Type B Intramural Hematoma of the Aorta: Evolution and Prognostic Value of Intimal Erosion

Purpose: The prognosis and treatment of type B intramural hematoma (IMH) remain unclear. Intimal erosions could be the target of preventive endovascular treatment, but we have no therapeutic criterion on which to decide preventive treatment. Materials and Methods: A prospective multislice computed tomography (CT) study was carried out in 44 patients with type B IMH to assess morphologic evolution and intimal erosion to determine reliable predictive factors that would permit endovascular treatment. Follow-up range was 24-1,440 days. Results: Intimal anomalies consisted of intimal erosion and aortic branch artery lesions. Fifty-eight intimal anomalies were seen on initial CT in 38 patients (86%). Twenty-five anomalies in 22 patients were considered as intimal erosions, of which nine (36%) were visible only on delayed-phase CT. Hematoma regressed in 23 patients (53%). Twenty-one patients (47%) showed morphologic progression. Eleven of these (52%) required endovascular treatment. Twenty of the 25 initial intimal erosions (80%) progressed and caused 19 of the 21 morphologic evolutions (90%). Progression was related to initial intimal erosion and to IMH thickness. Intimal erosion measuring greater than 10 mm had unfavorable progression at 1 month (positive predictive value, 100%). Conclusions: Complications or morphologic progression were related to a preexisting intimal anomaly visualized on initial CT. Multislice CT with systematically delayed phase and millimetric thin slices could increase the detection rate of intimal anomalies.