Contrast agents injected into the patient’s bloodstream improve the clarity of ultrasound images by reflecting sound waves differently than normal tissues. Contrast agents are typically microspheres consisting of a gas encased in a lipid shell.
Higher quality ultrasound images broaden the range of diagnostic applications while offering numerous advantages over other imaging modalities. Contrast Enhanced Ultrasound, known as CEU, is accurate, noninvasive and cost effective. CEU also spares patients from ionizing radiation, anesthesia or sedation, and its portability allows the diagnostic tool to travel to the patient; it can be used in emergency departments and intensive care units, where some patients cannot be safely moved to separate scanning facilities.
CEU leads to diagnoses that are more accurate. One study, “The Impact of Contrast Echocardiography on Evaluation of Ventricular Function and Clinical Management in a Large Prospective Cohort,’’ published in the Journal of the American College of Cardiology, found that the improved visualization of endocardial borders reduced uninterpretable results from 11.7 percent to 0.3 percent. Among 632 patients examined using echocardiography without contrast agents, image results indicated a suspected left ventricular thrombus in 35 patients and definite thrombi in three patients. Subsequent CEU scanning of the same patients revealed that only one of the suspected 35 thrombi was real, while positively identifying five additional left ventricular thrombi.
Numerous studies have found contrast agents used in ultrasound to be as safe as or safer than contrast agents commonly used in other modes of cardiac imaging. Heart disease remains the leading killer in the United States, and the use of high-tech imaging in emergency departments has quadrupled since 1996, raising concerns about increasing levels of radiation exposure. CEU use is expanding in diagnosing the liver, urinary tract, the scrotum, the female pelvis and in assessing abdominal transplants. Many experts now believe that ultrasound, including CEU, and MRI (magnetic resonance imaging) should be preferred over radiation-based diagnostic exams such as CT (computed tomography) or PET (positron emission tomography), in cases where the tests provide similar diagnostic information.
Learn more about Contrast Enhanced Ultrasound at the International Contrast Ultrasound Society website, and at the American Institute of Ultrasound in Medicine website.