Postexercise Lactate Clearance, T2 Relaxation, and J-Modulation in Human Skeletal Muscle Measured With Double-Quantum Filtered 1H MRS at 7 T

TY - JOUR

T1 - Postexercise Lactate Clearance, T2 Relaxation, and J-Modulation in Human Skeletal Muscle Measured With Double-Quantum Filtered 1H MRS at 7 T

AU - Repnin, Kostiantyn

AU - Rocha dos Santos, Vasco Rafael

AU - Cap, Veronika

AU - Frass-kriegl, Roberta

AU - Trattnig, Siegfried

AU - Kemp, Graham J.

AU - Meyerspeer, Martin

N1 - Publisher Copyright: © 2026 The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.

PY - 2026/6

Y1 - 2026/6

N2 - Purpose 1H MRS lactate measurements are potentially valuable for studying energy metabolism in working skeletal muscle, but some technical obstacles need to be overcome. Spectral filtering to isolate the lactate signal from overlapping lipid resonances shows promise. We report a novel sequence with 3D localisation and a CH-selective double quantum filter (DQF) which enables dynamic postexercise single-shot measurement of cellular lactate T2 and clearance kinetics.Methods Using a two-channel 1H transceiver coil at 7 T we applied a localized CH-selective DQF sequence to postexercise calf muscle in 11 subjects. In one leg acquisitions with constant and incrementing TE were interleaved to measure lactate decrease and T2. In the other the CH-selective sequence was interleaved with the nonselective variant.Results Postexercise DQF shows lactate clearly in 4 s single-shot spectra. Fitting was able to separate lactate concentration kinetics from T2 and J-modulation: clearance t1/2 = 162 +/- 42 s and T2 = 138 +/- 20 ms (mean +/- SD); the scalar coupling constant fitted from time evolution was J = 16.6 +/- 0.8 Hz, closely matching J = 16.5 +/- 1.3 Hz derived from spectral splitting. Direct comparison showed 2.3 +/- 0.9 times higher signal with the new CH-selective sequence.Conclusions The new sequence improved lactate detection, enabling quantification from single shots postexercise with time resolution similar to 31P MRS. Measuring clearance and relaxation time constants of intramuscular lactate lays the groundwork for future absolute quantification and studies of intra- and extracellular lactate compartmentation based on dipolar coupling differences.

AB - Purpose 1H MRS lactate measurements are potentially valuable for studying energy metabolism in working skeletal muscle, but some technical obstacles need to be overcome. Spectral filtering to isolate the lactate signal from overlapping lipid resonances shows promise. We report a novel sequence with 3D localisation and a CH-selective double quantum filter (DQF) which enables dynamic postexercise single-shot measurement of cellular lactate T2 and clearance kinetics.Methods Using a two-channel 1H transceiver coil at 7 T we applied a localized CH-selective DQF sequence to postexercise calf muscle in 11 subjects. In one leg acquisitions with constant and incrementing TE were interleaved to measure lactate decrease and T2. In the other the CH-selective sequence was interleaved with the nonselective variant.Results Postexercise DQF shows lactate clearly in 4 s single-shot spectra. Fitting was able to separate lactate concentration kinetics from T2 and J-modulation: clearance t1/2 = 162 +/- 42 s and T2 = 138 +/- 20 ms (mean +/- SD); the scalar coupling constant fitted from time evolution was J = 16.6 +/- 0.8 Hz, closely matching J = 16.5 +/- 1.3 Hz derived from spectral splitting. Direct comparison showed 2.3 +/- 0.9 times higher signal with the new CH-selective sequence.Conclusions The new sequence improved lactate detection, enabling quantification from single shots postexercise with time resolution similar to 31P MRS. Measuring clearance and relaxation time constants of intramuscular lactate lays the groundwork for future absolute quantification and studies of intra- and extracellular lactate compartmentation based on dipolar coupling differences.

KW - T2 relaxation time

KW - Dipolar coupling

KW - Double-quantum filter

KW - In vivo

KW - Lactate

KW - Single-voxel spectroscopy

KW - Skeletal muscle

UR - https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=meduni_vienna_pure&SrcAuth=WosAPI&KeyUT=WOS:001685696300001&DestLinkType=FullRecord&DestApp=WOS_CPL

U2 - 10.1002/mrm.70295

DO - 10.1002/mrm.70295

M3 - Article

C2 - 41667412

SN - 0740-3194

VL - 95

SP - 3065

EP - 3076

JO - Magnetic Resonance in Medicine

JF - Magnetic Resonance in Medicine

IS - 6

M1 - PMID 8505245

ER -