title: Acute focal nephritis: its true sonographic face.
abstract: BACKGROUND
  Acute focal nephritis is an inflammatory process of the renal parenchyma affecting principally the cortex of the kidney. It is considered a midpoint in the spectrum of upper urinary tract infections, ranging from uncomplicated pyelonephritis to intrarenal abscesses. Until recently the hyperechoic sonographic appearance of this lesion was considered uncommon.
  
  
  OBJECTIVE
  To determine the relative prevalence of hyperechoic and hypoechoic sonographic appearance of focal renal lesions in patients with the clinical diagnosis of acute pyelonephritis and to correlate the findings with those of the color Doppler examinations.
  
  
  METHODS
  We reviewed the sonograms of 367 patients hospitalized with the clinical diagnosis of acute pyelonephritis. The sonograms were reviewed for acute renal inflammatory changes. When a focal lesion was detected, we noted the echogenicity, side, form, location and color Doppler characteristics.
  
  
  RESULTS
  Abnormal sonographic findings related to the infection were found in 78 cases. In 52 patients a focal lesion was diagnosed. Forty-seven focal lesions appeared hyperechoic related to the adjacent parenchyma. These lesions were more frequently located at the upper pole and were wedge-shaped in most of the cases. The areas appeared hypo/avascular on the color Doppler examination.
  
  
  CONCLUSIONS
  Our data suggest that the most common appearance of acute focal nephritis is an area of increased echogenicity in the parenchyma of the affected kidney.
authors.affiliation: Department of Diagnostic Imaging, Meir Medical Center, Kfar Saba, Israel. rathaus@bezeqint.net
authors.forename: Valeria
authors.initials: V
authors.lastname: Rathaus
authors.forename: Myriam
authors.initials: M
authors.lastname: Werner
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D005490:Focal Infection / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D007223:Infant; D007557:Israel; D007668:Kidney / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011704:Pyelonephritis / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D018615:Ultrasonography, Doppler, Color