MRS glucose mapping and PET joining forces: re-evaluation of the lumped constant in the rat brain under isoflurane anaesthesia

Research output: Contribution to journalArticle


Although numerous positron emission tomography (PET) studies with (18) F-fluoro-deoxyglucose (FDG) have reported quantitative results on cerebral glucose kinetics and consumption, there is a large variation between the absolute values found in the literature. One of the underlying causes is the inconsistent use of the lumped constants (LCs), the derivation of which is often based on multiple assumptions that render absolute numbers imprecise and errors hard to quantify. We combined a kinetic FDG-PET study with magnetic resonance spectroscopic imaging (MRSI) of glucose dynamics in Sprague-Dawley rats to obtain a more comprehensive view of brain glucose kinetics and determine a reliable value for the LC under isoflurane anaesthesia. Maps of Tmax /CMRglc derived from MRSI data and Tmax determined from PET kinetic modelling allowed to obtain an LC-independent CMRglc . The LC was estimated to range from 0.33 ± 0.07 in retrosplenial cortex to 0.44 ± 0.05 in hippocampus, yielding CMRglc between 62 ± 14 and 54 ± 11 μmol/min/100 g, respectively. These newly determined LCs for four distinct areas in the rat brain under isoflurane anaesthesia provide means of comparing the growing amount of FDG-PET data available from translational studies.


  • Malte F Alf
  • João M N Duarte
  • Hongxia Lei
  • Stefanie D Krämer
  • Vladimir Mlynarik
  • Roger Schibli
  • Rolf Gruetter
External organisations
  • Swiss Federal Institute of Technology
Research areas and keywords


  • Algorithms, Anesthetics, Inhalation, Animals, Biological Transport, Brain, Brain Chemistry, Cerebral Cortex, Fluorine Radioisotopes, Fluorodeoxyglucose F18, Glucose, Hippocampus, Isoflurane, Magnetic Resonance Spectroscopy, Models, Biological, Multimodal Imaging, Positron-Emission Tomography, Radiopharmaceuticals, Rats, Rats, Sprague-Dawley, Thalamus, Comparative Study, Journal Article, Research Support, Non-U.S. Gov't
Original languageEnglish
Pages (from-to)672-82
Number of pages11
JournalJournal of Neurochemistry
Issue number4
Publication statusPublished - 2014 May
Publication categoryResearch
Externally publishedYes