Computed tomography in the diagnosis and differential diagnosis of glioblastomas. A qualitative study of 295 cases.

The CT patterns of 295 glioblastomas examined with pre- and postcontrast scans using an EMI scanner Mark I (Matrix 160/160) have been reviewed and compared with the CT appearances of other brain tumors, metastases and abscesses. There is a great variety of CT patterns with glioblastomas. However, a garland-shaped CT appearance, representing a subgroup of ring-shaped lesions, seems to be most typical for glioblastomas since it was observed in 19% of ring-shaped glioblastomas but in only one out of 172 metastases and in no case of an astrocytoma grade II or an abscess in our series. The initial CT diagnosis, based on the CT finding, the patient's history and the clinical data, was correct in 69.8% of the glioblastomas, 41 recurrent glioblastomas included. In 12% of the cases the presence of a glioblastoma was within differential diagnosis. These results lead to the conclusion that in many cases additional diagnostic methods, such as serial scintigraphy and/or cerebral angiography, are required for a reliable differential diagnosis.