title: Aortic branch artery pseudoaneurysms accompanying aortic dissection. Part I. Pseudoaneurysm anatomy.
abstract: OBJECTIVE
  Small areas of blood flow are sometimes seen within an otherwise thrombosed false lumen on computed tomography (CT) scans of intramural hematomas of the aorta. These are blood-filled spaces that, although they have no apparent communication with the true lumen, appear isodense with the aorta on contrast-enhanced CT scans. The purpose of this report is to describe angiographic and autopsy studies that establish the nature of this entity and describe the principal CT features distinguishing it from a penetrating ulcer.
  
  
  METHODS
  Conventional angiographic and CT aorta findings in two cases with small collections of contrast material within an otherwise thrombosed false lumen of an aortic dissection are discussed. Also examined is another case with pathologic and histologic findings in addition to those of small collections of contrast material within an otherwise thrombosed false lumen of an aortic dissection, which illustrate the pathoanatomy of these lesions.
  
  
  RESULTS
  Angiographic and necropsy evidence shows that some of these lesions represent branch artery pseudoaneurysms and, as such, are secondary to an intramural hematoma, not the primary cause of it.
  
  
  CONCLUSIONS
  Difficulty in demonstrating communication between these collections of contrast material and the adjacent true lumen of the aorta on helical CT examinations and the characteristic location of these lesions along the nonpleural portion of the aortic circumference distinguish them from penetrating ulcers and should suggest the diagnosis of branch artery pseudoaneurysm. Demonstration of a branch artery originating from the contrast collection confirms the diagnosis. These branch artery pseudoaneurysms should be distinguished from penetrating atherosclerotic ulcers.
authors: Department of Radiology, Division of Vascular and Interventional Radiology, University of Michigan Medical Center, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109-0326, USA. davidwms@med.umich.edu
authors: David M
authors: DM
authors: Williams
authors: Paul
authors: P
authors: Cronin
authors: Narasimham
authors: N
authors: Dasika
authors: Gilbert R
authors: GR
authors: Upchurch
authors: Himanshu J
authors: HJ
authors: Patel
authors: Michael G
authors: MG
authors: Deeb
authors: Gerald
authors: G
authors: Abrams