Content area
Full Text
Received Nov 20, 2017; Revised Mar 15, 2018; Accepted Mar 27, 2018
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
1. Introduction
Atherosclerosis is a degenerative disease that occurs in relatively large arteries by progressive thickening of the intima of the vessel wall [1, 2]. Accumulation of low-density lipoproteins within the intima and migration of macrophages into subendothelial spaces are regarded as the two important steps that lead to the initiation of atherosclerosis [3, 4]. Several reports in the literature have shown that atherosclerotic lesions of the thoracic aorta are a stronger predictor of coronary artery disease than conventional risk factors, and transesophageal echocardiography (TEE) has become a commonly used technique to evaluate thoracic aortic atherosclerotic plaques [5–7]. Noncalcified plaques are divided into lipid-laden plaques (soft plaques) which are hypoechoic and fibrous plaque (hard plaques) which are hyperechoic. With TEE, however, air in the trachea and left bronchus limits visualization of the upper part of the ascending aorta and the proximal arch [8]. Chatzikonstantinou et al. [8] reported that 64-row MDCT angiography could detect more plaques in a grading system throughout the aortic arch compared to TEE. Volumetric data acquired with a thinner collimation is expected to provide more accurate volume measurement [9]. Curved planar reformations (CPR) which allow a single two-dimensional image display of structures that run through multiple oblique planes have been reported to be useful in evaluating the regional calcified plaque condition of the coronary artery [10].
In this retrospective study, we evaluated the validity of semiautomatic volumetry of the low attenuation portion of the thoracic aortic plaques based on CT attenuation on CPR using MDCT angiographic data with 0.5 mm collimation. Next, we evaluated the low attenuation in the thoracic aortic plaques correlated with abdominal aortic aneurysm (AAA), coronary arterial disease (CAD), and hypertension.
2. Material and Methods
2.1. Study Group
Approval for this retrospective study was obtained from our institutional review board, and informed consent was waived. The clinical and radiological database sets at our hospital were searched for 115 consecutive patients for whom both MDCT thoracic and abdominal angiography and MDCT coronary angiography were conducted between March 2015...