title: Urinary stone differentiation in patients with large body size using dual-energy dual-source computed tomography.
abstract: OBJECTIVE
  To evaluate the ability of 100/Sn140 kV (Sn, tin filter) dual-energy computed tomography (CT) to differentiate urinary stone types in a patient cohort with a wide range of body sizes.
  
  
  METHODS
  Eighty human urinary stones were categorised into four groups (uric acid; cystine; struvite, oxalate and brushite together; and apatite) and imaged in 30-50-cm-wide water tanks using clinical 100/Sn140 kV protocols. The CT number ratio (CTR) between the low- and high-energy images was calculated. Thresholds for differentiating between stone groups were determined using receiver operating characteristics (ROC) analysis. Additionally, 86 stones from 66 patients were characterised using the size-adaptive CTR thresholds determined in the phantom study.
  
  
  RESULTS
  In phantoms, the area under the ROC curve for differentiating between stone groups ranged from 0.71 to 1.00, depending on phantom size. In patients, body width ranged from 28.5 to 50.0 cm, and 79.1 % of stones were correctly characterised. Sensitivity and specificity for correctly identifying the stone category were 100 % and 100 % (group 1), 100 % and 95.3 % (group 2), 85.7 % and 60.9 % (group 3), and 52.6 % and 92.5 % (group 4).
  
  
  CONCLUSIONS
  Dual-energy CT can provide in vivo urinary stone characterisation for patients over a wide range of body sizes.
  
  
  CONCLUSIONS
  • Dual-energy CT helps assessment of urinary stone composition in vivo. • 100/Sn140 kV DECT differentiates among four stone types with 79.1 % accuracy. • In vivo diagnostic test achievable in patients with many body sizes.
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Mingliang
authors.initials: M
authors.lastname: Qu
authors.forename: Giselle
authors.initials: G
authors.lastname: Jaramillo-Alvarez
authors.forename: Juan C
authors.initials: JC
authors.lastname: Ramirez-Giraldo
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Xinhui
authors.initials: X
authors.lastname: Duan
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.forename: Terri J
authors.initials: TJ
authors.lastname: Vrtiska
authors.forename: Amy E
authors.initials: AE
authors.lastname: Krambeck
authors.forename: John
authors.initials: J
authors.lastname: Lieske
authors.forename: Cynthia H
authors.initials: CH
authors.lastname: McCollough
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D049628:Body Size; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014545:Urinary Calculi / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D055815:Young Adult