Quantitative MRI of the Spinal Cord

Quantitative MRI of the Spinal Cord
Author: Julien Cohen-Adad
Publisher: Academic Press
Total Pages: 331
Release: 2014-01-16
Genre: Medical
ISBN: 0123972825
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Quantitative MRI of the Spinal Cord is the first book focused on quantitative MRI techniques with specific application to the human spinal cord. This work includes coverage of diffusion-weighted imaging, magnetization transfer imaging, relaxometry, functional MRI, and spectroscopy. Although these methods have been successfully used in the brain for the past 20 years, their application in the spinal cord remains problematic due to important acquisition challenges (such as small cross-sectional size, motion, and susceptibility artifacts). To date, there is no consensus on how to apply these techniques; this book reviews and synthesizes state-of-the-art methods so users can successfully apply them to the spinal cord. Quantitative MRI of the Spinal Cord introduces the theory behind each quantitative technique, reviews each theory’s applications in the human spinal cord and describes its pros and cons, and suggests a simple protocol for applying each quantitative technique to the spinal cord. Chapters authored by international experts in the field of MRI of the spinal cord Contains “cooking recipes —examples of imaging parameters for each quantitative technique—designed to aid researchers and clinicians in using them in practice Ideal for clinical settings

High Resolution Quantitative MRI in a Non-Surgical Model of Spinal Cord Injury

High Resolution Quantitative MRI in a Non-Surgical Model of Spinal Cord Injury
Author: Wendy K. Oakden
Publisher:
Total Pages:
Release: 2015
Genre:
ISBN:
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Magnetic resonance imaging (MRI) is very sensitive to the presence of damage resulting from injury or disease, but often lacks specificity. Quantitative MRI can significantly increase the specificity in the presence of pathology but must be validated, often using an animal model, for each type of injury or disease. In the case of spinal cord injury (SCI) most models are difficult to image, either due to the location of the injury, or as a result of damage to surrounding tissues resulting from invasive surgical procedures. This thesis describes a non-surgical model of rat SCI which uses MR guided focused ultrasound and microbubbles to create an injury the cervical spinal cord which is optimal for performing quantitative MRI, and compares it with other models of SCI using MRI, histology, and immunohistochemistry. It also describes the difficulties encountered when implementing the quantitative T2 (qT2) MR sequence at the very high resolution required to image the rat spinal cord, the limitations on the qT2 sequence due to the presence of diffusion, and how the effects of diffusion were minimized. Using the new SCI model and qT2 sequence, qT2 and diffusion data were acquired at 24 hours, 1 week, and 2 weeks following SCI, and the quantitative MRI parameters were correlated with histology. The increased specificity gained using quantitative MRI will increase the information available at each timepoint, reducing both the variability and cost of longitudinal studies aimed at developing treatments for SCI.

MULTIPARAMETRIC MRI OF THE PEDIATRIC SPINAL CORD

MULTIPARAMETRIC MRI OF THE PEDIATRIC SPINAL CORD
Author: Shiva Shahrampour
Publisher:
Total Pages: 0
Release: 2023
Genre:
ISBN:
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Quantitative magnetic resonance imaging (MRI) measurements of the pediatric spinal cord is important for both diagnostic and treatment planning. In recent years several quantitative MRI (qMRI) techniques that have been developed and tested to measure functional and structural information of the spinal cord tissue and microstructure. Several of the existing structural and functional imaging biomarkers (i.e., diffusion tensor imaging (DTI)) have demonstrated potential for providing microstructural information about the spinal cord. However, due to the lack of a standard anatomical template of the pediatric spinal cord, quantification of the spinal cord tissue has been challenging. Therefore, one of the goals of this work is to develop and test tools for quantification as well as the creation of a standard structural template of the typically developing (TD) pediatric spinal cord. This will allow automated measurement of normative values of the spinal cord cross-sectional area (SCCSA) at various levels of the spinal cord. Furthermore, to examine the white matter (WM) microstructure of the pediatric cord we developed a processing pipeline for the atlas-based generation of TD pediatric spinal cord WM tracts. This will facilitate the measurements of normative diffusion values for various WM tracts.A group of 30 TD subjects (age range of 6-17 years old (12.38 ±2.81)), who had no evidence of spinal cord injury or pathology were recruited. We utilized a multiparametric MRI protocol, including high-resolution T2-w structural and diffusion-weighted MRI images to scan the subjects on a 3T MRI scanner. The diffusion data were acquired using a novel iFOV DTI sequence. For quantification, a post-processing pipeline was utilized to generate the structural pediatric template. Next, WM tracts were generated using an atlas-based approach, and diffusion metrics (FA, MD, RD and AD) were quantified in 34 tracts identified in the processing pipeline. Normative SCCSA and DTI diffusion indices were generated for the TD population. Lastly, we demonstrated that DTI indices (i.e. FA) can be a predictive measure of components of the clinical test for spinal cord injury, as well as an indicator of the white matter tracts integrity. Therefore, in the final step of this work, we expanded our quantitative analysis to look at the microstructural and macrostructural changes in 15 children with chronic spinal cord injury (SCI) (AIS A-D, mean age of 12.8 ± 3.1 years). This included measurements of SCCSA, diffusion metrics and T2* WM/GM ratio of various white matter tracts in the patient population. We also examined the relationships between all the metrics and the ISNCSCI clinical scores in SCI subjects. We then compared these measurements between the TD and SCI patients to evaluate the diagnostic utility of these techniques and biomarkers. Statistically significant difference was observed between the two populations in the studied metrics. The results show that the proposed techniques may have the potential to be used as surrogate biomarkers for the quantification of the injured spinal cord. Keywords: diffusion tensor imaging, typically developing, spinal cord injury, spinal cord cross-sectional area, fractional anisotropy, mean diffusivity, axial diffusivity, radial diffusivity.

Multiparametric Quantitative MRI of the Cervical Spinal Cord to Measure Microstructure and Tissue Injury

Multiparametric Quantitative MRI of the Cervical Spinal Cord to Measure Microstructure and Tissue Injury
Author: Allan Russell Martin
Publisher:
Total Pages:
Release: 2017
Genre:
ISBN:
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An array of spinal cord (SC) quantitative MRI (qMRI) techniques can measure aspects of microstructure and tissue injury. This research develops a clinically feasible multiparametric MRI protocol, including diffusion tensor imaging (DTI) fractional anisotropy (FA), magnetization transfer ratio (MTR), and measurement of SC cross-sectional area (CSA). A novel biomarker of white matter (WM) injury is also introduced, normalizing T2*WI WM signal intensity by grey matter (T2*WI WM/GM). A study of 40 healthy subjects establishes methods, normalization procedures, normative values, and reliability. 58 patients with degenerative cervical myelopathy (DCM) are studied, showing significant differences in 10 metrics. Combining these measures using multivariate methods overcomes the limitations of each technique, achieving good diagnostic accuracy and clinical correlation. T2*WI WM/GM shows strong potential as a novel biomarker, comparing favourably with established biomarkers FA and MTR. Our study of healthy subjects identifies an alarming rate of asymptomatic SC compression (ASCC) at 50%. Objective criteria and automated shape analysis are developed to create a new definition of SC compression, and qMRI demonstrates significant tissue injury in this group. This finding suggests the potential for pre-symptomatic diagnosis of DCM and other spinal pathologies. Finally, a longitudinal study compares multiparametric qMRI with clinical measures for monitoring disease progression in DCM, indicating that modified Japanese Orthopedic Association (mJOA) score is insensitive to detect progression, whereas qMRI showed tissue progression more often than comprehensive clinical assessments. These results suggest that natural history studies employing mJOA underestimate progression, due to neuroplasticity and behavioural adaptation. Combined qMRI and clinical data are now being used to inform surgical decision-making for individual patients. Reliable multiparametric assessment of SC microstructure is possible using clinically suitable methods. This approach shows strong clinical utility for individual patients, including good diagnostic accuracy, correlations with impairment, detection of tissue injury in asymptomatic individuals, and detection of progressive tissue injury in DCM patients.

Quantitative Magnetic Resonance Imaging

Quantitative Magnetic Resonance Imaging
Author: Nicole Seiberlich
Publisher: Academic Press
Total Pages: 1094
Release: 2020-11-18
Genre: Computers
ISBN: 0128170581
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Quantitative Magnetic Resonance Imaging is a ‘go-to’ reference for methods and applications of quantitative magnetic resonance imaging, with specific sections on Relaxometry, Perfusion, and Diffusion. Each section will start with an explanation of the basic techniques for mapping the tissue property in question, including a description of the challenges that arise when using these basic approaches. For properties which can be measured in multiple ways, each of these basic methods will be described in separate chapters. Following the basics, a chapter in each section presents more advanced and recently proposed techniques for quantitative tissue property mapping, with a concluding chapter on clinical applications. The reader will learn: The basic physics behind tissue property mapping How to implement basic pulse sequences for the quantitative measurement of tissue properties The strengths and limitations to the basic and more rapid methods for mapping the magnetic relaxation properties T1, T2, and T2* The pros and cons for different approaches to mapping perfusion The methods of Diffusion-weighted imaging and how this approach can be used to generate diffusion tensor maps and more complex representations of diffusion How flow, magneto-electric tissue property, fat fraction, exchange, elastography, and temperature mapping are performed How fast imaging approaches including parallel imaging, compressed sensing, and Magnetic Resonance Fingerprinting can be used to accelerate or improve tissue property mapping schemes How tissue property mapping is used clinically in different organs Structured to cater for MRI researchers and graduate students with a wide variety of backgrounds Explains basic methods for quantitatively measuring tissue properties with MRI - including T1, T2, perfusion, diffusion, fat and iron fraction, elastography, flow, susceptibility - enabling the implementation of pulse sequences to perform measurements Shows the limitations of the techniques and explains the challenges to the clinical adoption of these traditional methods, presenting the latest research in rapid quantitative imaging which has the possibility to tackle these challenges Each section contains a chapter explaining the basics of novel ideas for quantitative mapping, such as compressed sensing and Magnetic Resonance Fingerprinting-based approaches

Quantitative MRI of the Brain

Quantitative MRI of the Brain
Author: Mara Cercignani
Publisher: CRC Press
Total Pages: 855
Release: 2018-01-12
Genre: Science
ISBN: 1315363550
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Building on the success of the first edition of this book, the winner of the 2004 British Medical Association Radiology Medical Book Competition, Quantitative MRI of the Brain: Principles of Physical Measurement gives a unique view on how to use an MRI machine in a new way. Used as a scientific instrument it can make measurements of a myriad of physical and biological quantities in the human brain and body. For each small tissue voxel, non-invasive information monitors how tissue changes with disease and responds to treatment. The book opens with a detailed exposition of the principles of good practice in quantification, including fundamental concepts, quality assurance, MR data collection and analysis and improved study statistical power through minimised instrumental variation. There follow chapters on 14 specific groups of quantities: proton density, T1, T2, T2*, diffusion, advanced diffusion, magnetisation transfer, CEST, 1H and multi-nuclear spectroscopy, DCE-MRI, quantitative fMRI, arterial spin-labelling and image analysis, and finally a chapter on the future of quantification. The physical principles behind each quantity are stated, followed by its biological significance. Practical techniques for measurement are given, along with pitfalls and examples of clinical applications. This second edition of this indispensable 'how to' manual of quantitative MR shows the MRI physicist and research clinician how to implement these techniques on an MRI scanner to understand more about the biological processes in the patient and physiological changes in healthy controls. Although focussed on the brain, most techniques are applicable to characterising tissue in the whole body. This book is essential reading for anyone who wants to use the gamut of modern quantitative MRI methods to measure the effects of disease, its progression, and its response to treatment. Features: The first edition was awarded the book prize for Radiology by the British Medical Association in 2004 Written by an authority in the field: Professor Tofts has an international reputation for quantification in MRI Gives specific ‘how to’ information for implementation of MRI measurement sequence techniques

Quantitative MRI of the Brain

Quantitative MRI of the Brain
Author: Paul Tofts
Publisher: John Wiley & Sons
Total Pages: 678
Release: 2003
Genre: Medical
ISBN: 9780470847213
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A 'how to' manual of quantitative MR, essential for anyone who wants to use the gamut of modern quantitative methods to measure the effects of neurological diseases, its progression and its response to treatment. It is also designed for research-minded radiologists, neurologists and MRI physicists who are considering undertaking quantitative work, as well as those already in the field.