Imaging description

Segmental arterial mediolysis is a rare idiopathic non-arteriosclerotic non-inflammatory disease first described in 1976 characterized by spontaneous degeneration in the medial layer of the visceral branches of the abdominal aorta, leading to varying combinations of intramural hemorrhage, periadventitial fibrin deposition, aneurysm formation, and dissection [1]. The diagnosis should be considered when CT arteriography shows isolated dissection, small saccular aneurysms, or a “string of beads” appearance in the visceral branches of the abdominal aorta (Figures 53.1–53.3) [2–4].

Importance

The frequency of segmental arterial mediolysis may be underestimated because angiography is not usually performed for gastrointestinal hemorrhage or abdominal pain. The findings may be subtle and overlooked at CT, although the diagnosis may become commoner with the increasing availability of high resolution multidetector CT.

Typical clinical scenario

Segmental arterial mediolysis typically presents with gastrointestinal hemorrhage or abdominal pain in middle-aged and elderly patients, although cerebral involvement has been reported in young adults [5]. The natural history of the disease is poorly understood. Ruptured aneurysms or segmental arterial thrombosis may be treated by reconstruction with a graft or patch, while stenoses may be managed with angioplasty.