Ventilation-perfusion lung scintigraphy as a guide for pulmonary angiography in the localization of pulmonary emboli

PURPOSE: To assess the appropriateness of ventilation-perfusion (V-P) scint igraphic abnormalities as a guide to pulmonary angiography for the diagnosi s of pulmonary embolism (PE). MATERIALS AND METHODS: V-P scintigrams and pulmonary angiograms of 104 pati ents with angiographically proved PE were reviewed by two nuclear medicine physicians and two interventional radiologists. For V-P scintigrams, the lu ng with the larger amount of perfusion abnormality was determined followed by identification of specific robes. Pulmonary angiograms were similarly ev aluated for lateralization and lobar distribution of PE. Conclusions were i nitially reached independently and subsequently by consensus. RESULTS: Interobserver agreement for lateralization was 88% (kappa = 0.75) for V-P scintigraphy and 98% (kappa = 0.96) for pulmonary angiography. In 7 2 patients, V-P scintigrams predicted unilateral embolus; 64 patients under went pulmonary angiography of the suspected side. Eight patients underwent contralateral angiography only. Of the 64 patients, 61 (95%) had PE on the predicted side at angiography. V-P scintigrams predicted lobar distribution in 55 patients. Of these, PE was found in the predicted lobe in 42 (76%). CONCLUSION: Localization of perfusion abnormalities at V-P scintigraphy pro vides useful information for the interventional radiologist and serves as a n accurate guide for determining the initial approach for pulmonary angiogr aphy.