Quantitative MRI and MRSI (spectroscopic imaging, Core Project I) measures in combination hypothetically provide superior sensitivity and specificity for detection and characterization of pathological lesions for diagnosis, prognosis, and therapeutic monitoring of human diseases. Optimal combinations of measures are disease and tissue specific. The intrinsically higher signal-to-noise ratio at 4.1T is 2.7 times greater than at 1.5T which enables more definitive studies at higher spatial resolution or shorter imaging time. The intrinsically higher TI relaxation times at 4.1T provide a unique ability to differentiate tissue type and characterize lesions. Develop optimized quantitative MRI acquisition protocols including high resolution morphometry, T1 and T2 relaxometry, and volumetry. Additional contrast mechanisms, such as diffusion and perfusion, will be investigated. Estimate normal ranges for various tissue types and age by pilot control studies. Assist clinical collaboration projects in determining optimal combinations of measures for various diseases. Develop integrated analysis and display software. Develop a gapped toroidal head RF coil especially for deep brain structures. All proposed MRI pulse sequences have been coded and tested. Several collaborative projects have utilized the quantitative relaxometry in combination with quantitative MRSI (Core project 1). 20 normal controls were studied with the quantitative relaxometry to estimate normal ranges for temporal and frontal lobes. 8 temporal lobe epilepsy patients were studied with quantitative diffusion imaging. Commercial and custom integration analysis and display software is being evaluated to select the most useful for integration. Theoretical analysis, computer modeling, and prototype testing of the gapped toroidal coil have begun. ? Several collaborative projects investigating focal human epilepsy use the normal relaxometry and MRSI metabolite ranges to detect and characterize epileptogenic and secondary lesions. During the next year a head gradient and rapid imaging methods (Core Project II) will be used to increase the information collected and substantially decrease the acquisition time. These improvements will particularly improve volumetry, diffusion, and perfusion measurements. Software evaluation and integration will continue and a prototype toroidal coil will be tested in human studies.
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