ESPE Abstracts

I will review the latest developments in imaging of the brain using magnetic resonance. Over the last twenty years imaging of the diffusion of water molecules in the tissue has emerged as the method of choice for measuring the structure of brain tissue. The development of so called diffusion tensor imaging had allowed measurement of anisotropy which reflects how aligned or coherent is the underlying structure of myelinated axons in white matter. For example we have shown in children with growth hormone deficiency that anisotropy is reduced. Despite the success of diffusion tensor imaging its limitations have long been recognised, namely that it lacks specificity. For example changes in anisotropy may be brought about by changes in axonal density and orientation. A new class of diffusion models have emerged under the name of ’microstructure imaging’ which allow the inference of axonal density and diameter. A more recent advance is to couple this with magnetisation transfer imaging that is sensitive to myelin content, thereby allowing calculation of g ratio maps which represents the ratio of the axon to myelin diameter. I will describe the emergence of these new methods and the prospects for deploying them in patients with pathologies affecting the endocrine system in the brain.