MRI is a non-invasive neuroimaging modality able to track and quantify brain changes. Literature review shows increased grey matter in the frontal, parietal and temporal lobes in judo and other martial arts athletes compared to non-athletes ^1-3. We wish to establish if the differences in judo children can be seen with other quantitative measures such as fractional anisotropy of white matter tracks and MR spectroscopy which may be more sensitive indicators compared to volumetric changes.

Fourteen young judo athletes (17 to 20 years old with mean age of 19 years) with normal body mass index (BMI) who practice judo underwent MRI scans on a 3T MR scanner (MAGNETOM Skyra) with a 32-channel phased-array receive-only head coil. High-resolution anatomical images were acquired using sagittal 3D MPRAGE and coronal T2-weighted 3D SPACE. Diffusion tensor imaging (DTI) was obtained in the axial plane with spatial resolution of 2X2X2mm³. The DTI sequence was performed with 64 diffusion-encoding directions and a b-value of 1000s/mm². MR spectroscopy was obtained at 2 levels within the brain using multi-voxel chemical shift imaging (CSI), at the level of basal ganglia as well as at the level of centrum semiovale. Comparison was made against healthy children with normal BMI who are not known to engage in sports activities regularly.

Fractional anisotropy (FA) of major white matter tracks (corpus callosum, internal capsule, superior longitudinal fasciculus) were compared between both groups. Probabilistic and deterministic tractography was used to track and generate intra-voxel crossing fibres that intersect the region of interest, to determine the FA and calculate mean FA ratios.

Absolute values of N-acetylaspartate (NAA) and Creatine (Cr) in the right and left deep grey nuclei at the level of the basal ganglia and right and left frontal and parietal white matter at the level of the centrum semiovale were tabulated. NAA/Cr ratios were generated for these regions.

Statistical significance of the quantitative values between the young judo athletes and normal children was calculated using two sample t-test on SPSS.

Structural T1, T2 weighted images of the brains of all subjects were reported as normal by an FRCR trained radiologist. No acute infarct was detected with diffusion weighted imaging and no abnormal hemorrhage seen within the brain parenchyma on susceptibility weighted imaging.

Based on probabilistic and deterministic fibre-tracking, the mean FA of the age-gender matched judo athletes was 0.65±0.02 in the corpus callosum, 0.57±0.14 in the right corticospinal track, 0.59±0.13 in the left corticospinal track, 0.51±0.11 in the right superior longitudinal fasciculus, 0.51±0.1 in the left superior longitudinal fasciculus compared to controls who had FA of 0.55±0.06 in the corpus callosum, 0.50±0.04 in the right corticospinal track, 0.49±0.02 in the left corticospinal track, 0.44±0.03 in the right superior longitudinal fasciculus, 0.42±0.04 in the left superior longitudinal fasciculus.

There was statistically significant increase in FA values for the judo children in the internal capsule (p<0.00005), corpus callosum (p<0.001) and superior longitudinal fasciculus (p<0.00005) when compared to the control group of normal children.

Children who do judo have NAA/Cr ratios of 1.56±0.18 in the right lentiform nucleus, 1.46±0.32 in the left lentiform nucleus, 1.80±0.21 in the right thalamus, 1.76±0.27 in the left thalamus, 1.89±0.16 in the frontal white matter, 1.76±0.15 in the left frontal white matter, 2.04±0.21 in the right parietal white matter, 1.94±0.17 in the left parietal white matter. As NAA/Cr ratios were not available for our control population, comparison was made against the normal NAA/Cr values published in the literature as shown in table 1.

Our young judo athletes show generalised increased FA in the white matter tracks when compared against normal controls indicating that there is more extensive changes on DTI than the focal grey matter volumetric measurements published in the literature.^1-3

MR spectroscopy showed slightly higher NAA/Cr ratios in the bilateral parietal white matter of children who practice judo when compared to published literature of normal sedentary individuals^4-6 while NAA/Cr ratios in the frontal white matter and lentiform nuclei were not significantly different. This increased NAA/Cr ratio in the parietal white matter would support the increased cortical grey matter described in judo athletes in the literature³.

Both DTI and MR spectroscopy demonstrate quantitative differences in children who do judo with the former showing generalized increased FA and the latter showing increased NAA/Cr ratios in the bilateral parietal white matter, supporting structural changes described in the literature.