IntroductionIsolated abdominal aortic dissection (IAAD) has been reported to account for 1.1%–4.1% of all aortic dissections. If detected late, it is associated with a risk of aortic rupture. We investigated the risk factors and characteristic imaging findings of incidentally discovered IAAD using abdominal ultrasonography (AUS) during health check‐up and hereby report our findings.MethodsThe study sample included 41 patients with abdominal aortic abnormalities identified by AUS performed during a health check‐up at our hospital and who were diagnosed with IAAD by contrast‐enhanced computed tomography (CT); in addition, 205 patients were included in the nonevent group. Furthermore, risk factors and characteristic imaging findings of IAAD were examined retrospectively.ResultsCompared with the nonevent group, smoking and fatty liver were observed significantly more frequently in the IAAD group. Ultrasound findings indicated an intimal flap in 35 cases (85.4%), whereas CT scan revealed displacement of intimal calcifications in 32 cases (78.0%).ConclusionCompared with the nonevent group, there were significantly more cases of fatty liver and smoking habits in the IAAD group. In older patients with risk factors for fatty liver and smoking habits, if IAAD is suspected, it is important to monitor the abdominal aorta using ultrasonography during health check‐ups.