title: Genitourinary abnormalities in an asymptomatic screening population: findings on virtual colonoscopy.
abstract: BACKGROUND
  The true incidences of genitourinary conditions in the modern era are not completely known. We sought to determine the incidence of genitourinary abnormalities in a group of asymptomatic adult patients undergoing axial imaging with virtual colonoscopy.
  
  
  METHODS
  We performed a post-hoc analysis of imaging results from a prospective, IRB-approved study that randomized patients to screening "virtual" CT colonography (CTC) followed by standard endoscopic colonoscopy. CTC scans were reviewed separately by an independent radiologist and a urologist for genitourinary abnormalities. Genitourinary abnormalities were characterized as of minor, moderate, or major clinical significance. Identified nephroliths were categorized by location, laterality, size, and number. Student's t-tests and Fisher's exact-tests were used for continuous and categorical variables as appropriate.
  
  
  RESULTS
  Of 490 patients undergoing CTC and eligible for analysis, no genitourinary abnormalities were found in 294 (60%), minor genitourinary abnormalities were found in 100 (20.4%), moderate genitourinary abnormalities were found in 86 (17.6%), and major genitourinary abnormalities were found in 10 (2%). Renal cysts (n = 60, 12%) were the most common minor urologic findings. Moderate and major genitourinary findings of nephrolithiasis, adrenal adenomas, and renal masses were noted in 13.9%, 3%, and 2% of the population, respectively. The largest stone was 1.2 cm, and the smallest was 1 mm; while 59% had stones < 3mm, 20% between 3 mm and 5 mm, 18% between 5 mm and 10 mm, and 3% > 10 mm in size. Unilateral stones were found in 85%, while bilateral were found in 15%, and the average number of stones was 2, (range 1 - 16). Age and male sex were significantly associated with moderate or major genitourinary findings p = 0.04 and p = 0.05, respectively.
  
  
  CONCLUSIONS
  CT colonography in an asymptomatic screening population helped to identify nephrolithiasis in 13.9%. Moderate and major urologic abnormalities were found in 20% of the cohort. Risk factors included male sex and older age.
authors.affiliation: Naval Medical Center San Diego, CA, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Durbin
authors.forename: Sean P
authors.initials: SP
authors.lastname: Stroup
authors.forename: Hernan O
authors.initials: HO
authors.lastname: Altamar
authors.forename: James O
authors.initials: JO
authors.lastname: L'esperance
authors.forename: Dane R
authors.initials: DR
authors.lastname: Lacey
authors.forename: Brian K
authors.initials: BK
authors.lastname: Auge
mesh_terms: D000328:Adult; D000368:Aged; D058070:Asymptomatic Diseases; D023881:Colonography, Computed Tomographic; D005260:Female; D052776:Female Urogenital Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014481:United States / Q000453:epidemiology