Quantification of [18F]DPA-714 binding in the human brain: initial studies in healthy controls and Alzheimer's disease patients

J Cereb Blood Flow Metab. 2015 May;35(5):766-72. doi: 10.1038/jcbfm.2014.261. Epub 2015 Feb 4.

Abstract

Fluorine-18 labelled N,N-diethyl-2-(2-[4-(2-fluoroethoxy)phenyl]-5,7-dimethylpyrazolo[1,5-α]pyrimidine-3-yl)acetamide ([(18)F]DPA-714) binds to the 18-kDa translocator protein (TSPO) with high affinity. The aim of this initial methodological study was to develop a plasma input tracer kinetic model for quantification of [(18)F]DPA-714 binding in healthy subjects and Alzheimer's disease (AD) patients, and to provide a preliminary assessment whether there is a disease-related signal. Ten AD patients and six healthy subjects underwent a dynamic positron emission tomography (PET) study along with arterial sampling and a scan protocol of 150 minutes after administration of 250 ± 10 MBq [(18)F]DPA-714. The model that provided the best fits to tissue time activity curves (TACs) was selected based on Akaike Information Criterion and F-test. The reversible two tissue compartment plasma input model with blood volume parameter was the preferred model for quantification of [(18)F]DPA-714 kinetics, irrespective of scan duration, volume of interest, and underlying volume of distribution (VT). Simplified reference tissue model (SRTM)-derived binding potential (BPND) using cerebellar gray matter as reference tissue correlated well with plasma input-based distribution volume ratio (DVR). These data suggest that [(18)F]DPA-714 cannot be used for separating individual AD patients from healthy subjects, but further studies including TSPO binding status are needed to substantiate these findings.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease* / diagnostic imaging
  • Alzheimer Disease* / metabolism
  • Female
  • Fluorine Radioisotopes* / administration & dosage
  • Fluorine Radioisotopes* / pharmacokinetics
  • Humans
  • Kinetics
  • Male
  • Middle Aged
  • Models, Biological*
  • Positron-Emission Tomography*
  • Pyrazoles* / administration & dosage
  • Pyrazoles* / adverse effects
  • Pyrimidines* / administration & dosage
  • Pyrimidines* / adverse effects
  • Radiography
  • Receptors, GABA / metabolism*
  • Time Factors

Substances

  • Fluorine Radioisotopes
  • N,N-diethyl-2-(2-(4-(2-fluoroethoxy)phenyl)-5,7-dimethylpyrazolo(1,5-a)pyrimidin-3-yl)acetamide
  • Pyrazoles
  • Pyrimidines
  • Receptors, GABA
  • TSPO protein, human