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Embolism

Also called: Paradoxical Embolism, Thromboembolism

- Summary
- About embolisms
- Types and differences
- Risk factors and causes
- Signs and symptoms
- Diagnosis methods
- Treatment options
- Questions for your doctor

Reviewed By:
Kerry Prewitt, M.D., FACC
Abdou Elhendy, MD, PhD, FACC, FAHA
Robert I. Hamby, M.D., FACC, FACP

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Diagnosis methods for embolisms

Diagnosis of an embolism can be difficult and relies greatly on the patient’s recent medical history, keen observation of the patient’s current symptoms and the type of embolism that is suspected.

Deep vein thrombosis is the leading cause of a pulmonary embolism, one of the most dangerous types of embolus. When a pulmonary embolism is suspected in someone with a history of deep vein thrombosis, tests may include the following:

Physical examination.
Electrocardiogram (EKG). A recording of the heart’s electrical activity, depicted as a graph on a moving strip of paper or video monitor. The highly sensitive electrocardiograph machine helps detect heart abnormalities, disease and damage by measuring the heart’s rhythms and electrical impulses.
Arterial blood gas (ABG) study. A blood test on an arterial blood sample (taken from a small artery in the wrist) that measures oxygen, carbon dioxide, bicarbonate and acid/base balance to evaluate lung performance.
Chest x-ray. A radiation-based imaging test that offers the physician a picture of the general size, shape and structure of the heart and lungs.
Pulmonary ventilation and perfusion scan (V/Q Scan). Two tests usually given together to detect pulmonary emboli. They are:

Ventilation scintiscan, which images the lungs following the inhalation of radioactive gas in order to determine the distribution of ventilation.
Perfusion scintigram, which provides multiple images of the lungs to assess lung perfusion following the intravenous injection of radioactive particles into the bloodstream. The particles are then scanned as they pass through the pulmonary bloodstream.

Contrast-enhanced CT scan of the chest. A series of x-rays, analyzed by computer to provide cross-sectional views, that are contrast-enhanced by a dye given to the patient (by injection or by mouth) prior to the scan to help visualize abnormalities in the chest.
Pulmonary angiogram. A test used to visualize blood clots in the lung on x-rays. The test involves the insertion of a thin catheter into the pulmonary artery through which iodine dye is injected to enhance the image of any blood clots present in the lung.
Doppler ultrasound of the deep venous system. A sensitive noninvasive monitor that uses ultra-high-frequency sound waves to measure blood flow velocity and changes in blood density that occur in pulmonary embolism.
D-dimer test. A type of blood test used to diagnose thrombosis. While a negative result can rule out the presence of a thrombosis, a positive test requires further testing to positively identify a thrombosis. For this reason, the test is usually used to rule out an embolism.

A cerebral embolism is one of the most common causes of stroke. When it is suspected, a CT scan is performed to determine whether the symptoms are due to a blockage of a cerebral artery or bleeding from a cerebral blood vessel or due to some other brain disorder. The results of the CT scan largely determine the treatment that will be given. The possibility of a paradoxical embolism must also be considered. To further determine the cause and extent of damage following an embolism, other tests may include:

Electroencephalogram (EEG)
Cardiac catheterization
Magnetic resonance imaging (MRI)
Blood tests
Transesophageal echocardiogram

Diagnostic tests used to study other types of embolisms vary with the nature and size of the embolism and the part of the body affected. These tests include the following:

Arterial blood gas study.
Chest x-ray.
Electrocardiogram (EKG).
Angiogram. Considered the “gold standard” for imaging many suspected embolisms despite its inherent risks. The test consists of the injection of a radiopaque dye into a blood vessel in order to visualize a blockage or embolism with various x-ray imaging devices.
Doppler ultrasound. The most sensitive noninvasive monitor, this is commonly used to detect and locate embolisms by using high–frequency sound waves to measure blood flow velocity and changes in blood density in blood vessels.
Computed tomography scan (CT scan).
Magnetic resonance imaging (MRI).