title: Rarity of isolated pulmonary embolism and acute aortic syndrome occurring outside of the field of view of dedicated coronary CT angiography.
abstract: BACKGROUND
  Although triple rule-out CT angiography (TRO) to simultaneously evaluate acute coronary syndrome (ACS), pulmonary embolism (PE), and acute aortic syndrome (AAS) is increasingly used in many institutions, TRO is inevitably associated with increased radiation exposure due to extended z-axis coverage compared with dedicated coronary CT angiography (DCTA).
  
  
  OBJECTIVE
  To determine the frequency of exclusion of findings of AAS, PE, and significant incidental non-cardiac pathology that may be the cause of acute chest pain when using a restricted DCTA field of view (FOV).
  
  
  METHODS
  We retrospectively reviewed CT images and charts of 103 patients with acute PE and 50 patients with AAS. Either non-ECG gated dedicated pulmonary or aortic CT angiography was performed using 16- or 64-slice multidetector CT (MDCT). We analyzed the incidence of isolated PE, AAS, or significant non-cardiac pathology outside of DCTA FOV (i.e. from tracheal carina to the base of heart).
  
  
  RESULTS
  There were two cases of isolated PE (2/103, 1.9%) excluded from the FOV of DCTA. One case of PE was isolated to the subsegmental pulmonary artery in the posterior segment of the right upper lobe. In the second case, pulmonary embolism in the left main pulmonary artery was located out of the FOV of DCTA because the left main pulmonary artery was retracted upwardly by fibrotic scar in the left upper lobe due to prior tuberculosis. There was no case of AAS and significant non-cardiac pathology excluded from the FOV of DCTA. AAS (n = 50) consisted of penetrating atherosclerotic ulcer (n = 7), intramural hematoma (n = 5) and aortic dissection (n = 38).
  
  
  CONCLUSIONS
  As isolated PE, AAS, and significant non-cardiac pathology outside of the DCTA FOV rarely occur, DCTA may replace TRO in the evaluation of patients with non-specific acute chest pain and a low pre-test probability of PE or aortic dissection.
authors.affiliation: Department of Diagnostic Radiology Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Hwa Yeon
authors.initials: HY
authors.lastname: Lee
authors.forename: In Sup
authors.initials: IS
authors.lastname: Song
authors.forename: Seung Min
authors.initials: SM
authors.lastname: Yoo
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Rho
authors.forename: Jae Youn
authors.initials: JY
authors.lastname: Moon
authors.forename: In Jai
authors.initials: IJ
authors.lastname: Kim
authors.forename: Sang Wook
authors.initials: SW
authors.lastname: Lim
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Sung
authors.forename: Dong Hun
authors.initials: DH
authors.lastname: Cha
authors.forename: Charles S
authors.initials: CS
authors.lastname: White
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging; D000208:Acute Disease; D000784:Aortic Dissection / Q000000981:diagnostic imaging*; D001014:Aortic Aneurysm / Q000000981:diagnostic imaging*; D017023:Coronary Angiography / Q000379:methods*; D006801:Humans; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D013577:Syndrome; D014057:Tomography, X-Ray Computed / Q000379:methods*