John Robery Eisenbrey PhD, Abstract Co-Author: Nothing to Disclose

Jaydev Dave, Abstract Co-Author: Nothing to Disclose

Flemming Forsberg PhD, Presenter: Equipment support, Toshiba Corporation Equipment support, Siemens AG Research collaboration, General Electric Company Research collaboration, Ultrasonix Medical Corporation Research collaboration, Toshiba Corporation

To create parametric images based on contrast perfusion factors derived from subharmonic imaging (SHI; receiving at 1/2 the transmit frequency) of breast lesions. Also to explore the usefulness of parametric SHI for characterizing breast tumors.

Several contrast ultrasound (US) modes have applied parametric imaging, but they suffer from reduced blood-to-tissue signal due to the tissue’s ability to express signal at the transmit and higher harmonic frequencies. SHI parametric imaging should be better suited, because SHI signals are generated exclusively by the contrast, eliminating all tissue signals. Grayscale SHI data (transmitting/receiving at 4.4/2.2 MHz) was obtained from 16 breast lesions using a modified Logiq 9 scanner (GE Healthcare, Milwaukee, WI). A cumulative maximum intensity (CMI) image processing techniques for depicting vascular architecture was applied. The automated motion compensation algorithm was used to align all frames throughout the time sequence. Time to peak intensity and perfusion (in ml/min/g) were measured for each pixel and used to create parametric images. Filtering was optimized and performed on a basis of both time to peak and CMI.

Parametric images from the subharmonic were successfully created for all patients. Regions of interest were selected based off of CMI images and average time to peak was determined in order to differentiate primary and secondary tumor vasculature. While images were found to be heavily dependent on filter parameters, all provided relevant information such as potential differentiation between diseased and healthy vasculature (a 2.0 sec variation) and differentiation between primary and secondary tumor vasculature (a 0.8 sec variation).

Parametric imaging based on breast SHI may be a useful tool in determining tumor perfusion characteristics due to generation of signal exclusively from US contrast agents confined to the vasculature.

It may be possible in the future to characterize breast lesions based on parametric SHI images.

Eisenbrey, J, Dave, J, Forsberg, F, Feasibility of Parametric Imaging Using Subharmonic Signals from US Contrast Agents in Patients with Breast Masses.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9015697.html