title: The role of aortic wall CT attenuation measurements for the diagnosis of acute aortic syndromes.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Radiology, University of California, Davis, 4860 Y Street, Sacramento, CA 95817, United States; Departments of Radiology and Cardiothoracic Surgery, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15213, United States. Electronic address: friedrich.knollmann@ucdmc.ucdavis.edu.
authors.forename: Friedrich D
authors.initials: FD
authors.lastname: Knollmann
authors.forename: Joan M
authors.initials: JM
authors.lastname: Lacomis
authors.forename: Iclal
authors.initials: I
authors.lastname: Ocak
authors.forename: Thomas
authors.initials: T
authors.lastname: Gleason
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000784:Aortic Dissection / Q000000981:diagnostic imaging*; D001014:Aortic Aneurysm / Q000000981:diagnostic imaging*; D001027:Aortography / Q000379:methods*; D050197:Atherosclerosis / Q000000981:diagnostic imaging*; D005260:Female; D006406:Hematoma / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013577:Syndrome; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards; D055815:Young Adult
keywords: Aorta; Computed tomography; Hematoma