Figure 3.

The change in mean pO₂ under hyperoxia challenge for the MS tissue classes. (A) pO₂ data were acquired under normoxia (black) and once again under carbogen (95% O₂, 5% CO₂) breathing gas challenge (red). The pO₂ in viable tumor class increased from 45.73 ± 4.30 to 61.06 ± 5.98 mm Hg, and the adipose tissue class and low-T₂ necrosis class also exhibited a significant increase of pO₂. The high-ADC necrosis class showed no change in pO₂. The overall response is a weighted average of the four tissue classes. Data are shown as means ± SEM. (B) An example of a pO₂ spatial map response to hyperoxia challenge. There was a heterogeneous response within the tumor, some areas increased dramatically, whereas other regions did not respond. *P < .05 and ***P < .001; NS, not significant.