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Three-dimensional saturation transfer ³¹P-MRI in muscles of the lower leg at 3.0 T.

Parasoglou P, Xia D, Chang G, Regatte RR - Sci Rep (2014)

Bottom Line: However, due to the low MR sensitivity of the (31)P nucleus, most studies on clinically approved magnetic fields (≤3.0 T) have been performed with coarse resolution and limited tissue coverage.We imaged the lower leg muscles of ten healthy volunteers (total experimental time: 40 min, nominal voxel sizes 0.5 mL), and found statistically significant differences between the kinetics of the CK reaction among muscle groups.Our developed technique may allow in the future the early detection of focal metabolic abnormalities in diseases that affect the function of the skeletal muscle.

View Article: PubMed Central - PubMed

Affiliation: Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Department of Radiology, Center for Biomedical Imaging, New York University Langone Medical Center, New York, NY, USA.

ABSTRACT
The creatine kinase (CK) reaction plays a critical role in skeletal muscle function, and can be studied non-invasively using phosphorus ((31)P) saturation transfer (ST) techniques. However, due to the low MR sensitivity of the (31)P nucleus, most studies on clinically approved magnetic fields (≤3.0 T) have been performed with coarse resolution and limited tissue coverage. However, such methods are not able to detect spatially resolved metabolic heterogeneities, which may be important in diseases of the skeletal muscle. In this study, our aim was to develop and implement a (31)P-MRI method for mapping the kinetics of the CK reaction, and the unidirectional phosphocreatine (PCr) to adenosine triphosphate (ATP) metabolic fluxes in muscles of the lower leg on a clinical 3.0 T MR scanner. We imaged the lower leg muscles of ten healthy volunteers (total experimental time: 40 min, nominal voxel sizes 0.5 mL), and found statistically significant differences between the kinetics of the CK reaction among muscle groups. Our developed technique may allow in the future the early detection of focal metabolic abnormalities in diseases that affect the function of the skeletal muscle.

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Saturation transfer spectroscopy (ST-31P-MRS) and imaging (ST-31P-MRI) pulse sequences.A saturation transfer module consists of a train of Gaussian pulses, which saturates the γ-ATP resonance. Spoiler gradients are used between two consecutive pulses to destroy any remaining transverse magnetization. The number of Gaussian pulses defines tsat in each experiment. A) Unlocalized 31PMRS data were acquired by sampling the free induction decay (FID) after implementing the ST module. B) Identical ST preparation module as in 31P-MRS, followed by a spectrally selective 31P-MRI imaging sequence.
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f4: Saturation transfer spectroscopy (ST-31P-MRS) and imaging (ST-31P-MRI) pulse sequences.A saturation transfer module consists of a train of Gaussian pulses, which saturates the γ-ATP resonance. Spoiler gradients are used between two consecutive pulses to destroy any remaining transverse magnetization. The number of Gaussian pulses defines tsat in each experiment. A) Unlocalized 31PMRS data were acquired by sampling the free induction decay (FID) after implementing the ST module. B) Identical ST preparation module as in 31P-MRS, followed by a spectrally selective 31P-MRI imaging sequence.

Mentions: Our imaging approach (Fig. 4B) is based on a fast 3D-TSE sequence, which excites and acquires a single resonance of the 31P-MR spectrum (i.e. PCr). By trading spectral information for imaging speed, we are able to accelerate acquisition time and increase spatial resolution compared to 31P-MRS1819 approaches, while obtaining full coverage of the muscle. As shown in Eq.2, estimation of kf only requires measurement of PCr signal at different saturation times.


Three-dimensional saturation transfer ³¹P-MRI in muscles of the lower leg at 3.0 T.

Parasoglou P, Xia D, Chang G, Regatte RR - Sci Rep (2014)

Saturation transfer spectroscopy (ST-31P-MRS) and imaging (ST-31P-MRI) pulse sequences.A saturation transfer module consists of a train of Gaussian pulses, which saturates the γ-ATP resonance. Spoiler gradients are used between two consecutive pulses to destroy any remaining transverse magnetization. The number of Gaussian pulses defines tsat in each experiment. A) Unlocalized 31PMRS data were acquired by sampling the free induction decay (FID) after implementing the ST module. B) Identical ST preparation module as in 31P-MRS, followed by a spectrally selective 31P-MRI imaging sequence.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048915&req=5

f4: Saturation transfer spectroscopy (ST-31P-MRS) and imaging (ST-31P-MRI) pulse sequences.A saturation transfer module consists of a train of Gaussian pulses, which saturates the γ-ATP resonance. Spoiler gradients are used between two consecutive pulses to destroy any remaining transverse magnetization. The number of Gaussian pulses defines tsat in each experiment. A) Unlocalized 31PMRS data were acquired by sampling the free induction decay (FID) after implementing the ST module. B) Identical ST preparation module as in 31P-MRS, followed by a spectrally selective 31P-MRI imaging sequence.
Mentions: Our imaging approach (Fig. 4B) is based on a fast 3D-TSE sequence, which excites and acquires a single resonance of the 31P-MR spectrum (i.e. PCr). By trading spectral information for imaging speed, we are able to accelerate acquisition time and increase spatial resolution compared to 31P-MRS1819 approaches, while obtaining full coverage of the muscle. As shown in Eq.2, estimation of kf only requires measurement of PCr signal at different saturation times.

Bottom Line: However, due to the low MR sensitivity of the (31)P nucleus, most studies on clinically approved magnetic fields (≤3.0 T) have been performed with coarse resolution and limited tissue coverage.We imaged the lower leg muscles of ten healthy volunteers (total experimental time: 40 min, nominal voxel sizes 0.5 mL), and found statistically significant differences between the kinetics of the CK reaction among muscle groups.Our developed technique may allow in the future the early detection of focal metabolic abnormalities in diseases that affect the function of the skeletal muscle.

View Article: PubMed Central - PubMed

Affiliation: Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Department of Radiology, Center for Biomedical Imaging, New York University Langone Medical Center, New York, NY, USA.

ABSTRACT
The creatine kinase (CK) reaction plays a critical role in skeletal muscle function, and can be studied non-invasively using phosphorus ((31)P) saturation transfer (ST) techniques. However, due to the low MR sensitivity of the (31)P nucleus, most studies on clinically approved magnetic fields (≤3.0 T) have been performed with coarse resolution and limited tissue coverage. However, such methods are not able to detect spatially resolved metabolic heterogeneities, which may be important in diseases of the skeletal muscle. In this study, our aim was to develop and implement a (31)P-MRI method for mapping the kinetics of the CK reaction, and the unidirectional phosphocreatine (PCr) to adenosine triphosphate (ATP) metabolic fluxes in muscles of the lower leg on a clinical 3.0 T MR scanner. We imaged the lower leg muscles of ten healthy volunteers (total experimental time: 40 min, nominal voxel sizes 0.5 mL), and found statistically significant differences between the kinetics of the CK reaction among muscle groups. Our developed technique may allow in the future the early detection of focal metabolic abnormalities in diseases that affect the function of the skeletal muscle.

Show MeSH
Related in: MedlinePlus