title: Significance and diagnostic accuracy of renal calculi found by ultrasonography in patients with asymptomatic microscopic hematuria.
abstract: BACKGROUND
  The purpose of the present study was to evaluate the clinical significance and the accuracy of the diagnosis of renal calculi incidentally found by ultrasonography (US).
  
  
  METHODS
  A total of 906 subjects (639 men and 267 women) aged 18-78 years were referred for asymptomatic microscopic hematuria. Of these, 743 patients who underwent US were studied.
  
  
  RESULTS
  Hyperechogenic spots in the central echo complex suggesting renal calculi were noted in 195 patients (21.5%). The occurrence of hyperechogenic spots was higher in patients with 20 or more urinary red blood cells per high-power field (chi(2) = 4.896, P = 0.0269) and in men than in women (chi(2) = 7.101, P = 0.0077), but it was lowest in patients who were 29 years old or younger. Of these 195 patients, who were followed up for 1-161 months (average: 33.5 months), 24 patients (12.3%) needed urological management. Extracorporeal shockwave lithotripsy was carried out in eight patients, transureteral lithotripsy was carried out in three patients, spontaneous passage occurred in 11 patients and medication for hyperuricemia was initiated in two patients (1%). Among the patients in whom hyperechogenic spots were found on the kidney by US but calculi were not visible on abdominal plain radiographs, 39 patients underwent computed tomography. Of them, 31 patients were confirmed to have renal calculi.
  
  
  CONCLUSIONS
  The obtained results suggest that US is an effective and reliable means of detecting renal calculi in patients with asymptomatic microscopic hematuria, and in facilitating prompt urological intervention or predicting the natural course of renal calculi.
authors.affiliation: Department of Urology, School of Medicine, Keio University, Tokyo, Japan. kmarumo@sc.itc.keio.ac.jp
authors.forename: Ken
authors.initials: K
authors.lastname: Marumo
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Horiguchi
authors.forename: Ken
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Mototsugu
authors.initials: M
authors.lastname: Oya
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohigashi
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Asakura
authors.forename: Jun
authors.initials: J
authors.lastname: Nakashima
authors.forename: Masaru
authors.initials: M
authors.lastname: Murai
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006417:Hematuria / Q000000981:diagnostic imaging / Q000209:etiology*; D006801:Humans; D007669:Kidney Calculi / Q000150:complications* / Q000000981:diagnostic imaging*; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D015203:Reproducibility of Results; D012307:Risk Factors; D014463:Ultrasonography