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

Acta Oncol. 2013 Oct;52(7):1287-92. doi: 10.3109/0284186X.2013.824608. Epub 2013 Aug 30.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

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

Substances

  • Contrast Media
  • Gadolinium DTPA