Epilepsy with focal cerebral calcification: role of magnetization transfer MR imaging.

BACKGROUND Some patients with focal cerebral calcification (FCC) have no seizure or a benign course of epilepsy, whilst others with a similar lesion have uncontrolled epilepsy. AIMS To look for perilesional hyperintensity, presumed to be indicative of gliosis, around FCC on magnetization transfer (MT) MRI and to correlate seizure outcome with its presence. SETTING AND DESIGN Case control study. MATERIAL AND METHODS Fifty-one patients with epilepsy and 30 controls with single calcified cerebral lesion on CT were studied. Clinical and treatment details were noted. EEG and T1, T2, MT and contrast enhanced MRI were done. STATISTICAL ANALYSIS USED Student's t test. RESULTS On MT MRI, perilesional gliosis was seen around the focal calcified lesion in 17 (33.3%) patients. None of the controls had perilesional gliosis. The mean monthly seizure frequency was significantly higher in the 17 patients having perilesional gliosis (2.63+1.15) as compared to the 34 patients without it (0.59+0.63; P= 0.0014). Perilesional gliosis was seen in 8 out of 11 (72.7%) patients who were on 2 AEDs and in all 5 (100%) patients who were on 3 or more AEDs. It was present only in 4 (11.4%) out of 35 patients who were on one AED. CONCLUSION Gliosis around a cerebral calcified lesion as seen on T1 weighted MT MRI indicates poor seizure control.