title: Unenhanced low-dose versus standard-dose CT localization in patients with upper urinary calculi for minimally invasive percutaneous nephrolithotomy (MPCNL).
abstract: OBJECTIVE
  With the ethical concern about the dose of CT scan and wide use of CT in protocol of suspected renal colic, more attention has been paid to low dose CT. The aim of the present study was to make a comparison of unenhanced low-dose spiral CT localization with unenhanced standard-dose spiral CT in patients with upper urinary tract calculi for minimally invasive percutaneous nephrolithotomy (MPCNL) treatment.
  
  
  METHODS
  Twenty eight patients with ureter and renal calculus, preparing to take MPCNL, underwent both abdominal low-dose CT (25 mAs) and standard-dose CT (100 mAs). Low-dose CT and standard-dose CT were independently evaluated for the characterization of renal/ureteral calculi, perirenal adjacent organs, blood vessels, indirect signs of renal or ureteral calculus (renal enlargement, pyeloureteral dilatation), and the indices of localization (percutaneous puncture angulation and depth) used in the MPCNL procedure.
  
  
  RESULTS
  In all 28 patients, low-dose CT was 100 per cent coincidence 100 per cent sensitive and 100 per cent specific for depicting the location of the renal and ureteral calculus, renal enlargement, pyeloureteral dilatation, adjacent organs, and the presumptive puncture point and a 96.3 per cent coincidence 96 per cent sensitivity and 93 per cent specificity for blood vessel signs within the renal sinus, and with an obvious lower radiation exposure for patients when compared to standard-dose CT (P<0.05). The indices of puncture depth, puncture angulation, and maximum calculus transverse diameter on the axial surface showed no significant difference between the two doses of CT scans, with a significant variation in calculus visualization slice numbers (P<0.05).
  
  
  CONCLUSIONS
  Our findings show that unenhanced low-dose CT achieves a sensitivity and accuracy similar to that of standard-dose CT in assessing the localization of renal ureteral calculus and adjacent organs conditions and identifying the maximum calculus transverse diameter on the axial surface, percutaneous puncture depth, and angulation in patients, with a significant lower radiation exposure, who are to be treated by MPCNL, and can be used as an alternative localization method.
authors.forename: Jiang
authors.initials: J
authors.lastname: Licheng
authors.forename: Fan
authors.initials: F
authors.lastname: Yidong
authors.forename: Wang
authors.initials: W
authors.lastname: Ping
authors.forename: Yan
authors.initials: Y
authors.lastname: Keqiang
authors.forename: Wang
authors.initials: W
authors.lastname: Xueting
authors.forename: Zhang
authors.initials: Z
authors.lastname: Yingchen
authors.forename: Gao
authors.initials: G
authors.lastname: Lei
authors.forename: Ding
authors.initials: D
authors.lastname: Jiyang
authors.affiliation: Department of Urology, Qilu Hospital, Shandong University, Jinan, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Zhonghua
mesh_terms: D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007668:Kidney / Q000473:pathology; D009403:Nephrostomy, Percutaneous / Q000379:methods*; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*; D014513:Ureter / Q000473:pathology; D014545:Urinary Calculi / Q000175:diagnosis* / Q000601:surgery