scholarly journals Ultra-high-field 7-T MRI in multiple sclerosis and other demyelinating diseases: from pathology to clinical practice

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Nicolo’ Bruschi ◽  
Giacomo Boffa ◽  
Matilde Inglese
Keyword(s):  
Multiple Sclerosis ◽  
High Field ◽  
Neurological Diseases ◽  
Lesion Detection ◽  
Demyelinating Diseases ◽  
Metabolic Imaging ◽  
Central Vein ◽  
Ultra High Field ◽  
Functional Features

Abstract Magnetic resonance imaging (MRI) is essential for the early diagnosis of multiple sclerosis (MS), for investigating the disease pathophysiology, and for discriminating MS from other neurological diseases. Ultra-high-field strength (7-T) MRI provides a new tool for studying MS and other demyelinating diseases both in research and in clinical settings. We present an overview of 7-T MRI application in MS focusing on increased sensitivity and specificity for lesion detection and characterisation in the brain and spinal cord, central vein sign identification, and leptomeningeal enhancement detection. We also discuss the role of 7-T MRI in improving our understanding of MS pathophysiology with the aid of metabolic imaging. In addition, we present 7-T MRI applications in other demyelinating diseases. 7-T MRI allows better detection of the anatomical, pathological, and functional features of MS, thus improving our understanding of MS pathology in vivo. 7-T MRI also represents a potential tool for earlier and more accurate diagnosis.

scholarly journals Imaging cortical multiple sclerosis lesions with ultra-high field MRI

2021 ◽  
Author(s):  
Mads Alexander Just Madsen ◽  
Vanessa Wiggermann ◽  
Stephan Bramow ◽  
Jeppe Romme Christensen ◽  
Finn Sellebjerg ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
High Field ◽  
Lesion Detection ◽  
Cortical Lesion ◽  
Type I ◽  
Type Ii ◽  
Cortical Lesions ◽  
Ultra High Field ◽  
Type Iv

Background: Cortical lesions are abundant in multiple sclerosis (MS), yet difficult to visualize in vivo. Ultra- high field (UHF) MRI at 7T and above provides technological advances suited to optimize the detection of cortical lesions in MS. Purpose: To provide a narrative and quantitative systematic review of the literature on UHF MRI of cortical lesions in MS. Methods: A systematic search of all literature on UHF MRI of cortical lesions in MS published before September 2020. Quantitative outcome measures included cortical lesion numbers reported using 3T and 7T MRI and between 7T MRI sequences, along with sensitivity of UHF MRI towards cortical lesions verified by histopathology. Results: 7T MRI detected on average 52±26% (mean±95% confidence interval) more cortical lesions than the best performing image contrast at 3T, with the largest increase in type II-IV intracortical lesion detection. Across all studies, the mean cortical lesion number was 17±6/patient. In progressive MS cohorts, approximately four times more cortical lesions were reported than in CIS/early RRMS, and RRMS. Superiority of one MRI sequence over another could not be established from available data. Post- mortem lesion detection with UHF MRI agreed only modestly with pathological examinations. Mean pro- and retrospective sensitivity was 33±6% and 71±10%, respectively, with the highest sensitivity towards type I and type IV lesions. Conclusion: UHF MRI improves cortical lesion detection in MS considerably compared to 3T MRI, particularly for type II-IV lesions. Despite modest sensitivity, 7T MRI is still capable of visualizing all aspects of cortical lesion pathology and could potentially aid clinicians in diagnosing and monitoring MS, and progressive MS in particular. However, standardization of acquisition and segmentation protocols is needed.

scholarly journals An integrated RF-receive/B0-shim array coil boosts performance of whole-brain MR spectroscopic imaging at 7 T

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Morteza Esmaeili ◽  
Jason Stockmann ◽  
Bernhard Strasser ◽  
Nicolas Arango ◽  
Bijaya Thapa ◽  
...  
Keyword(s):  
High Field ◽  
Human Subjects ◽  
Spectroscopic Imaging ◽  
Metabolic Imaging ◽  
Ultra High Field ◽  
Whole Brain ◽  
Metabolite Quantification ◽  
Noise Ratio ◽  
Array Coil

Abstract Metabolic imaging of the human brain by in-vivo magnetic resonance spectroscopic imaging (MRSI) can non-invasively probe neurochemistry in healthy and disease conditions. MRSI at ultra-high field (≥ 7 T) provides increased sensitivity for fast high-resolution metabolic imaging, but comes with technical challenges due to non-uniform B0 field. Here, we show that an integrated RF-receive/B0-shim (AC/DC) array coil can be used to mitigate 7 T B0 inhomogeneity, which improves spectral quality and metabolite quantification over a whole-brain slab. Our results from simulations, phantoms, healthy and brain tumor human subjects indicate improvements of global B0 homogeneity by 55%, narrower spectral linewidth by 29%, higher signal-to-noise ratio by 31%, more precise metabolite quantification by 22%, and an increase by 21% of the brain volume that can be reliably analyzed. AC/DC shimming provide the highest correlation (R2 = 0.98, P = 0.001) with ground-truth values for metabolite concentration. Clinical translation of AC/DC and MRSI is demonstrated in a patient with mutant-IDH1 glioma where it enables imaging of D-2-hydroxyglutarate oncometabolite with a 2.8-fold increase in contrast-to-noise ratio at higher resolution and more brain coverage compared to previous 7 T studies. Hence, AC/DC technology may help ultra-high field MRSI become more feasible to take advantage of higher signal/contrast-to-noise in clinical applications.

scholarly journals Hyperpolarized 13C MR metabolic imaging can detect neuroinflammation in vivo in a multiple sclerosis murine model

2017 ◽  
Vol 114 (33) ◽  
pp. E6982-E6991 ◽  
Author(s):  
Caroline Guglielmetti ◽  
Chloé Najac ◽  
Alessandro Didonna ◽  
Annemie Van der Linden ◽  
Sabrina M. Ronen ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Pyruvate Dehydrogenase ◽  
Neurological Diseases ◽  
Mononuclear Phagocytes ◽  
Metabolic Reprogramming ◽  
Pyruvate Dehydrogenase Kinase ◽  
Metabolic Imaging ◽  
Imaging Method ◽  
Pyruvate Dehydrogenase Kinase 1

Proinflammatory mononuclear phagocytes (MPs) play a crucial role in the progression of multiple sclerosis (MS) and other neurodegenerative diseases. Despite advances in neuroimaging, there are currently limited available methods enabling noninvasive detection of MPs in vivo. Interestingly, upon activation and subsequent differentiation toward a proinflammatory phenotype MPs undergo metabolic reprogramming that results in increased glycolysis and production of lactate. Hyperpolarized (HP) 13C magnetic resonance spectroscopic imaging (MRSI) is a clinically translatable imaging method that allows noninvasive monitoring of metabolic pathways in real time. This method has proven highly useful to monitor the Warburg effect in cancer, through MR detection of increased HP [1-13C]pyruvate-to-lactate conversion. However, to date, this method has never been applied to the study of neuroinflammation. Here, we questioned the potential of 13C MRSI of HP [1-13C]pyruvate to monitor the presence of neuroinflammatory lesions in vivo in the cuprizone mouse model of MS. First, we demonstrated that 13C MRSI could detect a significant increase in HP [1-13C]pyruvate-to-lactate conversion, which was associated with a high density of proinflammatory MPs. We further demonstrated that the increase in HP [1-13C]lactate was likely mediated by pyruvate dehydrogenase kinase 1 up-regulation in activated MPs, resulting in regional pyruvate dehydrogenase inhibition. Altogether, our results demonstrate a potential for 13C MRSI of HP [1-13C]pyruvate as a neuroimaging method for assessment of inflammatory lesions. This approach could prove useful not only in MS but also in other neurological diseases presenting inflammatory components.

scholarly journals In vivo imaging of cortical pathology in multiple sclerosis using ultra-high field MRI

Neurology ◽  
2009 ◽  
Vol 73 (12) ◽  
pp. 941-948 ◽  
Author(s):  
C. Mainero ◽  
T. Benner ◽  
A. Radding ◽  
A. van der Kouwe ◽  
R. Jensen ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
In Vivo Imaging ◽  
High Field ◽  
Ultra High Field ◽  
High Field Mri ◽  
Cortical Pathology ◽  
Ultra High Field Mri

scholarly journals Brain and Spinal Cord MRI in Multiple Sclerosis: an Update

2017 ◽  
Vol 01 (04) ◽  
pp. E294-E306 ◽  
Author(s):  
Mike Wattjes ◽  
Peter Raab
Keyword(s):  
Multiple Sclerosis ◽  
Quantitative Mri ◽  
Central Vein ◽  
Resonance Imaging ◽  
Ultra High Field ◽  
Important Differential Diagnosis ◽  
Magnetic Resonance Imaging Mri ◽  
Near Future ◽  
Brain And Spinal Cord

AbstractMagnetic resonance imaging (MRI) plays an important role in the diagnosis of multiple sclerosis and has been incorporated into the McDonald diagnostic criteria for MS. In particular, for the exclusion of important differential diagnosis and comorbidities, new MRI markers have been established such as the “central vein sign”. In addition to diagnostic purposes, the role of MRI in MS monitoring is becoming increasingly important, particularly for pharmacovigilance. This includes treatment efficacy monitoring, prediction of treatment response and safety monitoring. Quantitative MRI methods and ultra-high-field MRI offer the opportunity for the quantitative assessment of damage in normal-appearing brain tissue. However, the standardization of these techniques with the goal of implementation in clinical routine will be one of the major challenges in the near future.

In vivo manganese tract tracing of frontal eye fields in rhesus macaques with ultra-high field MRI: Comparison with DWI tractography

NeuroImage ◽  
2018 ◽  
Vol 181 ◽  
pp. 211-218 ◽  
Author(s):  
David J. Schaeffer ◽  
Kevin D. Johnston ◽  
Kyle M. Gilbert ◽  
Joseph S. Gati ◽  
Ravi S. Menon ◽  
...  
Keyword(s):  
High Field ◽  
Rhesus Macaques ◽  
Frontal Eye Fields ◽  
Tract Tracing ◽  
Ultra High Field ◽  
High Field Mri ◽  
Ultra High Field Mri

Improved MR Thermometry to Measure Brain Temperatures

2008 ◽  
Author(s):  
Devashish Shrivastava ◽  
Lance DelaBarre ◽  
Timothy Hanson ◽  
J. Thomas Vaughan
Keyword(s):  
High Field ◽  
Core Body Temperature ◽  
Temperature Response ◽  
Time History ◽  
Rf Heating ◽  
Mr Thermometry ◽  
Ultra High Field ◽  
High Fields ◽  
Rf Safety

An MR thermometry technique with sub-degree celsius accuracy is needed to measure in vivo temperatures vs. time in porcine brains at ultra-high fields. Porcine models are used to study thermoregulatory temperature response of the ultra-high field radiofrequency (RF) heating. The porcine hot critical temperature limit is comparable to and lower than that of humans. Also, porcine thermoregulatory mechanisms are similar to humans. Thus, conservative porcine thermoregulatory temperature responses can help develop new RF safety thresholds for ultra-high field human MRI. Sub-degree C temperature accuracy is needed since RF safety guidelines limit the maximum in vivo head temperature change due to RF heating to 1 °C over the core body temperature. Three-dimensional temperature maps over time are required since non-uniform RF power deposition at ultra-high fields and blood flow produce non-uniform in vivo temperatures with local hot spots. Thermogenic hazards are related to in vivo temperatures and temperature-time history — and not to the typically measured whole head average specific absorption rate.

scholarly journals P.063 Stereotactic targeting of hippocampal substructures using ultra-high field magnetic resonance imaging: Feasibility study in patients with epilepsy

2018 ◽  
Vol 45 (s2) ◽  
pp. S32-S33
Author(s):  
JC Lau ◽  
J DeKraker ◽  
KW MacDougall ◽  
H Joswig ◽  
AG Parrent ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Dentate Gyrus ◽  
High Field ◽  
Longitudinal Axis ◽  
The Body ◽  
7 Tesla ◽  
Resonance Imaging ◽  
Ultra High Field

Background: The hippocampus can be divided longitudinally into the head, body, and tail; and unfolded medial-to-laterally into the subiculum, cornu ammonis (CA) sectors, and the dentate gyrus. Ultra-high field (≥ 7 Tesla; 7T) magnetic resonance imaging (MRI) enables submillimetric visualization of these hippocampal substructures which could be valuable for surgical targeting. Here, we assess the feasibility of using 7T MRI in conjunction with a novel computational unfolding method for image-based stereotactic targeting of hippocampal substructures. Methods: 53 patients with drug-resistant epilepsy were identified undergoing first-time implantation of the hippocampus. An image processing pipeline was created for computationally transforming post-operative electrode contact locations into our hippocampal coordinate system. Results: Of 178 implanted hippocampal electrodes (88 left; 49.4%), 25 (14.0%) were predominantly in the subiculum, 85 (47.8%) were in CA1, 23 (12.9%) were in CA2, 18 (10.1%) were in CA3/CA4, and 27 (15.2%) were in dentate gyrus. Along the longitudinal axis, hippocampal electrodes were most commonly implanted in the body (92; 51.7%) followed by the head (86; 48.3%). Conclusions: 7T MRI enables high-resolution anatomical imaging on the submillimeter scale in in vivo subjects. Here, we demonstrate the utility of 7T imaging for identifying the relative location of SEEG electrode implantations within hippocampal substructures for the invasive investigation of epilepsy.

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