Introduction: Patients with minor strokes and Transient Ischemic Attacks (TIAs) are at risk of recurrent strokes and cognitive decline. Stroke lesions appear as white matter hyperintensities on T2 MR images. We investigated microstructural changes in normal appearing white matter (NAWM) of patients with TIAs and minor stroke.
Hypothesis: Longitudinal changes in texture analysis parameters (angular second moment [ASM] and entropy) of NAWM would correspond to a qualitative increase in diseased tissue.
Methods: FLAIR MRI data was obtained within 24hrs of injury (baseline [n=86]), and at 3 follow-up times (90D, n=40; 18M, n=46; and 3Y, n=60). 14 regions of interest (ROIs) were manually placed bilaterally on the NAWM of the baseline FLAIR image in 2 locations in the medial temporal lobes (MDTL), genu, splenium, periventricular (PVT), frontal (FWM), parietal (PWM), and posterior cortex WM (COV). ASM and entropy were measured using the GLCM Texture Analysis tool in ImageJ. Friedman’s ANOVA addressed longitudinal changes.
Results: Significant changes for 6 ROIs [MDTLR, Splenium, FWMR, PWMR, COVL, COVR (p<0.05)] were observed longitudinally. ASM decreases were seen at 90 days, with a return to baseline by 3 years (Fig1a). An increase in entropy was seen at 90 days; with no return to baseline for 5/6 ROIs (Fig1b).
Conclusion: Texture analysis (ASM and entropy) may effectively quantify diseased tissue consistent with qualitative examination of NAWM in FLAIR sequences. Diseased tissue appears maximally present at 90 days with some return to baseline by 3 years.