Detection of acute kidney injury with hyperpolarized [¹³C, ¹⁵N]Urea and multiexponential relaxation modeling

Abstract

Twitter: @james_grist Funding information Children's Cancer and Leukaemia Group; LundbeckfondenPurpose: To assess the utility of Laplacian fitting to describe the differences in hyperpolarized [ 13 C, 15 N]urea T 2 relaxation in ischemic and healthy rodent kidneys. Methods: Six rats with unilateral renal ischemia were investigated. [ 13 C, 15 N]Urea T 2 mapping was undertaken with a radial fast spin echo method, with subsequent postprocessing performed with regularized Laplacian fitting. Results: Simulations showed that Laplacian fitting was stable down to a signal-tonoise ratio of 20. In vivo results showed a significant increase in the mono-and decrease in biexponential pools in ischemia reperfusion injury kidneys, in comparison to healthy (14 ± 10% versus 4 ± 2%, 85 ± 10% versus 95 ± 3%; P < .05). Conclusion:We demonstrate, for the first time, the differences in multiexponential behavior of [ 13 C, 15 N]urea between the healthy and ischemic rodent kidney. The distribution of relaxation pools were found to be both visually and numerically significantly different. The ability to improve the information level in hyperpolarized MR, by using the relaxation contrast mechanisms is an appealing option, that can easily be adopted in large animals and even in clinical studies in the near future. K E Y W O R D SAKI, hyperpolarization, kidney, MRI, T 2 relaxation

Creating a clinical platform for carbon‐13 studies using the sodium‐23 and proton resonances

“…Hyperpolarized 13 C‐MRI is a powerful technique to noninvasively probe tissue metabolism in many normal and diseased tissues, such as brain, heart, kidneys, and cancer 4,8,25‐27 . For example, increased lactate signal has been shown to correlate with more aggressive tumors, and a reduction in this lactate is seen in a wide range of tumor models following treatment 28‐30 .…”

“…Hyperpolarized 13 C‐MRI is a powerful technique to noninvasively probe tissue metabolism in many normal and diseased tissues, such as brain, heart, kidneys, and cancer. 4 , 8 , 25 , 26 , 27 For example, increased lactate signal has been shown to correlate with more aggressive tumors, and a reduction in this lactate is seen in a wide range of tumor models following treatment. 28 , 29 , 30 This work is now being translated into humans, and early clinical research has shown elevated hyperpolarized 13 C‐lactate in prostate cancer as well as in brain and breast tumors.…”

Migraine‐Associated Mutation in the Na,K‐ATPase Leads to Disturbances in Cardiac Metabolism and Reduced Cardiac Function

“…For each experiment, a sample of 127 mg of [1‐ 13 C]pyruvic acid mixed with 15 mmol/L AH111501 was polarized in a SPINALIGNER (Polarize IVS, Copenhagen, Denmark) polarizer for >1.5 hours at 6.7 T at 1.3 K, to ensure a reproducible polarization of 50% on average, similar to previous reports in the SPINLAB polarizer. 30 Each mouse received over 5 seconds an intravenous injection of 100 μL per 25 g body weight of 125 mmol/L hyperpolarized [1‐ 13 C]‐pyruvate. A slice‐selective 13 C spectroscopy‐free induction decay sequence with a repetition time of 1 second, flip angle of 10°, and slice thickness of 10 mm covering the entire heart was used.…”

Hyperpolarized 13C MRI: A novel approach for probing cerebral metabolism in health and neurological disease

“…Early clinical studies have focused on the use of hyperpolarized pyruvate to probe both glycolysis and TCA metabolism for oncological, renal, and cardiac metabolism. [22][23][24][25][26][27][28][29][30][31] This review explores the application of 13 C-MRI to cerebral imaging and its future potential in the clinic.…”