Hyperdense middle cerebral artery sign is associated with increased risk of hemorrhagic transformation after intravenous thrombolysis for patients with acute ischaemic stroke.

Haemorrhagic transformation (HT) is an infrequent but serious complication of intravenous thrombolysis therapy (IVT) for acute ischemic stroke. The hyperdense middle cerebral artery sign (HMCAS) is a possible radiological predictor. We aimed to assess the association between HMCAS and HT in a retrospective study. We included all patients with acute anterior circulation ischaemic stroke who received IVT between October 2007 and December 2011. Baseline characteristics were collected, including demographics, stroke risk factors and stroke type. Presence of HMCAS on baseline CT scans was evaluated. Follow-up CT scans were examined for HT, categorised according to the European Australasian Acute Stroke Study (ECASS) classification. The presence of symptomatic intracerebral haemorrhage (sICH) was defined according to Safe Implementation of Thrombolysis in Stroke Monitoring Study (SITS-MOST) criteria. The association between HT and HMCAS was assessed by univariate and multivariate logistic regression analysis. We included 182 consecutive patients treated with IVT in this study. HMCAS was present in 70 patients (38.5%). Patients with HMCAS had higher baseline National Institutes of Health Stroke Scale scores (p<0.001) and more frequent early ischaemic changes on baseline CT scan (p<0.001) than those without HMCAS. We identified 49 instances (26.9%) of HT in 182 follow-up CT scans. HMCAS was associated with HT in univariate analysis (unadjusted odds ratio [OR]=4.151, 95% confidence interval [CI]: 2.081-8.279, p<0.001) and remained an independent risk factor of HT in multivariate analysis (adjusted OR=2.691, 95% CI: 1.231-5.882, p=0.013). There was no statistically significant difference in the frequency of sICH between the HMCAS group and the non-HMCAS group. We concluded that HMCAS is common in anterior circulation infarction and is independently predictive of HT after thrombolytic therapy.