Ultra-high field 1H magnetic resonance imaging approaches for acute hypoxia.

Abstract

BACKGROUND:

Currently, radiation treatments are being optimised based on in vivo imaging of radioresistant, hypoxic tumour areas. This study aimed at detecting nicotinamide's reduction of acute hypoxia in a mouse tumour model by two clinically relevant magnetic resonance imaging (MRI) methods at ultra-high magnetic field strength.

MATERIAL AND METHODS:

The C3H mammary carcinoma was grown to 200 mm(3) in the right rear foot of CDF1 mice. The mice were anaesthetised with ketamine and xylazine prior to imaging. A treatment group received nicotinamide intraperitoneally (i.p.) at the dose 1000 mg/kg, and a control group received saline. MRI was performed at 16.4 T with a spatial resolution of 0.156 × 0.156 × 0.5 mm(3). The imaging protocol included BOLD imaging and two DCE-MRI scans. Initial area under the curve (IAUC) and the parameters from the extended Toft's model were estimated from the DCE-MRI data. Tumour median values of 1) T2* mean, 2) T2* standard deviation, 3) DCE-MRI parameters, and 4) DCE-MRI parameter differences between scans were compared between the treatment groups using Student's t-test (significance level p < 0.05).

RESULTS:

Parametric maps showed intra- and inter-tumour heterogeneity. Blood volume was significantly larger in the nicotinamide-treated group, and also the blood volume difference between the two DCE-MRI scans was significantly larger in the treatment group.

CONCLUSION:

Higher blood volume and blood volume variation was observed by DCE-MRI in the treatment group. Other DCE-MRI parameters showed no significant differences, and the higher blood volume was not detected by BOLD MRI. The higher blood volume variation seen with DCE-MRI may be influenced by the drug effect reducing over time, and furthermore the anaesthesia may play an important role.

• Authors: Thomas Nielsen, Niels Chr Nielsen, Thomas H Holm, Leif Ostergaard, Michael R Horsman, Morten Busk
• Journal: Acta oncologica (Stockholm, Sweden) (Acta Oncol) Vol. 52 Issue 7 Pg. 1287-92 (Oct 2013) ISSN: 1651-226X [Electronic] England
• PMID: 23992112 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Contrast Media
• Gadolinium DTPA

Topics

• Acute Disease
• Animals
• Area Under Curve
• Contrast Media
• Female
• Gadolinium DTPA
• Hypoxia (diagnosis, metabolism)
• Magnetic Resonance Imaging
• Mammary Neoplasms, Animal (diagnosis, metabolism)
• Mice
• Mice, Inbred C3H