title: Improvement of image quality with beta-blocker premedication on ECG-gated 16-MDCT coronary angiography.
abstract: OBJECTIVE
  The objective of our study was to assess the effect of beta-blockers on image quality of ECG-gated 16-MDCT coronary angiography.
  
  
  METHODS
  Coronary CT angiography was performed in two groups: group 1, 24 volunteers (mean age, 50 years; mean heart rate, 69 beats per minute [bpm]; range, 47-97 bpm); and group 2, 15 patients with current ischemic heart disease (mean age, 54 years; mean heart rate, 54 bpm; range, 48-69 bpm) who were premedicated with 20-40 mg of oral propranolol 1 hr before the study. CT scans were obtained on a 16-MDCT scanner with a 12 x 0.75 mm collimation and 420-msec rotation using nonionic contrast material (80 mL; injection rate, 4 ml/sec). Images were reconstructed at 30-80% of the cardiac cycle in increments of 5%. Image quality of the following eight coronary segments was assessed by two radiologists in consensus: left main coronary artery; proximal and middle segments of the left anterior descending (LAD) and left circumflex (LCX) coronary arteries; and the proximal, middle, and distal segments of the right coronary artery (RCA). Image quality was assessed, using a 5-point grading scale, as grades 1-5. Images assessed as grade 4 or 5 were considered to be of diagnostically acceptable quality.
  
  
  RESULTS
  In group 1, grade 4 or 5 image quality was achieved for visualization of 92% of the left main coronary arteries; 96% of the proximal LAD coronary arteries; 88% of the middle LAD, proximal LCX, and middle LCX coronary arteries; 83% of the proximal RCAs; 58% of the middle RCAs; and 96% of the distal RCAs. In group 2, this level of image quality was achieved in 100% of the left main coronary arteries, proximal and middle LAD arteries, and proximal LCX arteries; 87% of the middle LCX arteries; and 93% of the proximal, middle, and distal RCAs.
  
  
  CONCLUSIONS
  Reduction of heart rates with beta-blocker premedication improves the image quality of CT coronary angiography, especially in terms of the visualization of the right coronary artery.
authors.affiliation: Department of Radiology, Ewha Womans University MokDong Hospital, 911-1 MokDong YangCheon-Ku, Seoul 158-710, South Korea.
authors.forename: Sung Shine
authors.initials: SS
authors.lastname: Shim
authors.forename: Yookyung
authors.initials: Y
authors.lastname: Kim
authors.forename: Soo Mee
authors.initials: SM
authors.lastname: Lim
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage*; D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000188:drug therapy; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011433:Propranolol / Q000008:administration & dosage*; D011856:Radiographic Image Enhancement; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D000319:Adrenergic beta-Antagonists; D011433:Propranolol