Measurement of individual organ tissue oxygen levels can provide information to help evaluate and optimize medical interventions in many areas including wound healing, resuscitation strategies, and cancer therapeutics. Echo planar 19F MRI has previously focused on tumor oxygen measurement at low oxygen levels (pO 2) <30 mmHg. It uses the linear relationship between spin-lattice relaxation rate (R 1) of hexafluorobenzene (HFB) and pO 2. The feasibility of this technique for a wider range of pO 2values and individual organ tissue pO 2 measurement was investigated in a rat model. Spin-lattice relaxation times (T 1= 1/R 1) of hexafluorobenzene were measured using 19F saturation recovery echo planar imaging. Initial in vitro studies validated the linear relationship between R 1 and pO 2 from 0 to 760 mmHg oxygen partial pressure at 25, 37, and 41°C at 7 Tesla for hexafluorobenzene. In vivo experiments measured rat tissue oxygen (ptO2) levels of brain, kidney, liver, gut, muscle, and skin during inhalation of both 30 and 100% oxygen. All organ ptO 2 values significantly increased with hyperoxia (P < 0.001). This study demonstrates that 19F MRI of hexafluorobenzene offers a feasible tool to measure regional ptO2 in vivo, and that hyperoxia significantly increases ptO2 of multiple organs in a rat model.
- fluorine MRI
- tissue oxygen tension
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging