Human In Vivo ³¹P Spectroscopy of Skin: Potentially a Powerful Tool for Noninvasive Study of Metabolism in a Cutaneous Tissue

Abstract

The first application of human in vivo phosphorus (31P) magnetic resonance spectroscopy to analysis of skin metabolism is presented. Our results confirm that phosphocreatine is a major energy phosphometabolite in human skin. Human in vivo 31P spectroscopy utilizing a skin coil designed in our laboratory can have clinical applications in cutaneous surgery and clinical dermatology, and will facilitate understanding of the pathophysiology of skin disease. In vitro experiments with fresh human skin indicate that complete utilization of phosphocreatine is followed by utilization of adenosine triphosphate (ATP) molecules during ischemia. These experiments also suggest that the majority of phosphocreatine in human skin is localized in epidermal and papillary dermis.

Use of the Fourier Series Window Protocol with a Zig-Zag Surface Coil in31P NMR Human Skin Spectroscopy. A Theoretical Study

“…The small absolute and relative concentration of phosphorus metabolites in skin compared to muscle demand that additional spatial localization is required. Although we have restricted our discussion to the zig-zag surface coil, this same observation is also applicable to other surface coil designs for which a minimal B, field penetration is claimed, for example, the slotted crossover coil used by Nagel et al," Schweizer et al,I3 Chen et al I4 and Bohning et al" and the counter-rotating current probeJ6 used by Zemtsov et al 17 The field profile of these coils is also dependent on the gap width between adjacent conductors, as in the zig-zag surface coil. However, the real advantage of using the zig-zag design is that the largest possible area of surface tissue can be interrogated without increasing the B, field penetration.…”

Advances in MR imaging of the skin

“…The main difficulty in obtaining in vivo 31 P spectra of the skin is the need for perfect isolation of the skin because adjacent muscle represents a large reservoir of phosphorus. Most studies published have used a surface coil with restricted depth sensitivity to avoid signal contamination from muscle (25)(26)(27)(28). Such a selection method alone (25) is probably insufficient because even minor contamination by muscle in the selected region introduces significant errors.…”

“…Such a selection method alone (25) is probably insufficient because even minor contamination by muscle in the selected region introduces significant errors. A method based on the acquisition of two spectra at different RF power settings enabled Bohning et al (26) to subtract the contribution of muscle from spectra of the skin and to obtain skin phosphorus spectra of the calves of volunteers: the acquisition time, however, was 4 h and the SNR was 2-3. Using both a depth-selective surface coil 12 mm in diameter and a phase-encoding method generating 0.5 mm thick slices parallel to the skin surface, the present authors' group was unable to detect significant phosphorus signals out of the noise, with acquisition times of the order of 1 h even with a dedicated HTS 31 P surface coil with a loaded quality factor of several thousand.…”

In vivo phosphorus NMR spectroscopy of skin using a crossover surface coil

“…It is clear that underlying muscle is contributing to our skin spectra, as shown by data in Table 1. However, substantial quantities of PCr have been observed by MRS in split-thickness skin grafts removed from a human cadaver 90-120 min postmortem ( 7) and in spectra taken from human skin 150 min after dermatome surgery (6). PCr was also observed in Sprague-Dawley rat skin after a surgical flap was cut, elevated away from the body wall musculature, and isolated from the body with a Faraday shield ( 13).…”