The application of Multi-slice spiral CT Angiography in type IIIb aortic dissection

Objective:To explore the value of muti-slice spiral CT angiography (MSCT) in type Ⅲb aortic dissection.Methods:The MSCT images of 81 patients were analyzed retrospectively. In the present study, 16-slice spiral CT was employed, with Iohexol as contrast medium (300 mg/100ml). The rate was 3～4 ml/s, with the sure-star techniques. The scanning ranged from arcus aortic end to common iliac artery crotch.Results:Of the 81 cases, 21 were found to be type Ⅲb aortic dissection. MSCT image clearly showed the intimal rupture, which included sigle entry tear in 20 cases and two entry tears in 1 case. The distances less than 1.5 cm and more than 1.5 cm between intimal rupture and left Suvcalviam artery were 2 cases and 19 cases, respectively. The intimal flap showed line form, arc-shape and spiral form. The thickness was 1～3 mm and the true and false lumen were showed different in density and, moreover, the true lumen was small and narrow. Lastly, false lumens in 17 cases located on left or left-anterior side.Conclusion:MSCTA is an effective and non-invasive method in the diagnosis, classification, and location of intimal rupture of aortic dissection. The crescent valve, which is flexural and herniated toward the false lumen and, the false lumen, which located on left or left-anterior side, are CT features of type Ⅲb aortic dissection.