title: Model-based iterative reconstruction in low-dose CT colonography-feasibility study in 65 patients for symptomatic investigation.
abstract: OBJECTIVE
  To compare image quality on computed tomographic colonography (CTC) acquired at standard dose (STD) and low dose (LD) using filtered-back projection, adaptive statistical iterative reconstruction, and model-based iterative reconstruction (MBIR) techniques.
  
  
  METHODS
  A total of 65 symptomatic patients were prospectively enrolled for the study and underwent STD and LD CTC with filtered-back projection, adaptive statistical iterative reconstruction, and MBIR to allow direct per-patient comparison. Objective image noise, subjective image analyses, and polyp detection were assessed.
  
  
  RESULTS
  Objective image noise analysis demonstrates significant noise reduction using MBIR technique (P < .05) despite being acquired at lower doses. Subjective image analyses were superior for LD MBIR in all parameters except visibility of extracolonic lesions (two-dimensional) and visibility of colonic wall (three-dimensional) where there were no significant differences. There was no significant difference in polyp detection rates (P > .05). Doses: LD (dose-length product, 257.7), STD (dose-length product, 483.6).
  
  
  CONCLUSIONS
  LD MBIR CTC objectively shows improved image noise using parameters in our study. Subjectively, image quality is maintained. Polyp detection shows no significant difference but because of small numbers needs further validation. Average dose reduction of 47% can be achieved. This study confirms feasibility of using MBIR in this context of CTC in symptomatic population.
authors: Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth, United Kingdom; Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, University of Hong Kong, Room 406, Block K, Pok Fu Lam Road, Hong Kong. Electronic address: varv@hku.hk.
authors: Varut
authors: V
authors: Vardhanabhuti
authors: Department of Radiology, Torbay Hospital, Torquay, United Kingdom.
authors: Julia
authors: J
authors: James
authors: Department of Radiology, Derriford Hospital, Plymouth, United Kingdom.
authors: Rehaan
authors: R
authors: Nensey
authors: University of Exeter Medical School, Exeter, United Kingdom.
authors: Christopher
authors: C
authors: Hyde
authors: Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth, United Kingdom; Department of Radiology, Derriford Hospital, Plymouth, United Kingdom.
authors: Carl
authors: C
authors: Roobottom
mesh_terms: D000368:Aged; D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic / Q000379:methods*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging*; D003287:Contrast Media; D003974:Diatrizoate Meglumine; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*
chemical_list: D003287:Contrast Media; D003974:Diatrizoate Meglumine
keywords: CT colonography; Low dose; MBIR; model-based iterative reconstruction