Computed tomography-guided frame-based stereotactic brain biopsy of non-enhancing lesions using indirect evidence of target selection, technical consideration, and early clinical experience.

Background: The objective was to study the effectiveness and diagnostic outcome of frame-based stereotactic brain biopsy (STB) done for contrast non-enhancing lesions using indirect evidence of target selection observed in a plain computed tomography (CT) scan of the head. Methods: Data of patients with contrast non-enhancing brain lesions who underwent STB are collected retrospectively from NIMHANS Bangalore, hospital neurosurgery database from January 2021 to March 2023. Those cases subjected to plain CT scans after fixing the stereotactic frame to the head were included in the study. A final histopathological report analysis of these cases was done to assess the diagnostic accuracy. Results: A total of 27 such cases were biopsied. The mean age of subjects was 44.04 ± 17.812 years. Most subjects were in the age group 31-40 years (29.6%). About 55.6% were male and 44.4% were female. The most common site of biopsy was the frontal lobe. The most common indirect evidence on CT was perilesional edema at 33.3% and periventricular location at 33.3%, followed by intralesional calcification at 11.1%. Our diagnostic accuracy was 92.59%. The asymptomatic hemorrhage rate was 2%, and an increase in perilesional edema was seen in 2% of cases. Conclusion: Indirect targeting is a safe and intuitive method for biopsy of contrast non-enhancing lesions. Due consideration is to be given to various findings visible in non-contrast CT scans of the head as indirect evidence of target selection while performing frame-based STB of contrast non-enhancing lesions. This method will also be helpful in resource-limited centers, especially in low-income countries.