title: Determination of glomerular filtration rate using dynamic CT-angiography: simultaneous acquisition of morphological and functional information.
abstract: OBJECTIVE
  To determine the feasibility of a dynamic CT angiography-protocol in regard to simultaneous assessment of morphology and function.
  
  
  METHODS
  Fourteen patients with renal graft dysfunction received a dynamic computed tomography angiography (CTA) using a 128-slice CT-scanner with continuous bi-directional table movement, allowing to cover a scan range of 18 cm within 1.75 seconds. Twelve scans of the entire kidney were acquired every 3.5 seconds with the aim to simultaneously obtain CTA and renal function data. The glomerular filtration rate (GFR) was calculated by a modified Patlak method and compared with creatinine-based formulas (MDRD 4 and endogenous creatinine clearance), that served as reference standard.
  
  
  RESULTS
  GFR obtained from dynamic CTA correlates well with the GFR derived by creatinine-based formulas with a correlation coefficient of r = 0.8986; P < 0.0001. The average absolute deviation was 8.1 mL/min. The mean amount of contrast medium required was 35 mL. The average effective dose was 13.8 mSv.
  
  
  CONCLUSIONS
  Dynamic CTA offers the possibility to determine the GFR and thus facilitates simultaneous assessment of morphology and function. Additionally, our dynamic CTA-protocol helps to significantly reduce the amount of contrast medium, which is beneficial for patients with impaired renal function.
authors.affiliation: Department of Clinical Radiology, University Hospitals Grosshadern, Ludwig-Maximilians-University of Munich, Munich, Germany. andreas.helck@med.unimuenchen.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Helck
authors.forename: Wieland H
authors.initials: WH
authors.lastname: Sommer
authors.forename: Ernst
authors.initials: E
authors.lastname: Klotz
authors.forename: Matthias
authors.initials: M
authors.lastname: Wessely
authors.forename: Steven Pieter
authors.initials: SP
authors.lastname: Sourbron
authors.forename: Konstantin
authors.initials: K
authors.lastname: Nikolaou
authors.forename: Dirk A
authors.initials: DA
authors.lastname: Clevert
authors.forename: Mike
authors.initials: M
authors.lastname: Notohamiprodjo
authors.forename: Wolf D
authors.initials: WD
authors.lastname: Illner
authors.forename: Maximilian
authors.initials: M
authors.lastname: Reiser
authors.forename: Hans-Christoph
authors.initials: HC
authors.lastname: Becker
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D000792:Angiography / Q000379:methods*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult