Problems in noninvasive imaging of pulmonary embolism

The current state of pulmonary embolism diagnosis is unsatisfactory to both the clinician and the imaging specialist. The ventilation-prefusion scintigram is the mainstay of current practice but requires sophisticated interpretation, produces too many indeterminate readings, and is not sufficiently specific. In addition to its inherent limitations, it suffers from a lack of prospective clinical evaluation: it is likely however, that this will be remedied over the next few years. A nearer-term improvement would be increased uniformity in diagnostic categorization and improved communication of the implications of such categorization to referring physicians. Perfusion scintigraphy will likely remain a primary screening examination. New modalities now being developed and evaluated are cause for hope that the diagnosis of acute pulmonary embolism can be made more specific. Such tehniques could also be useful in monitoring the adequacy of anticoagulant therapy.