title: Role of MDCT coronary angiography in the evaluation of septal vs interarterial course of anomalous left coronary arteries.
abstract: BACKGROUND
  Conventional coronary angiography (CCA) may be inaccurate to distinguish between interarterial and septal subtypes of anomalous left coronary arteries (CAs).
  
  
  OBJECTIVE
  We compared the classification of anomalous left CA arising from the right sinus of Valsalva (RSV) or right CA on the basis of multidetector computed tomography coronary angiography (MDCTCA) with the classification derived from CCA.
  
  
  METHODS
  A retrospective review of 6000 consecutive electrocardiographic-gated MDCTCAs identified 15 cases of anomalous left main or left anterior descending CA arising from the RSV or right CA coursing between the aorta and the main pulmonary artery. On the basis of MDCTCA findings, the proximal course of each vessel was classified into 3 subtypes: 1, interarterial; 2, septal; and 3, mixed. CCA was reviewed in 5 cases (33%) and classified according to traditional criteria. When CCA images were not available, 3-dimensional volume-rendered reconstructions were used to simulate CCA.
  
  
  RESULTS
  On the basis of MDCTCA, subtypes were distributed as type 1 (n = 2), type 2 (n = 4), and type 3 (n = 8). One case could not be classified into any of these subtypes and was classified as type 4, right ventricular infundibulum (RVI). Applying CCA criteria, 2 cases would have been classified as interarterial and 14 as septal without appreciation of the mixed or RVI subtypes.
  
  
  CONCLUSIONS
  Classification of anomalous left CAs into either septal or interarterial may be too simplistic. There is an anatomic spectrum of anomalous left CAs detected by MDCTCA that challenges the traditional classification based on CCA.
authors.affiliation: Department of Medical Imaging, Division of Cardiothoracic Imaging, Toronto General Hospital, University of Toronto, University Health Network, Mount Sinai Hospital, Toronto, ON, Canada. fstorres@terra.com.br
authors.forename: Felipe S
authors.initials: FS
authors.lastname: Torres
authors.forename: Elsie T
authors.initials: ET
authors.lastname: Nguyen
authors.forename: Carole J
authors.initials: CJ
authors.lastname: Dennie
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Crean
authors.forename: Eric
authors.initials: E
authors.lastname: Horlick
authors.forename: Mark D
authors.initials: MD
authors.lastname: Osten
authors.forename: Narinder
authors.initials: N
authors.lastname: Paul
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001027:Aortography; D017023:Coronary Angiography / Q000379:methods*; D003330:Coronary Vessel Anomalies / Q000145:classification / Q000000981:diagnostic imaging*; D005260:Female; D006346:Heart Septum / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D009864:Ontario; D011237:Predictive Value of Tests; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D012850:Sinus of Valsalva / Q000002:abnormalities / Q000000981:diagnostic imaging; D009626:Terminology as Topic; D014057:Tomography, X-Ray Computed