title: Shepherd's crook right coronary artery: a multidetector computed tomography coronary angiography study.
abstract: BACKGROUND
  Shepherd's crook deformity of the right coronary artery (RCA) is considered a haemodynamically non-significant course anomaly. It may be challenging for cardiologists during percutaneous transluminal coronary angioplasty.
  
  
  OBJECTIVE
  To investigate the radiological anatomy of the high riding course of the proximal segment of the RCA, especially focused on the Shepherd's crook RCA (SCRCA), on multidetector computed tomography (MDCT) coronary angiography.
  
  
  METHODS
  A total of 1,118 MDCT coronary angiography examinations were reviewed retrospectively (349 [31.2%] male; 769 [68.8%] female, age range from 18 to 88 years [54.4 ± 14.7 years, mean ± standard deviation]). We classified the segments that had a higher course than RCA ostium (high riding RCA) into two types: type 1--courses turning inferior with an angle equal to or more than 90 degrees, type 2 (SCRCA)--courses turning inferior with an angle less than 90 degrees. The origin of the sinoatrial node artery (SANA) and conus artery were also noted.
  
  
  RESULTS
  High riding RCA was detected in 146 (13%) patients. Of them, 105 (71%) had type 1 and 41 (29%) had type 2. Atherosclerotic plaque formations, to varying degrees, were presented in 10 (24.3%) of the patients with SCRCA. Approximately half of SANA originated from the SCRCA segment of the RCA in SCRCA cases.
  
  
  CONCLUSIONS
  This is the first study about SCRCA that has been performed with MDCT coronary angiography. This study brings important anatomical knowledge to cardiologists. To have knowledge about the origin of the SANA prior to PTCA procedures is important to prevent possible arrhythmias and infarcts.
authors.affiliation: Department of Radiology, GATA Haydarpasa Training Hospital, Uskudar, Istanbul, Turkey. mzsaglam@yahoo.com.
authors.forename: Muzaffer
authors.initials: M
authors.lastname: Saglam
authors.forename: Ersin
authors.initials: E
authors.lastname: Ozturk
authors.forename: Ali Kemal
authors.initials: AK
authors.lastname: Sivrioglu
authors.forename: Cahit
authors.initials: C
authors.lastname: Kafadar
authors.forename: Kemal
authors.initials: K
authors.lastname: Kara
authors.forename: Guner
authors.initials: G
authors.lastname: Sonmez
authors.forename: Omer
authors.initials: O
authors.lastname: Uz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography; D003330:Coronary Vessel Anomalies / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D055815:Young Adult