Quantifying T2 relaxation time changes within lesions defined by apparent diffusion coefficient in grey and white matter in acute stroke patients

Damion, R. A. et al. (2019) Quantifying T2 relaxation time changes within lesions defined by apparent diffusion coefficient in grey and white matter in acute stroke patients. Physics in Medicine and Biology, 64(9), 095016. (doi: 10.1088/1361-6560/ab1442) (PMID:30921782)

Abstract

The apparent diffusion coefficient (ADC) of cerebral water, as measured by diffusion MRI, rapidly decreases in ischaemia, highlighting a lesion in acute stroke patients. The MRI T 2 relaxation time changes in ischaemic brain such that T 2 in ADC lesions may be informative of the extent of tissue damage, potentially aiding in stratification for treatment. We have developed a novel user-unbiased method of determining the changes in T 2 in ADC lesions as a function of clinical symptom duration based on voxel-wise referencing to a contralateral brain volume. The spherical reference method calculates the most probable pre-ischaemic T 2 on a voxel-wise basis, making use of features of the contralateral hemisphere presumed to be largely unaffected. We studied whether T 2 changes in the two main cerebral tissue types, i.e. in grey matter (GM) and white matter (WM), would differ in stroke. Thirty-eight acute stroke patients were accrued within 9 h of symptom onset and scanned at 3 T for 3D T 1-weighted, multi b-value diffusion and multi-echo spin echo MRI for tissue type segmentation, quantitative ADC and absolute T 2 images, respectively. T 2 changes measured by the spherical reference method were 1.94  ±  0.61, 1.50  ±  0.52 and 1.40  ±  0.54 ms h−1 in the whole, GM, and WM lesions, respectively. Thus, T 2 time courses were comparable between GM and WM independent of brain tissue type involved. We demonstrate that T 2 changes in ADC-delineated lesions can be quantified in the clinical setting in a user unbiased manner and that T 2 change correlated with symptom onset time, opening the possibility of using the approach as a tool to assess severity of tissue damage in the clinical setting.

• Item Type: Articles
• Additional Information: The study is funded by the Dunhill Medical Trust (grants R385/1114 and OSRP1/1006). Support by the National Institute for Health Research Oxford Biomedical Centre Programme, the National Institute for Health Research Clinical Research Network, and the Wellcome Trust Institutional Strategic Support Fund (2015-2015) are acknowledged. We acknowledge the support of the National Institute for Health Research Clinical Research Network (NIHR CRN).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Muir, Professor Keith
• Authors: Damion, R. A., Knight, M. J., McGarry, B. L., Bosnell, R., Jezzard, P., Harston, G. W.J., Carone, D., Kennedy, J., El-Tawil, S., Elliot, J., Muir, K. W., Clatworthy, P., and Kauppinen, R. A.
• College/School: College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
• Journal Name: Physics in Medicine and Biology
• Publisher: IOP Publishing
• ISSN: 0031-9155
• ISSN (Online): 1361-6560
• Published Online: 29 April 2019
• Copyright Holders: Copyright © 2019 Institute of Physics and Engineering in Medicine
• First Published: First published in Physics in Medicine and Biology 64(9):095016
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher