Dynamic Sonographic Tissue Perfusion Measurement with the PixelFlux Method

Publisher Summary This chapter provides an introduction to a novel technique (the PixelFlux technique) of color Doppler sonographic perfusion measurement, which allows the quantification of tumor tissue perfusion along with a normal ultrasound investigation of the tumor. The procedure for this technique involves the scanning of a relevant structure such as tumor with a suitable presetting of all available specifications of the ultrasound equipment and transducer using as high a frequency as possible to achieve a high resolution and to depict color Doppler signals as sensitively as possible. An imaging plane is selected, the transducer is held in this plane, and a video clip with duration of at least one full heartbeat is recorded. The video clip is transferred to a PC with installed PixelFlux software and the clip is opened by PixelFlux and the calibration of distances as well as color bar are carried out automatically with DICOM clips. A picture archiving and communication system (PACS) function is included in PixelFlux that allows review of clips, region of interest (ROI), and all measurements, as well as export of measurements to a statistical software. With the PixelFlux technique the parameters that are calculated from a video sequence recording at least one full heart cycle include mean flow velocity throughout the entire region of interest (ROI), mean perfused area in relation to the ROI, area of the ROI, perfusion intensity throughout the entire ROI, and tissue resistance index (TRI) of velocity/of area/of perfusion intensity. When contrast enhancers (CE) are used to enhance color signals in a tumor, care should be taken to avoid blooming artifacts that are color signals massively splashed across vessel borders and thus cause errors in perfusion quantification.