Cerebral white matter lesions may be partially reversible in patients with carotid artery stenosis

Abstract

Contrary to the common belief that age-related WMLs (also known as leukoaraiosis) are a progressive condition, a case of partial reversal of WMLs shortly after carotid artery stenting is described. A 75-year-old man presented with frequent TIAs, which were attributed to right ICA stenosis. He subsequently underwent successful carotid artery stenting. Follow-up MR imaging a week after the procedure showed improvement of WMLs in the right cerebral hemisphere. Pixel-by-pixel image analysis showed that the reversed WMLs tended to have higher lambda1 and lower signal intensity on b = 0 images compared with nonreversed lesions, but by only approximately 10%.

Fig 1.

Two consecutive FLAIR images and MR angiography. A, Preprocedural FLAIR (delay time, 2200 ms; TR/TE, 8000/100 ms) demonstrates WMLs. B, Preprocedural MR angiography (TR/TE, 30/2.3 ms) shows poor visualization of the right anterior circulation branches. C, Postprocedural FLAIR a week later shows partial WML resolution in the right hemisphere (arrow/arrowhead). D, MR angiogram shows restoration of flow in the right ICA. E, Preprocedural perfusion-weighted images show MTT elongation at the right anterior circulation territory with compensatory vasodilation, indicated by increased cerebral blood volume. F, After the procedure, the MTT elongation is normalized. Increased cerebral blood flow at the same territory indicates postprocedural hyperperfusion, but the patient remained asymptomatic.

Fig 2.

Image analysis on pre- and postprocedural images. A, Image coregistration was performed between the pre- and postprocedural FLAIR. B, Segmentation of the pixels with WMLs was then done. C, Subtraction images yielded pixels with/without reversal. Coregistration of these data onto the DWI/DTI (DWI: TR/TE, 6000/88 ms; b = 1000 s/mm²) and b = 0 imaging was performed to characterize the nature of the WMLs.