Glial Tumors: Can You Rely on MRI? An Analysis Showing Agreement with Histopathology in Western India

Background: There is a dearth of evidence on the agreement between Magnetic Resonance Imaging (MRI) and histopathology for glioma in India. This study attempted to describe the profile of patients with glioma and to determine the agreement between MRI and histopathology diagnosis. Material and Methods: We conducted a record-based secondary data analysis of 211 patients diagnosed with glioma at the Department of Pathology of Civil Hospital Ahmedabad from October 2015 to October 2017. Biopsies received were processed and slides were examined. The demographic characteristics, clinical profile and MRI diagnosis of the patients were obtained from Laboratory Information System (LIS). Cohen's kappa was calculated for showing agreement between MRI and histopathology. Frozen section examination was done for tissues sent intraoperatively. Results: Among 211 patients with glial tumors, 165 (78%) had astrocytoma while 23 (11%) each had oligodendroglioma and ependymoma. Around two-third (64%) of astrocytoma occurred among males and about twothird (64%) of ependymoma were seen among 0-29 years age-group. The kappa agreement value of 0.635 denoted a substantial agreement between the histopathology and MRI for astrocytoma. The kappa agreement value between the two procedures for ependymoma was 0.365 suggesting a fair agreement and for oligodendroglioma was 0.08 suggesting poor agreement. Frozen section examination diagnosed 86% of astrocytoma, 83% of oligodendroglioma and 75% of ependymoma correctly. Conclusion: We conclude from the study that neurosurgeons should be cautious in pre-surgical procedures for oligodendroglial and ependymal tumors diagnosed by MRI as there are chances of misdiagnosis. Frozen section examination should be considered in such cases.