title: Evaluation of coronary artery in-stent restenosis by 64-section computed tomography: factors affecting assessment and accurate diagnosis.
abstract: OBJECTIVE
  To determine factors affecting the ability of 64-multislice computed tomography (MSCT) to detect, assess, and accurately diagnose significant coronary arterial in-stent restenosis (ISR).
  
  
  METHODS
  The institutional review board approved this study and waived informed consent. Sixty patients underwent CT coronary angiography using 64-MSCT, after implantation of coronary artery stents (n=91). We assessed diagnostic accuracy for ISR with CT in comparison with conventional coronary angiography as the gold standard, visually and with measurement of in-stent coronary lumen density. Possible factors that influenced the diagnostic performance of CT were evaluated, which included image quality (IQ), stent characteristics, and location.
  
  
  RESULTS
  Sixty-nine stents (75.8%) were assessable. Low IQ, location in the left circumflex coronary artery, and narrow stent diameter were associated with poor assessment (P<0.05). In stents that could be assessed, sensitivity, specificity, positive predictive value, and negative predictive value of 64-MSCT were 90.0%, 73.5%, 58.1%, and 94.7%, respectively, for significant ISR. The diagnostic accuracy in assessable stents showed a significant increase with better IQ, thinner strut thickness, and nondrug eluting stent. False-positive diagnoses of ISR by CT were explained by coronary lumen density measurements.
  
  
  CONCLUSIONS
  Evaluation of stents by 64-MSCT is not recommended in stents with diameters of < or = 2.75 mm or stents located at the left circumflex coronary artery. The diagnostic accuracy of 64-MSCT is affected by IQ and strut thickness in assessable stents. Significant ISR can be excluded with high reliability in selected patients.
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University Medical Center, Seodaemun-gu, Seoul, Korea.
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Chung
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Jin
authors.initials: J
authors.lastname: Hur
authors.forename: Hye Jeong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Kyu Ok
authors.initials: KO
authors.lastname: Choe
authors.forename: Tae Hoon
authors.initials: TH
authors.lastname: Kim
authors.forename: Byoung Wook
authors.initials: BW
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D023903:Coronary Restenosis / Q000000981:diagnostic imaging*; D005260:Female; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007479:Iopamidol; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D011856:Radiographic Image Enhancement / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D015607:Stents; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007479:Iopamidol