title: Comparison of radiation dose and image quality from single-energy and dual-energy CT examinations in the same patients screened for hepatocellular carcinoma.
abstract: OBJECTIVE
  To compare radiation dose surrogates [volume CT dose index (CTDIvol), dose-length product (DLP), size-specific dose estimate (SSDE), and effective dose] and image noise in a cohort of patients undergoing hepatocellular carcinoma screening who underwent both single-energy CT (SECT) and dual-energy CT (DECT).
  
  
  METHODS
  In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study, 74 adults (mean age 59.5 years) underwent 64 section SECT (120 kVp and weight-based reference mAs) and 128 section dual-source DECT (100/Sn 140 kVp and CTDIvol, adjusted to match the CDTIvol of the SECT protocol) on different occasions. Noise levels were measured in the liver, inferior vena cava (IVC), retroperitoneal (RP) fat, and aorta. Generalized linear models were constructed to compare dose and noise, adjusting for effective diameter.
  
  
  RESULTS
  The total DLP (1371.11 mGy-cm, SD = 527.91) and effective dose (20.57 mSv, SD = 7.92) with SECT were significantly higher than the DLP (864.84 mGy-cm, SD = 322.10) and effective dose (12.97 mSv, SD = 4.83) with DECT (p < 0.001). The differences between SECT and DECT increased as the patient's effective diameter increased (p < 0.001). Noise levels in the liver (22.4 versus 21.9 HU), IVC (22.3 versus 23.4 HU), and RP fat (23.5 versus 23 HU) were similar for DECT and SECT (p > 0.05) but were significantly lower in the aorta for DECT (25.3 versus 26.4 HU; p = 0.006).
  
  
  CONCLUSIONS
  DECT imaging of the abdomen can achieve noise levels comparable to those seen with SECT imaging without a dose penalty to patients.
authors.affiliation: Abdominal Imaging Section, Imaging Institute, Cleveland Clinic, 9500 Euclid Avenue, Mail Code L10, Cleveland, OH 44195, USA. Electronic address: puryska@ccf.org.
authors.forename: A S
authors.initials: AS
authors.lastname: Purysko
authors.affiliation: Siemens Medical Solutions USA, Inc. 51 Valley Stream Parkway, Malvern, PA 19355, USA.
authors.forename: A N
authors.initials: AN
authors.lastname: Primak
authors.affiliation: Abdominal Imaging Section, Imaging Institute, Cleveland Clinic, 9500 Euclid Avenue, Mail Code L10, Cleveland, OH 44195, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Baker
authors.affiliation: Quantitative Health Sciences, Imaging Institute, Cleveland Clinic, 9500 Euclid Avenue, Mail Code L10, Cleveland, OH 44195, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Obuchowski
authors.affiliation: Abdominal Imaging Section, Imaging Institute, Cleveland Clinic, 9500 Euclid Avenue, Mail Code L10, Cleveland, OH 44195, USA.
authors.forename: E M
authors.initials: EM
authors.lastname: Remer
authors.affiliation: Department of Gastroenterology and Hepatology, Digestive Disease Institute, Cleveland Clinic, 9500 Euclid Avenue, Mail Code A51, Cleveland, OH 44195, USA.
authors.forename: B
authors.initials: B
authors.lastname: John
authors.affiliation: Abdominal Imaging Section, Imaging Institute, Cleveland Clinic, 9500 Euclid Avenue, Mail Code L10, Cleveland, OH 44195, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Herts
mesh_terms: D000328:Adult; D000368:Aged; D001822:Body Burden; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*