title: Power Doppler imaging of acute renal transplant rejection.
abstract: OBJECTIVE
  We evaluated the usefulness of power Doppler imaging (PDI) in diagnosing acute renal-transplant rejection.
  
  
  METHODS
  Twenty-eight patients underwent 33 renal-transplant biopsies for suspected acute rejection. Patterns of renal parenchymal vascularity revealed by PDI in patients with abnormal biopsy results were compared with patterns in a group who had normal biopsy results. PDI examinations were reviewed retrospectively by 2 independent radiologists who had no knowledge of the biopsy results. A PDI diagnosis of acute rejection required marked vascular pruning in both the cortex and medulla. PDI results then were compared with transplant-biopsy results.
  
  
  RESULTS
  The sensitivity and specificity of PDI for diagnosing acute renal-transplant rejection were 40% and 100%, respectively. None of the patients with negative biopsy results had PDI abnormalities. The negative predictive value of PDI was 33%, and the positive predictive value was 100%.
  
  
  CONCLUSIONS
  In our study, an abnormal sonogram was highly predictive of acute transplant rejection. However, a normal sonogram did not exclude the possibility of rejection.
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D001706:Biopsy; D001783:Blood Flow Velocity; D003937:Diagnosis, Differential; D005260:Female; D006084:Graft Rejection / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007672:Kidney Cortex / Q000098:blood supply / Q000000981:diagnostic imaging; D007679:Kidney Medulla / Q000098:blood supply / Q000000981:diagnostic imaging; D016030:Kidney Transplantation / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018608:Ultrasonography, Doppler