SAIP - ULTRASOUND

Ultrasound is a versatile animal imaging technique.  It relies on reflected sound waves traveling through tissue and can produce an image in near real-time.  Light travels at a characteristic speed in “average tissue” but may travel faster in some tissues than others.  These differences can be exploited to create a highly useful sonograpic image. Our device, the Vevo 770 (VisualSonics, Toronto, Canada) is especially adapted to mouse imaging.  Ultrasound is especially useful for the quick evaluation of non-cranial events (e.g. is the tumor larger?); however its relatively poor image contrast prevents it from being the primary imaging tool in many cases.  Because the probe is directly applied to the body of the mouse it is important that the region of the pathology (e.g. tumor) is known for ultrasound to be successful.  Ultrasound cannot be used in air containing spaces like the lung and bowel. Bone and calcification do not transmit sound so all tissue behind a bone or calcified mass will not be seen. Ultrasound is NOT a good screening tool for cancer because it is labor intensive and there can be artifacts.  However, for rapid assessment of masses and organs ultrasound is ideal.  Because there is no ionizing radiation, ultrasound can be repeated at frequent intervals.  In utero imaging in mice is possible for transgenic animal models.  Finally, we can use intravenous injection of microbubble contrast agents (small bubbles of perfluorocarbon gas contained in a lipid shell) to demonstrate areas of increased vascularity.


The Visualsonics Vevo 770 in SAIP-F.  Scanning is performed on a platform and robotic imaging (for 3dimensional scans) is feasible with this unit.

Example of an ultrasound through a cystic kidney.  All of the black circles in the kidney represent fluid filled structures within the kidney (Courtesy Laura Schmidt, NCIFCRF)