Objectives: To determine if measurements of aortic wall attenuation can improve the CT diagnosis ofacute aortic syndromes.Methods: CT reports from a ten year period were searched for acute aortic syndromes (AAS). Studies withboth an unenhanced and a contrast enhanced (CTA) series that had resulted in the diagnosis of intramuralhematoma (IMH) were reviewed. Diagnoses were confirmed by medical records. The attenuation of aorticwall abnormalities was measured. The observed attenuation threshold was validated using studies from39 new subjects with a variety of aortic conditions.Results: The term "aortic dissection" was identified in 1206, and IMH in 124 patients' reports. IMH wasconfirmed in 31 patients, 21 of whom had both unenhanced and contrast enhanced images. All 21 hadpathologic CTA findings, and no CTA with IMH was normal. Attenuation of the aortic wall was greater than45 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 unenhancedimages did not improve accuracy.Conclusions: Measurements of aortic wall attenuation in CTA have a high negative predictive value forthe diagnosis of acute aortic syndromes.
- Computed tomography
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging