Recommendations on the safe use of ultrasound contrast agents

Clinical applications and safety concerns Clinical users should balance the expected clinical benefit from ultrasound contrast agents against the possibility of associated bioeffects. Caution should be exercised in the use of microbubble ultrasound in tissues where damage to microvasculature could be dangerous. Some areas of concern include the brain, the eye, the fetus and the neonate. Clinical users of contrast echocardiography should be alert to the possibility of cardiac rhythm disturbances. Electrocardiograms should be monitored during these procedures. Idiosyncratic allergy-like or hypersensitivity reactions are rare but recognized untoward side effects with currently approved agents. Health care professionals are advised to carefully follow the instructions of the package inserts of ultrasound contrast agents. Health care professionals should be alerted to the possibility of rare adverse side effects whenever ultrasound contrast agents are administered to patients, and should be prepared to appropriately treat them should any occur. The mechanical index (MI) is a useful but imperfect guide for safety and no absolute threshold can be defined. Bioeffects have been observed in small animals in ultrasound contrast agent studies with MI as low as 0.4; the clinical implications are yet to be determined. Strategies that reduce the likelihood of bioeffects include: