- Toward Better Understanding of Flow Diversion in Bifurcation Aneurysms
Fundamental electric and fluid dynamics principles were applied to generate equations describing the relationships between changes in flow and the degree of vessel coverage in settings of variable collateral support to the jailed territory. The authors studied a simplified hypothetic system with minimum assumptions to generate the most conservative outcomes. Up to 30% metal coverage of any branch territory is very likely to be well-tolerated regardless of device or artery size or the availability of immediate collateral support, provided that no acute thrombus forms to further reduce jailed territory perfusion.
- Spinal Epidural Arteriovenous Fistula with Perimedullary Venous Reflux: Clinical and Neuroradiologic Features of an Underestimated Vascular Disorder
Thirteen consecutive patients were diagnosed with deep lumbosacral spinal dural arteriovenous fistula at a single center between 2006 and 2018. Paraparesis was present in 12 (92%) patients. Sphincter dysfunction and sensory symptoms were observed in 7 (54%) and 6 (46%) patients, respectively. The mean duration of symptoms was 6 ± 8 months. Congestive myelopathy on MR imaging was present in all patients. Prominent arterialized perimedullary veins were demonstrated in only 3 cases. Time-resolved contrast-enhanced dynamic MRA revealed arterialized perimedullary veins and an arterialized ventrolateral epidural pouch in 9/10 (90%) patients, mostly located ventrolaterally. The authors conclude that time-resolved contrast-enhanced dynamic MRA is a powerful diagnostic tool for identifying arterialized perimedullary veins as well as an arterialized ventrolateral epidural pouch.