Integration of arterial spin labeling into stereotactic radiosurgery planning of cerebral arteriovenous malformations

Purpose To test whether the combined use of 4D arterial spin labeling angiography (4D ASL) and contrast-enhanced magnetic resonance angiography (4D CE-MRA) can work as a prospective alternative to digital subtraction angiography (DSA) for the delineation of the arteriovenous malformation (AVM) nidus in stereotactic radiosurgery (SRS) planning. Materials and Methods A custom 4D ASL sequence and a proof-of-concept software tool to integrate 4D ASL data to SRS planning were implemented. Ten AVM patients were scanned at 3T. Two observers independently contoured niduses in two separate sessions. Reference niduses were contoured using DSA, 4D ASL, and 4D CE-MRA. Test niduses were contoured using 4D ASL and 4D CE-MRA only. Reference and test niduses from both observers were compared in terms of volume, distance between centers of volumes (dCOV), and the Jaccard index (JI). Results In volume comparisons, excellent intraobserver and interobserver agreements were obtained (intraclass correlation coefficients: 0.99 and 0.98, respectively). Median dCOV, JIs between reference and test niduses were 0.55 mm, 0.78 for Observer 1 and were 0.6 mm, 0.78 for Observer 2. None of the dCOV and JI parameters varied significantly among the delineation methods or the observers (P = 0.84, P = 0.39). Conclusion Our preliminary results indicate that reproducibility of the target volumes with high agreement levels is achievable without using DSA. The combined use of high temporal resolution 4D ASL and high spatial resolution and vessel-to-background contrast 4D CE-MRA provided sufficient spatiotemporal angiographic information for the delineation of AVM niduses. Level of Evidence: 2 J. Magn. Reson. Imaging 2017