Correlations of Noninvasive BOLD and TOLD MRI With pO2 and Relevance to Tumor Radiation Response

Magn Reson Med. 2014 May;71(5):1863-73. doi: 10.1002/mrm.24846. Epub 2013 Jun 27.

Abstract

Purpose: To examine the potential use of blood oxygenation level dependent (BOLD) and tissue oxygenation level dependent (TOLD) contrast MRI to assess tumor oxygenation and predict radiation response.

Methods: BOLD and TOLD MRI were performed on Dunning R3327-AT1 rat prostate tumors during hyperoxic gas breathing challenge at 4.7 T. Animals were divided into two groups. In Group 1 (n = 9), subsequent (19) F MRI based on spin lattice relaxation of hexafluorobenzene reporter molecule provided quantitative oximetry for comparison. For Group 2 rats (n = 13) growth delay following a single dose of 30 Gy was compared with preirradiation BOLD and TOLD assessments.

Results: Oxygen (100%O2 ) and carbogen (95%O2 /5%CO2 ) challenge elicited similar BOLD, TOLD and pO2 responses. Strong correlations were observed between BOLD or R2* response and quantitative (19) F pO2 measurements. TOLD response showed a general trend with weaker correlation. Irradiation caused a significant tumor growth delay and tumors with larger changes in TOLD and R1 values upon oxygen breathing exhibited significantly increased tumor growth delay.

Conclusion: These results provide further insight into the relationships between oxygen sensitive (BOLD/TOLD) MRI and tumor pO2 . Moreover, a larger increase in R1 response to hyperoxic gas challenge coincided with greater tumor growth delay following irradiation.

Keywords: BOLD; MRI; carbogen; hypoxia; oximetry; oxygen; radiation response.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Biomarkers, Tumor / metabolism*
  • Magnetic Resonance Imaging / methods*
  • Male
  • Molecular Imaging / methods
  • Oximetry / methods*
  • Oxygen / metabolism*
  • Prostatic Neoplasms / metabolism*
  • Prostatic Neoplasms / pathology
  • Prostatic Neoplasms / radiotherapy*
  • Rats
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Statistics as Topic
  • Treatment Outcome

Substances

  • Biomarkers, Tumor
  • Oxygen