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Brain Infarct Segmentation and Registration on MRI or CT for Lesion-symptom Mapping
Published on: September 25, 2019
MRI Assessment of Ischemic Lesion Evolution within White and Gray Matter
Lise-Prune Berner1, Tae-Hee Cho, Julie Haesebaert
1Department of Neuroradiology, Hospices Civils de Lyon, Lyon, France.
Background:
In acute ischemic stroke (AIS), gray matter (GM) and white matter (WM) have different vulnerabilities to ischemia. Thus, we compared the evolution of ischemic lesions within WM and GM using MRI.
Methods:
From a European multicenter prospective database (I-KNOW), available T1-weighted images were identified for 50 patients presenting with an anterior AIS and a perfusion weighted imaging (PWI)/diffusion weighted imaging (DWI) mismatch ratio of 1.2 or more. Six lesion compartments were outlined: initial DWI (b = 1,000 s/mm2) lesion, initial PWI-DWI mismatch (Tmax >4 s and DWI-negative), final infarct mapped on 1-month fluid-attenuated inversion recovery (FLAIR) imaging, lesion growth between acute DWI and 1-month FLAIR, DWI lesion reversal at 1 month and salvaged mismatch. The WM and GM were segmented on T1-weighted images, and all images were co-registered within subjects to the baseline MRI. WM and GM proportions were calculated for each compartment.
Results:
Fifty patients were eligible for the study. Median delay between symptom onset and baseline MRI was 140 min. The percentage of WM was significantly greater in the following compartments: initial mismatch (52.5 vs. 47.5%, p = 0.003), final infarct (56.7 vs. 43.3%, p < 0.001) and lesion growth (58.9 vs. 41.2%, p < 0.001). No significant difference was found between GM and WM percentages within the initial DWI lesion, DWI reversal and salvaged mismatch compartments.
Conclusions:
Ischemic lesions may extend preferentially within the WM. Specific therapeutic strategies targeting WM ischemic processes may deserve further investigation.
Insights
Acute ischemic stroke lesions preferentially affect white matter (WM). This study found WM had a greater percentage in initial mismatch, final infarct, and lesion growth compared to gray matter (GM).
Area of Science:
- Neurology
- Radiology
- Neuroimaging
Background:
- Acute ischemic stroke (AIS) affects gray matter (GM) and white matter (WM) differently.
- Understanding lesion evolution in WM and GM is crucial for treatment.
Purpose of the Study:
- To compare the evolution of ischemic lesions in WM versus GM in patients with AIS.
- To determine if lesion compartments show preferential involvement of WM or GM.
Main Methods:
- Analysis of T1-weighted and PWI/DWI MRI scans from 50 AIS patients.
- Segmentation of WM and GM, and calculation of their proportions within six lesion compartments.
- Co-registration of all images to baseline MRI for accurate comparison.
Main Results:
- White matter (WM) comprised a significantly greater percentage of the initial mismatch, final infarct, and lesion growth.
- No significant difference in WM vs. GM proportions was observed in the initial DWI lesion, DWI reversal, or salvaged mismatch.
- Median delay from symptom onset to baseline MRI was 140 minutes.
Conclusions:
- Ischemic lesions in AIS appear to preferentially extend within the white matter.
- Further research into therapeutic strategies targeting white matter ischemic processes is warranted.
