Prominent hypointense vessel on susceptibility-weighted images accompanying hyperacute and acute large infarction.

BACKGROUND Multiple prominent hypointense vessels on susceptibility-weighted image (SWI) have been found in the ischemic territory of patients with acute ischemic stroke. SWI is suitable for venous imaging. PURPOSE To evaluate the conditions of prominent hypointense vessel (PHV) in hyperacute and acute cerebral infarctions using susceptibility-weighted image (SWI). MATERIALS AND METHODS Magnetic resonance images, including SWI, of 284 patients with acute infarction were evaluated. Based on lesion size, the infarction was classified as a small (  3 cm) infarction. Stage of infarction was classified as hyperacute (  6 h, < 1 week) on the basis of the onset of stroke. The site of infarction was categorised as a deep grey matter or a mixed (cortical and/or deep grey matter) infarction. The venous structures were analysed qualitatively for the calibre difference between ipsilateral and contralateral hemispheres. We quantitatively analysed the relationship between the size of areas with PHV on SWI and the abnormalities on MR angiography, apparent diffusion coefficient value, and signal intensity on T2WI in the 271 patients. RESULTS PHV over the infarction site was observed in 54.1% (137/253) of the large infarctions, and 19.3% (6/31) of the small infarctions on SWI. PHV was demonstrated in 63.1% (118/187) of mixed infarctions and 25.8% (25/97) of deep grey matter infarctions, and 59.2% (58/98) in hyperacute and 45.7% (85/186) of acute infarctions. The presence of PHV was statistically significant in the size and region of cerebral infarction (p < 0.05), and was not significant in the stage of infarction (p = 0.137). Quantitative analysis revealed significant differences in the MRA abnormalities and ADC values in the PHV ( +) group (p < 0.05) and no significant difference in the T2WI SI ratio in the PHV ( +) group (p = 0.086), compared with PHV (-) group. CONCLUSION PHV on SWI was more prominent at the portions with the large and mixed infarctions. PHV was observed both in hyperacute and acute infarction.