The change of relative incidences of intracranial tumors after the use of computed tomography in Taiwan.

The improved diagnostic capacity of computed tomography (CT) may have resulted in improved detection of intracranial tumors. We were interested to know whether the frequency of intracranial tumors has changed after the introduction of CT in Taiwan. The relative incidences of intracranial tumors in Taiwan were analyzed from the hospital based data. Our data showed that meningiomas were the most encountered intracranial tumors. Neuroepithelial tumors in our series (in the post-CT era) (23.9%) were apparently lower than those found in the pre-CT era (36.0%). However, the relative incidences of meningiomas and pituitary adenomas after the use of CT (24.2%, 21.1%, respectively) were much higher than those found before the use of CT (14.5%, 7.7%, respectively). Our data suggest that the increased incidence for benign tumors and the decreased incidence for malignant tumors may have resulted from the improved diagnostic capacity of CT, which reduces the number of undetected tumor cases.