title: Quantitative measurement of oxygen metabolic rate in the rat brain using microPET imaging of briefly inhaled 15O-labelled oxygen gas.
abstract: OBJECTIVE
  The quantitative measurement of cerebral metabolic rate of oxygen (CMRO(2)) for rats using positron emission tomography (PET) has been technically difficult. The present study was performed to provide a technique to measure CMRO(2) for rats using a dedicated animal PET technique.
  
  
  METHODS
  CMRO(2) in the rat brain was quantitatively measured under alpha-chloralose anaesthesia (30 mg . kg(-1) . h(-1), intravenous infusion) using a PET imaging technique. In our experiment, the (15)O-labelled gas tracer (O(15)O) was administered by a bolus insufflation into the lung through a surgically placed cannula in the trachea. The tracer distribution was then dynamically imaged using the microPET. Unlike other conventional PET methods in which a series of arterial blood samples need to be withdrawn for the measurement of an arterial input function, no arterial blood sampling was employed. Instead, the heart was scanned in dynamic mode at the same time of imaging the brain, and the region of interest drawn over the heart was analysed to obtain an arterial input function.
  
  
  RESULTS
  The CMRO(2) value (micromol . 100 g(-1) . min(-1)) from 10 rats was 208 +/- 15 (mean +/- SD).
  
  
  CONCLUSIONS
  Our results suggest that the microPET-based CMRO(2) measurement in the rat brain combined with a non-invasive measurement of arterial input function is promising, especially for many applications involving small animals in which repeated measurements of absolute CMRO(2) need to be performed.
authors.affiliation: Research Imaging Center, University of Texas Health Science Center, San Antonio, 78229, USA. yees@uthscsa.edu
authors.forename: Seong-Hwan
authors.initials: SH
authors.lastname: Yee
authors.forename: Kihak
authors.initials: K
authors.lastname: Lee
authors.forename: Paul A
authors.initials: PA
authors.lastname: Jerabek
authors.forename: Peter T
authors.initials: PT
authors.lastname: Fox
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005740:Gases / Q000008:administration & dosage; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008657:Metabolic Clearance Rate; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D010104:Oxygen Radioisotopes / Q000008:administration & dosage; D049268:Positron-Emission Tomography / Q000379:methods* / Q000662:veterinary; D019275:Radiopharmaceuticals; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D005740:Gases; D010104:Oxygen Radioisotopes; D019275:Radiopharmaceuticals; D010100:Oxygen