a fast and robust method for measuring T1 in the whole cervical spinal cord in vivo, and to assess its reproducibility. METHODS A spatially nonselective adiabatic inversion pulse is combined with zonally oblique-magnified multislice echo-planar imaging to produce a reduced field-of-view inversion-recovery echo-planar imaging protocol. Multi- inversion time data are obtained by cycling slice order throughout sequence repetitions. Measurement of T1 is performed using 12 inversion times for a total protocol duration of 7 min. Reproducibility of regional T1 estimates is assessed in a scan-rescan experiment on five heathy subjects. RESULTS Regional mean (standard deviation) T1 was: 1108.5 (±77.2) ms for left lateral column, 1110.1 (±83.2) ms for right lateral column, 1150.4 (±102.6) ms for dorsal column, and 1136.4 (±90.8) ms for gray matter. Regional T1 estimates showed good correlation between sessions (Pearson correlation coefficient = 0.89 (P value < 0.01); mean difference = 2 ms, 95% confidence interval ± 20 ms); and high reproducibility (intersession coefficient of variation approximately 1% in all the regions considered, intraclass correlation coefficient = 0.88 (P value < 0.01, confidence interval 0.71-0.95)). CONCLUSIONS T1 estimates in the cervical spinal cord are reproducible using inversion-recovery zonally oblique-magnified multislice echo-planar imaging. The short acquisition time and large coverage of this method paves the way for accurate T1 mapping for various spinal cord pathologies. Magn Reson Med 79:2142-2148, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- Marco Battiston
- NMR Research Unit, Queen Square MS Center, Department of Neuroinflammation, UCL Institute of Neurology, University College London, London, United Kingdom
| | | | - Ferran Prados
- NMR Research Unit, Queen Square MS Center, Department of Neuroinflammation, UCL Institute of Neurology, University College London, London, United Kingdom.,Translational Imaging Group, Center for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Francesco Grussu
- NMR Research Unit, Queen Square MS Center, Department of Neuroinflammation, UCL Institute of Neurology, University College London, London, United Kingdom
| | - Marios C Yiannakas
- NMR Research Unit, Queen Square MS Center, Department of Neuroinflammation, UCL Institute of Neurology, University College London, London, United Kingdom
| | - Sebastien Ourselin
- Translational Imaging Group, Center for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Claudia A M Gandini Wheeler-Kingshott
- NMR Research Unit, Queen Square MS Center, Department of Neuroinflammation, UCL Institute of Neurology, University College London, London, United Kingdom.,Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy.,Brain MRI 3T Mondino Research Center, C. Mondino National Neurological Institute, Pavia, Italy
| | - Rebecca S Samson
- NMR Research Unit, Queen Square MS Center, Department of Neuroinflammation, UCL Institute of Neurology, University College London, London, United Kingdom
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David G, Freund P, Mohammadi S. The efficiency of retrospective artifact correction methods in improving the statistical power of between-group differences in spinal cord DTI. Neuroimage 2017; 158:296-307. [PMID: 28669912 PMCID: PMC6168644 DOI: 10.1016/j.neuroimage.2017.06.051] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 06/19/2017] [Accepted: 06/21/2017] [Indexed: 11/10/2022] Open
Abstract
Diffusion tensor imaging (DTI) is a promising approach for investigating the white matter microstructure of the spinal cord. However, it suffers from severe susceptibility, physiological, and instrumental artifacts present in the cord. Retrospective correction techniques are popular approaches to reduce these artifacts, because they are widely applicable and do not increase scan time. In this paper, we present a novel outlier rejection approach (reliability masking) which is designed to supplement existing correction approaches by excluding irreversibly corrupted and thus unreliable data points from the DTI index maps. Then, we investigate how chains of retrospective correction techniques including (i) registration, (ii) registration and robust fitting, and (iii) registration, robust fitting, and reliability masking affect the statistical power of a previously reported finding of lower fractional anisotropy values in the posterior column and lateral corticospinal tracts in cervical spondylotic myelopathy (CSM) patients. While established post-processing steps had small effect on the statistical power of the clinical finding (slice-wise registration: −0.5%, robust fitting: +0.6%), adding reliability masking to the post-processing chain increased it by 4.7%. Interestingly, reliability masking and registration affected the t-score metric differently: while the gain in statistical power due to reliability masking was mainly driven by decreased variability in both groups, registration slightly increased variability. In conclusion, reliability masking is particularly attractive for neuroscience and clinical research studies, as it increases statistical power by reducing group variability and thus provides a cost-efficient alternative to increasing the group size. A novel outlier rejection technique (reliability masking) is introduced. Standard artifact correction has little effect on the statistical power of between-group differences. Reliability masking improves the statistical power of between-group differences. This improvement is driven by decreased group-level variability.
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Affiliation(s)
- Gergely David
- Spinal Cord Injury Center Balgrist, Balgrist University Hospital, Zurich, Switzerland; Department of Systems Neuroscience, Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Patrick Freund
- Spinal Cord Injury Center Balgrist, Balgrist University Hospital, Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom; Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Siawoosh Mohammadi
- Department of Systems Neuroscience, Medical Center Hamburg-Eppendorf, Hamburg, Germany; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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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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Samson RS, Lévy S, Schneider T, Smith AK, Smith SA, Cohen-Adad J, Gandini Wheeler-Kingshott CAM. ZOOM or Non-ZOOM? Assessing Spinal Cord Diffusion Tensor Imaging Protocols for Multi-Centre Studies. PLoS One 2016; 11:e0155557. [PMID: 27171194 PMCID: PMC4865165 DOI: 10.1371/journal.pone.0155557] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/29/2016] [Indexed: 12/02/2022] Open
Abstract
The purpose of this study was to develop and evaluate two spinal cord (SC) diffusion tensor imaging (DTI) protocols, implemented at multiple sites (using scanners from two different manufacturers), one available on any clinical scanner, and one using more advanced options currently available in the research setting, and to use an automated processing method for unbiased quantification. DTI parameters are sensitive to changes in the diseased SC. However, imaging the cord can be technically challenging due to various factors including its small size, patient-related and physiological motion, and field inhomogeneities. Rapid acquisition sequences such as Echo Planar Imaging (EPI) are desirable but may suffer from image distortions. We present a multi-centre comparison of two acquisition protocols implemented on scanners from two different vendors (Siemens and Philips), one using a reduced field-of-view (rFOV) EPI sequence, and one only using options available on standard clinical scanners such as outer volume suppression (OVS). Automatic analysis was performed with the Spinal Cord Toolbox for unbiased and reproducible quantification of DTI metrics in the white matter. Images acquired using the rFOV sequence appear less distorted than those acquired using OVS alone. SC DTI parameter values obtained using both sequences at all sites were consistent with previous measurements made at 3T. For the same scanner manufacturer, DTI parameter inter-site SDs were smaller for the rFOV sequence compared to the OVS sequence. The higher inter-site reproducibility (for the same manufacturer and acquisition details, i.e. ZOOM data acquired at the two Philips sites) of rFOV compared to the OVS sequence supports the idea that making research options such as rFOV more widely available would improve accuracy of measurements obtained in multi-centre clinical trials. Future multi-centre studies should also aim to match the rFOV technique and signal-to-noise ratios in all sequences from different manufacturers/sites in order to avoid any bias in measured DTI parameters and ensure similar sensitivity to pathological changes.
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Affiliation(s)
- Rebecca S. Samson
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom
- * E-mail:
| | - Simon Lévy
- Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, QC, Canada
- Functional Neuroimaging Unit, University of Montreal, Montreal, QC, Canada
| | - Torben Schneider
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom
- Philips Healthcare, Guilford, Surrey, United Kingdom
| | - Alex K. Smith
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Seth A. Smith
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Julien Cohen-Adad
- Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, QC, Canada
- Functional Neuroimaging Unit, University of Montreal, Montreal, QC, Canada
| | - Claudia A. M. Gandini Wheeler-Kingshott
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom
- Brain MRI 3T Center, C. Mondino National Neurological Institute, Pavia, Italy
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
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Zhang Y, Guo X, Wang M, Wang L, Tian Q, Zheng D, Shi D. Reduced Field-of-View Diffusion Tensor Imaging of the Optic Nerve in Retinitis Pigmentosa at 3T. AJNR Am J Neuroradiol 2016; 37:1510-5. [PMID: 27056427 DOI: 10.3174/ajnr.a4767] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 02/06/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Diffusion tensor imaging may reflect pathology of the optic nerve; however, the ability of DTI to evaluate alterations of the optic nerve in retinitis pigmentosa has not yet been assessed, to our knowledge. The aim of this study was to investigate the diagnostic potential of reduced FOV-DTI in optic neuropathy of retinitis pigmentosa at 3T. MATERIALS AND METHODS Thirty-eight patients and thirty-five healthy controls were enrolled in this study. Measures of visual field and visual acuity of both eyes in all subjects were performed. A reduced FOV-DTI sequence was used to derive fractional anisotropy, apparent diffusion coefficient, principal eigenvalue, and orthogonal eigenvalue of the individual optic nerves. Mean fractional anisotropy, ADC, and eigenvalue maps were obtained for quantitative analysis. Further analyses were performed to determine the correlation of fractional anisotropy, ADC, principal eigenvalue, and orthogonal eigenvalue with optic nerves in patients with mean deviation of the visual field and visual acuity, respectively. RESULTS The optic nerves of patients with retinitis pigmentosa compared with control subjects showed significantly higher ADC, principal eigenvalue, and orthogonal eigenvalue and significantly lower fractional anisotropy (P < .01). For patients with retinitis pigmentosa, the mean deviation of the visual field of the optic nerve was significantly correlated with mean fractional anisotropy (r = 0.364, P = .001) and orthogonal eigenvalue (r = -0.254, P = .029), but it was not correlated with mean ADC (P = .154) and principal eigenvalue (P = .337). Moreover, no correlation between any DTI parameter and visual acuity in patients with retinitis pigmentosa was observed (P > .05). CONCLUSIONS Reduced FOV-DTI measurement of the optic nerve may serve as a biomarker of axonal and myelin damage in optic neuropathy for patients with retinitis pigmentosa.
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Affiliation(s)
- Y Zhang
- From the Departments of Radiology (Y.Z., M.W., L.W., Q.T., D.S.)
| | - X Guo
- Ophthalmology (X.G.), Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - M Wang
- From the Departments of Radiology (Y.Z., M.W., L.W., Q.T., D.S.)
| | - L Wang
- From the Departments of Radiology (Y.Z., M.W., L.W., Q.T., D.S.)
| | - Q Tian
- From the Departments of Radiology (Y.Z., M.W., L.W., Q.T., D.S.)
| | - D Zheng
- GE Healthcare (D.Z.), Beijing, China
| | - D Shi
- From the Departments of Radiology (Y.Z., M.W., L.W., Q.T., D.S.)
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Downey K, Attygalle AD, Morgan VA, Giles SL, MacDonald A, Davis M, Ind TEJ, Shepherd JH, deSouza NM. Comparison of optimised endovaginal vs external array coil T2-weighted and diffusion-weighted imaging techniques for detecting suspected early stage (IA/IB1) uterine cervical cancer. Eur Radiol 2016; 26:941-50. [PMID: 26162579 PMCID: PMC4778155 DOI: 10.1007/s00330-015-3899-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 06/09/2015] [Accepted: 06/22/2015] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To compare sensitivity and specificity of endovaginal versus external-array coil T2-W and T2-W + DWI for detecting and staging small cervical tumours. METHODS Optimised endovaginal and external array coil MRI at 3.0-T was done prospectively in 48 consecutive patients with stage Ia/Ib1 cervical cancer. Sensitivity/specificity for detecting tumour and parametrial extension against histopathology for a reading radiologist were determined on coronal T2-W and T2W + DW images. An independent radiologist also scored T2-W images without and with addition of DWI for the external-array and endovaginal coils on separate occasions >2 weeks apart. Cohen's kappa assessed inter- and intra-observer agreement. RESULTS Median tumour volume in 19/38 cases positive on subsequent histology was 1.75 cm(3). Sensitivity, specificity, PPV, NPV were: reading radiologist 91.3 %, 89.5 %, 91.3 %, 89.5 %, respectively; independent radiologist T2-W 82.6 %, 73.7 %, 79.1 %, 77.8 % for endovaginal, 73.9 %, 89.5 %, 89.5 %, 73.9 % for external-array coil. Adding DWI improved sensitivity and specificity of endovaginal imaging (78.2 %, 89.5 %); adding DWI to external-array imaging improved specificity (94.7 %) but reduced sensitivity (66.7 %). Inter- and intra-observer agreement on T2-W + DWI was good (kappa = 0.67 and 0.62, respectively). CONCLUSION Endovaginal coil T2-W MRI is more sensitive than external-array coil for detecting tumours <2 cm(3); adding DWI improves specificity of endovaginal imaging but reduces sensitivity of external-array imaging. KEY POINTS • Endovaginal more accurate than external-array T2-W MRI for detecting small cervical cancers. • Addition of DWI improves sensitivity and specificity of endovaginal T2-W imaging. • Addition of DWI substantially reduces sensitivity of external-array T2-W imaging.
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Affiliation(s)
- Kate Downey
- CRUK Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Surrey, SM2 5PT, UK
| | - Ayoma D Attygalle
- Department of Histopathology, The Royal Marsden NHS Foundation Trust, Fulham Road, London, SW3 6JJ, UK
| | - Veronica A Morgan
- CRUK Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Surrey, SM2 5PT, UK
| | - Sharon L Giles
- CRUK Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Surrey, SM2 5PT, UK
| | - A MacDonald
- CRUK Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Surrey, SM2 5PT, UK
| | - M Davis
- Department of Gynaecology, Kingston Hospital, Galsworthy Road, Kingston-upon-Thames, Surrey, KT2 7QB, UK
| | - Thomas E J Ind
- Gynecology Unit, The Royal Marsden NHS Foundation Trust, Fulham Road, London, SW3 6JJ, UK
| | - John H Shepherd
- Gynecology Unit, The Royal Marsden NHS Foundation Trust, Fulham Road, London, SW3 6JJ, UK
| | - Nandita M deSouza
- CRUK Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Surrey, SM2 5PT, UK.
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Yamada H, Yamamoto A, Okada T, Kanagaki M, Fushimi Y, Porter DA, Tanji M, Hojo M, Miyamoto S, Togashi K. Diffusion tensor imaging of the optic chiasm in patients with intra- or parasellar tumor using readout-segmented echo-planar. Magn Reson Imaging 2016; 34:654-61. [PMID: 26806681 DOI: 10.1016/j.mri.2016.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Revised: 01/12/2016] [Accepted: 01/14/2016] [Indexed: 11/19/2022]
Abstract
PURPOSE To evaluate the impact of surgery on the optic pathway of patients with intra- or parasellar mass lesions, as evidenced by readout-segmented DTI. MATERIALS AND METHODS Twenty-four patients with intra- or parasellar mass lesions were included in the study. Readout-segmented DTI and T2WI were obtained before and after surgery. The ROIs were set on the optic chiasm as well as the anterior and posterior optic tracts. For each ROI, axial diffusivity (AD), radial diffusivity (RD), fractional anisotropy (FA), and ADC values were calculated. DTI parameters in preoperative studies of all patients were compared and related to the presence of tumor compression. In patients who underwent surgery, pre- and postoperative DTI parameters were compared. The correlation between DTI parameters and visual function was determined. RESULTS In the preoperative studies, the optic chiasm of patients with tumor compression showed significant lower AD and RD values. The optic chiasm of patients with visual field disorder showed significantly lower AD and RD values compared to patients without the disorder. There was a negative correlation with a trend toward significance between FA values and visual field disorder scores. The comparative analysis of patients in pre- and postoperative studies showed that the optic chiasm of patients with tumor compression presented a significant lower FA (0.41 versus 0.30, p=0.0068) and higher RD values after surgery. CONCLUSIONS DTI is a useful tool to assess the impact of surgery on the optic chiasm and nerve.
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Affiliation(s)
- Hirofumi Yamada
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Akira Yamamoto
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Tomohisa Okada
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Mitsunori Kanagaki
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Yasutaka Fushimi
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - David A Porter
- Fraunhofer MEVIS, Universitätsallee 29, 28359, Bremen, Germany
| | - Masahiro Tanji
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Masato Hojo
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Susumu Miyamoto
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Kaori Togashi
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
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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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Role of Diffusion Tensor MR Imaging in Degenerative Cervical Spine Disease: a Review of the Literature. Clin Neuroradiol 2015; 26:265-76. [DOI: 10.1007/s00062-015-0467-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/10/2015] [Indexed: 12/13/2022]
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Viallon M, Cuvinciuc V, Delattre B, Merlini L, Barnaure-Nachbar I, Toso-Patel S, Becker M, Lovblad KO, Haller S. State-of-the-art MRI techniques in neuroradiology: principles, pitfalls, and clinical applications. Neuroradiology 2015; 57:441-67. [PMID: 25859832 DOI: 10.1007/s00234-015-1500-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 02/04/2015] [Indexed: 12/20/2022]
Abstract
This article reviews the most relevant state-of-the-art magnetic resonance (MR) techniques, which are clinically available to investigate brain diseases. MR acquisition techniques addressed include notably diffusion imaging (diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), and diffusion kurtosis imaging (DKI)) as well as perfusion imaging (dynamic susceptibility contrast (DSC), arterial spin labeling (ASL), and dynamic contrast enhanced (DCE)). The underlying models used to process these images are described, as well as the theoretic underpinnings of quantitative diffusion and perfusion MR imaging-based methods. The technical requirements and how they may help to understand, classify, or follow-up neurological pathologies are briefly summarized. Techniques, principles, advantages but also intrinsic limitations, typical artifacts, and alternative solutions developed to overcome them are discussed. In this article, we also review routinely available three-dimensional (3D) techniques in neuro MRI, including state-of-the-art and emerging angiography sequences, and briefly introduce more recently proposed 3D quantitative neuro-anatomy sequences, and new technology, such as multi-slice and multi-transmit imaging.
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Affiliation(s)
- Magalie Viallon
- CREATIS, UMR CNRS 5220 - INSERM U1044, INSA de Lyon, Université de Lyon, Lyon, France,
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Optic nerve diffusion tensor imaging parameters and their correlation with optic disc topography and disease severity in adult glaucoma patients and controls. J Glaucoma 2015; 23:513-20. [PMID: 23632406 DOI: 10.1097/ijg.0b013e318294861d] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate optic nerve diffusion tensor imaging (DTI) parameters in glaucoma patients and controls, and to correlate DTI parameters with the rim area obtained with Heidelberg retina tomography (HRT) and with the severity of glaucomatous damage using the Glaucoma Staging System. DESIGN Pilot study. METHODS Twenty-seven patients with glaucoma and 12 control subjects underwent DTI and HRT imaging. Main outcome measures included: fractional anisotropy, mean diffusivity, axial diffusivity, radial diffusivity, HRT rim area, and Glaucoma Staging System stage. RESULTS In group comparison, mean diffusivity (1.33 vs. 0.91 μm/ms, P=0.0002), axial diffusivity (1.70 vs. 1.43 μm/ms, P=0.036), and radial diffusivity (1.24 vs. 0.71 μm/ms, P<0.0001) were significantly higher and fractional anisotropy (0.21 vs. 0.44, P<0.0001) was significantly lower in the glaucoma compared with those of control subjects. In glaucoma patients, mean, axial, and radial diffusivities increased and fractional anisotropy decreased as rim area decreases and the Glaucoma stage increased (P<0.05). However, there were no statistically significant differences in the DTI parameters when adjacent pairs of stages were compared (P>0.05). CONCLUSIONS DTI may be a useful technique for detection and evaluation of glaucomatous damage in the optic nerve, particularly for patients in whom conventional imaging and perimetry are not possible. Future studies are needed to evaluate how DTI parameters change longitudinally with glaucomatous damage within the visual pathways and address cerebrospinal fluid partial volume effects in diffusion tensor quantification, especially for patients with advanced glaucoma stage.
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Neurite orientation dispersion and density imaging of the healthy cervical spinal cord in vivo. Neuroimage 2015; 111:590-601. [PMID: 25652391 DOI: 10.1016/j.neuroimage.2015.01.045] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 01/14/2015] [Accepted: 01/24/2015] [Indexed: 12/14/2022] Open
Abstract
Here we present the application of neurite orientation dispersion and density imaging (NODDI) to the healthy spinal cord in vivo. NODDI provides maps such as the intra-neurite tissue volume fraction (vin), the orientation dispersion index (ODI) and the isotropic volume fraction (viso), and here we investigate their potential for spinal cord imaging. We scanned five healthy volunteers, four of whom twice, on a 3T MRI system with a ZOOM-EPI sequence. In accordance to the published NODDI protocol, multiple b-shells were acquired at cervical level and both NODDI and diffusion tensor imaging (DTI) metrics were obtained and analysed to: i) characterise differences in grey and white matter (GM/WM); ii) assess the scan-rescan reproducibility of NODDI; iii) investigate the relationship between NODDI and DTI; and iv) compare the quality of fit of NODDI and DTI. Our results demonstrated that: i) anatomical features can be identified in NODDI maps, such as clear contrast between GM and WM in ODI; ii) the variabilities of vin and ODI are comparable to that of DTI and are driven by biological differences between subjects for ODI, have similar contribution from measurement errors and biological variation for vin, whereas viso shows higher variability, driven by measurement errors; iii) NODDI identifies potential sources contributing to DTI indices, as in the brain; and iv) NODDI outperforms DTI in terms of quality of fit. In conclusion, this work shows that NODDI is a useful model for in vivo diffusion MRI of the spinal cord, providing metrics closely related to tissue microstructure, in line with findings in the brain.
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Mallik S, Samson RS, Wheeler-Kingshott CAM, Miller DH. Imaging outcomes for trials of remyelination in multiple sclerosis. J Neurol Neurosurg Psychiatry 2014; 85:1396-404. [PMID: 24769473 PMCID: PMC4335693 DOI: 10.1136/jnnp-2014-307650] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/27/2014] [Accepted: 03/30/2014] [Indexed: 12/02/2022]
Abstract
Trials of potential neuroreparative agents are becoming more important in the spectrum of multiple sclerosis research. Appropriate imaging outcomes are required that are feasible from a time and practicality point of view, as well as being sensitive and specific to myelin, while also being reproducible and clinically meaningful. Conventional MRI sequences have limited specificity for myelination. We evaluate the imaging modalities which are potentially more specific to myelin content in vivo, such as magnetisation transfer ratio (MTR), restricted proton fraction f (from quantitative magnetisation transfer measurements), myelin water fraction and diffusion tensor imaging (DTI) metrics, in addition to positron emission tomography (PET) imaging. Although most imaging applications to date have focused on the brain, we also consider measures with the potential to detect remyelination in the spinal cord and in the optic nerve. At present, MTR and DTI measures probably offer the most realistic and feasible outcome measures for such trials, especially in the brain. However, no one measure currently demonstrates sufficiently high sensitivity or specificity to myelin, or correlation with clinical features, and it should be useful to employ more than one outcome to maximise understanding and interpretation of findings with these sequences. PET may be less feasible for current and near-future trials, but is a promising technique because of its specificity. In the optic nerve, visual evoked potentials can indicate demyelination and should be correlated with an imaging outcome (such as optic nerve MTR), as well as clinical measures.
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Affiliation(s)
- Shahrukh Mallik
- Department of Neuroinflammation, NMR Research Unit, Queen Square Multiple Sclerosis Centre, University College London (UCL) Institute of Neurology, London, UK
| | - Rebecca S Samson
- Department of Neuroinflammation, NMR Research Unit, Queen Square Multiple Sclerosis Centre, University College London (UCL) Institute of Neurology, London, UK
| | - Claudia A M Wheeler-Kingshott
- Department of Neuroinflammation, NMR Research Unit, Queen Square Multiple Sclerosis Centre, University College London (UCL) Institute of Neurology, London, UK
| | - David H Miller
- Department of Neuroinflammation, NMR Research Unit, Queen Square Multiple Sclerosis Centre, University College London (UCL) Institute of Neurology, London, UK
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Jeong HK, Dewey BE, Hirtle JAT, Lavin P, Sriram S, Pawate S, Gore JC, Anderson AW, Kang H, Smith SA. Improved diffusion tensor imaging of the optic nerve using multishot two-dimensional navigated acquisitions. Magn Reson Med 2014; 74:953-63. [PMID: 25263603 DOI: 10.1002/mrm.25469] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/08/2014] [Accepted: 08/29/2014] [Indexed: 11/08/2022]
Abstract
PURPOSE A diffusion-weighted multishot echo-planar imaging approach combined with SENSE and a two-dimensional (2D) navigated motion correction was investigated as an alternative to conventional single-shot counterpart to obtain optic nerve images at higher spatial resolution with reduced artifacts. METHODS Fifteen healthy subjects were enrolled in the study. Six of these subjects underwent a repeated acquisition at least 2 weeks after the initial scan session to address reproducibility. Both single-shot and multishot diffusion tensor imaging studies of the human optic nerve were performed with matched scan time. Effect of subject motions were corrected using 2D phase navigator during multishot image reconstruction. Tensor-derived indices from proposed multishot were compared against conventional single-shot approach. Image resolution difference, right-left optic nerve asymmetry, and test-retest reproducibility were also assessed. RESULTS In vivo results of acquired multishot images and quantitative maps of diffusion properties of the optic nerve showed significantly reduced image artifacts (e.g., distortions and blurring), and the derived diffusion indices were comparable to those from other studies. Single-shot scans presented larger variability between right and left optic nerves than multishot scans. Multishot scans also presented smaller variations across scans at different time points when compared with single-shot counterparts. CONCLUSION The multishot technique has considerable potential for providing improved information on optic nerve pathology and may also be translated to higher fields.
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Affiliation(s)
- Ha-Kyu Jeong
- Philips Healthcare Korea, Seoul, Republic of Korea.,Division of Magnetic Resonance Research, Korea Basic Science Institute, Chungbook, Republic of Korea
| | - Blake E Dewey
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA
| | - Jane A T Hirtle
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Psychology and Human Development, Vanderbilt University, Nashville, Tennessee, USA
| | - Patrick Lavin
- Department of Neurology, Vanderbilt University, Nashville, Tennessee, USA.,Department of Ophthalmology, Vanderbilt University, Nashville, Tennessee, USA
| | - Subramaniam Sriram
- Department of Neurology, Vanderbilt University, Nashville, Tennessee, USA
| | - Siddharama Pawate
- Department of Neurology, Vanderbilt University, Nashville, Tennessee, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Adam W Anderson
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Hakmook Kang
- Department of Biostatistics, Vanderbilt University, Nashville, Tennessee, USA
| | - Seth A Smith
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
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Post-mortem cardiac diffusion tensor imaging: detection of myocardial infarction and remodeling of myofiber architecture. Eur Radiol 2014; 24:2810-8. [DOI: 10.1007/s00330-014-3322-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 06/24/2014] [Accepted: 07/07/2014] [Indexed: 12/12/2022]
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Samson RS, Kolappan M, Thomas DL, Symms MR, Connick P, Miller DH, Wheeler-Kingshott CAM. Development of a high-resolution fat and CSF-suppressed optic nerve DTI protocol at 3T: application in multiple sclerosis. FUNCTIONAL NEUROLOGY 2014; 28:93-100. [PMID: 24125558 DOI: 10.11138/fneur/2013.28.2.093] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Clinical trials of neuroprotective interventions in multiple sclerosis require outcome measures that reflect the disease pathology. Measures of neuroaxonal integrity in the anterior visual pathways are of particular interest in this context, however imaging of the optic nerve is technically challenging. We therefore developed a 3T optic nerve diffusion tensor imaging protocol incorporating fat and cerebrospinal fluid suppression and without parallel imaging. The sequence used a scheme with six diffusion-weighted directions, b = 600 smm(-2) plus one b ≈ 0 (b(0)) and 40 repetitions, averaged offline, giving an overall scan time of 30 minutes. A coronal oblique orientation was used with voxel size 1.17 mm x 1.17 mm x 4 mm, We validated the sequence in 10 MS patients with a history of optic neuritis and 11 healthy controls: mean fractional anisotropy was reduced in the patients: 0.346(±0.159) versus 0.528(±0.123), p<0.001; radial diffusivity was increased: 0.940(±0.370)x10(-6) mm(2) s(-1) compared to 0.670(± 0.221)x10(-6) mm(2) s(-1) (p<0.01). No significant differences were seen for mean diffusivity or mean axial diffusivity.
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Wargo CJ, Moore J, Gore JC. A comparison and evaluation of reduced-FOV methods for multi-slice 7T human imaging. Magn Reson Imaging 2013; 31:1349-59. [PMID: 23891434 PMCID: PMC3947502 DOI: 10.1016/j.mri.2013.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 05/09/2013] [Indexed: 10/26/2022]
Abstract
Eight different reduced field-of-view (FOV) MRI techniques suitable for high field human imaging were implemented, optimized, and evaluated at 7T. These included selective Inner-Volume Imaging (IVI) based methods, and Outer-Volume Suppression (OVS) techniques, some of which were previously unexplored at ultra-high fields. Design considerations included use of selective composite excitation and adiabatic refocusing radio-frequency (RF) pulses to address B1 inhomogeneities, twice-refocused spin echo techniques, frequency-modulated pulses to sharply define suppressed regions, and pulse sequence designs to improve SNR in multi-slice scans. The different methods were quantitatively compared in phantoms and in vivo human brain images to provide measurements of relative signal to noise ratio (SNR), power deposition (specific absorption rate, SAR), suppression of signal, artifact strength and prevalence, and general image quality. Multi-slice signal losses in out-of-slice locations were simulated for IVI methods, and then measured experimentally across a range of slice numbers. Corrections for B1 nonuniformities demonstrated an improved SNR and a reduction in artifact power in the reduced-FOV, but produced an elevated SAR. Multi-slice sequences with reordering of pulses in traditional and twice-refocused IVI techniques demonstrated an improved SNR compared to conventional methods. The combined results provide a basis for use of reduced-FOV techniques for human imaging localized to a small FOV at 7T.
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Affiliation(s)
- Christopher J Wargo
- Institute of Imaging Science, Vanderbilt University, 1161 21st Ave. South, MCN AA-1105 Nashville, TN 37232-2310, USA; Department of Radiology and Radiological Sciences, Vanderbilt University, 116 21st Ave. South, MCN CCC-1106, Nashville, TN 37232-2675, USA.
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Finsterbusch J. Functional neuroimaging of inner fields-of-view with 2D-selective RF excitations. Magn Reson Imaging 2013; 31:1228-35. [DOI: 10.1016/j.mri.2013.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 01/28/2013] [Accepted: 03/08/2013] [Indexed: 11/16/2022]
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Taviani V, Nagala S, Priest AN, McLean MA, Jani P, Graves MJ. 3T diffusion-weighted MRI of the thyroid gland with reduced distortion: preliminary results. Br J Radiol 2013; 86:20130022. [PMID: 23770539 PMCID: PMC3745056 DOI: 10.1259/bjr.20130022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 05/23/2013] [Accepted: 06/07/2013] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE Single-shot diffusion-weighted (DW) echo planar imaging (EPI), which is commonly used for imaging the thyroid, is characterised by severe blurring and distortion. The objectives of this work were: 1, to show that a reduced-field of view (r-FOV) DW EPI technique can improve image quality; and 2, to investigate the effect of different reconstruction strategies on the resulting apparent diffusion coefficients (ADCs). METHODS We implemented a single-shot, r-FOV DW EPI technique with a two-dimensional radiofrequency excitation pulse for DW imaging of the thyroid at 3T. Images were reconstructed using root sum of squares (SOS) and an optimal-B1 reconstruction (OBR). Phantom and in vivo experiments were performed to compare r-FOV and conventional full-FOV DW EPI with root SOS and OBR. RESULTS r-FOV with OBR substantially improved image quality at 3T. In phantoms, r-FOV gave more accurate ADCs than full-FOV. In vivo r-FOV always gave lower ADC values with respect to the full-FOV technique irrespective of the reconstruction used and whether only two or multiple b-values were used to compute the ADCs. CONCLUSION r-FOV DW EPI can reduce image blurring and distortion at the expense of a low signal-to-noise ratio. OBR is a promising reconstruction technique for accurate ADC measurements in lower signal-to-noise ratio regimes, although further studies are needed to characterise its performance. ADVANCES IN KNOWLEDGE DW imaging of the thyroid at 3T could potentially benefit from r-FOV acquisition strategies, such as the r-FOV DW EPI technique proposed in this paper.
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Affiliation(s)
- V Taviani
- Department of Radiology, University of Cambridge, Cambridge, UK.
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Karampinos DC, Melkus G, Shepherd TM, Banerjee S, Saritas EU, Shankaranarayanan A, Hess CP, Link TM, Dillon WP, Majumdar S. Diffusion tensor imaging and T2 relaxometry of bilateral lumbar nerve roots: feasibility of in-plane imaging. NMR IN BIOMEDICINE 2013; 26:630-637. [PMID: 23208676 PMCID: PMC3634898 DOI: 10.1002/nbm.2902] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 09/30/2012] [Accepted: 11/12/2012] [Indexed: 06/06/2023]
Abstract
Lower back pain is a common problem frequently encountered without specific biomarkers that correlate well with an individual patient's pain generators. MRI quantification of diffusion and T2 relaxation properties may provide novel insight into the mechanical and inflammatory changes that occur in the lumbosacral nerve roots in patients with lower back pain. Accurate imaging of the spinal nerve roots is difficult because of their small caliber and oblique course in all three planes. Two-dimensional in-plane imaging of the lumbosacral nerve roots requires oblique coronal imaging with large field of view (FOV) in both dimensions, resulting in severe geometric distortions using single-shot echo planar imaging (EPI) techniques. The present work describes initial success using a reduced-FOV single-shot spin-echo EPI acquisition to obtain in-plane diffusion tensor imaging (DTI) and T2 mapping of the bilateral lumbar nerve roots at the L4 level of healthy subjects, minimizing partial volume effects, breathing artifacts and geometric distortions. A significant variation in DTI and T2 mapping metrics is also reported along the course of the normal nerve root. The fractional anisotropy is statistically significantly lower in the dorsal root ganglia (0.287 ± 0.068) than in more distal regions in the spinal nerve (0.402 ± 0.040) (p < 10(-5) ). The T2 relaxation value is statistically significantly higher in the dorsal root ganglia (78.0 ± 11.9 ms) than in more distal regions in the spinal nerve (59.5 ± 7.4 ms) (p < 10(-5) ). The quantification of nerve root DTI and T2 properties using the proposed methodology may identify the specific site of any degenerative and inflammatory changes along the nerve roots of patients with lower back pain.
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Affiliation(s)
- Dimitrios C Karampinos
- Department of Radiology and Biomedical Imaging, University of California-San Francisco, CA, USA
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