title: Assessment of renal perfusion with contrast-enhanced ultrasound: Preliminary results in early diabetic nephropathies.
abstract: OBJECTIVE
  We performed a prospective study to evaluate the value of contrast-enhanced ultrasound (CEUS) in quantitative evaluation of renal cortex perfusion in patients suspected of early diabetic nephropathies (DN), with the estimated GFR (MDRD equation) as the gold standard.
  
  
  METHODS
  The study protocol was approved by the hospital review board; each patient gave written informed consent. Our study included 46 cases (21 males and 25 females, mean age 55.6 ± 4.14 years) of clinical confirmed early DN patients. After intravenous bolus injection of 1 ml sulfur hexafluoride microbubbles of ultrasound contrast agent, real time CEUS of renal cortex was performed successively using a 2-5 MHz convex probe. Time-intensity curves (TICs) and quantitative indexes were created with Qlab software. Receiver operating characteristic (ROC) curves were used to predict the diagnostic criteria of CEUS quantitative indexes, and their diagnostic efficiencies were compared with resistance index (RI) and peak systolic velocity (PSV) of renal segmental arteries by chi square test. Our control group included forty-five healthy volunteers. Difference was considered statistically significant with P <  0.05.
  
  
  RESULTS
  Changes of area under curve (AUC), derived peak intensity (DPI) were statistically significant (P <  0.05). DPI less than 12 and AUC greater than 1400 had high utility in DN, with 71.7% and 67.3% sensitivity, 77.8% and 80.0% specificity. These results were significantly better than those obtained with RI and PSV which had no significant difference in early stage of DN (P > 0.05).
  
  
  CONCLUSIONS
  CEUS might be helpful to improve early diagnosis of DN by quantitative analyses. AUC and DPI might be valuable quantitative indexes.
authors.affiliation: Department of Ultrasound, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Department of Ultrasound, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Wen-Ping
authors.initials: WP
authors.lastname: Wang
authors.affiliation: Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Lin
authors.affiliation: Department of Ultrasound, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Peili
authors.initials: P
authors.lastname: Fan
authors.affiliation: Department of Ultrasound, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Mao
mesh_terms: D019540:Area Under Curve; D003287:Contrast Media / Q000737:chemistry*; D003928:Diabetic Nephropathies / Q000000981:diagnostic imaging*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007668:Kidney / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D045423:Microbubbles; D008875:Middle Aged; D010477:Perfusion; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013459:Sulfur Hexafluoride / Q000737:chemistry; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D013459:Sulfur Hexafluoride
keywords: Contrast-enhanced ultrasound; color doppler flow imaging; diabetic nephropathies; quantitative index; time-intensity curve