RESUMO
<p><b>OBJECTIVE</b>To investigate the characteristics of the spontaneous isolated superior mesenteric artery dissection (SISMAD) on computed tomography angiography (CTA).</p><p><b>METHODS</b>Twenty-five patients with unexplained acute abdominal pain received CTA.</p><p><b>RESULTS</b>Four cases with the SISMAD were found and all were male with a mean age of (45.3±6.7) years. Two patients had hypertension history. CT showed enlarged diameter of the superior mesenteric artery with dissection in 4 cases, intimal flap and visible false lumen in 2 cases, ulcer-like laceration in 1 case, and intramural hematoma in 1 case. The proximal lacerations or entries were all at the proximal segment of the superior mesenteric artery. CTA classifications were type Ia (n=2), IIb (n=1), and III (n=1). Two patients underwent repeated CTA when discharged, and progressive changes were discovered.</p><p><b>CONCLUSION</b>CTA can clearly show the characteristics of the superior mesenteric artery dissection, confirm the diagnosis, and provide an important basis for the classification and follow-up observation.</p>