Abstracts

RATIONALE: To evaluate quality of standard and high resolution MRI in drug resistant epilepsy. METHODS: About 500 files of epilepsy patients undergoing presurgical evaluation during 1996 and 1999 were checked for written findings of standard MRI by the original radiologist (1) and by an experienced neuroradiologists (2) as well as written findings of our high resolution MRI (3). All three kinds of reports were available for 125 patients, 93 of those underwent surgical resection. Results were correlated to pathological diagnosis when patient underwent surgical resection. RESULTS: Standard MRI findings described 48% of scans as normal. In 10% only non focal abnormalities were described. Hippocampal sclerosis was described in 7%. When standard MRI scans were reassessed by epileptological experienced neuroradiologists 28% of scans were excluded due to poor image quality. 21% were described as normal, hippocampal sclerosis was diagnosed in 17%. In high resolution MRI, 10% were described as normal, 5% showed non focal abnormalities and 45% showed hippocampal sclerosis. The remaining 40% showed other focal lesions. Over all sensitivity for focal lesions of standard MRI was 37%, of expert reassessment 58% and of high resolution MRI 85%. Over all specificity for histopathology of standard MRI was 18%, for expert assessment 32%, and for high resolution MRI 82%. CONCLUSIONS: Even with the improved image quality over the last years, standard MRI is an inadequate method for detecting focal lesions in epilepsies. Hence, in drug resistant epilepsy patients institutions with an epileptological expertise should provide a high resolution MRI as a starting point for presurgical evaluation. Using standard MRI in these patients means wasting health-care money and probably withhold presurgical evaluation that may cure patients epilepsy.