Suspected pulmonary embolism. The difficulties of diagnostic evaluation.
It is impossible to prove or disprove a diagnosis of acute pulmonary embolism on clinical grounds. Diagnostic evaluation is best carried out by first attempting to identify a provable alternative diagnosis that can explain a patient's symptoms. Once the diagnosis of pulmonary embolism is seriously considered, a ventilation-perfusion (V/Q) scan is the next step. A positive ("high-probability") or negative ("normal-perfusion") scan is an appropriate diagnostic end point. Unfortunately, most V/Q scans are nondiagnostic, and the workup must be pursued further. Color-flow (duplex) ultrasound, if available, is the next logical step. If a site of deep venous thrombosis cannot be identified, pulmonary angiography is indicated. Newer methods, such as D-dimer measurement and spiral computed tomography, are being studied.
Miller
G H
GH
George Washington University Medical Center, Washington, DC.
Feied
C F
CF
D006801:Humans; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D011877:Radionuclide Imaging; D014692:Ventilation-Perfusion Ratio