EMBOLISM DIAGNOSIS |
|
|
An embolism can be diagnosed through the patient's history, a
physical exam, and diagnostic tests. For arterial emboli, cardiac
ultrasound and/or arteriography are ordered. For a pulmonary
embolism, a chest x ray, lung scan, pulmonary angiography,
electrocardiography, arterial blood gas measurements, and venography
or venous ultrasound could be ordered.
Diagnosing an arterial embolism
Ultrasound uses sound waves to create an image of the heart, organs
or arteries. The technician applies gel to a hand-held transducer
then presses it against the patient's body. The ultrasound's sound
waves arteries are converted into an image that can be displayed on
a monitor. Performed in an outpatient diagnostic laboratory, the
test takes 30–60 minutes.
An arteriogram is an x ray in which a contrast medium is injected to
make the arteries visible on the x ray. It can be performed in a
radiology unit, outpatient clinic, or diagnostic center of a
hospital.
Diagnosing a pulmonary embolism
A chest x ray can show fluid build-up and detect other respiratory
diseases. The perfusion lung scan shows poor flow of blood in areas
beyond blocked arteries. The patient inhales a small amount of
radiopharmaceutical and pictures of airflow into the lungs are taken
with a gamma camera. Then a different radiopharmaceutical is
injected into an arm vein and lung blood flow is scanned. A normal
result essentially rules out a pulmonary embolism. A lung scan can
be performed in a hospital or an outpatient facility and takes about
45 minutes.
Pulmonary angiography is the most reliable test for diagnosing a
pulmonary embolism but it is not used often because it is expensive,
invasive, and not readily available in most hospitals. Pulmonary
angiography is a radiographic test which involves injection of a
radio contrast agent to show the pulmonary arteries. A cinematic
camera records the blood flow through the patient, who lies on a
table. Pulmonary angiography is usually performed in a hospital's
radiology medicine department and takes 30–60 minutes.
An electrocardiograph shows the heart's electrical activity and
helps distinguish a pulmonary embolism from a heart attack.
Electrodes covered with conducting jelly are placed on the patient's
chest, arms, and legs. Impulses of the heart's activity are traced
on paper. The test takes about 10 minutes.
Arterial blood gas measurements are sometimes helpful but, alone,
they are not diagnostic for pulmonary embolism. Blood is taken from
an artery instead of a vein, usually in the wrist.
Venography is used to look for the most likely source of a pulmonary
embolism, deep vein thrombosis. It is very accurate, but it is not
used often, because it is painful, expensive, exposes the patient to
a fairly high dose of radiation, and can cause complications.
Venography identifies the location, extent, and degree of attachment
of the blood clots and enables the condition of the deep leg veins
to be assessed. A contrast solution is injected into a foot vein
through a catheter. The physician observes the movement of the
solution through the vein with a fluoroscope while a series of x
rays are taken. Venography takes between 30–45 minutes and can be
done in a physician's office, a laboratory, or a hospital.
Radionuclide venography, in which a radioactive isotope is injected,
is occasionally used, especially if a patient has had reactions to
contrast solutions. Venous ultrasound is the preferred evaluation of
leg veins. |
|
|
| EMBOLISM RELATED ITEMS |
|
|
|
|