MR Neurography: Normative Values in Correlation to Demographic Determinants in Children and Adolescents

To determine normative morphological and functional magnetic resonance (MR) neurography values in children and adolescents in correlation to demographic determinants.

In this study 29 healthy underage subjects (mean age 13.9 years, range 10-17 years) were examined using a standardized MR neurography protocol of the lumbosacral plexus and the right lower extremity at 3 T. Volumes of the dorsal root ganglia L3-S2, cross-sectional area of the sciatic and tibial nerves, as well as T2-weighted contrast nerve-muscle ratio and quantitative diffusion tensor imaging (DTI) values of the sciatic nerve were obtained and correlated with the demographic parameters sex, age, height and weight.

While all obtained morphological and functional MR neurography values did not differ between male and female sex, dorsal root ganglia volume, sciatic and tibial nerve cross-sectional area correlated positively with age, height, and weight. The T2-weighted signal of the sciatic nerve was independent of demographic determinants. Negative correlation was found for fractional anisotropy (FA) with age, height, and weight, whereas radial diffusivity (RD) showed a positive correlation only with age. Mean diffusivity (MD) and axial diffusivity (AD) revealed no correlation with demographic determinants.

The results of this study suggest that selection of sex-matched controls for further studies assessing peripheral nerve pathologies in underage patients may not be necessary; however, control subjects should be adapted to age, height, and weight of the patient population, especially if assessing dorsal root ganglia volume, nerve cross-sectional area and DTI.