Segmental evaluation of the corpus callosum of people with low and normal B12 value by diffusion tensor sequence and examination by volumetric analysis method

Vitamin B12 works as a cofactor of the enzymes responsible for myelination in the central nervous system. Some systemic and especially neurological findings occur in cases where vitamin B12 deficiency occurs, such as impaired absorption and lack of absorption. Neurological signs go unnoticed clinically for a long time. Again, conventional MRI findings are also not very clear. However, neurological findings are better understood with sequences such as Diffusion Tensor Imaging (DTG). It is known that vitamin B12 deficiency specifically affects the posterolateral part of the spinal cord. In our study, Diffusion Tensor parameters were used to divide the Corpus Callosum into segments according to the Hofer classification and to determine whether there is a segment in which it is specifically involved. The corpus callosum is a white matter pathway consisting of commisural fibers that connect both hemispheres of the brain. It has functions that have important clinical effects in many areas such as cognitive, emotional, movement, attention. Due to its myelin-dense structure, it is affected by processes that disrupt myelination in the corpus callosum. For this reason, in our study, we aimed to determine whether there is a volume loss in the group with low vitamin B12 levels. In our study, 70 cases were evaluated. Of these 70 cases, 45 of the vitamin B12 levels were below 200 pg/ ml, while 25 cases had a vitamin B12 level above 200 pg/ ml. With Magnetic Resonance imaging (MRI) images obtained in the form of 3D FFE SENSE with a 1 mm thick thin-section matrix (256x256) on the sagittal plane, the Volume of the corpus callosum was measured with the ITK SNAP pragram in both groups. Again, after the MRI images in Dicom format are converted to Nifti format, with an open-coded FSL program (http://www.fmrib.ox.ac.uk/fsl /), Diffusion tensor parameters were extracted on the Corpus Callosum, which was divided into segments according to Hofer segmentation. A Deciency correlation was found between vitamin B12 level and corpus callosum volume. The corpus callosum volume of those with low vitamin B12 levels was found to be lower compared to those with normal levels. As a result, vitamin B12 deficiency has been shown to have an atrophic effect on the corpus callosum, an important white matter and commissural network. In those with low vitamin B12 levels, a statistically significant difference was found between the diffusion tensor parameters mean (MD), radial (RD), fractional anisotropy (FA) in segment 4 and MD, RD, axial (AD) in segment 5 compared to the other segments. MD and RD segments 4 and 5, which are significant in both segments, also show a significant increase. They are also known in the literature as the two parameters most affected by demyelination. In our study, it was determined that the posterior part of the corpus callosum can be specifically affected in vitamin B12 deficiency, as well as in spinal cord involvement. The clinical signs of vitamin B12 deficiency appear late, and conventional MRI also has no specific findings. In this respect, our study will be clinically useful for the early detection and treatment of vitamin B12 deficiency.