title: Multi-detector computed tomography to analyze in-stent restenoses at different heart rates.
abstract: OBJECTIVE
  This study was performed to evaluate the visualization of coronary in-stent restenosis by multi-detector computed tomography (MDCT).
  
  
  METHODS
  A restenosis phantom with different stented stenoses was used. The phantom was placed into a dynamic heart phantom with heart rates from 40 to 120 bpm. MDCT was performed with two scan protocols: a standard and an ultra-high resolution scan protocol.
  
  
  RESULTS
  Using the ultra-high resolution protocol, artifacts occurred at 0.6 mm around the stent struts (p < 0.001). Artifacts compromised the discrimination between no stenosis and low-grade stenosis. Approximately 73% of the central lumen diameter was able to be assessed without limiting artifacts allowing the discrimination of no or low vs. moderate and high-grade stenoses (p < 0.05). Using the standard protocol in the dynamic phantom, the image quality and visibility of stenoses decreased with an increasing heart rate (p < 0.0002 and p < 0.004). This was able to be compensated by analysis in an appropriate RR-interval. At the optimal RR-interval, an assessment of the grade of stenoses > 30% was feasible up to 120 bpm.
  
  
  CONCLUSIONS
  Multi-detector computed tomography ultra-high resolution scans allowed the assessment of a wide range of degrees of in-stent restenoses. In this experimental setup, standard protocols allowed a discrimination of low, moderate and high-grade stenoses even at heart rates above 100 bpm.
authors.affiliation: Klinik und Poliklinik für Kardiologie und Angiologie, Universitäres Herzzentrum Hamburg. rkoester@uke.uni-hamburg.de
authors.forename: R
authors.initials: R
authors.lastname: Köster
authors.forename: U
authors.initials: U
authors.lastname: van Stevendaal
authors.forename: M
authors.initials: M
authors.lastname: Grass
authors.forename: J
authors.initials: J
authors.lastname: Yamamura
authors.forename: J
authors.initials: J
authors.lastname: Kaehler
authors.forename: G
authors.initials: G
authors.lastname: Adam
authors.forename: T
authors.initials: T
authors.lastname: Meinertz
authors.forename: P G
authors.initials: PG
authors.lastname: Begemann
mesh_terms: D016477:Artifacts; D023903:Coronary Restenosis / Q000000981:diagnostic imaging*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015588:Observer Variation; D019047:Phantoms, Imaging; D012680:Sensitivity and Specificity; D015607:Stents; D036542:Tomography, Spiral Computed