The Effect of Pulsatility Index on Infarct Volume in Acute Lacunar Stroke

Purpose: Lacunar stroke, in the context of small vessel disease, is a type of cerebral infarction caused by occlusion of a penetrating artery. Pulsatility index (PI) is an easily measurable parameter in Transcranial Doppler ultrasound (TCD) study. PI reflects distal cerebral vascular resistance and has been interpreted as a surrogate marker of small vessel disease. We hypothesized that an increased PI, a marker of small vessel disease, might be associated with a larger infarct volume in acute lacunar stroke. Materials and Methods: This study included 64 patients with acute lacunar stroke who underwent TCD and brain MRI. We evaluated the association between the mean PI value of bilateral middle cerebral arteries and infarct volume on diffusion-weighted MRI using univariate and multivariate linear regression. Results: The mean infarct volume and PI were 482.18 +/- 406.40 mm(3) and 0.86 +/- 0.18, respectively. On univariate linear regression, there was a significant positive association between PI and infarct volume (p=0.001). In the multivariate model, a single standard deviation increase of PI (per 0.18) was associated with an increase of 139.05 mm(3) in infarct volume (95% confidence interval, 21.25 to 256.85; p=0.022). Conclusion: We demonstrated that PI was an independent determinant of infarct volume in acute lacunar stroke. The PI value measured in acute stroke may be a surrogate marker of the extent of ischemic injury.