Evaluation of the accuracy with which radiologists define intracranial tumor histology on CT and MRI

Management of patients with intracranial tumor depends on accurate diagnosis of its histology. The aim of this study was to identify the accuracy with which radiologists were able to diagnose the tumor type on CT or MRI. Two groups of patients with definitive histopathological diagnoses and with complete radiological documentation were included into the study. The first group contained 85 of 110 patients operated on because of posterior cranial fossa tumor between Jan. 1, 2001, and Feb. 30, 2003. The second group comprised 63 of 100 patients operated on because of supratentorial tumor between Jan.1 and June 30, 2002. Cases with multiple cerebral metastases or recurrent brain tumors were excluded. Accuracy, sensitivity, and specificity were calculated.In the first group the histological diagnoses were as follows: 25 neurilemmomas, 19 metastases, 16 meningiomas, 10 hemangioblastomas, 7 gliomas, and in the remaining 8 other types. The sensitivities of the radiological diagnoses for the above-mentioned histological types were, respectively, 92, 89, 81, 70, 86, and 25%. The general accuracy was 80%. In the second group, 19 were high-grade gliomas, 16 meningiomas, 10 metastases, 7 low-grade gliomas, 7 hypophyseal adenomas,and the remaining 4 were others. The sensitivities of radiological diagnoses were, respectively, 84%,100%, 70%, 57%, 86%, and 50%. The general accuracy was 81%. CT with contrast, supplemented by MRI in more difficult cases, has high histological diagnostic sensitivity in common intracranial tumors. The diagnostic sensitivity in rare tumors is not satisfactory. (author)