Various magnetic resonance imaging patterns of chronic subdural hematomas: indicators of the pathogenesis?

Magnetic resonance (MR) imaging can detect various patterns in chronic subdural hematomas. These patterns were compared to the computed tomography (CT) appearances and chemical analysis of the content in 60 hematomas from 44 patients. The hematomas could be classified into five types on both T(1)- and T(2)-weighted images: low, high, and mixed intensity, isointensity, and layered. Combining the T(1)- and T(2)-weighted images of all 60 hematomas revealed a total of 14 different imaging patterns. Combining the CT and MR imaging findings of 55 hematomas identified 25 different patterns. Analysis of the hematoma contents showed that hemolysis-related parameters, such as potassium, glutamate oxaloacetate transaminase, bilirubin, lactate dehydrogenase, and protein concentration, were markedly higher than in the peripheral blood, and there were significant correlations between these parameters. Mixed intensity hematomas were significantly thicker than the other types, and showed markedly higher values of hemolysis-related parameters. Factors affecting the CT and MR imaging findings, such as fresh bleeding, hemolysis, and hemoglobin changes, coexist in a hematoma to varying degrees, and these factors may interact with the age of the hematoma to produce the different patterns that are observed.