 detect pericardi effus radioisotop heart scan mark differ cardiac silhouett six-foot chest roentgenogram cardiac blood pool determin radioiso- tope scan consist pericardi effus thicken observ cardiac blood pool separ liver margin interposit peri- cardial fluid thicken separ demonstr presenc normal pericardium appreci featur 400 radioiodin human serum albumin 50 colloid radiogold scan outlin blood pool demonstr posit liver 