Noninvasive detection of intracardiac thrombosis: 131-I fibrinogen cardiac survey.

Cardiac survey following administration of 131-1 autologous fibrinogen is a noninvasive technique for the detection of intracardiac thrombosis. Fibrinogen is isolated from plasma by a rapid salting-out method with ammonium sulfate and is iodinated with chloramine T. The purity of 131-fibrinogen, expressed as clottable radioactivity, is greater than 90%. Cardiac survey consisting of serial gamma camera imaging or rectilinear scanning after intravenous administration of 131-I fibrinogen was conducted in dogs with freshly induced thromobosis of the left atrial appendage. An accumulation of radioactivity was detectable in the area of the left atrium and confirmed in each of nine dogs sacrificed. Similarly, 20 patients with heart disease predisposing to intracardiac thrombosis were surveyed. Eight of nine patients with positive studies and 11 of 11 with negative studies were confirmed subsequently at surgery or autopsy. Cardiac survey with 131-I fibrinogen is a simple and noninvasive method of detecting intracardiac thrombosis.