Figure 5.

Hyperpolarized [1-¹³C]pyruvate MRI detects higher lactate production in the infarcting penumbra in porcine stroke. From ischemia (1 h) to the reperfused timepoint (3.5 h), the infarct expanded into the penumbra. There were no differences in cerebral blood flow (CBF) measured with arterial spin labeling or apparent diffusion coefficient (ADC) values between the progressing (red arrows) and the non-progressing parts (green arrow) of the penumbra (a). The parts of the penumbra that progressed to infarct displayed a higher rate of the pyruvate-to-lactate metabolism compared to the parts of the penumbra that did not (b). This effect was present in both model-based and model-free approaches. The relative CBF (rCBF) and mean transit time (MTT) measured with pyruvate perfusion suggested worse perfusion in the progressing regions. Examples are from one representative animal. Data are shown as individual observations (n = 4) with mean ± SD. Tested with linear mixed-effect models.