In the last decade, rapid developments in magnetic resonance imaging (MRI) have provided new technologies that allow functional examination of the developing and adult brain in a fully non-invasive manner. For instance, it is presently possible to assess brain neuroanatomy using morphometric MRI, the location of white matter connections using diffusion tensor imaging (DTI), brain chemistry using spectroscopic imaging (MRSI), or cerebral blood flow (CBF) using arterial spin labeling (ASL). At Kennedy Krieger Institute, we have a large population of children with learning disabilities, who could benefit from a multi-modality MRI protocol. However, such a comprehensive exam is presently not possible due to the inherent time-consuming nature of each MRI modality.
The aim of this proposal is to develop a complete high-quality fast multi-modal brain examination targeted at pediatric populations, including both structural and metabolic information. The goal of the proposal is to reduce the length of such a multi-modal protocol to less than an hour. To accomplish this, we have formulated the following aims. In the first aim, we will combine parallel imaging (""""""""Sensitivity Encoding"""""""", SENSE) with multi-slice MRSI to provide localized metabolic information in a scan time of less than 10 min. In the second aim, we will develop a multi-coil method to measure absolute blood flow using ASL, also combined with a rapid three-dimensional parallel acquisition, for a maximum scan time of 5 min. In the third aim, we propose to combine whole-brain multi-orientation diffusion tensor imaging (DTI) with SENSE to reduce both artifacts, and scan time to less than 15 min. Furthermore, we will also acquire a rapid high-resolution (<4 min) anatomical scan suitable for quantitative morphometry and regular diagnostic T1- and T2-weighted images (~5 min). Associated data analysis and processing software will also be developed. Each method will be tested on phantoms and ten normal volunteers and compared with existing techniques in terms of sensitivity, resolution, and degree of artifact reduction. The resulting fast multi-modal examination will be tested on twenty children without known disability. It will allow minimization of motion-related artifacts in images acquired on pediatric patient populations, without compromising resolution or diagnostic evaluation. We expect the combination of white matter fiber characterization, metabolic imaging, CBF measurements and anatomical mapping to provide a powerful method for the study of neurological disease, normal and abnormal brain development in children.
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