Lateral decubitus pneumoencephalography-angiography for localizing atrial and paraatrial vascular lesions.

In two cases where computed tomography (CT) and cerebral angiography failed to determine whether an arteriovenous malformation was within or directly adjacent to the atrium of a lateral ventricle, lateral decubitus pneumoencephalography combined with cerebral angiography successfully localized the lesions. This procedure may be necessary in the workup of angiographically vascular lesions in the atrial-paraatrial region if on CT the ventricular surface is poorly defined or surgical clips from a previous operation obscure the lesion or the adjacent ventricle. Interpretation of this study involves triangulation of the vascular lesions relative to the ventricle or observation of the movement of the lesion relative to the movement of the ventricle on differently angulated frontal projections. Since the surgical approach is influenced by the radiographic differentiation of an intraventricular from a paraventricular mass, this procedure is crucial in evaluating these vascular abnormalities.