Quantification of Ischemic Lesion using Intravoxel Incoherent Motion and prediction of Motor Outcome with Diffusion Kurtosis Imaging in Acute Stroke

Objectives

Phase 1

To assess the utility of the hybrid IVIM sequence to differentiate the ischemic core from the penumbra

To determine the association between the IVIM parameters and stroke severity

Phase 2

To analyze whether DKI parameters predict motor outcomes 1 and 3 months after acute ischemic stroke

To compare the DKI parameters in the lesioned and the contralateral hemispheres along the pathway in the brain

Procedure

Phase 1

The thoroughly signed informed consent from the patient, if conscious, if not from the patient’s legal guardian, and later, once the patient is stable, the patient’s signature will also be obtained. Those who meet the inclusion criteria will undergo an MRI brain-stroke protocol. The IVIM raw data will be post-processed using in-built software to acquire parametric maps for relative Cerebral blood flow (rCBF), Diffusion Coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f). An ellipse ROI will be placed in the core. A symmetrical ROI will be placed in the contralateral normal hemisphere of the brain, and the third ROI will be placed in the penumbra. The numerical values obtained as Mean ± SD will then be tabulated. The baseline NIHSS score will be noted.

Phase 2

Those fitting the inclusion criteria will undergo the MRI brain stroke protocol after signing an informed consent. The obtained DKI raw data will be post-processed using the Diffusion analysis software. Ellipse ROI will be placed in the following regions of the affected as well as the contralateral hemisphere: ischemic lesion, precentral gyrus, supplementary motor area, post-central gyrus, Posterior Limb of Internal Capsule, corona radiata, corpus callosum, and perilesional white matter. The parametric values from each Mean Diffusivity (MD), Fractional Anisotropy (FA), Mean Kurtosis (MK), Radial Kurtosis (RK), Axial Kurtosis (AK), and Kurtosis Anisotropy (KA) will be obtained for all the ROIs. A physiotherapist will evaluate the baseline Fugl Meyer assessment (FMA) score for the upper and lower limbs. When the patient arrives for the standard 1-month follow-up, the FMA score will be noted. At 3rd month follow-up FMA score will again be noted.

Significance of the study

This study will aid in the early detection of salvageable tissue in cases of acute ischemic stroke, which then, if treated immediately, will prevent the further deterioration of tissue that would otherwise lead to catastrophic complications. It will also aid in determining the amount of motor damage already caused in the acute setting, thereby enabling appropriate treatment and rehabilitation measures to be taken accordingly, leading to a better prognosis.