title: Low-Dose (10%) Computed Tomography May Be Inferior to Standard-Dose CT in the Evaluation of Acute Renal Colic in the Emergency Room Setting.
abstract: Noncontrast CT is the standard of care to evaluate nephrolithiasis. We evaluated the performance of low-dose CT (LDCT) scan for evaluation of renal colic in the emergency room (ER).
  
  
  
  Patients visiting the ER with suspected nephrolithiasis received a standard-dose CT (SDCT) and an LDCT. Two urologists read the LDCTs and later they read SDCTs. Stone information was recorded on a diagram of the renal system. Findings on SDCTs and LDCTs were correlated through side-by-side comparison of the diagrams. Later, the two urologists adjudicated all nonconcordance between SDCTs and LDCTs in an unblinded manner.
  
  
  
  Twenty-seven patients were included. SDCTs revealed 27 stones in 18 patients. Mean stone size was 3.81 mm. LDCTs revealed 27 stones in 18 patients with a mean stone size of 4.7 mm (p = 0.23). Overall sensitivity and specificity of LDCTs were 70% and 39%, respectively. There were eight false-positive and eight false-negative stones. All the false-positive stones on LDCTs were placed in the ureter, in which all of the corresponding SDCTs were visible calcifications outside the ureter. Of the eight false-negative stones on LDCTs, seven were visible calcifications on the SDCTs and the eighth stone was 1 mm and was not visible.
  
  
  
  LDCT may not perform well in the evaluation of suspected nephrolithiasis in the acute setting. LDCT scan accurately demonstrates calcifications; however, accurate placement of calcifications in or out of the urinary tract may be diminished due to impaired resolution of soft tissue structures.
authors.affiliation: 1 Department of Urology, Detroit Medical Center, College of Osteopathic Medicine, Michigan State University, Detroit, Michigan.
authors.forename: Ibraheem M
authors.initials: IM
authors.lastname: Malkawi
authors.affiliation: 1 Department of Urology, Detroit Medical Center, College of Osteopathic Medicine, Michigan State University, Detroit, Michigan.
authors.forename: Esther
authors.initials: E
authors.lastname: Han
authors.affiliation: 1 Department of Urology, Detroit Medical Center, College of Osteopathic Medicine, Michigan State University, Detroit, Michigan.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Atalla
authors.affiliation: 1 Department of Urology, Detroit Medical Center, College of Osteopathic Medicine, Michigan State University, Detroit, Michigan.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Santucci
authors.affiliation: 2 Department of Emergency Medicine, Wayne-State University , Detroit, Michigan.
authors.forename: Brian
authors.initials: B
authors.lastname: O'Neil
authors.affiliation: 1 Department of Urology, Detroit Medical Center, College of Osteopathic Medicine, Michigan State University, Detroit, Michigan.
authors.forename: Jason B
authors.initials: JB
authors.lastname: Wynberg
mesh_terms: D000328:Adult; D003085:Colic; D004636:Emergency Service, Hospital; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D011874:Radiometry; D056844:Renal Colic; D015203:Reproducibility of Results; D018401:Sample Size; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014513:Ureter / Q000000981:diagnostic imaging*; D014572:Urology / Q000379:methods; D055815:Young Adult