title: Limitations of 64-detector-row computed tomography coronary angiography: calcium and motion but not short experience.
abstract: BACKGROUND
  Recently, 64-detector-row computed tomography coronary angiography (CTA) has been introduced for the noninvasive diagnosis of coronary artery disease.
  
  
  OBJECTIVE
  To evaluate the diagnostic capacity and limitations of a newly established CTA service.
  
  
  METHODS
  In 101 outpatients with suspected coronary artery disease, 64-detector-row CTA (VCT Lightspeed 64; GE Healthcare, Milwaukee, Wisc., USA) was performed before invasive coronary angiography (ICA). The presence of >50% diameter coronary stenosis on CTA was rated by two radiologists recently trained in CTA, and separately by an experienced colleague. Diagnostic performance of CTA was calculated on segment, vessel, and patient levels, using ICA as a reference. Segments with a proximal reference diameter <2 mm or with stents were not analyzed.
  
  
  RESULTS
  In 51 of 101 patients and 121 of 1280 segments, ICA detected coronary stenosis. In 274 of 1280 (21%) segments, CTA had non-diagnostic image quality, the main reasons being severe calcifications (49%), motion artifacts associated with high or irregular heart rate (45%), and low contrast opacification (14%). Significantly more women (43%) had non-diagnostic scans compared to men (20%). A heart rate above 60 beats per minute was associated with significantly more non-diagnostic patients (38% vs. 18%). In the 1006 diagnostic segments, CTA had a sensitivity of 78%, specificity of 95%, positive predictive value (PPV) of 54%, and negative predictive value (NPV) of 98% for detecting significant coronary stenosis. In 29 patients, CTA was non-diagnostic. In the remaining 72 patients, sensitivity was 100%, specificity 65%, PPV 79%, and NPV 100%. The use of a more experienced CTA reader did not improve diagnostic performance.
  
  
  CONCLUSIONS
  CTA had a very high negative predictive value, but the number of non-diagnostic scans was high, especially in women. The main limitations were motion artifacts and vessel calcifications, while short experience in CTA did not influence the interpretation.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Mir-Akbari
authors.forename: J
authors.initials: J
authors.lastname: Ripsweden
authors.forename: J
authors.initials: J
authors.lastname: Jensen
authors.forename: P
authors.initials: P
authors.lastname: Pichler
authors.forename: C
authors.initials: C
authors.lastname: Sylvén
authors.forename: K
authors.initials: K
authors.lastname: Cederlund
authors.forename: A
authors.initials: A
authors.lastname: Rück
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009038:Motion; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed