title: Accuracy and efficiency of determining urinary calculi composition using dual-energy computed tomography compared with Hounsfield unit measurements for practicing physicians.
abstract: OBJECTIVE
  To compare speed and accuracy for determining urinary calculi composition between dual-energy computed tomography (DECT) and Hounsfield unit (HU) measurements of calculi by a set of reviewers at varying levels of training and practice.
  
  
  METHODS
  Sixteen patients with known stone composition were randomly selected. Fourteen reviewers of varying levels of practice interpreted DECT and HU images from the selected patients to predict stone composition in 2 sessions (day 1: tutorial or flow sheet available for image interpretation and day 2: tutorial or flow sheet not available). Reviewers recorded HU values, stone color, and predicted stone composition as they were timed. Accuracy of image interpretation, determination of calculi composition, and interpretation time were compared.
  
  
  RESULTS
  DECT accuracy: image interpretation 100% (day 1) and 94% (day 2); predicted stone composition: 100% (day 1) and 73% (day 2). Mean interpretation time was the same for both days, 21 seconds per study (range, 11-40 seconds). HU accuracy: image interpretation 97% (day 1) and 91% (day 2); predicted stone composition was 45% accurate on both days. Mean interpretation time was 53 seconds per study (range, 28-79 seconds) and 41 seconds per study (range, 19-71 seconds) on days 1 and 2, respectively. Overall accuracy of determination of stone composition and interpretation time for DECT were essentially double those of the HU images (87% vs 45% and 21 vs 47 seconds, respectively). Reviewer's experience level did not affect accuracy or speed.
  
  
  CONCLUSIONS
  DECT is easier to learn, faster to interpret, and more accurate than HU in determining urinary calculi composition for physicians at various levels of training and practice.
authors.affiliation: Department of Radiology, Mayo Clinic, Jacksonville, FL.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Jepperson
authors.affiliation: Division of Nephrology, Department of Medicine, Mayo Clinic, Jacksonville, FL.
authors.forename: El-Sayed H
authors.initials: el-SH
authors.lastname: Ibrahim
authors.affiliation: Department of Urology, Mayo Clinic, Jacksonville, FL.
authors.forename: Abby
authors.initials: A
authors.lastname: Taylor
authors.affiliation: Department of Radiology, Mayo Clinic, Jacksonville, FL.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Cernigliaro
authors.affiliation: Division of Nephrology, Department of Medicine, Mayo Clinic, Jacksonville, FL.
authors.forename: William E
authors.initials: WE
authors.lastname: Haley
authors.affiliation: Department of Urology, Mayo Clinic, Jacksonville, FL. Electronic address: thiel.david@mayo.edu.
authors.forename: David D
authors.initials: DD
authors.lastname: Thiel
mesh_terms: D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007091:Image Processing, Computer-Assisted; D015588:Observer Variation; D010820:Physicians; D015203:Reproducibility of Results; D012984:Software; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014545:Urinary Calculi / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D014572:Urology / Q000592:standards