Diagnostic accuracy of MRI for middle cerebral artery stenosis: a postmortem study.

Background and Purpose: Magnetic resonance imaging (MRI) has been widely applied in detecting intracranial large artery stenosis, but there have been few validation studies to compare with histopathology. The aim of the postmortem study is to assess the accuracy of MRI in identifying middle cerebral artery (MCA) stenosis.
Methods: We recruited, consecutively, Chinese postmortem autopsies in our hospital during 19 months. MRI was performed in the postmortem brains to scan the cross-sections of MCAs with barium expanding the artery lumen. The MCAs were then removed for histopathologic studies. With histopathology as a reference standard, the accuracy of MRI was evaluated, and the correlation between MCA stenosis identified by MRI and radiologically or histopathologically evident brain infarcts was investigated.
Results: Seventy-six consecutive autopsies were recruited. The sensitivity and specificity of MRI in detecting more than 30% MCA stenosis were 38.6% and 92.2%, with a positive predictive value of 87.2% and negative predictive value of 52.2%, and the corresponding values of MRI in identifying more than 50% MCA stenosis were 57.1%, 90.8%, 50%, and 83.0%, respectively. Both more than 30% and more than 50% MCA stenosis identified by MRI were found to be associated with infarctions in the corresponding MCA territory (P= 0.001, odds ratio = 4.365, 95% CI: 1.684-11.313; and P= 0.039, odds ratio = 2.694, 95% CI: 1.139-6.377).
Conclusions: Our study demonstrates the agreement between ex vivo MRI and histopathology in identifying MCA stenosis, and the correlation between the MCA stenosis identified by MRI and radiologically or histopathologically evident brain infarcts.