Coronary CT Angiography

Last updated date: 12-Mar-2023

Originally Written in English

Coronary CT Angiography

One of the most prevalent diagnostic problems faced by practicing clinicians is chest pain, which is typically a predictor of cardiovascular disease. Despite breakthroughs in medical and procedural therapy, cardiovascular disease remains a primary cause of morbidity and mortality globally. Coronary artery disease (CAD) is a type of cardiovascular disorders that necessitates prompt, precise, and cost-effective diagnosis. Based on clinical presentation, history, clinical examination findings, ECG abnormalities, and cardiac enzyme levels, patients can be divided into three groups: low, intermediate, and high pretest probability of ischemic heart disease. When attempting to determine the presence of CAD and estimate its extent in these patients once acute coronary syndrome has been excluded, the clinician has a wide range of diagnostic techniques to select from. Coronary computed tomographic angiography (CCTA) is an anatomical test that can promptly deliver these answers to a diagnostician in intermediate-risk individuals.


What is Coronary CT Angiography?

Coronary CT angiography (CCTA) is a cardiac imaging procedure that determines whether plaque formation has blocked the coronary arteries, which feed the heart with blood. Plaque is a substance that forms along the inner layer of the arteries and is made up of fat, cholesterol, and calcium. Plaque, which forms over time, can limit or totally block blood flow in some circumstances. Patients undergoing a CCTA scan are given an intravenous injection of iodine-containing contrast media to achieve the best feasible images of the heart blood vessels.

A CT scan, often referred to as a CAT scan or a CT scan, is a diagnostic medical imaging procedure. It provides several images or photos of the body, identical to standard x-rays.

Images from a CT scan can be reformatted in various planes. It's even possible to produce three-dimensional displays. These images can be viewed on a computer display, printed on film or using a 3D printer, or converted to a CD or DVD by a doctor.

Internal organs, bones, soft tissue, and blood vessels are more detailed in CT pictures than in standard x-rays. This is particularly true of blood vessels and soft tissues.


Coronary CT Angiography Indications

Coronary CT Angiography Indications

Many doctors recommend using CCTA with caution in patients who have:

  • An aberrant anatomy of the coronary arteries is suspected.
  • Patients with chest pain (angina) and normal, non-diagnostic, or unexplained lab and ECG data are at low or moderate risk for coronary artery disease.
  • Atypical chest pain with a low to intermediate risk in the emergency room.
  • Non-acute chest pain
  • with a prior normal stress test result, new or worsening symptoms
  • Stress test findings that are confusing or inconclusive
  • new-onset heart failure with decreased cardiac function and a low to moderate risk of coronary artery disease
  • Before non-coronary heart surgery, If you have an intermediate risk of coronary artery disease.
  • Bypass grafts for the coronary arteries.

CCTA can give crucial information on the existence and degree of plaque in the coronary arteries for patients who match the above criteria. It can detect other probable reasons for symptoms, such as a collapsed lung, blood clot in the veins leading to the lungs, or aortic anomalies, in addition to coronary artery narrowing as the source of chest pains. Your primary care doctor or cardiology specialist will decide whether CCTA is right for you after consulting with a radiologist who will conduct the test.


Coronary CT Angiography Contraindications 

A big individual may not be able to fit inside the entrance of a traditional CT scanner. They could also be beyond the weight limit for the movable table, which is normally 200 kilograms.

Because image quality may be impaired in patients who are extremely overweight or have irregular heart rhythms, this test may not be appropriate for them.

Invasive coronary angiography, unlike CCTA, which is solely a diagnostic procedure, can be utilized for both diagnosis and treatment in a single session. During a CCTA, if a narrowing or obstruction is discovered, it cannot be addressed at the same time. Because patients with a significant risk of coronary artery disease and typical symptoms are more likely to require intervention, coronary angiography may be used instead of CCTA. When there are large areas of old, calcified plaque, as in older individuals, CCTA might be difficult to interpret.


How Should I Prepare for Coronary CT Angiography?

Prepare for Coronary CT Angiography

To the test, dress loose-fitting clothing. For the procedure, you may have to shift into a gown.

Metal artifacts, such as jewelry, eyeglasses, dentures, and hairpins, can cause CT pictures to be distorted. Leave them at house or take them off before the examination. Hearing aids and removable dental work got to be removed for some CT tests. Metal underwire brassieres will need to be removed by women. If feasible, you ought to remove any piercings.

If the exam will include contrast media, the doctor may advise you not to eat or drink anything for a few hours before the exam. Tell the doctor about all of the drugs and any sensitivities you have. The doctor may prescribe drugs (typically a steroid) to lessen the chance of an adverse reaction if you have a known allergy to contrast material. Contact the doctor well ahead of the test date to minimize any unnecessary delays.

Tell the doctor about any recent diseases or other medical conditions you've had, as well as any family history of heart disease, asthma, diabetes, kidney disease, or thyroid issues. Any of these factors could raise the chance of a negative effect.

You may be urged to avoid the following the day before and the day of the test:

  • Diet pills and caffeinated beverages such as coffee, tea, energy drinks, and sodas. These can raise heart rate and make it difficult for the exam to detect plaque in the coronary arteries.
  • Viagra or a comparable drug that is used to treat erectile dysfunction. They're incompatible with the drugs you will be given throughout the procedure.

You may be requested to take a beta-blocker the night before the operation to lower your heart rate and improve the quality of the examination.

If a sedative or anesthesia will be used during the exam, the child may be instructed not to eat or drink anything for several hours before. Children who have lately been ill will not be anesthetized or sedated in most cases. If this is the case, or if you believe the kid is becoming ill, you should discuss rescheduling the CT exam with the doctor.

You should also tell the doctor if the child is taking any drugs and if he or she has any sensitivities, particularly to intravenous or oral contrast substances. At the time of the CT examination, the allergy information should be shared with the CT technician or nurse. You should notify the doctor and technician ahead of time if the child has a known contrast media allergy.

Also tell the doctor if the child has had any recent diseases or other medical disorders, as well as if the child has a family history of heart disease, asthma, diabetes, renal disease, or thyroid issues. Any of these factors could influence whether or not the child will receive contrast material during the CT scan.

If there is any chance that a woman is pregnant, she should always tell the doctor and the CT technologist. 

Ask the doctor how to proceed if you are nursing at the time of the exam. Pumping breast milk ahead of time may be beneficial. Keep it on hand in case you need it until all of the contrast media has been removed from the body (about one day after the test). However, studies demonstrate that the quantity of contrast absorbed by the newborn during breastfeeding is exceedingly minimal, according to the most recent American College of Radiology (ACR) Manual on Contrast Media.


What Does the Equipment Look Like?

A CT scanner is a huge donut-shaped machine with a short passage in the middle. You will be lying on a little table that slides into and out of this small tunnel. The x-ray tube and electronic x-ray sensors are situated opposite each other in a ring called a gantry that rotates around you. A separate control room houses the computer workstation that analyzes the imaging data. This is where the technologist controls the scanner and keeps a close eye on the exam. Using a loudspeaker and microphone, the technician will be able to hear and speak with you.

CCTA is fairly similar to a regular CT scan. The CT scanner's speed and the usage of a heart monitor to assess the heart rate are the main differences.


On Coronary CT Angiography

X-rays travel through the body during the scan and are detected by special detectors in the machine. Higher numbers of these detectors (particularly 65 or more) usually result in clearer final shots. As a result, CCTA is also known as multi-detector or multi-slice computed tomography. The information gathered during the CCTA is utilized to determine coronary artery structure, plaque, vessel narrowing, and, in some situations, cardiac function. To fully examine the heart and coronary arteries, the radiologist will utilize the computer to make three-dimensional images and images in multiple planes.

Contrast material is used to make the blood vessels under examination stand out by turning them bright white.


Coronary CT Angiography Scans

Coronary CT Angiography Scans

During the procedure, the nurse will provide you with a gown to wear.

Electrodes (tiny, sticky discs) will be placed on three small locations of the chest by the technologist. To help the electrodes adhere, men may need to shave a small portion of their chest. The electrodes are connected to an electrocardiograph (ECG) monitor, which displays the electrical activity of the heart during the procedure.

During the examination, a nurse or technologist will implant an intravenous line into a vein in the arm to provide contrast dye. You may be provided a beta-blocker medication through the same IV line or by mouth while in the CT scanner to assist reduce the heart rate and improve image quality. Nitroglycerin can be taken as a tablet, a spray under the tongue, or a patch on the skin to dilate and increase the visibility of the coronary arteries.

You may be requested to raise your arms overhead while lying on the scanning table for the length of the exam. This will aid in the improvement of image quality.

The table will then travel quickly through the scanner to spot the right scan start location. The table will then be progressively moved through the scanner for the CT scan. The machine may do numerous rounds depending on the type of CT scan.

During the scanning, the technologist may ask you to hold your breath. Artifacts on the photographs can be caused by any movement, including breathing and body motions. This decrease in image quality can look similar to the blurring seen in photos of moving objects.

If you have trouble holding your breath for 5 to 15 seconds, talk to your doctor. Breathing during the scan causes image blurring, which might lead to an inconclusive evaluation.

When the exam is over, the technologist will ask you to wait while they ensure that the images are of sufficient quality for the radiologist to interpret accurately.

Before you leave the hospital, the doctor or nurse will remove the intravenous line.

If the heart rate is slow and stable, the CCTA scan normally takes around 15 minutes, along with all preparations. If the basal heart rate is rapid and a beta-blocker is given to bring it down, it may take longer. If you take a beta-blocker by mouth, it usually takes at least one hour for it to work. Even if the medication is injected directly into a vein, it may take many doses and up to 25 minutes to achieve the desired heart rate.


What Will I Experience During and After the Procedure?

During and After the Procedure

Except for the needle stick when the Intravenous line is inserted, most CT tests are quick, painless, and simple.

Though the scan is harmless, you may experience minor discomfort as a result of staying still for several minutes or having an Intravenous line inserted. A CT exam might be stressful if you have trouble sitting still, are apprehensive, anxious, or in pain. Under the supervision of a doctor, the technician or nurse may prescribe medication to assist you to cope with the CT scan.

The doctor will screen you for chronic or acute kidney damage if the exam uses an iodinated contrast substance. When the nurse puts the needle into the vein to give contrast material intravenously, you will feel a pinprick. As the contrast is administered, you may feel warm or flushing. A metallic taste may also be present in the mouth. This will be over shortly. You may have a strong desire to urinate. These are, however, simply temporary negative effects of the contrast injection.

The drug used to reduce the pulse rate has been reported to produce dizziness in some individuals when they rapidly stand up due to a drop in blood pressure. As a result, you will frequently be instructed to carefully rise from the seat at the table before standing. The dizziness is minor and only arises on rare occasions. If you are given drugs, your blood pressure may be measured before, during, and after the examination. The nitroglycerin pill may cause a headache; however, this is not harmful and will pass shortly.

You may notice distinctive light lines projected across the body when you enter the Imaging system. These lines will help you get into the proper position on the examination table. You may hear modest buzzing, clicking, or whirring sounds from newer CT scanners. During the imaging procedure, the CT scanner's internal pieces, which are generally not visible to you, rotate around you.

Unless there are unique circumstances, you will be alone in the examination room during the CT scan. A parent using a lead shield, for example, may choose to remain in the room with their child. Through a built-in intercom system, the technologist will always be able to see, hear, and talk to you.

The technologist will withdraw the intravenous line after the CT scan. They will use a small dressing to patch the small hole produced by the needle. You can quickly resume your everyday activities.


Coronary CT Angiography Interpretation

The images will be analyzed by a radiologist, a doctor who is specially educated to supervise and interpret radiology exams. The radiologist will provide the doctor who requested the exam an official report.

If you have chest pain, the radiologist will transmit the findings to the emergency department doctor, and a preliminary report will be presented to you right soon.

It is possible that you will need a follow-up test. If this is the case, the physician will explain why. A follow-up test may be necessary to further analyze a potential problem with more perspectives or unique imaging technology. It may also check to determine if an issue has changed over time. Follow-up exams are frequently the most effective approach to determine whether treatment is working or whether a problem requires attention.


What are the Benefits vs. Risks

Benefits vs. Risks

Coronary CT Angiography Benefits

  • Coronary CT angiography is a non-invasive procedure. Cardiac catheterization with coronary angiography is an alternate test that is more invasive and has more difficulties due to the implantation of a long catheter into the femoral and radial arteries that extend all the way to the heart and move the catheter in the blood vessels. Invasive catheterization necessitates a longer recovery time for the patient.
  • CT has the advantage of being able to view bone, soft tissue, and blood vessels all at once. It is consequently well-suited to determining various causes of the discomfort, such as an aortic injury or a thrombus in the lungs.
  • CT scanning, unlike traditional x-rays, produces highly detailed images of a variety of tissues.
  • CT scans are quick and painless.
  • CT scans have been proved to be cost-effective in a variety of medical situations.
  • When compared to MRI, CT is less sensitive to patient movement.
  • Unlike an MRI, a CT scan will not be hampered by an implantable medical device of any kind.
  • After a CT scan, no radiation is left in the patient's body.
  • CT scanning uses x-rays, which should have no acute negative effects.


Risks of Coronary CT Angiography

  • The contrast substance used in CT scanning may affect renal function in some individuals with abnormal renal function.
  • Skin damage or injury to blood vessels and nerves can occur if contrast media seeps out of the vessel being administered and spreads under the skin where the Intravenous line is placed, albeit this is uncommon. If you have any pain in the arm near the Injection sites during intravenous contrast injection, tell the technologist right away.
  • Excessive radiation exposure always carries a small risk of cancer. The advantage of a precise diagnosis, on the other hand, considerably surpasses the risk of CT scanning.
  • If there is any likelihood that a woman is pregnant, she should always tell her doctor and the x-ray or CT technician.
  • Because of the possible risk to the unborn baby, doctors generally do not recommend CT screening for pregnant women unless it is medically required.
  • According to IV contrast manufacturers, mothers should not nurse their kids for one to two days after receiving the contrast dye. However, studies demonstrate that the quantity of contrast taken by the newborn during breastfeeding is exceedingly minimal, according to the most recent American College of Radiology (ACR) Manual on Contrast Media. 
  • Iodine-containing contrast materials pose a low risk of significant allergic reactions, and radiology departments are well-equipped to manage them.



Coronary CT Angiography

Coronary CT angiography adds to the diagnosticians' armament of tools for detecting and managing cardiovascular disease. CCTA minimizes the dangers of invasive coronary angiography while simultaneously providing a cost-effective, fast, and reliable means of determining CAD. Non-contrast CCTA study segments can also provide prognostic value, while post-processing techniques such as three-dimensional volumetric structuring can reveal heart anatomy. Radiation and contrast exposure are both risks of CCTA, however, as CT technology improves, these disadvantages will likely be reduced in the future.