title: New classification of aortic dissection during the cardiac cycle as pulsating type and static type evaluated by electrocardiogram-gated multislice CT.
abstract: OBJECTIVE
  In some four-dimensional images acquired by electrocardiogram (ECG)-gated multislice computed tomography (MSCT) of thoracic aortic dissection (AD), true lumen (TL) gets larger (pulsating-type), whereas in others, TL and false lumen (FL) do not change (static-type) in a cardiac cycle. We have characterized these types.
  
  
  METHODS
  Twenty subjects (10 with a double-barrel type thoracic descending AD and 10-controls) were enrolled. MSCT covered the thorax, and reconstructed every 10% from 0-90% of the R-R interval. Two physicians measured the TL and FL areas of descending thoracic aorta for each phase at 1) left-pulmonary-artery, 2) left-main-coronary-artery, and 3) right-coronary-artery levels.
  
  
  RESULTS
  By designating the pulsating-range acquired from the control data as normal, AD subjects were classified as pulsating or static type when the maximum area of TL was >125% of the minimum TL area at any of the 3 levels. Five subjects were classified as pulsating and 5 as static-type AD. Excluding those with entry at the distal portion of the descending-thoracic-aorta with retrograde flow in FL, the mean-period from onset was 4.3+/-5.9 in the pulsating-type and 42.0+/-13.0 months in the static-type (P<0.05). Percentages with entry at the distal-portion of the descending-thoracic-aorta with retrograde flow in FL in the pulsating-type and static-type were 0% and 40%, respectively.
  
  
  CONCLUSIONS
  In AD, pulsating-type is more common if in the acute-phase from onset or the entry is not located at the distal-portion of descending-thoracic-aorta with retrograde flow in FL. This new classification of AD may usefully differentiate unstable-AD affected by cardiac pulsation from stable-AD.
authors.affiliation: Department of Cardiovascular Science and Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8670, Japan.
authors.forename: Taichi
authors.initials: T
authors.lastname: Murayama
authors.forename: Nobusada
authors.initials: N
authors.lastname: Funabashi
authors.forename: Masae
authors.initials: M
authors.lastname: Uehara
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takaoka
authors.forename: Issei
authors.initials: I
authors.lastname: Komuro
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000784:Aortic Dissection / Q000145:classification* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging*; D001014:Aortic Aneurysm / Q000145:classification* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology; D014057:Tomography, X-Ray Computed / Q000379:methods