Use of an ultrasonic contrast method in the diagnosis of valvular regurgitation and intracardiac shunts

Injection of normal saline solution or indocyanine green dye through intracardiac catheters results in ultrasonic reflections from the site of injection. To evaluate the diagnostic usefulness of this observation, ultrasonic transducers were first placed directly on the pulmonary artery or ascending aorta of six open chest dogs. The rapid injection of 5 ml of normal saline solution into the femoral vein or left atrium produced a “cloud” of contrast echoes filling the pulmonary artery or ascending aorta. Thus, the echo-reflecting phenomenon persists during the passage of blood across two cardiac valves. Sixty-two patients aged 2 months to 70 years were then studied during cardiac catheterization; recordings were made during injection of indocyanine green dye or normal saline solution. Contrast echoes appeared in the left atrium after left ventricular injection in 14 of 16 patients with mitral regurgitation. Aortic root injection produced contrast echoes in the left ventricle in 13 of 16 patients with aortic regurgitation. Valvular regurgitation as small as 10 percent by angiographic determination was detected. Shunting was detected In patients with atrial and ventricular septal defects, patent ductus arteriosus and tetralogy of Fallot. Catheter-induced mitral regurgitation was demonstrated in one patient. This method is a sensitive and accurate qualitative technique for detecting intracardiac shunts and valvular regurgitation.