CT pulmonary angiography

Presently for the workup of pulmonary embolism.

Presently is the pref2242ed first-line test for pulmonary embolism.

A one minute examination, which is able to directly visualize blood clots within the pulmonary arteries and which has good sensitivity for the diagnosis of pulmonary embolism.

It is generally widely available, and is widely used when a pulmonary embolus is considered.

In a review of 589 CTAs order to process the possibility of a pulmonary embolism in an emergency department: only 9% of the patients were diagnosed by this procedure with a pulmonary embolism, a third of the patients were noted to have an alternative explanation for their symptoms such as a pleural effusion, pulmonary infiltrate, atelectasis, or pericarditis and these findings will already known in more than half the patients from an admission chest x-ray, a new incidental findings were found in 136 (23%) patients with a previously unknown pulmonary nodule, lymphadenopathy or mass, which deserved future evaluation(Hall, WB).

In the above study, incidental asymptomatic findings, outnumbered pulmonary embolism by a factor of 2.5.

With the advent of pulmonary CT angiography the incidence of pulmonary embolus has increased, mortality has changed little, and case mortality has decreased.

The increased incidence of PE is occurring in a population of nonfatal emboli.

The risk of pulmonary embolus may actually be decreasing due to quality improvements in care such as increased prophylaxis against venous thromboembolism in hospitalized patients.

PE incidence has increased in surgical patients and has increased even more dramatically among obstetric patients, tripling in the years since the advent of CT pulmonary angiography (Wiener RS et al).

With the use of pulmonary angiogram CT scans there has been an epidemic of disease due to increased overdiagnosis of clinically unimportant cases.

Overdiagnosis PE by CT pulmonary angiogram explains the increased incidence of pulmonary embolus, decreased case fatality, and minimal changes immortality.

Overdiagnosis in the above sentence is defined as the detection of an abnormality that will never cause symptoms or death.

Sensitivity for the diagnosis of pulmonary embolus is 83%, and specificity is 96% (Stein PD).

About 40% of readings are either false positives or false negative(Stein PD).

In smaller pulmonary emboli involving more distal blood vessels the positive predictive value for this test drops from 97% to 68% for segmental vessels and 25% for sub segmental branches, a distribution found in more than one third of the cases of pulmonary embolism (Anderson DR).

Deliveries an increased radiation dose to the breast, thyroid, and lung with up to 91mSv.

Ventilation/perfusion (V/Q) lung scan associated with up to 0.9 mSv.

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