Ultrasound as a tool for perfusion imaging
The application of contrast agents to enhance assessment of tissue blood flow was perhaps the first application of microbubble contrast agents. Even today, the only FDA approved indication for contrast ultrasound is the enhancement of myocardial perfusion imaging in challenging cardiology patients. However, upon closer inspection, it becomes readily obvious that clinical use of contrast provides very meager information. This information is limited to enhancement (or lack thereof) of portions of the myocardium after an infarct, and the results are non-quantitative. It has thus been one of our goals to improve the quantitative ability of contrast ultrasound, to enable broader utility in assessing pathology. Recent aspects of this goal have included understanding the relationship between contrast agent distribution, contrast agent dose, and administration method, on data consistency. We have also explored contrast imaging in 3-D, and we have calibrated image-derived measurements to known flow values. Finally, we have been applying our technology and our discoveries to assess blood flow in normal and healthy organs, and in tumors, to provide crucial information to scientists and physicians developing new methods to treat disease.