Correlation Between Gadolinium-Diethylenetriaminepentaacetic Acid Contrast Enhancement and Thallium-201 Chloride Uptake in Pediatric Brainstem Glioma

Abstract

We previously showed that thallium-201 (²⁰¹Tl) chloride is accumulated in over 75% of brain tumors, including brainstem gliomas. The imaging of ²⁰¹Tl with single photon emission computed tomography (SPECT) may require an abnormal increase in permeability of tumor vessels to allow penetration of the blood-brain barrier. To test this hypothesis, we evaluated the correlation between gadolinium enhancement and the degree of ²⁰¹T1 uptake on SPECT and the contributions of either gadolinium enhancement or ²⁰¹Tl uptake to the prognosis in children with brainstem gliomas. Forty-two sets of paired SPECT scans and magnetic resonance imaging (MRI) scans were obtained longitudinally in 13 cases. Altogether, 31 of 42 pairs (74%) of scans showed concordance between the presence of gadolinium enhancement and ²⁰¹Tl uptake. There were no cases that demonstrated ²⁰¹Tl uptake but lacked gadolinium enhancement. The results indicate that ²⁰¹Tl SPECT is of value primarily when brainstem tumors have vessels that are demonstrably permeable to gadolinium, prior to or as a result of radiotherapy. (J Child Neurol 1997; 12:341-348).