The donut sign: a new angiographic sign for partially thrombosed aneurysms with flow-induced intraluminal thrombus.

Three patients are described with unruptured large partially thrombosed aneurysms with a peculiar donut-shaped remaining lumen. Observations suggest that the flow geometry of the aneurysm and parent vessels induces a preferential circular laminar flow inside the aneurysm followed by partial intraluminal thrombosis leaving a donut-shaped lumen to accommodate the circular flow. This flow mechanism of thrombus formation inside aneurysms is different from the more common repeated intramural dissections and hemorrhages that cause growth in most large and giant partially thrombosed aneurysms.

The quantification of glenoid bone loss in anterior shoulder instability; MR-arthro compared to 3D-CT.

Objective: The purpose of this study is to investigate if magnetic resonance imaging with intra-articular contrast (MR-arthro) is as reliable as three-dimensionally reconstructed computed tomography imaging (3D-CT) in quantifying the glenoid bone loss in patients with anterior shoulder instability.

Materials And Methods: Thirty-five patients were included. Sagittal MR-arthro and 3D-CT images of the glenoid surface were obtained pre-operatively.