Computed Tomography Imaging Features and Classification of Isolated Dissection of the Superior Mesenteric Artery

ObjectivesTo analyze computed tomography (CT) imaging features of isolated dissection of the superior mesenteric artery (SMA).MethodsThe imaging findings of 20 consecutive patients with isolated dissection of the SMA were retrospectively evaluated and categorized according to a new imaging classification: Type A, dissections localized at the curved part of the SMA and extended proximally; Type B, dissections limited to the curved part; Type C or D, dissections localized at the curved part and extended distally without or with involved ileocolic or distal ileal arteries. The relationship between classification and symptoms and treatment effect is discussed, and prior reported cases where CT images were available were classified and analyzed.ResultsThe dissections were around the curved part of the SMA in all 20 patients. In symptomatic patients, the true lumen was more stenosed, the dissection started nearer the SMA ostium, and the dissection was longer. The best effect of conservative treatment was achieved in Type B cases. When dissection extended distally, the effect progressively worsened from Type B to Type D.ConclusionsThe new classification is useful for describing the imaging features of isolated dissection of the SMA.