CT and MR imaging of chronic subdural hematomas: a comparative study.

UNLABELLED QUESATIONS UNDER STUDY / PRINCIPLES: This study was designed to compare CT and MR appearances of chronic subdural haematomas as well as CT- and MR-guided measurements of haematoma thicknesses. METHODS CT and MR images of 48 chronic subdural haematomas of 34 patients were reviewed retrospectively. The thickness measurements and imaging characteristics of haematomas were compared. RESULTS Levelling was observed in 25% of haematomas, and most of them (60%) had intrahaematomal membranes. All membranes could be delineated by MR imaging, whereas only 27% were defined by CT. Mixed density (52%) and T1 hyperintensity (59%) were commonly observed in membraned haematomas, but the difference was not statistically significant. Haematomas were measured significantly thicker on MR images. All patients had been treated with burr-hole cranio-tomy and irrigation. CONCLUSIONS MR imaging is more sensitive than CT in determining the size and internal structures of chronic subdural haematomas.