The role of aortic wall CT attenuation measurements for the diagnosis of acute aortic syndromes

• Published in: European journal of radiology Vol. 82; no. 12; pp. 2392 - 2398
• Main Authors: Knollmann, Friedrich D, Lacomis, Joan M, Ocak, Iclal, Gleason, Thomas
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 01.12.2013
• Subjects: Acute Disease; Adult; Aged; Aged, 80 and over; Aneurysm, Dissecting - diagnostic imaging; Aorta; Aortic Aneurysm - diagnostic imaging; Aortography - methods; Atherosclerosis - diagnostic imaging; Computed tomography; Female; Hematoma; Hematoma - diagnostic imaging; Humans; Male; Middle Aged; Radiographic Image Interpretation, Computer-Assisted - methods; Radiographic Image Interpretation, Computer-Assisted - standards; Radiology; Reproducibility of Results; Sensitivity and Specificity; Syndrome; Tomography, X-Ray Computed - methods; Tomography, X-Ray Computed - standards; Young Adult; Computed tomography; Aorta; Hematoma
• ISSN: 0720-048X; 1872-7727
• DOI: 10.1016/j.ejrad.2013.09.007

Abstract Objectives To determine if measurements of aortic wall attenuation can improve the CT diagnosis of acute aortic syndromes. Methods CT reports from a ten year period were searched for acute aortic syndromes (AAS). Studies with both an unenhanced and a contrast enhanced (CTA) series that had resulted in the diagnosis of intramural hematoma (IMH) were reviewed. Diagnoses were confirmed by medical records. The attenuation of aortic wall abnormalities was measured. The observed attenuation threshold was validated using studies from 39 new subjects with a variety of aortic conditions. Results The term “aortic dissection” was identified in 1206, and IMH in 124 patients’ reports. IMH was confirmed in 31 patients, 21 of whom had both unenhanced and contrast enhanced images. All 21 had pathologic CTA findings, and no CTA with IMH was normal. Attenuation of the aortic wall was greater than 45 HUs on the CTA images in all patients with IMH. When this threshold was applied to the new group, sensitivity for diagnosing AAS was 100% (19/19), and specificity 94% (16/17). Addition of unenhanced images did not improve accuracy. Conclusions Measurements of aortic wall attenuation in CTA have a high negative predictive value for the diagnosis of acute aortic syndromes.