A low-cost Mr compatible ergometer to assess post-exercise phosphocreatine recovery kinetics

Naimon, Niels D.; Walczyk, Jerzy; Babb, James S.; Khegai, Oleksandr; Che, Xuejiao; Alon, Leeor; Regatte, Ravinder R.; Brown, Ryan; Parasoglou, Prodromos

doi:10.1007/s10334-016-0605-9

Cited by 6 publications

(7 citation statements)

References 48 publications

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“…Plantar flexion exercises were performed using a custom built MR compatible ergometer 39 . An exercise protocol was designed to ensure enough PCr depletion while keeping the pH change minimal.…”

Section: Methodsmentioning

confidence: 99%

Dynamic 31P-MRI and 31P-MRS of lower leg muscles in heart failure patients

Menon

Xia

Katz

et al. 2021

Sci Rep

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Impaired oxidative metabolism is one of multi-variate factors leading to exercise intolerance in heart failure patients. The purpose of the study was to demonstrate the use of dynamic 31P magnetic resonance spectroscopy (MRS) and 31P magnetic resonance imaging (MRI) techniques to measure PCr resynthesis rate post-exercise as a biomarker for oxidative metabolism in skeletal muscle in HF patients and controls. In this prospective imaging study, we recruited six HF patients and five healthy controls. The imaging protocol included 31P-MRS, spectrally selective 3D turbo spin echo for 31P-MRI, and Dixon multi-echo GRE for fat–water imaging on a 3 T clinical MRI scanner. All the subjects were scanned pre-exercise, during plantar flexion exercise, and post-exercise recovery, with two rounds of exercise for 31P -MRS and 31P-MRI, respectively. Unpaired t-tests were used to compare 31P-MRS and 31P-MRI results between the HF and control cohorts. The results show that PCr resynthesis rate was significantly slower in the HF cohort compared to the controls using 31P-MRS (P = 0.0003) and 31P-MRI (P = 0.0014). 31P-MRI showed significant differences between the cohorts in muscle groups (soleus (P = 0.0018), gastrocnemius lateral (P = 0.0007) and gastrocnemius medial (P = 0.0054)). The results from this study suggest that 31P-MRS/31P-MRI may be used to quantify lower leg muscle oxidative metabolism in HF patients, with 31P-MRI giving an additional advantage of allowing further localization of oxidative metabolism deficits. Upon further validation, these techniques may serve as a potentially useful clinical imaging biomarker for staging and monitoring therapies in HF-patients.

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Section: Methodsmentioning

confidence: 99%

Dynamic 31P-MRI and 31P-MRS of lower leg muscles in heart failure patients

Menon

Xia

Katz

et al. 2021

Sci Rep

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“…In a subset of nine subjects, a standardized exercise protocol was performed, which consisted of 90 s of plantar flexion following a metronome at 40 beats per minute. The mechanical mean power output during plantar flexion was estimated based on angular displacement of the ergometer pedal, which was monitored by an angle sensor, and the force generated by the sum of elastic bands that resisted motion .…”

Section: Methodsmentioning

confidence: 99%

“…The imaging protocol included one 1 H‐MRI acquisition for spatial localization and muscle segmentation followed by two 31 P acquisitions: one at rest to obtain metabolite maps of PCr and ATP, and one dynamic to assess PCr recovery kinetics and pH measurement after exercise. Subjects exercised on an in‐house developed ergometer , while a dual‐tuned array with eight 31 P and eight 1 H receivers was used for radiofrequency (RF) transmission and reception .…”

Section: Methodsmentioning

confidence: 99%

Dynamic phosphocreatine imaging with unlocalized pH assessment of the human lower leg muscle following exercise at 3T

Khegai

Madelin

Brown

et al. 2017

Magnetic Resonance in Med

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Purpose To development a high temporal resolution imaging method that measures muscle-specific phosphocreatine (PCr) resynthesis time constant (τPCr) and pH changes in muscles of the lower leg following exercise on a clinical 3T MRI scanner. Methods We developed a frequency-selective 3D non-Cartesian FLORET sequence to measure PCr with 17-mm nominal isotropic resolution (28 mm actual resolution) and 6-s temporal resolution to capture dynamic metabolic muscle activity. The sequence was designed to additionally collect inorganic phosphate spectra for pH quantification, which were localized using sensitivity profiles of individual coil elements. Nineteen healthy volunteers were scanned while performing a plantar flexion exercise on an in-house developed ergometer. Data were acquired with a dual-tuned multi-channel coil array that enabled phosphorus imaging and proton localization for muscle segmentation. Results After a 90-s plantar flexion exercise at 0.66 Hz with resistance set to 40 % of the maximum voluntary contraction, τPCr was estimated at 22.9 ± 8.8 s (mean ± standard deviation) with statistical coefficient of determination r2 = 0.89 ± 0.05. The corresponding pH values after exercise were in the range of 6.9–7.1 in the gastrocnemius muscle. Conclusion The developed technique allows measurement of muscle-specific PCr resynthesis kinetics and pH changes following exercise, with a temporal resolution and accuracy comparable to that of single voxel 31P-MRS sequences.

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“…While other efforts to self-construct MR-compatible ergometers have been described in the past, even including force sensors, 3,16 the force recording part was not described in detail and validation was mainly performed in MR spectroscopy setups.…”

Section: Discussionmentioning

confidence: 99%

OpenForce MR: A low‐cost open‐source MR‐compatible force sensor

Santini

Bieri

Deligianni

2018

Concepts Magn Reson

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Measuring the force exerted by muscles during dynamic MR acquisition (either imaging or spectroscopy) provides important information for the standardization of the exercise performed in the scanner and is therefore important for reproducible results in musculoskeletal imaging. However, existing commercial solutions for such measurements are often very expensive and impractical. In this work, a novel, open‐source, versatile force sensor made of non‐magnetic, off‐the‐shelf components is presented. The sensor is based on four aluminum Wheatstone bridge load cells enclosed in a custom‐built aluminum frame. These cells are connected to an Arduino microcontroller for data acquisition and serial communication with a host computer, on which a dedicated program visualizes and logs the recorded force in real time. All components were chosen to be compatible with the MR environment, commercially available, and low cost. The sensor was calibrated with a commercial dynamometer and subsequently tested in multiple MR acquisition scenarios (static morphological imaging, cine imaging during contraction, velocity‐encoded imaging). The sensor correctly recorded data during all tested sequences, without cross‐interference between the MR and the force acquisitions. Minor susceptibility artifacts are visible in the immediate vicinity of the sensor, but they did not impair the evaluation of the muscle of interest. In conclusion, the development of a low‐cost, MR‐compatible force sensor is feasible, and its usage does not interfere with MR acquisition. The full specifications of the sensor, including hardware design, firmware and host software are publicly released as open‐source for the potential benefit of the whole community.

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A low-cost Mr compatible ergometer to assess post-exercise phosphocreatine recovery kinetics

Cited by 6 publications

References 48 publications

Dynamic 31P-MRI and 31P-MRS of lower leg muscles in heart failure patients

Dynamic 31P-MRI and 31P-MRS of lower leg muscles in heart failure patients

Dynamic phosphocreatine imaging with unlocalized pH assessment of the human lower leg muscle following exercise at 3T

OpenForce MR: A low‐cost open‐source MR‐compatible force sensor

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