Mapping angiography and transarterial technetium macroaggregated albumin particle simulation of recurrent atypical intracranial meningioma: feasibility for potential vascular brachytherapy

Atypical meningioma (AM) (WHO-II) has a recurrence rate of 28% after gross total resection (GTR) with limited salvage options. Transarterial therapies may provide treatment opportunities in AM patients who exhausted standard-of-care therapy. In cases where favorable tumor vasculature and particle simulation demonstrate acceptable target dose, Yttrium-90 trans-arterial radioemobilization (TARE) could theoretically provide salvage therapy. A 67-year-old man presented with recurrent AM post gross total resection with adjuvant radiotherapy in 2012, 2014, and 2016. The patient was deemed a poor candidate for additional therapies. Tumor vasculature mapping was performed to determine TARE candidacy. Super-selective angiography and contrast-enhanced cone-beam computed tomography angiosomes demonstrated predominant pial collaterals and minor supply from a middle meningeal artery branch. Particle simulation was performed by infusing 0.3 mCi of 99mTc-macroaggregated albumin (99mTc-MAA). SPECT/CT-MRI fusion demonstrated conformal activity solely within the tumor volume perfused by the middle meningeal artery branch with a lung shunt fraction of 54.7%. The patient subsequently received off-label Nivolumab (PD-1 inhibitor). Mapping angiography for AM using 99mTc-MAA is feasible. It may identify candidates for TARE and potential AM patients with favorable blood supply. The potential for conformal intracranial vascular brachytherapy is intriguing, however, altered arterial supply in recurrent tumors is challenging.

Keywords: 99mTc-macroaggregated albumin (99mTc-MAA); Brachytherapy; Cone beam CT; Mapping angiography; Meningioma; Transarterial radioembolization (TARE); Yttrium-90 (Y-90).