Introduction
The clinical diagnosis of venous thromboembolism (VTE) is dif ficult and sometimes
unreliable. Pulmonary angiography and contrast venography are used as reference tests
for pulmonary embolism (PE) and deep vein thrombosis (DVT), respectively.1,2 However, due to the invasive nature of these reference tests, the optimal and clinically
acceptable diagnosis of VTE remains a matter of some debate. Until recently, standard
diagnostic strate gy in suspected pulmonary embolism (PE) consisted of a lung perfusion
scan, followed by venous ultrasound (VUS), if a lung perfusion scan did not produce
a definitive diagnosis. Eventually pulmonary angiography was performed.3,4 In clinical practice this strategy has rarely been respected because it required
many pulmonary angiographic examinations. Diagnostic managemen was often halted prematurely
without performing pulmonary angiography and, thus, without final confirmation or
exclusion o PE.5-7 In addition, suspected DVT is often managed only on the basis of single VUS examination,
which, unfortunately, has a rel atively low sensitivity when used to visualize the
vasculature below the knee.8
This chapter focuses on newer, noninvasive diagnostic tests that permit direct imaging
of venous thromboemboli. While the place of those tests in diagnostic algorithms remains
to be fully determined, they may already be helpful in simplifying the diagnostic
management of patients in many clinical situations including those patients at high-risk
of venous thromboem bolism. These patients represent a non-homogeneous group such
as patients with recent major surgery, serious medical dis eases, or a concomitant
history of VTE or thrombophilia According to a recent consensus statement, screening
for VTE is technically possible, but, in the presence of effective prophy laxis, neither
was demonstrated to be necessary or cost effec tive.9 Therefore, the main effort should be focused on effective diagnostic management of
those patients who present with symptoms and/or signs suggestive of VTE.
