title: Renal diffusion-weighted imaging in diabetic nephropathy: correlation with clinical stages of disease.
abstract: OBJECTIVE
  We aimed to assess the correlation between renal apparent diffusion coefficient (ADC) values measured by diffusion-weighted imaging (DWI) and the clinical stages of diabetic nephropathy.
  
  
  METHODS
  DWI (b value, 0 and 600 s/mm2) was performed in 78 patients with clinically confirmed diabetic nephropathy (study group) and 22 volunteers without diabetes mellitus or any renal disease (control group). The mean ADCs were calculated from multiple region-of-interest circles positioned in the renal cortex. Diabetic nephropathy was clinically categorized into five stages based on the values of urinary albumin excretion and glomerular filtration rate (GFR).
  
  
  RESULTS
  Mean renal ADC values of patients with stage 3 or 4 disease were significantly lower than those in patients with stage 1 or 2 disease and the control group (P < 0.001). ADC values of patients with stage 5 disease were significantly lower than those in patients with stage 4 (P = 0.003), stage 3 (P = 0.020), stages 2 and 1, and the control group (P < 0.001). Significant correlations were found between mean renal ADC values and clinical stages of diabetic nephropathy (r=-0.751, P < 0.001), between mean renal ADC values and estimated GFR values (r=0.642, P < 0.001), and between mean renal ADC values and urinary albumin excretion (r=-0.419, P < 0.001).
  
  
  CONCLUSIONS
  Renal ADC values show a significant correlation with clinical stages of diabetic nephropathy. As a relatively simple and noninvasive tool without contrast media administration, renal quantitative DWI may potentially play a role in making clinical decisions in the follow-up of diabetic patients.
authors.affiliation: Department of Radiology, Finike State Hospital, Antalya, Turkey. bakiyagci@yahoo.com.
authors.forename: Pınar
authors.initials: P
authors.lastname: Cakmak
authors.forename: Ahmet Baki
authors.initials: AB
authors.lastname: Yağcı
authors.forename: Belda
authors.initials: B
authors.lastname: Dursun
authors.forename: Duygu
authors.initials: D
authors.lastname: Herek
authors.forename: Semin Melahat
authors.initials: SM
authors.lastname: Fenkçi
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D003928:Diabetic Nephropathies / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results