Multifocal signal loss lesions on T2*-weighted gradient echo MRI are not a predictor of hemorrhagic vs. ischemic stroke in patients with advanced leukoaraiosis.

Abstract

P20 Objective: To determine whether multifocal signal loss lesions (MSLL) on T2*-weighted gradient echo MRI (GE-MRI) are always more strongly associated with hemorrhagic stroke (ICH) than ischemic stroke (infarction). Background: MSLL on GE-MRI represent previous microbleeds, which may be a direct marker of increased vascular fragility. Thus, GE-MRI might enable recognition of the bleeding-prone microangiopathy and prediction of a patient’s hemorrhagic risk. However, if MSLL reflect microangiopathy, they will also be associated with leukoaraiosis; the latter is commonly associated with occlusive-type vascular lesions. Methods: We studied 72 consecutive acute stroke patients (43 men and 29 women, 64.9 ± 10.5 years, 31 ICH and 41 infarction) with hypertension and no cardiac source of embolism who were admitted to our hospital from March 1997 to July 1998. GE-MRI was used to count MSLL which were defined as focal areas of homogeneous round signal loss with a diameter of up to 5 mm. Leukoaraiosis was classified into none-or-mild (absent, punctate) and advanced (early confluent, confluent) white-matter hyperintensities. We also counted lacunae. Multiple logistic regression analysis was used to evaluate the relative contributions of MSLL, leukoaraiosis, and lacunae in discriminating between ICH and infarction. Leukoaraiosis was analyzed as a dummy variable (none-or-mild vs. advanced). Results: The association between MSLL and ICH significantly differed by leukoaraiosis ( p = 0.003 for MSLL-leukoaraiosis interaction term). The number of MSLL on GE-MRI was significantly more strongly associated with ICH than infarction (odds ratio [OR], 2.06; 95% confidence interval [CI], 1.29 to 3.30) when leukoaraiosis was none-or-mild. However, the presence of advanced leukoaraiosis produced a decrease in the OR of MSLL to 1.01. ([CI], 0.98 to 1.05) Conclusion: Our study shows that MSLL on GE-MRI are not a predictor of ICH vs. infarction in patients with advanced leukoaraiosis. Therefore, in the evaluation of GE-MRI for bleeding-prone microangiopathy, the extent of leukoaraiosis should always be considered.