title: A new technique for noise reduction at coronary CT angiography with multi-phase data-averaging and non-rigid image registration.
abstract: OBJECTIVE
  To investigate the feasibility of a newly developed noise reduction technique at coronary CT angiography (CTA) that uses multi-phase data-averaging and non-rigid image registration.
  
  
  METHODS
  Sixty-five patients underwent coronary CTA with prospective ECG-triggering. The range of the phase window was set at 70-80% of the R-R interval. First, three sets of consecutive volume data at 70%, 75% and 80% of the R-R interval were prepared. Second, we applied non-rigid registration to align the 70% and 80% images to the 75% image. Finally, we performed weighted averaging of the three images and generated a de-noised image. The image noise and contrast-to-noise ratio (CNR) in the proximal coronary arteries between the conventional 75% and the de-noised images were compared. Two radiologists evaluated the image quality using a 5-point scale (1, poor; 5, excellent).
  
  
  RESULTS
  On de-noised images, mean image noise was significantly lower than on conventional 75% images (18.3 HU ± 2.6 vs. 23.0 HU ± 3.3, P < 0.01) and the CNR was significantly higher (P < 0.01). The mean image quality score for conventional 75% and de-noised images was 3.9 and 4.4, respectively (P < 0.01).
  
  
  CONCLUSIONS
  Our method reduces image noise and improves image quality at coronary CTA.
  
  
  CONCLUSIONS
  • We introduce a new method for image noise reduction at cardiac CT. • Multiple data acquisitions of an object and their averaging yield lower noise. • Our method uses multi-phase images reconstructed from unused redundant imaging data. • It reduces image noise by averaging multi-phase images transformed by non-rigid registration. • This method achieves a 20% image noise reduction at cardiac CT.
authors.affiliation: Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan, sa104@rg8.so-net.ne.jp.
authors.forename: Fuminari
authors.initials: F
authors.lastname: Tatsugami
authors.forename: Toru
authors.initials: T
authors.lastname: Higaki
authors.forename: Yuko
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Takuji
authors.initials: T
authors.lastname: Yamagami
authors.forename: Shuji
authors.initials: S
authors.lastname: Date
authors.forename: Chikako
authors.initials: C
authors.lastname: Fujioka
authors.forename: Masao
authors.initials: M
authors.lastname: Kiguchi
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Kihara
authors.forename: Kazuo
authors.initials: K
authors.lastname: Awai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio
chemical_list: D003287:Contrast Media
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