H-1- and P-31-magnetic resonance spectroscopy and imaging as a new diagnostic tool to evaluate neuropathic foot ulcers in Type II diabetic patients

Aims/hypothesis. We studied 36 Type II (non-insulin-dependent) diabetic pat ients without occlusive arterial diseases in the lower extremities and 12 a ge-matched and sex-matched non-diabetic subjects to clarify the association between diabetic polyneuropathy and foot ulcers using H-1- and P-31-magnet ic resonance spectroscopy and imaging. Methods. The 36 diabetic patients consisted of 12 patients with superficial foot ulcers and 24 patients free from this disease. We measured fat to wat er and phosphocreatine to inorganic phosphate (PCr:Pi) ratios and calculate d the intracellular pH of resting plantar muscles by depth-resolved surface -coil spectroscopy using an H-1-P-31 double tuned coil. Furthermore, foot v asculature, fat and PCr contents of plantar muscles were visualised by phas e-contrast angiography, T-1-weighted spin-echo imaging and P-31-chemical sh ift imaging. Results. The 12 foot ulcer patients showed a reduced PCr to Pi ratio (p < 0 .001) and peripheral nerve functions (p < 0.01-0.001) but an increased fat to water ratio (p < 0.001) and intracellular pH (p < 0.001) compared with t he 24 patients without ulcers. From stepwise multiple regression analyses, motor nerve function as well as severity of nephropathy was associated with both fat to water and PCr to Pi ratios. When these patients were categoris ed into three groups based on their level of motor nerve function, the freq uency of foot ulcers of the lowest group was higher than that of the highes t group. Conclusion/interpretation. Our findings indicated that motor nerve dysfunct ion in diabetic patients was closely associated with impaired energy metabo lism, fatty infiltration and increased intracellular pH of plantar muscles and high frequency of foot ulcers. These new techniques could contribute to help clarify the predisposing factors for foot ulcers.