High Resolution Diffusion Imaging Of Small Animal In Clinical MRI System

Diffusion-weighted imaging (DWI), a quantitative magnetic resonance imaging (MRI) technique, is sensitive to water diffusion in tissue caused by the random motion of water molecules. DWI has been extensively studied in both neurological and extraneuro logical applications including cerebral ischemic stroke,tumor grading, differential diagnosis of benign and malignant tumors, characterization of viable and necrotic tissues, assessment of organ functions, prediction of pathologic outcomes, and evaluation of tumor response to therapies.Small animal imaging is an invaluable tool for modeling brain damage incurred from a variety of causes, from spontaneously-occurring to genetically-linked neurodegenerative diseases to environmental insults from trauma and neurotoxins. DWI has been particularly useful for developing longitudinal animal models of human conditions that follow a dynamic course, such as stroke, because of the micro structural alteration of white matter that can occur below the detection of conventional MR imaging of macro structureThe most often used pulse sequence for small animal diffusion weighted imaging in clinical MRI scanner is single shot echo planar imaging (EPI). However, EPI is very susceptible to off-resonance effects, such as main field inhomogeneity,local susceptibility gradients, and chemical shift, which all may lead to severe image degradation.In this study, we implemented a high resolution spin echo diffusion weighted imaging (SE-DWI) in clinical3T MRI system. To reduce the motion artifacts, navigator echoes were acquired to correct the phase errors. Navigation echo can reduce motion artifacts effectively.The result from ischemic rat brain demonstrated that SE-DWI was feasible for imaging small animals in clinical MRI scanner.