Pulmonary angiography for pulmonary emboli: rational selection of oblique views.

In the performance of pulmonary arteriography, the anteroposterior projection may be insufficient for the diagnosis of pulmonary embolism, and additional views, usually oblique, are required. Of 57 positive pulmonary arteriograms which were reviewed, additional views were necessary in 26 cases. The efficacy of the additional views in each case was assessed with regard to the demonstration of the segmental arteries of the various lobes of the lung. Following an inconclusive anteroposterior injection, the best visualization of the arteries of the right lung can generally be obtained with an injection made in the right posterior oblique projection. Similarly, following an inconclusive anteroposterior injection, the left posterior oblique or lateral view is recommended for optimal visualization of the pulmonary vasculature of the left lung.