title: Iterative Reconstructions in Reduced-Dose CT: Which Type Ensures Diagnostic Image Quality in Young Oncology Patients?
abstract: To compare adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) algorithms for reduced-dose computed tomography (CT).
  
  
  
  Forty-four young oncology patients (mean age 30 ± 9 years) were included. After routine thoraco-abdominal CT (dose 100%, average CTDIvol9.1 ± 2.4 mGy, range 4.4-16.9 mGy), follow-up CT was acquired at 50% (average CTDIvol4.5 ± 1.2 mGy, range 2.2-8.4 mGy) in 29 patients additionally at 20% dose (average CTDIvol1.9 ± 0.5 mGy, range 0.9-3.4 mGy). Each reduced-dose CT was reconstructed using both ASIR and MBIR. Four radiologists (two juniors and two seniors) blinded to dose and technique read each set of CT images regarding objective and subjective image qualities (high- or low-contrast structures), subjective noise or pixilated appearance, diagnostic confidence, and lesion detection.
  
  
  
  At all dose levels, objective image noise was significantly lower with MBIR than with ASIR (P < 0.001). The subjective image quality for low-contrast structures was significantly higher with MBIR than with ASIR (P < 0.001). Reduced-dose abdominal CT images of patients with higher body mass index (BMI) were read with significantly higher diagnostic confidence than images of slimmer patients (P < 0.001) and had higher subjective image quality, regardless of technique. Although MBIR images appeared significantly more pixilated than ASIR images, they were read with higher diagnostic confidence, especially by juniors (P < 0.001).
  
  
  
  Reduced-dose CT during the follow-up of young oncology patients should be reconstructed with MBIR to ensure diagnostic quality. Elevated body mass index does not hamper the quality of reduced-dose CT.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Lausanne, University of Lausanne, Rue du Bugnon, 1011 Lausanne, Switzerland.
authors.forename: Bastien
authors.initials: B
authors.lastname: Pauchard
authors.affiliation: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Kai
authors.initials: K
authors.lastname: Higashigaito
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Lausanne, University of Lausanne, Rue du Bugnon, 1011 Lausanne, Switzerland.
authors.forename: Aicha
authors.initials: A
authors.lastname: Lamri-Senouci
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Lausanne, University of Lausanne, Rue du Bugnon, 1011 Lausanne, Switzerland; EEG Brain Mapping Core, Centre for Biomedical Imaging (CIBM), Lausanne, Switzerland.
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Knebel
authors.affiliation: Department of Medical Oncology, University Hospital Lausanne, University of Lausanne, Lausanne, Switzerland.
authors.forename: Dominik
authors.initials: D
authors.lastname: Berthold
authors.affiliation: Institute of Radiation Physics, University Hospital Lausanne, University of Lausanne, Lausanne, Switzerland.
authors.forename: Francis Robert
authors.initials: FR
authors.lastname: Verdun
authors.affiliation: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Hatem
authors.initials: H
authors.lastname: Alkadhi
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Lausanne, University of Lausanne, Rue du Bugnon, 1011 Lausanne, Switzerland. Electronic address: sabine.schmidt@chuv.ch.
authors.forename: Sabine
authors.initials: S
authors.lastname: Schmidt
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D009369:Neoplasms / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D000069079:Radiation Exposure; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D059629:Signal-To-Noise Ratio; D016037:Single-Blind Method; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
keywords: Computed tomography (MDCT); computer-assisted; image processing; medical oncology; radiation exposure; radiographic image enhancement