Characteristics of Patients with Target Magnetic Resonance Mismatch Profile: Data from Two Geographically and Racially Distinct Populations

Background: Recently, the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution (DEFUSE) and the Echoplanar Imaging Thrombolytic Evaluation Trial (EPITHET) trialists suggested that diffusion-perfusion magnetic resonance imaging (MRI) can classify patients into 4 subgroups likely to differentially experience benefit or harm from reperfusion therapies. However, there is a lack of data comparing MR mismatch profiles between different race-ethnic groups. In addition, clinical factors affecting MR mismatch profiles are not well described. Methods: We analyzed clinical and pretreatment MRI data of patients from 2 geographically and ethnically distinct study populations ( Seoul, South Korea, and Los Angeles, Calif., USA) who are eligible for recanalization therapy. Diffusion-perfusion mismatch regions were classified among the 4 DEFUSE MR profiles: target mismatch, no mismatch, small lesion and malignant. Results: A total of 147 South Korean and 162 Southern Californian subjects (64.2% Whites) were included. Pretreatment MRIs revealed that the MR mismatch profiles were different in the 2 study populations (p < 0.001). Target mismatch was more prevalent in Southern Californian subjects (67.9%) compared with South Korean subjects (58.5%), whereas the small lesion pattern was more prevalent in the latter (9.9 vs. 23.1%). After adjusting for covariables, 3 features independently decreased the likelihood of presence of target mismatch: history of diabetes (OR 0.369, 95% CI 0.196-0.694), small versus large arterial occlusion (OR 0.052, 95% CI 0.01-0.255) and largest size (highest tertile) of diffusion-weighted imaging (DWI) lesion volume (OR 0.516, 95% CI 0.266-0.999). The one feature independently increasing target mismatch likelihood was intermediate size (middle tertile) DWI volume (OR 2.977, 95% CI 1.431-6.195). Conclusions: Target mismatch profiles are present in 55-70% of patients. Target mismatch is less common in patients with diabetes, small vessel occlusion, Asian ethnicity and extensive DWI lesions, and more common in patients with DWI lesions of intermediate size. Copyright (C) 2009 S. Karger AG, Basel