Asymmetric Dilatation of Virchow-Robin Space in Unilateral Internal Carotid Artery Stenosis

Tae-Sub Chung¹, Ah Young Park¹, Sang Huyn Suh¹

Problem: To test the hypothesis that chronic ischemia followed by white matter atrophy is associated with Virchow-Robin spaces (VRSs) dilatation by determining the relationship between unilateral internal carotid artery (ICA) stenosis and asymmetric dilatation of VRSs on the same side. Methods: We retrospectively reviewed axial T2-weighted and diffusion weighted MR images (GE Signa Excita 3-T) of 46 patients with severe unilateral ICA stenosis (>70%), diagnosed by carotid contrast MRA and carotid digital subtraction angiography (DSA) between Feb. 2007 and Sep. 2009. Hyperintense lesions in the pre- and post-central gyri and corona radiata along CST pathway in the high convexity white matter on T2WI were included as VRSs. All lesions were graded into score 0 (None), score 1 (linear hyperintensity not extending to the corona radiata), score 2 (linear hyperintensity extending to the corona radiata) and score 3 (round or oval hyperintensity larger than 2mm). We statistically analyzed the difference of VRSs score between bilateral hemispheres, the correlation between VRSs socre and severity of ICA stenosis, the correlation between VRSs score and age, and the difference of ipsilateral VRSs scores according to existence of infarction. Results: The VRSs on the ipsilateral and contralateral sides showed statistical difference (p<0.01). The relationship between the patients age and VRSs score showed positive correlation(p<0.01) There was no significant correlation between VRSs score and ICA stenosis severity. The ipsilateral VRS scores were significantly higher in the cases with infarction than without infarction(p<0.05).Conclusion: Our results suggest that chronic ischemic process and subsequent white matter degeneration and atrophy is a factor of VRSs dilatation. Therefore, if we detect the unusual VRSs dilatation on brain MR, it is worth considering the possibility of ischemic condition and necessity of further workup.