[Histographic analysis of computed tomography of cerebral hemispheric tumors]

The aim of this report is to assess the possibility of digital processing of computed tomography for histological diagnosis of brain tumors. For this purpose, percent histograms of x-ray attenuation value of lesions were analysed in 113 cases of histologically verified hemispheric tumors. Sixteen histograms obtained from normal brain parenchyma served as controls. Histograms were made from the same slices before and after contrast enhancement. The result were as follows; Histograms of benign tumors such as meningiomas and low grade astrocytomas characteristically showed similar pattern with normal subjects, whereas histographic patterns of the more malignant tumors such as malignant astrocytomas, metastases and glioblastomas were more heterogeneous with lower peak and wider curve. Displacement of the histogram to the higher density following contrast material administration was important clue in histographic analysis. The most prominent displacement was observed in meningiomas, followed by metastases with nodular type enhancement and malignant astrocytomas. Displacement in low grade astrocytomas and oligodendrogliomas was very slight and less than that of normal brain. Tumors showing ring enhancement such as glioblastomas and brain abscesses had wide histogram curve with twin peaks. Conclusively, it is possible to detect histological nature of cerebral tumors through CT scanning, using histographic analysis of the digital data.