title: Influence of heart rate on vessel visibility in noninvasive coronary angiography using new multislice computed tomography: experience in 94 patients.
abstract: OBJECTIVE
  Initial reports indicate that coronary artery lesions might be visualized with high sensitivity and specificity by the use of recently introduced multislice computed tomography (MSCT). Current CT technology offers a temporal resolution of 250 ms. In case of heart rates (HRs) >65 beats/min (bpm), however, the reconstruction software switches from a single-phase algorithm (using data from one heart cycle only) to a biphase algorithm using image data of two consecutive heart cycles, improving temporal resolution to down to 125 ms. Thus, it was the aim of the present study to evaluate the influence of the patients' (pts) HR on image quality expressed by vessel segment visibility.
  
  
  RESULTS
  MSCT scans (Somatom VZ) were performed in 94 pts. Ten coronary segments were analyzed in each patient with regard to image quality (RCA: segments [sgts] 1-4, LMS: sgt 5, LAD: sgts 5-8, LCX: sgts 11, 12). A total of 697 of 940 (74.1%) sgts were accurately visualizable (RCA: 244/376 [64.9%], LMS: 94/94 [100%], LAD: 232/283 (82.3%), LCX: 146/188 [77.7%]). Beta-blocker therapy had a significant influence on mean HR (65 pts on beta-blocker, HR 65.1+/-10.7 bpm vs. 29 pts, HR 71.6+/-12.2 bpm, P=.01). A significant inverse correlation between HR and segmental visibility was found (r=-.48, P<.0001), with best visibility in pts with lower HRs (n=14 pts with 10 analyzable sgts, HR 60+/-10.1 vs. n=8 pts with 4 analyzable sgts, HR 79.9+/-6.9, P<.0001).
  
  
  CONCLUSIONS
  Our results indicate that vessel visibility is highly dependent on the pts HR. Best vessel visibility was found in pts with HR <65 bpm with single-phase image reconstruction. Thus, it appears to be advisable to evaluate, and if needed, to lower the pts HRs before undergoing MSCT coronary angiography in order to achieve best image quality.
authors.affiliation: Department of Internal Medicine, Division of Cardiology, University of Tuebingen, Tuebingen, Germany. stephen.schroeder@med.uni-tuebingen.de
authors.forename: Stephen
authors.initials: S
authors.lastname: Schroeder
authors.forename: Andreas F
authors.initials: AF
authors.lastname: Kopp
authors.forename: Axel
authors.initials: A
authors.lastname: Kuettner
authors.forename: Christof
authors.initials: C
authors.lastname: Burgstahler
authors.forename: Christian
authors.initials: C
authors.lastname: Herdeg
authors.forename: Martin
authors.initials: M
authors.lastname: Heuschmid
authors.forename: Andreas
authors.initials: A
authors.lastname: Baumbach
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Karl R
authors.initials: KR
authors.lastname: Karsch
authors.forename: Ludger
authors.initials: L
authors.lastname: Seipel
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000503:physiopathology; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*