As many as 50% of patients with isolated DVT will be found to have silent pulmonary embolism (i.e. no chest pain or shortness of breath) on VQ scanning. Studies performed in the last year or so with CT scanning show that this percentage is much higher.
The clinical take-home point is NOT to get a pulmonary CTA on suspected DVT patients but to remember that many patients can and do have PE in the absence of cardiopulmonary symptoms. Pretty frightening....
