Magnetic Resonance Angiography–Diffusion Mismatch Reflects Diffusion–Perfusion Mismatch in Patients with Hyperacute Cerebral Infarction

BackgroundWe evaluated whether clinical–diffusion mismatch (CDM) or magnetic resonance angiography (MRA)–diffusion mismatch (MDM) is useful in detecting diffusion–perfusion mismatch (DPM) in hyperacute cerebral infarction within 3 hours after stroke onset.MethodsAmong patients with cerebral infarction who arrived within 3 hours after stroke onset at our hospital between May 2007 and December 2010, we included 21 patients (16 men and 5 women; mean age 70 ± 7.8 years) with cerebral infarction of the anterior circulation, and in whom magnetic resonance imaging (diffusion-weighted imaging)/MRA and computed tomograpic perfusion of the head were performed at the time of arrival. DPM-positive status was defined as a difference between DWI abnormal signal area and mean transit time prolongation area (≥20% on visual assessment). CDM-positive status was defined as a National Institute of Health Stroke Scale score ≥8 and DWI–Alberta Stroke Program Early CT Score (ASPECTS) ≥8. MDM-positive status was defined as a major artery lesion and DWI-ASPECTS ≥6.ResultsTen of 21 patients had DPM. In all DPM-positive patients, MRA revealed a major artery lesion. Of the 10 DPM-positive patients, 6 were CDM-positive. CDM detected DPM with a sensitivity of 60% and a specificity of 64%. The positive likelihood ratio was 1.65. Of the 10 DPM-positive patients, all were MDM-positive. MDM detected DPM with a sensitivity of 100% and a specificity of 82%. The positive likelihood ratio was 5.5.ConclusionsIn hyperacute cerebral infarction within 3 hours after onset, MDM, as compared with CDM, was able to detect DPM with higher sensitivity and specificity. This suggests that MDM is more reflective of DPM.