title: Assessment of image quality and low-contrast detectability in abdominal CT of obese patients: comparison of a novel integrated circuit with a conventional discrete circuit detector at different tube voltages.
abstract: OBJECTIVE
  To compare image quality and low-contrast detectability of an integrated circuit (IC) detector in abdominal CT of obese patients with conventional detector technology at low tube voltages.
  
  
  METHODS
  A liver phantom with 45 lesions was placed in a water container to mimic an obese patient and examined on two different CT systems at 80, 100 and 120 kVp. The systems were equipped with either the IC or conventional detector. Image noise was measured, and the contrast-to-noise-ratio (CNR) was calculated. Low-contrast detectability was assessed independently by three radiologists. Radiation dose was estimated by the volume CT dose index (CTDIvol).
  
  
  RESULTS
  The image noise was significantly lower, and the CNR was significantly higher with the IC detector at 80, 100 and 120 kVp, respectively (P = 0.023). The IC detector resulted in an increased lesion detection rate at 80 kVp (38.1 % vs. 17.2 %) and 100 kVp (57.0 % vs. 41.0 %). There was no difference in the detection rate between the IC detector at 100 kVp and the conventional detector at 120 kVp (57.0 % vs. 62.2 %). The CTDIvol at 80, 100 and 120 kVp measured 4.5-5.2, 7.3-7.9 and 9.8-10.2 mGy, respectively.
  
  
  CONCLUSIONS
  The IC detector at 100 kVp resulted in similar low-contrast detectability compared to the conventional detector with a 120-kVp protocol at a radiation dose reduction of 37 %.
authors.affiliation: Clinic of Radiology and Nuclear Medicine, University of Basel Hospital, Petersgraben 4, 4031, Basel, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Euler
authors.forename: T
authors.initials: T
authors.lastname: Heye
authors.forename: M
authors.initials: M
authors.lastname: Kekelidze
authors.forename: G
authors.initials: G
authors.lastname: Bongartz
authors.forename: Z
authors.initials: Z
authors.lastname: Szucs-Farkas
authors.forename: C
authors.initials: C
authors.lastname: Sommer
authors.forename: B
authors.initials: B
authors.lastname: Schmidt
authors.forename: Sebastian T
authors.initials: ST
authors.lastname: Schindera
mesh_terms: D000368:Aged; D054893:Cone-Beam Computed Tomography / Q000379:methods; D004560:Electricity; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D009765:Obesity / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000379:methods*