title: Myocardial delayed enhancement with dual-source CT: advantages of targeted spatial frequency filtration and image averaging over half-scan reconstruction.
abstract: BACKGROUND
  Clinical utility of myocardial delayed-enhancement CT is currently limited because of relatively poor contrast-to-noise ratio (CNR) and artifacts. Targeted spatial-frequency filtration (TSFF) is a hybrid algorithm of half- and full-scan reconstruction that can achieve both high temporal resolution and improved stability of myocardial signal.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate image quality of delayed-enhancement CT using TSFF with image averaging and its reproducibility in infarct assessment in comparison with conventional half-scan reconstruction (HALF).
  
  
  METHODS
  Forty patients with suspected coronary artery disease underwent delayed-enhancement CT with HALF and TSFF using dual-source CT. Two blinded readers independently determined the presence and size of delayed enhancement. Image quality, signal-to-noise ratio and CNR were assessed. The presence of delayed enhancement on CT was compared with magnetic resonance imaging in 12 patients.
  
  
  RESULTS
  TSFF with averaging of 4 image stacks acquired during 1 breathhold demonstrated significantly better image quality compared with HALF. Good left ventricular lumen-myocardium contrast was consistently achieved with TSFF in patients who received iodine dose of >600 mg I/kg. The signal-to-noise ratio and CNR were 11.3 ± 4.2 and 4.5 ± 1.6 by TSFF, being significantly higher than those by HALF (7.9 ± 2.9 and 3.3 ± 1.8; P < .01 for both). Interobserver reproducibility of infarct sizing was markedly improved by using TSFF instead of HALF (intraclass correlation coefficient: 0.86 vs 0.50). Agreement with magnetic resonance imaging by kappa statistics was 0.85 with TSFF and 0.74 with HALF.
  
  
  CONCLUSIONS
  TSFF with image averaging can significantly improve image quality of delayed-enhancement CT and considerably enhances interobserver reproducibility of infarct sizing.
authors.affiliation: Department of Radiology, Mie University School of Medicine, 2-174 Edobashi, Tsu 514-8507, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kurobe
authors.affiliation: Department of Radiology, Mie University School of Medicine, 2-174 Edobashi, Tsu 514-8507, Japan. Electronic address: kakuya@clin.medic.mie-u.ac.jp.
authors.forename: Kakuya
authors.initials: K
authors.lastname: Kitagawa
authors.affiliation: Department of Radiology, Mie University School of Medicine, 2-174 Edobashi, Tsu 514-8507, Japan.
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Ito
authors.affiliation: Department of Radiology, Mie University School of Medicine, 2-174 Edobashi, Tsu 514-8507, Japan.
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Kurita
authors.affiliation: Department of Radiology, Mie University School of Medicine, 2-174 Edobashi, Tsu 514-8507, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Shiraishi
authors.affiliation: Department of Cardiology, Mie University School of Medicine, Tsu, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Nakamori
authors.affiliation: Department of Cardiology, Mie University School of Medicine, Tsu, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakajima
authors.affiliation: Department of Radiology, Mie University School of Medicine, 2-174 Edobashi, Tsu 514-8507, Japan.
authors.forename: Motonori
authors.initials: M
authors.lastname: Nagata
authors.affiliation: Department of Radiology, Mie University School of Medicine, 2-174 Edobashi, Tsu 514-8507, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Ishida
authors.affiliation: Department of Cardiology, Mie University School of Medicine, Tsu, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Dohi
authors.affiliation: Department of Cardiology, Mie University School of Medicine, Tsu, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ito
authors.affiliation: Department of Radiology, Mie University School of Medicine, 2-174 Edobashi, Tsu 514-8507, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Sakuma
mesh_terms: D000368:Aged; D000465:Algorithms; D016477:Artifacts; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media
keywords: Cardiac-gated imaging techniques; Cardiovascular disease; Diagnostic imaging; Myocardial infarction; X-ray computed tomography