Contrast ultrasound has positive effect on practice

Canadian and U.S. radiologists may face different regulatory restrictions when it comes to use of ultrasound contrast, but both agree on one thing: the agents have a positive effect on clinical practice, according to studies presented at the RSNA meeting on Monday.

Principal investigator Bina Lanka, a medical student at the University of Toronto, assessed the value of CE sonography for diagnosis and management of liver tumors in a tertiary clinical practice. The research team retrospectively reviewed data from 1088 patients collected between July 2003 and December 2005.

Use of CE sonography in this setting bolstered patient management by providing fast, accurate detection of liver masses and resolving uncertain findings by other imaging modalities. The team confirmed that the number of referrals for this type of CE ultrasound exam increased progressively during the two-year study period.

Researchers noted several positive implications of CE ultrasound use:

• It reduces referrals for other, more expensive imaging studies.

• It decreases time for diagnosis.

• Its use resolves incidental and indeterminate masses on baseline sonography.

• Improved patient outcomes result from changes in patient management.

"Contrast-enhanced sonography has had a very positive impact at our institution," Lanka said.

In a separate study, Dr. Yuko Kono, a radiologist at the University of California, San Diego, recorded results for off-label use of CE sonography in clinical practice between 2000 and 2006. The research team found that although few patients underwent CE sonography studies during this period, its use added critically valuable information in 75% of the cases in which it was used, without increasing risk.

"Ultrasound contrast is useful in many applications and helps clinical practice. We need ultrasound contrast media approval in the U.S.," Kono said.

Contrast sonography helped confirm or characterize liver lesions in 59 patients. It assessed vascular patency in 18, including seven transjugular intrahepatic porto-systemic shunts. It also helped evaluate renal, splenic, and other abdominal abnormalities. In most of these cases, CE sonography replaced inconclusive contrast CT or MR studies, Kono said.