Diagnosing pulmonary emboli: a critical review for the clinician and radiologist.

This review was undertaken with an eye of providing an evidence-based guide for internists in the utilization of the various techniques in the diagnosis of pulmonary emboli. Pulmonary angiography represents a group of tests that are used alone or in combination to evaluate for the presence of pulmonary emboli (PE)† and encompasses computed tomography (CT) pulmonary angiography (which is noninvasive), catheter digital subtraction angiography (DSA) (which requires a right heart catheterization), as well as magnetic resonance imaging (MRI) angiography. All forms of angiography require the use of intravenous contrast. CT pulmonary angiography and, to a lesser extent, conventional DSA (as it has to be performed by an interventional radiologist) are available emergently in almost all centers. Magnetic resonance imaging (MRI) angiography currently is limited to the clinical research setting and is limited by the cost and time it takes to perform a study.