1: Magn Reson Imaging.  2004 Sep;22(7):905-12.  

Effect of anesthesia on the signal intensity in tumors using BOLD-MRI:
Comparison with flow measurements by Laser Doppler flowmetry and oxygen
measurements by luminescence-based probes.

Baudelet C, Gallez B.

Laboratory of Medicinal Chemistry and Radiopharmacy, Laboratory of Biomedical
Magnetic Resonance, Universite Catholique de Louvain, Brussels, Belgium.

BOLD-contrast functional magnetic resonance imaging (MRI) was used to assess the
evolution of tumor oxygenation and blood flow after administration of four
different anesthetics: pentobarbital (60 mg/kg), ketamine/xylazine (80/8 mg/kg),
fentanyl/droperidol (0.078/3.9 mg/kg), and isoflurane (1.5%). Gradient echo
sequences were carried out at 4.7 Tesla in a TLT tumor model implanted in the
muscle of NMRI mice. In parallel experiments, tumor blood flow and tumor pO(2)
were measured using the OxyLite/OxyFlo probe system. A comparison was made with
the changes occurring in the skeletal muscle (host tissue). The signal intensity
was dramatically decreased in tumors after administration of anesthetics, except
isoflurane. These results correlated well with measurements of oxygenation and
blood perfusion. Isoflurane produced constant muscle pO(2) and blood perfusion
although large transient fluctuations in pO(2) and blood flow were reported in
some tumors. Our results emphasize the need for careful monitoring of the
effects of anesthesia when trying to identify new therapeutic approaches that
are aimed at modulating tumor hemodynamics.

PMID: 15288130 [PubMed - in process]