PERFUSION MEASUREMENT WITH ULTRASOUND AND MRI OF TUMORS IN MICE

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The project involves scanning mice with flank tumors and make perfusion measurements using the 7T MRI system and the ultrasound system. The study is primarily designed to understand the working of the perfusion measurements in ultrasound using the contrast agent provided by VisualSonics and comparing those measurements with MRI. The project will involve the use of contrast agents both in MRI and ultrasound. Animals (N=10) with tumors on the flank will be scanned first using the MRI systems and then the animal will be moved to the Ultrasound system. MRI experiments will primarily involve using a T1 measuring sequence followed by a bolus injection of Magnevist in the tail vein using the MR microinjector. Dynamic contrast enhanced images of the tumor will be collected using a 3D encoding sequence (depending on contrast dynamics). The T1 measuring sequence can be a simple spin-echo sequence. or FSE or a FLASH type sequence. T1 measurements are primarily made to perform quantitative calculations of the various perfusion metrics in the tumors. Perfusion measurements in ultrasound will be made using the custom-built VisualSonics program for blood flow measurements. Microbubbles will be used as the contrast agent. Post-analysis will include the quantification of the perfusing metrics from the images collected using both the imaging modalities. Comparison of the perfusion metrics will be made. Archival system will need to be able to archive derived data from both modalities.