Diagnosis of pulmonary embolism. Experimental evaluation of the accuracy of scintigraphically guided pulmonary arteriography

Technically refined angiograms and scintigrams were extremely sensitive in demonstrating experimental canine thromboemboli, both immediately after embolization and during the entire course of embolic lysis. Technical refinements included subselective, scintigraphically guided, magnification arteriography and eight-view perfusion scintigraphy. During thromboembolic lysis, excellent angiographic-scintigraphic correlation persisted. For every postembolic perfusion defect, the embolic basis could be demonstrated angiographically. Thus, apparent disparities between angiographic and scintigraphic evidence of embolism can no longer be attributed to lysis. Studies using nonresorbable Ivalon emboli indicated that localized spasm may play an important role in the perfusion defects that develop within a half hour embolization, and that this spasm subsides considerably within 24 hours.