Thallium-201 single photon emission computed tomography for the differentiation of malignant versus non-malignant intracranial space-occupying lesions in developing countries.

Background: Thallium-201 single-photon emission computed tomography (TI-SPECT) imaging has been used historically to distinguish malignant cerebral neoplasms from infectious etiologies.

Objectives: Our study aims to conduct a retrospective study, review existing literature, and perform meta-analysis on the use of TI-SPECT to differentiate malignant from non-malignant nervous system lesions when other advanced imaging modalities are not available, such as in resource-limited setting.

Methods: A retrospective study on the use of TI-SPECT in differentiating malignant versus non-malignant nervous system lesions was conducted in two tertiary hospitals in the Philippines. A systematic review of relevant studies regarding TI-SPECT for the central nervous system was also done. Meta-analysis was performed to generate pooled sensitivity and specificity.

Results: A total of 19 patients from 2 institutions were included in the analysis. Data from Philippine General Hospital showed a sensitivity of 83% (95% CI: 36%, 100%) and a specificity of 100% (95% CI: 16%, 100%), while St. Luke's Medical Center had a sensitivity of 100% (95% CI: 40%, 100%) and specificity of 100% (95% CI: 48%, 100%). Thirty-two (32) articles were qualitatively described and 24 datasets were subjected to meta-analysis. Pooled sensitivity and specificity were 89% (95% CI: 81%-94%) and 81% (95% CI: 73%-87%), respectively with an area under the curve (AUC) for diagnostic accuracy of 92%.

Conclusion: TI-SPECT imaging may be a potential diagnostic tool to discriminate malignant from non-malignant nervous system lesions when advanced imaging modalities such as PET/ MRI are not available. Due to the heterogeneity of the population in the studies included in both the quantitative and qualitative analyses, further studies are needed to validate these findings.