Volume Flow and Measures From Contrast Agents

RC125B

Volume Flow and Measures From Contrast Agents

Refresher/Informatics

Presented on November 30, 2014
Presented as part of RC125: Quantitative Imaging: Quantitative Imaging in Ultrasound

Oliver D. Kripfgans, Presenter: Research support, General Electric Company Equipment support, General Electric Company

1) Understand the pitfalls of ultrasound based blood flow acquisition, analysis, and interpretation. 2) Become familiar with current approaches of quantitative estimation of blood flow and learn how to minimize associated errors. Understand how volumetric blood flow estimation can become a biomarker. 3) Obtain an overview of current commercial ultrasound contrast agents as well as their availability in the US. 4) Learn about contrast agent enhanced measurements in a clinical setting and potential use of ultrasound contrast as a therapy agent.

Clinical ultrasound scanners typically offer three methods of blood flow acquisition, namely pulse wave, color flow and power Doppler. While real-time blood flow visualization is one of the perks of ultrasound, standardized quantitative methods are still unavailable to the radiologist. Pulse wave offers volumetric flow computation based on assumptions that are often violated. Color flow has never been directly quantitative as no angle correction can be dialed-in. The advent of 2D ultrasound arrays (electronic or mechanically swept) has enabled color flow and power Doppler acquisition in the coronal plane thus yielding Doppler angle as well as geometry independent flow information for direct quantification of in situ real-time volumetric flow. The RSNA's QIBA (Quantitative Imaging Biomarker Alliance) effort is targeting quantitative blood volume flow as a possible future biomarker. Ultrasound contrast agents have been approved for many clinical applications in Europe, Asia and Canada. The FDA has limited the use of ultrasound contrast agents in the US and essentially only cleared ultrasound contrast agents for cardiac applications. However, off-label application is practiced in the US. Its extend and benefits will be discussed in this course along with current approaches for ultrasound contrast agents based clinical measurements. Also included will be the use of contrast agents in enabling and quantifying therapeutic interventions.