title: Diffusion-weighted magnetic resonance imaging: new perspectives in the diagnostic pathway of non-complicated acute pyelonephritis.
abstract: OBJECTIVE
  The diagnosis of acute pyelonephritis (APN) requires demonstration of parenchymal involvement. When no predisposing conditions are found, non-complicated APN is suspected and CT or MRI should be performed. Diffusion-weighted (DW) MRI might be useful, quicker and cheaper than the standard gadolinium-enhanced (GE) MRI. The aim of this study is to compare DW-MRI with GE-MRI to test its diagnostic accuracy in APN.
  
  
  METHODS
  Of 318 consecutive patients hospitalised for APN, 279 underwent MRI. Four hundred and fourteen MR studies (first test and follow-up examinations) were gathered and data were processed using Diffusion Analysis software. DW-MRI has been compared with GE-MRI for evaluating diagnostic agreement.
  
  
  RESULTS
  Two hundred and forty-four patients were diagnosed as having APN; 35 were negative. One hundred and sixty-three APN cases were considered non-complicated and selected for the study. Among the 414 MR examinations, comparing DW-MRI with GE-MRI, positive correlation was found in 258 cases, negative in 133. There were 14 false-negatives and 9 false-positives. DW-MRI achieved sensitivity 95.2 %, specificity 94.9 %, positive predictive value 96.9 %, negative predictive value 92.3 % and accuracy 94.6 %.
  
  
  CONCLUSIONS
  DW-MRI is reliable for diagnosing non-complicated APN. The high diagnostic agreement between DW-MRI and GE-MRI offers new perspectives in diagnostic management, enabling diagnosis of non-complicated APN without using ionising radiation or contrast media.
  
  
  CONCLUSIONS
  • The diagnosis of acute pyelonephritis (APN) requires demonstration of renal involvement. • Hitherto magnetic resonance imaging required gadolinium enhancement (GE-MRI) to establish this diagnosis. • But diagnostic agreement between diffusion-weighted and GE-MRI offers new diagnostic opportunities. • Quantification of ADC values can help diagnose and monitor APN. • DW-MRI avoids ionising radiation and paramagnetic contrast medium administration.
authors.affiliation: Department of Diagnostic Imaging, San Luigi Gonzaga Hospital, University of Torino, Orbassano, Torino, Italy.
authors.forename: Agostino
authors.initials: A
authors.lastname: De Pascale
authors.forename: Giorgina Barbara
authors.initials: GB
authors.lastname: Piccoli
authors.forename: Sandro Massimo
authors.initials: SM
authors.lastname: Priola
authors.forename: Daniela
authors.initials: D
authors.lastname: Rognone
authors.forename: Valentina
authors.initials: V
authors.lastname: Consiglio
authors.forename: Irene
authors.initials: I
authors.lastname: Garetto
authors.forename: Laura
authors.initials: L
authors.lastname: Rizzo
authors.forename: Andrea
authors.initials: A
authors.lastname: Veltri
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D019786:Gadolinium DTPA; D006801:Humans; D007668:Kidney / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011704:Pyelonephritis / Q000175:diagnosis*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D019786:Gadolinium DTPA