Figure 1.

Imaging lactate production in prostate cancer xenografts. PC3 and DU145 xenografts were grown in the hind leg of male athymic nu/nu mice. A, Axial T2-weighted images of representative xenografts with coordinating hyperpolarized ¹³C pyruvate and ¹³C lactate maps and corresponding spectra following the injection of hyperpolarized [1-¹³C] pyruvate. Lactate and pyruvate maps and spectra represent average time intensity between 12 and 90 seconds after the start of the scan (injection of hyperpolarized [1-¹³C] pyruvate at 10 seconds) in a representative tumor. The spectra demonstrate elevated levels of lactate in DU145 tumors compared with PC3 tumors. B, The ratio of the AUC of lactate to the AUC of pyruvate in DU145 and PC3 xenografts measured with hyperpolarized [1-¹³C] pyruvate MRSI (n = 5 mice per cell line). C, The ratio of lactate to creatine in DU145 and PC3 xenografts as measured by ¹H-MRS. Bars, mean; error bars, SD; p.p.m., parts per million; *, P < 0.05 by paired t test; ns, not significant; P ≥ 0.05 by paired t test.