Does Microbleed Predict Hemorrhagic Transformation after Acute Atherothrombotic or Cardioembolic Stroke?

¹ Seoul National University Hospital, Korea, Republic of

^* To whom correspondence should be addressed. E-mail: sb0516{at}snu.ac.kr.

Accepted 5 December 2007

	Abstract

Objectives: Cerebral microbleeds (MBs) are known to be indicative of bleeding-prone microangiopathy and may predict incident intracerebral hemorrhage. However, there is controversy concerning the causal relationship between the presence of MBs and hemorrhagic transformation (HTf) after ischemic stroke.

Methods: Of the 1,034 patients with acute ischemic stroke who were consecutively admitted to our hospital, 377 patients with stroke due to large artery atherothrombosis or cardioembolism were selected for participation in this study. We examined the MBs using T2*-weighted gradient-echo MRI performed within 24 hours after admission, and the incidence of HTf was assessed using follow-up brain MRI during the hospitalization period.

Result: Of the 377 patients with stroke, 234 were male (62.1%) and the mean age was 66.2±11.7 years. MBs were initially found in 109 patients (28.9%), and newly incident HTf was noted during the hospitalization period in 74 patients (19.6%). The presence of MBs was not increased in the patients with HTf (24.3% vs. 30.0% in the patients without HTf: p=0.331). In addition, the number of MBs was not higher in the patients with HTf (0.7±1.5 vs. 1.8±8.1: p=0.234). This lack of significance between MBs and HTf persisted after stratification by stroke mechanism.

Conclusions: This study suggests that underlying MBs do not predict incident HTf after acute ischemic stroke. The clinical significance of MBs should be differentially evaluated according to the type of disease (intracerebral hemorrhage vs. HTf).

Keywords: MRI, hemorrhagic transformation, ischemic stroke, microbleed

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