Marcin Konrad Kolber MD, Abstract Co-Author: Nothing to Disclose

Mika Lidov MD, Abstract Co-Author: Nothing to Disclose

Jeremy Whang MD, Presenter: Nothing to Disclose

Classic signs of dissection of the carotid or vertebral arteries include crescent-shaped intramural hematoma, intimal flap, and narrowed lumen. However, these findings are not always reliable, and when present, may be difficult to identify or mimicked by artifact. We hope to expand the reader's toolkit for identifying dissections by providing a pictorial review of: Common pitfalls with MRI, MRA, and CTA resulting in a missed diagnosis Imaging pearls to improve sensitivity Artifacts impacting diagnosis

Pitfalls: Clot shine-through on MRA simulating normal flow-related enhancement Normal-sized lumen despite presence of intramural hematoma Occult hematoma on 2DTOF visible as halo sign on 3DTOF Clot not hyperintense on T1 or T2FS Distal occlusion with proximal slow flow, simulating the appearance of proximal dissection Peri-vertebral plexus simulating V2 dissection Pearls: Halo sign: T1 hyperintense thrombus surrounding the arterial lumen Susceptibility artifact on MRA source image, helping distinguish true lumen from clot Proper CT windowing to identify intimal flap and thrombus Artifacts: Signal loss in ICA bulb caused by turbulent flow Entry flow phenomenon Skull base flow gap

http://abstract.rsna.org/uploads/2014/14009660/14009660_ka4r.pdf

Kolber, M, Lidov, M, Whang, J, Beyond Flaps and Crescents: Pearls and Pitfalls in Diagnosing Craniocervical Dissection.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14009660.html