NIMG-109. A PILOT STUDY OF LYMPHOSCINTIGRAPHY WITH TRACER INJECTION IN THE HUMAN BRAIN. (14th November 2022)

• Record Type: Journal Article
• Authors: Coxon, Andrew; Desai, Rupen; Patel, Pujan; Vellimana, Ananth; Willie, Jon; Dowling, Joshua; Leuthardt, Eric; Kim, Albert; Johanns, Tanner; Siegel, Barry; Dunn, Gavin
• Is Part Of: Neuro-oncology. Volume 24(2022)Supplement 7
• Page Start: vii190
• Page End: vii190
• Publication Date: 2022-11-14
• Subjects: Brain Neoplasms -- Periodicals; Brain -- Tumors -- Periodicals; Brain -- Cancer -- Periodicals; Nervous system -- Cancer -- Periodicals; 616.99481
• DOI: 10.1093/neuonc/noac209.727
• Languages: English
• ISSNs: 1522-8517

Abstract

Abstract: INTRODUCTION: Many groups have reported lymphatic and glymphatic structures in animal and human brains, but tracer injection into the human brain to demonstrate real-time lymphatic drainage and mapping has not been reported. Technetium ( 99m Tc) tilmanocept is a radiopharmaceutical agent that binds CD206 and maps draining lymph nodes. We hypothesized that peritumoral 99m Tc-tilmanocept injection into the brain parenchyma would map drainage to cervical lymph nodes. Here we show a paucity of tracer movement after injection due to a presumed inefficiency of glymphatic and lymphatic drainage. METHODS: We enrolled 14 patients undergoing resection or stereotactic biopsy of suspected benign or malignant intracranial tumors. Patients received peritumoral injections of 99m Tc-tilmanocept followed by planar or tomographic imaging. One patient was excluded from analysis because of tracer leakage during injection. RESULTS: No patients showed drainage of 99m Tc-tilmanocept to regional lymph nodes. On average, after correcting for radioactive decay, 70.1% (95% CI: 60.0%, 81.6%) of the tracer in the injection site and 78.1% (95% CI: 71.1%, 85.1%) in the whole-head on the day of surgery remained the morning after, with variable radioactivity in the subarachnoid space. The remaining fraction at the injection site was much larger than the expected fraction of 1.12% (95% CI: 1.07%, 1.17%) based on previously reported clearance rates from non-brain injections. We determined that this lack of drainage was not due to sequestration by a large population of CD206 + cells via immunohistochemistry of peritumoral tissue sections. Patients with benign or malignant tumors and a patient who underwent or minimally invasive stereotactic biopsy all showed no drainage. DISCUSSION: In this pilot study, the lymphatic tracer 99m Tc-tilmanocept was injected into the brain parenchyma, and there was an absence of drainage to the cervical lymph nodes. Our work demonstrates an inefficiency of drainage from the brain parenchyma and highlights an opportunity to improve brain immunosurveillance.