Description: OBJECTIVE. The purpose of this study was to describe the various CT findings of isolated spontaneous splanchnic artery dissection and the treatment options and outcomes. MATERIALS AND METHODS. From January 1999 to May 2008, splanchnic artery dissection was diagnosed through CT angiography in 34 patients (28 men, six women) without recent trauma or aortic disease. All patients were classified as having either symptomatic ( n = 19) or asymptomatic ( n = 15) dissection. We analyzed imaging findings of intimal flap, aneurysmal dilatation, thrombosed false lumen, periarterial fatty infiltration, branch vessel involvement, bowel ischemic signs, and the extent of involvement of each artery with each treatment method and the outcomes. RESULTS. Intimal flap ( n = 37 [88.1%]; symptomatic, 22; asymptomatic, 15), thrombosed false lumen ( n = 27 [64.3%]; symptomatic, 19; asymptomatic, 8), and aneurysmal dilatation ( n = 22 [52.4%]; symptomatic, 14; asymptomatic, 8) were seen. Periarterial fatty infiltration and branch vessel involvement differed between the symptomatic and asymptomatic groups ( p 〈 0.01). Renal artery dissection was found in six patients (symptomatic, 3; asymptomatic, 3). Six patients were lost to follow-up. Treatments included conservative management without anticoagulation therapy ( n = 19; symptomatic, 8; asymptomatic, 11), endovascular stent insertions ( n = 6; symptomatic, 6; asymptomatic, 0), and surgery ( n = 3; symptomatic, 3; asymptomatic, 0). Patients with a follow-up interval of more than 10 days had disease in a stationary state ( n = 14; symptomatic, 4; asymptomatic, 10), were in improved condition ( n = 12; symptomatic, 11; asymptomatic, 1), or had progression of disease ( n = 2; symptomatic, 2; asymptomatic, 0). CONCLUSION. Intimal flap, thrombosed false lumen, and aneurysmal dilatation are the most common CT findings of spontaneous splanchnic artery dissection. In splanchnic artery dissection, conservative management without anticoagulation had good outcome except in patients with bowel ischemia, aneurysmal dilatation three times larger than a normal segment, or progression of dissection.