D. S. Fahmeed Hyder PhD

Professor of Diagnostic Radiology and of Biomedical Engineering; Technical Director, Magnetic Resonance Research Center (mrrc.yale.edu); Program Director, Core Center for Quantitative Neuroscience with Magnetic Resonance (qnmr.yale.edu)

Research Summary

Throughout my career I have strayed from conventional boundaries between fields. I was trained as biophysical chemist who now practices systems neuroscience and biomedical engineering. I was exposed to magnetic resonance early, and was trained as a spectroscopist, but I am recognized now more for imaging. My interests span functional and molecular imaging. In functional imaging, my work has been in the forefront of quantitative fMRI, which converts the neuroimaging signal into a measurable component of changes in neuronal activity. My work has revealed the large unmeasured baseline neuronal activity and its functional relevance for neuroimaging. My work on neuroenergetics answered a long-standing controversy about the source of energy for brain function by demonstrating that ATP produced by oxygen consumption mainly supports moment-to-moment increases in neuronal activity.

A new research direction with commercial potential (U.S. 61/277,413 and U.S. 61/561,515) is development of translatable molecular imaging techniques. The first patent deals with calibrating an MRI method called chemical exchange saturation transfer (CEST) that detects a subpopulation of water molecules that exchanges its protons with -OH or -NHx protons, and thereby generates a new MRI contrast. Our innovation enables quantitative CEST using slightly modified (i.e., in the cyclen backbone) FDA-approved MRI contrast agents for BIRDS because calibrating factors necessary (e.g., temperature, pH, agent concentration, etc.) are obtained. The second patent measures radio frequency induced tissue heating, known as specific absorption rate (SAR) with BIRDS. SAR is a significant setback in high-field MRI/MRS methods that require repeated and/or rapid radio frequency power deposition, e.g., decoupling fields in 13C MRS and multiple slice selections in high-resolution MRI sequences. The innovation is that our method allows SAR to be measured in absolute units for any pulse sequence at any magnetic field because the spatial distribution of temperature is mapped in 3D.

Selected Publications