Fig. 6.

HP ¹³C MRSI data collected on l-NAME–treated pregnant rats. (A) Pyruvate and lactate images collected 5 s apart following the injection of HP [1-¹³C]pyruvate in a pregnant rat (E18), starting ca. 4 s after completion of the metabolite’s injection. The ¹³C MRSI sets were recorded on a 10-mm-thick slice with a 1.5 × 1.5 mm² in-plane resolution and are shown overlaid on the corresponding anatomical ¹H MRI slice (obtained from the surface coil). The three dashed curves highlight placentas from different fetuses; P1, the placenta that exhibits the highest ¹³C signal intensity, was used for the analysis shown in B. (B) The ¹³C signal intensities extracted as a function of postinjection time from the voxel highlighted in the ¹³C images. The lines are best fits determined as described in the text and summarized in SI Appendix, Table S2. (C) Summary of the signal intensity ratios between the [1-¹³C]lactate and the total ¹³C signals integrated from placentas for naïve and l-NAME–treated rats, with n = 6 (naïve) and n = 8 (l-NAME) separate injections. (D) Idem as in C but upon comparing the ratios between total hyperpolarized ¹³C signals arising from within and from (within + without) placentas, in the same animal cohort.