CT evaluation of cystic brain disease

We retrospectively analysed CT findings of 47 cystic brain lesions of 44 patients, in which operation, biopsy 。 r follow-up study was needed for their final diagnosis The resul ts were as fo llows 1. The etio logic diseases of cystic brain lesions were 15 cases of brain abscess, 9 cases of astrocytoma, 5 cases of gliob lastoma multiforme, 3 cases of meningioma, 5 cases of craniopharyngioma, 1 case of hemangioblastoma, 2 cases of dermoid cyst and 4 cases of metastasis 2. We analyses the cystic les ions in view of their number, location, shape, perifocal edema, mass effect, wal l and its th ickness, evenness and characteristics of their inner and outer surfaces, mural nodule, ca lcification and contrast enhancement a. 13.3% of brain abscess and 75% of metastases were multiple in number, but the remainder showed single lesion b. The shape of cystic lesions were round or ovoid in 68%, lobulated in 8.5% and irregular in 23.5%, and no demonstrable difference of shape were noticed in different disease c. ln brain abscess, the wall of cystic les ions tend to be thin, even and smooth in inner surface, but the outer su rfaces were equally smooth or irregular d. Mural nodules were found in nearly half of the cases of astrocytoma, glioblastoma multiforme, metastasis and hemangioblastoma, but the brain abscess and dermoid cyst contained no mural nodule e. Meningiomas were found to be attached to dura mater and showed thickening of the inner table of adjacent skull or of the falx f. The presence of preceding infectious disease may be helpful in the diagnosis of brain abscess, but in 20% there were no demonstrable preceding infection g. Lung cancer was confirmed as primary site in two of the cystic metastatic disease, but other 2 cases show ed no demonstrable primary malignancy