Distribution of 15- and 137-mu diameter microspheres in the dog lung in the axial plane.

Oleic acid infusion, as a model of fat embolism, produces a predominantly peripheral lesion in the dog lung. The lung injury corresponds to the peripheral distribution of labeled oleic acid. The basis for this distribution of oleic acid is not known. Our hypothesis for this nonuniform distribution is that particle diameter plays a role in the subsequent distribution of infused oleic acid and the resulting lung injury. We injected 15-mu microspheres 85Sr and then 137-mu microspheres (141Ce) into the right atria of seven dogs, which were killed and the lungs removed. Analysis of the distribution of the two different diameter microspheres within axial slices from the left caudal lobe of each dog revealed a peripheral distribution of the larger diameter microspheres not seen with the smaller microspheres.