CT Angiography

What is CT Angiography?

CT Angiography is a non-invasive diagnostic procedure that is done for the evaluation of diseases and medical conditions affecting the blood vessels. The procedure is done by injecting contrast material into the blood vessels and then imaging them with the help of computed tomography (CT). While the procedure is more commonly done for the evaluation of blood vessels supplying to the heart, it is also used for the evaluation of the aorta, and blood vessels supplying the brain, kidneys, and lungs, as well as peripheral blood vessels.

Is the CT Angiography procedure an elective or an emergency procedure?

CT Angiography is mainly done as an elective procedure.

Types

CT Angiography may be of the following types based on the equipment used:

• Single Source 64 slice CT Angiography: It requires a larger dose of radio-contrast dye
• Dual Source 64 slice CT Angiography: It provides better resolution, and requires a lesser amount of radio-contrast dye
• Single Source 256 or 320 Slice CT Angiography: It provides a better image quality

Based on the blood vessels being visualized, CT Angiography may be of the following types:

• CT Coronary Angiography: It for visualization of the blood vessels supplying to the heart
• CT Angiography of the Aorta: It is for visualization of the aorta and its main branches
• CT Pulmonary Angiography: It is for the visualization of the pulmonary arteries in the lungs
• CT Renal Angiography: It for visualization of the blood vessels of the kidneys
• CT Carotid Angiography: It is for the visualization of the carotid arteries in the neck
• CT Vertebral Angiography: It is for the visualization of the vertebral arteries
• CT Intracranial Angiography: It is for the visualization of the blood vessels inside the brain
• CT Peripheral Angiography: It is for the visualization of the small arteries in the limbs

Indications

CT Angiography is done for the evaluation of blood vessels and is useful in the assessment of diseases or medical conditions that causes narrowing, widening, or blockage of blood vessels. Some common indications include:

• Aneurysms – Abnormal dilatation of blood vessels
• Stenosis – Narrowing of blood vessels
• Blockages – Mostly due to atherosclerotic plaques
• Blood clots
• Arteriovenous malformations
• Congenital abnormalities of blood vessels
• Tumors – The procedure is done to identify arteries supplying tumors to assist with chemoembolization
• Vessel rupture or trauma

Some specific indications include:

• Coronary (Heart) CT Angiography:
  • Diagnosis of coronary artery disease (CAD)
    • Detection of CAD in individuals without a history of heart disease
    • Assessment of coronary arteries in individuals undergoing non-cardiac surgery
    • Assessment of heart function and structure in adult congenital heart disease
  • Assessment of restenosis after placement of a stent
  • Assessment of patency after a Coronary Artery Bypass Grafting
• Pulmonary CT Angiography: It is for the evaluation of pulmonary embolism
• Renal CT Angiography: It is for the assessment of renal causes of hypertension due to renal artery stenosis
• Carotid and Intracranial CT Angiography: It is for the evaluation of stroke, aneurysms, and arteriovenous malformations

Contraindications & Risk factors

• History of a severe allergy to contrast materials
• Extremely obese individuals
• Pregnancy and breastfeeding
• Kidney failure

Investigations before the procedure

No specific investigations are required specifically before a CT Angiography.

Preoperative advice

The following measures are taken before a CT Angiography are:

• Risks and benefits of the procedure are explained
• Nothing by mouth at least 4 hours before the procedure
• To avoid caffeine at least 12 hours before the procedure
• To avoid smoking at least 12 hours before the procedure
• If there is a history of allergy to contrast material, then corticosteroids may be given prior to the procedure
• If the individual is breastfeeding, it is advised to pump the milk and store it so that it can be used until the contrast clears from the body (which usually takes about 24 hours)
• For CT Coronary Angiography – beta-blockers may be administered prior to the procedure

Intraoperative details

Anesthesia: It is usually not required.

Duration: A CT angiogram can last between 30 minutes to 2 hours, depending on the procedure that is being done.

Description of the procedure

The individual is made to lie on their back on the CT table and an IV drip is put in place to deliver the contrast material. Once the contrast is injected, the CT table is positioned and aligned to get the best images, and as the procedure progresses, the table is moved through the CT machine as required to capture all the images in the region of the body being evaluated. For some procedures, the individual may need to hold their breath, while for others, ECG leads may be attached to the body to simultaneously assess the heart rate and rhythm. Once the procedure is completed, and the quality of the images is confirmed to be adequate, the individual can proceed to be discharged.

Post-operative advice

CT Angiography is done as an outpatient procedure, and the individual can leave once the procedure is complete. If the procedure was done under sedation, then the individual is moved to a recovery room, where they are placed under observation till the sedation wears off.

Common post-procedure complaints are:

• Mild pain at the site of the placement of IV drip

Medications: None required.

Review: It is required by the attending specialists.

Return to normal activities: The procedure poses no limitations to normal daily activities, however, the level of activities and rest required is advised by the attending specialists.

Role of diet/ Exercise/ Lifestyle changes

No specific measures are required to be taken after a CT Angiography procedure unless specifically advised by the attending specialists.

Complications

Some complications although very rare, that are associated with Computed tomography angiography include:

• Severe allergic reaction to the contrast material with symptoms of hives, nausea, vomiting, breathlessness, loss of consciousness, low blood pressure
• Increased risk of cancer due to exposure to the radio-contrast material
• Risk of kidney failure in individuals with compromised kidney function
• Cardiac arrest

Prognosis

The prognosis of CT Angiography is excellent, and it has a lot of benefits that include that it is cheaper than catheter angiography, it can eliminate the need for surgical interventions, it is noninvasive, and is associated with fewer complications.

When to contact the doctor or hospital? / Indications for hospitalization if required

CT Angiography is done as an outpatient procedure, and no hospitalization is required. If there is a severe allergic reaction to the contrast material used, with symptoms of hives, breathlessness, loss of consciousness, low blood pressure, it is advisable to seek immediate medical attention.

Suggested clinical specialists/ Departments to consult for this procedure

• Radiology
• Cardiology