Effects of Corticosteroid (Dexamethasone) Administration on the Brain Scan

In a series of 12 cases with initially abnormal brain scans, repeat scan after dexamethasone therapy showed changes in 10 but none in 2. Two of the 10 reverted to nearly normal; 6 showed marked improvement although the lesions were still visible, and 1 showed slight improvement. One patient was on dexamethasone at the time the study was started and her scan showed dramatic, increased uptake after the drug was discontinued. Generally, clinical improvement correlated with improvement in the scan. Our clinical observations suggest that dexamethasone can cause changes in the 99mTc brain scan.