title: Assessment of coronary artery stent patency and restenosis using 64-slice computed tomography.
abstract: OBJECTIVE
  Restenosis remains a major limitation of coronary catheter-based stent placement. Therefore, a reliable noninvasive diagnostic method for the evaluation of stented coronary arteries would be highly desirable. Our aim was to evaluate the diagnostic accuracy of high-resolution 64-slice computed tomography (64SCT) in a pilot study for the assessment of the lumen of coronary artery stents.
  
  
  METHODS
  Twenty-five patients underwent 64SCT of the coronary arteries and quantitative x-ray coronary angiography (QCA) after coronary artery stent placement. 64SCT coronary angiography was performed with the following parameters: spatial resolution = 0.4 x 0.4 x 0.4 mm; temporal resolution = 83-165 milliseconds; contrast agent = 80 mL at a flow rate of 5 mL/second; retrospective electrocardiogram gating. The 64SCT scans were evaluated for image quality and for the presence of significant in-stent and peri-stent (proximal and distal) stenoses. Determinations were made of the sensitivity, specificity, diagnostic accuracy, and positive and negative predictive values (PPV and NPV) of 64SCT for the detection or exclusion of stenoses.
  
  
  RESULTS
  A total of 46 stents were evaluated, of which 45 (98%) were of diagnostic image quality. Significant in-stent restenosis or occlusion was detected on QCA in 8/45 cases (>/=50% stenosis = 6; occlusion = 2). The sensitivity, specificity, accuracy, PPV, and NPV of 64SCT for the detection of significant in-stent disease was 75%, 92%, 89%, 67%, and 94%, respectively. Both occluded coronary artery stents were correctly identified. The sensitivity, specificity, and accuracy values of 64SCT for the detection of significant proximal peri-stent stenoses were 75%, 95%, and 93%, respectively, whereas the values for detection of significant distal peri-stent stenoses were 67%, 85%, and 84%, respectively.
  
  
  CONCLUSIONS
  The high spatial and temporal resolution of 64SCT may permit improved assessment of stent occlusion and peri-stent disease, although detection of in-stent stenosis remains difficult.
authors.affiliation: Department of Clinical Radiology, University Hospitals - Grosshadern Ludwig-Maximilians University, Marchioninistr. 15, 81377 Munich, Germany. carsten.rist@med.uni-muenchen.de
authors.forename: Carsten
authors.initials: C
authors.lastname: Rist
authors.forename: Franz
authors.initials: F
authors.lastname: von Ziegler
authors.forename: Konstantin
authors.initials: K
authors.lastname: Nikolaou
authors.forename: Miles A
authors.initials: MA
authors.lastname: Kirchin
authors.forename: Bernd J
authors.initials: BJ
authors.lastname: Wintersperger
authors.forename: Thorsten R
authors.initials: TR
authors.lastname: Johnson
authors.forename: Andreas
authors.initials: A
authors.lastname: Knez
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Leber
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Christoph R
authors.initials: CR
authors.lastname: Becker
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography / Q000379:methods*; D023903:Coronary Restenosis / Q000000981:diagnostic imaging*; D023921:Coronary Stenosis / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015607:Stents; D014057:Tomography, X-Ray Computed; D014654:Vascular Patency