Progression of Cerebral White Matter Hyperintensities and the Associated Sonographic Index.

Purpose To evaluate the relationship between penetrating arterial pulsation and the progression of white matter hyperintensities (WMHs) by using the sonographic resistance index (RI) along the M1 segment of the middle cerebral artery (MCA). Materials and Methods The study design was approved by the institutional review board of Seoul National University Hospital. The study included 450 individuals who had undergone initial transcranial Doppler (TCD) sonography and magnetic resonance imaging, with follow-up imaging performed within 34-45 months, and who had no stenosis of 30% or more in the internal carotid artery or MCA or a history of stroke other than an old lacunar infarction. MRIR was defined as distal RI divided by proximal RI, where the distance between proximal MI and distal M1 was approximately 20 mm based on TCD evaluation. WMH progression was quantitatively evaluated by subtracting WMH volume at baseline from WMH volume at follow-up. Results At baseline, mean MRIR was 0.974 ± 0.045 (standard deviation), and mean WMH volume was 9.66 mL ± 14.54. After a mean of 38.3 months ± 3.4, the WMH volume change was 4.06 mL ± 7.35. WMH volume change was linearly associated with MRIR (r = 0.328, P < .001), along with the baseline WMH volume (r = 0.433, P < .001) and mean MCA pulsatility index (r = 0.275, P = .037). MRIR values greater than or equal to 1.000 were associated with a greater increase in WMH volume (P < .001). Conclusion MRIR might reflect the pulsation of penetrating arteries and is independently associated with WMH progression. © RSNA, 2017 Online supplemental material is available for this article.