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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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Related in: MedlinePlus

Saturation transfer 31P-MRI.A) Anatomical proton image where four major muscle groups are identified. B) PCr concentration map in a cross-section of the lower leg. C) ST-31P-MRI of the same cross-section at different saturation times. PCr signal intensity decreases as the system is allowed to exchange for longer time.
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f3: Saturation transfer 31P-MRI.A) Anatomical proton image where four major muscle groups are identified. B) PCr concentration map in a cross-section of the lower leg. C) ST-31P-MRI of the same cross-section at different saturation times. PCr signal intensity decreases as the system is allowed to exchange for longer time.

Mentions: Figure 3A shows an anatomical cross-section of the lower leg muscles of a lean subject (BMI = 19.5) and a cross-section of the PCr concentration map (Fig. 3B). PCr in the same cross-section decreases with increasing saturation time (tsat) as shown in Fig. 3C. By segmenting signals in the PCr images and fitting data to Eq.2 (methods), we estimated kf and the unidirectional flux of PCr to form ATP (Vf) for four muscle groups of the leg [Gastrocnemius Lateralis (GL) and Medialis (GM), Soleus (S), and Tibialis Anterior (TA)]. We estimated the intrinsic spin lattice relaxation (T1') in the presence of saturating irradiation17 from Eq.3. The results are summarized in Table 1. In the TA, kf was significantly lower than the GL (P = 0.002), the GM (P = 0.029) and the S (P = 0.037). The metabolic fluxes, Vf, in the TA were lower than both the GL (P < 0.001) and the GM (P = 0.043). We did not find any statistically significant differences among T1' values in the four muscle groups.


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 31P-MRI.A) Anatomical proton image where four major muscle groups are identified. B) PCr concentration map in a cross-section of the lower leg. C) ST-31P-MRI of the same cross-section at different saturation times. PCr signal intensity decreases as the system is allowed to exchange for longer time.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Saturation transfer 31P-MRI.A) Anatomical proton image where four major muscle groups are identified. B) PCr concentration map in a cross-section of the lower leg. C) ST-31P-MRI of the same cross-section at different saturation times. PCr signal intensity decreases as the system is allowed to exchange for longer time.
Mentions: Figure 3A shows an anatomical cross-section of the lower leg muscles of a lean subject (BMI = 19.5) and a cross-section of the PCr concentration map (Fig. 3B). PCr in the same cross-section decreases with increasing saturation time (tsat) as shown in Fig. 3C. By segmenting signals in the PCr images and fitting data to Eq.2 (methods), we estimated kf and the unidirectional flux of PCr to form ATP (Vf) for four muscle groups of the leg [Gastrocnemius Lateralis (GL) and Medialis (GM), Soleus (S), and Tibialis Anterior (TA)]. We estimated the intrinsic spin lattice relaxation (T1') in the presence of saturating irradiation17 from Eq.3. The results are summarized in Table 1. In the TA, kf was significantly lower than the GL (P = 0.002), the GM (P = 0.029) and the S (P = 0.037). The metabolic fluxes, Vf, in the TA were lower than both the GL (P < 0.001) and the GM (P = 0.043). We did not find any statistically significant differences among T1' values in the four muscle groups.

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