title: Dynamic 18F-fluoride small animal PET to noninvasively assess renal function in rats.
abstract: OBJECTIVE
  Renal function can be quantified by both laboratory and scintigraphic methods. In the case of small animal diagnostics, scintigraphic image-based methods are ideal since they can assess split renal function, work noninvasively, and can be repeated. The aim of this study is to validate a (18)F-PET-based method to quantify renal function in rats.
  
  
  METHODS
  Fluoride clearance was calculated from a dynamic whole body listmode acquisition of 60 min length in a small animal PET scanner following an i.v. injection of 15 MBq (18)F-fluoride. Volumes of interest (VOIs) were placed in the left ventricle and the bladder as well as traced around the kidney contours. The respective time-activity curves (TAC) were calculated. The renal (18)F-clearance was calculated by the ratio of the total renal excreted activity (bladder VOI) and the integral of the blood TAC. PET-derived renal function was validated by intraindividual measurements of creatinine clearance (n = 23), urea clearance (n = 23), and tubular excretion rate (TER-MAG3). The split renal function was derived from the injection of the clinically available radionuclide (99m)Tc-mercaptotriglycine by blood sampling and planar renography (n = 8).
  
  
  RESULTS
  In all animals studied, PET revealed high-quality TACs. PET-derived renal fluoride clearance was linearly correlated with intraindividual laboratory measures (PET vs. creatinine: r = 0.78; PET vs. urea: r = 0.73; PET vs. TER-MAG3: r = 0.73). Split function was comparable ((18)F-PET vs. MAG3-renography: r = 0.98). PET-derived measures were highly reproducible.
  
  
  CONCLUSIONS
  (18)F-PET is able to noninvasively assess renal function in rats and provides a significant potential for serial studies in different experimental scenarios.
authors.affiliation: Klinik und Poliklinik für Nuklearmedizin, 48149 Münster, Germany. uta.schnoeckel@uni-muenster.de
authors.forename: Uta
authors.initials: U
authors.lastname: Schnöckel
authors.forename: Stefan
authors.initials: S
authors.lastname: Reuter
authors.forename: Lars
authors.initials: L
authors.lastname: Stegger
authors.forename: Eberhard
authors.initials: E
authors.lastname: Schlatter
authors.forename: Klaus P
authors.initials: KP
authors.lastname: Schäfers
authors.forename: Sven
authors.initials: S
authors.lastname: Hermann
authors.forename: Otmar
authors.initials: O
authors.lastname: Schober
authors.forename: Gert
authors.initials: G
authors.lastname: Gabriëls
authors.forename: Michael
authors.initials: M
authors.lastname: Schäfers
mesh_terms: D000818:Animals; D049628:Body Size; D005459:Fluorides / Q000008:administration & dosage / Q000737:chemistry* / Q000493:pharmacokinetics; D005462:Fluorine Radioisotopes / Q000737:chemistry*; D007275:Injections, Intravenous; D007511:Ischemia / Q000601:surgery; D007668:Kidney / Q000000981:diagnostic imaging* / Q000502:physiology* / Q000503:physiopathology / Q000601:surgery; D007684:Kidney Tubules / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology; D008297:Male; D009392:Nephrectomy; D049268:Positron-Emission Tomography; D051381:Rats; D012015:Reference Standards; D012077:Renal Artery / Q000378:metabolism; D015424:Reperfusion; D015203:Reproducibility of Results; D017263:Technetium Tc 99m Mertiatide; D051598:Whole Body Imaging
chemical_list: D005462:Fluorine Radioisotopes; D017263:Technetium Tc 99m Mertiatide; D005459:Fluorides