The Diagnostic Value of Contrast Enhanced Ultrasound in Acute Aortic Dissection

Abstract

Acute aortic dissection is an life-threatening disease that symptoms come on abruptly and progress quickly. patients without treatment have a mortality approaching 1%-2% in the acute stage. Prompt and accurate diagnosis and timely treatment are profoundly important. CTA is first examination method selected to patents who are suspected for AD, but it has some limitations such as contrast agent allergy and radiation exposure. contrast enhanced ultrasound is convenient and safe, however the research on the AD is rare. From November 2015 to Jaunary 2017, We enrolled 41 patients (28 males and 13 females, mean age 57.8±11.1 years) with clinical suspicion of AD in Wuhan Union hospital. Conventional transthoracic echocardiography (TTE)、contrast transthoracic echocardiography (c-TEE) and multislice computed tomography angiography (MS-CTA) were performed to scan the whole aorta in sequence. Serving CTA as the reference standard, We compared conventional ultrasound with CEUS in diagnosing the characterization of AD. Of the 41 patients, 22 patients were diagnosed for AD and 20 underwent surgical repair. Using Stanford classification system, type A were detected in 40.9% (9/22) of patients, type B were seen in 59.1% (13/22). C-TEE correctly diagnosed all the patients, however Conventional TEE had 5 false-positive results because of artifacts (4 in ascending aorta and 1 in the arch). C-TEE distinguished a flap from an artifact in 5 cases, identifed the false lumen slow blood flow in 1 and defined the border of false lumen thrombosis clearly in 8. Conventional TEE visualized intmal flaps in 20 of 22 cases, with the use of contrast enhancement increased to 22 (p=0.49). Conventional TEE correctly identified the true lumen from false lumen in 19/22 (86.4%) cases, and c-TEE in 22/22 (100%) ( P = 0.23) cases. Specificity of conventional TEE increased after contrast enhancement from 73.68 to 100% (P =0.046) for the diagnosis of AD, and both two methods’ sensitivity are 100% (P=1.0). CEUS can accurately diagnose and analysis the characteristics of AD, it is superior than conventional ultrasound in discovering the details lesions of AD, and will provide important information for the diagnosis of AD.