Evaluation of a mobile NMR sensor for determining skin layers and locally estimating the T2eff relaxation time in the lower arm

摘要

Object The nuclear magnetic resonance (NMR) mobileuniversal- surface-explorer (MOUSE) was evaluated in a pilot study to determine its ability to detect physiological changes in human skin caused by physical or pharmacological interventions. Materials and methods The left lower arm skin thicknesses of ten male subjects were measured five times using a Profile NMR-MOUSE? (~1H, 19 MHz) before and after a venous occlusion manoeuvre. In five of the subjects, the T2eff relaxation times were derived from a bi-exponential fitting and were determined in the dermis and subcutis before and after applying a salve containing capsaicin. Results The dermis (including the epidermis) showed rather homogeneous signal amplitudes. The subcutis was characterised by higher and more variable amplitudes. The full-skin thickness values were affirmed by ultrasound imaging. The NMR profiles did not show significant skin swelling due to venous occlusion. In the dermis, capsaicin caused significant (p<0.05) decreases in both components of T_(2eff) (100 ± 19 ms-19 ± 10 ms; 9.5 ± 0.5 ms-7.2 ± 1.6 ms). In the subcutis, the T_(2eff) was not affected. Conclusion In principle, NMR-MOUSE profiles are capable of detecting skin structure. However, precise measurements are jeopardised by poor reproducibility, long acquisition times, and incompatibility between the geometries of the sensitive area of the instrument and the nonplanar structure of the skin. In the dermis, T _(2eff) contrast could be used to detect the changes in tissue composition caused by inflammatory reactions.