title: Reliability of a new method for coronary artery calcium or metal subtraction by 320-row cardiac CT.
abstract: OBJECTIVE
  To investigate the feasibility and diagnostic accuracy of subtraction CTA on patients with highly calcified coronary artery disease (CAD) or previous implanted stents, in comparison with invasive coronary angiography (ICA).
  
  
  METHODS
  Twenty-three patients were recruited. All conventional and subtraction CTA exams were performed using a 320-row CT. Subjective image quality score was assessed for each segment using a 4-point scale: 1-uninterpretable to 4-good image quality.
  
  
  RESULTS
  A total of 129 calcified or stented coronary segments were studied. Mean coronary image quality with conventional CTA was 2.73 ± 0.97 and in subtracted CTA 3.3 ± 0.92 (p < 0.01). After metal subtraction, image quality in stented coronary segments with >3 mm of diameter improved from 2.69 ± 0.97 to 3.34 ± 0.89 (p = 0.01) and in those with <3 mm of diameter from 2.11 ± 0.78 to 2.67 ± 0.87 (p = 0.17). There was an improvement in diagnostic accuracy to detect ICA stenosis >50 % by subtraction CTA compared with conventional CTA (AUC 0.93 to 0.87; p = 0.02).
  
  
  CONCLUSIONS
  Subtraction CTA is promising in overcoming limitations of conventional CTA due to calcium or metal artefacts, especially if no motion artefact is present or when stents > 3 mm are studied.
  
  
  CONCLUSIONS
  • Calcium and metal artefacts are still a limitation for conventional coronary CTA • Diagnostic accuracy is improved by subtraction as compared with conventional CTA • Subtraction CTA is a promising tool to overcome limitations of conventional CTA.
authors.affiliation: Cardiac Imaging Unit, Cardiology Department, Hospital Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Sant Antoni Maria Claret 167, 08025, Barcelona, Spain. dvilades@santpau.cat.|Clínica Creu Blanca, Universitat Autònoma de Barcelona, Sant Antoni Maria Claret 167, 08025, Barcelona, Spain. dvilades@santpau.cat.
authors.forename: David
authors.initials: D
authors.lastname: Viladés Medel
authors.affiliation: Cardiac Imaging Unit, Cardiology Department, Hospital Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Sant Antoni Maria Claret 167, 08025, Barcelona, Spain.|Clínica Creu Blanca, Universitat Autònoma de Barcelona, Sant Antoni Maria Claret 167, 08025, Barcelona, Spain.
authors.forename: Rubén
authors.initials: R
authors.lastname: Leta
authors.affiliation: Clínica Creu Blanca, Universitat Autònoma de Barcelona, Sant Antoni Maria Claret 167, 08025, Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Alomar Serralach
authors.affiliation: Cardiac Imaging Unit, Cardiology Department, Hospital Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Sant Antoni Maria Claret 167, 08025, Barcelona, Spain.|Clínica Creu Blanca, Universitat Autònoma de Barcelona, Sant Antoni Maria Claret 167, 08025, Barcelona, Spain.
authors.forename: Francesc
authors.initials: F
authors.lastname: Carreras Costa
authors.affiliation: Cardiac Imaging Unit, Cardiology Department, Hospital Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Sant Antoni Maria Claret 167, 08025, Barcelona, Spain.|Clínica Creu Blanca, Universitat Autònoma de Barcelona, Sant Antoni Maria Claret 167, 08025, Barcelona, Spain.
authors.forename: Guillem
authors.initials: G
authors.lastname: Pons-Lladó
mesh_terms: D015901:Angiography, Digital Subtraction / Q000379:methods*; D016477:Artifacts; D002118:Calcium; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000175:diagnosis*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D002118:Calcium
keywords: Artefact; Cardiac CTA; Coronary calcium subtraction; Metal stents; Subtraction CTA