Medical Imaging News

Cardiac CT

What is Cardiac CT for Calcium Scoring?

Computed tomography, most generally referred to as CT or CAT scan, is a clinical medical imaging procedure. Like standard x-rays, it creates numerous photographs from the interior of the body. It is a technique that utilizes special x-ray tools in order to generate pictures of the coronary arteries. This technique is done to determine whether the arteries are blocked and narrowed, which can be an indicator for atherosclerosis. The details gathered will help you determine whether you are at an elevated risk of experiencing a heart attack.

  • It is a non-invasive technique to obtain information of any plaque in the arteries and vessels.

What is Calcified plaque?

Calcified plaque results when there is a development of fat and different substances under the internal layer of the supply route. This material can calcify which flags the presence of atherosclerosis, an infection of the vessel, called coronary course illness (CAD).

People with this condition are at higher risk of heart attacks. In fact, with time, the plague builds-up and widens the arteries or even close blood flow to the heart. The effect may be chest pain, often referred to as angina, or a cardiac arrest. Since calcium is a marker of CAD, the amount of calcium found in a cardiac CT scan is a valuable prognosis tool. The results on cardiac CT are expressed as calcium ratings. Another name for this measure is coronary artery calcium score.

What are some common uses of the procedure?

The aim of a cardiac CT calcium score scan is to see whether CAD is present and to what degree, even though there are no signs. If your specialist feels like he would ask you to go for the test. You might not be having the symptoms but it is good to get yourself screened.

The key risk factors for CAD are:

• High levels of blood cholesterol

  • Family history of heart problems

• diabetes mellitus

• High blood pressure;

• smoking a cigarette

• overweight or obese;

• Physical inaction

How should I prepare?

Before the test;

  • Tell your primary care physician if there’s a chance you are pregnant.
  •  Tell if you have any new diseases, ailments, meds you’re taking
  • You will be told not to eat or drink anything and to avoid caffeine and smoking
  •  Leave any metals and jewellery  at home and wear free, open to dress.
  •  You might be asked to wear a loose gown.

What does the equipment look like?

The CT scanner is usually a large, donut-shaped system with a small tunnel in the middle. You’re going to lay on a small test table that slips in and out of this short tunnel. Rotating above you, an x-ray tube and an analog x-ray detector are placed opposite each other in a ring called a gantry. The machine workstation that processes the imagery information is housed in a different control space. This is where the technologist runs a scanner and tracks the test in clear vision.

How does the procedure work?

Xray examiners:

CT scanning works much like most x-ray examinations in several respects. X-rays are a source of radiation—like light or radio waves—that can be directed to the body. The various areas of the body absorb the x-rays in differing degrees..

Radiation:

In a traditional x-ray test, a tiny blast of radiation is guided and transferred through the body, capturing an image on a photographic film or a special image recording plate. Bones show white on the x-ray; soft tissue appears in shades of gray and air appears yellow.

With CT scanning, multiple x-ray rays and a series of automated x-ray monitors spin around you, measuring the amount of radiation consumed in the body.

Special computer program:

The scanner takes a series of pictures, and then the table shifts (axial scan). Often the examination table turns during the scan such that the x-ray beam takes a spiral path (spiral or helical scan). A special computer software processes this vast amount of data to produce two-dimensional cross-section images of the body, which are then projected on a monitor.

CT imaging is sometimes compared to looking into a loaf of bread by cutting the loaf into thin slices. When the image slices are reassembled by computer software, the result is a very detailed multidimensional view of the body’s interior.

multislice CT:

Detector technology refinements allow new CT scanners to receive several slices in a single rotation. These scanners, called multislice CT or multidetector CT, allow thinner slices to be created within a shorter period of time, resulting in more detail and additional display capabilities.

Fast:

Modern CT scanners are so fast that they can search through large parts of the body in just a few seconds. This pace is helpful for all patients, but particularly children, the elderly and critically ill.

How is the procedure performed?

Positioning:

The technologist starts by putting you on the CT exam table, normally lying flat on your back. Straps and pillows can be used to help you maintain the proper posture and stay in the test..

Recording:

Electrodes (small adhesive disks) would be connected to the chest and the electrocardiograph (ECG) system that tracks the electrical pulse of the heart. This makes it easier to record CT scans when the heart does not contract vigorously.

  • The table moves rapidly through the scanner to decide the right starting place for the scans. Then the table moves slowly around the machine while the real CT scan is done. Depending on the form of CT scan, the computer may make many runs.
  • Patients are asked to hold their breath for 10 to 20 seconds as the pictures are captured.

Waiting:

  • Upon completion of the test, you will be asked to wait until the technologist verifies that the photographs are of high enough quality for correct interpretation. The entire process, including the actual CT scan, is normally performed within 10 minutes.
  • You will lay on a table under an arch-shaped scanner for an EBCT scan. You will remain clothed, and your head will never be enclosed. You will be asked to hold your breath at times during the scan to ensure you stay motionless..

What will I experience during and after the procedure?

  • The CT exam is painless, Although the scan is painless, you may have some irritation from remaining for a few minutes or from an IV. If you have a hard time keeping still are very tense, worried, or pain-ridden, you can find a CT exam exhausting. The technologist or nurse, under the supervision of a doctor, can give you some medicine to support you with the CT test.
  • • You can see special light lines projected onto your body as you reach the CT scanner. These lines are used to ensure that you are accurately positioned. You can detect small ringing, scratching and whirling sounds with modern CT scanners. This arise when the internal portions of the CT scanner, which are not normally visible to you, revolve around you throughout the imaging process.
  • You will be alone in the consultation room for the CT scan, unless there are exceptional conditions. For eg, often a parent wearing a lead shield can remain in a room with a child. However the technician will still be able to see, hear and communicate to you with an automated intercom device. You should go back to your usual activities after the CT test.

Who interprets the results and how do I get them?

The pictures would be examined by a radiologist, a specialist professionally qualified to supervise and interpret radiology experiments. The radiologist would give an official report to the doctor who requested the examination.

Negative test:

A negative calcium CT scan indicates no calcification inside the coronary arteries. This implies the CAD is missing or so limited that this technique cannot be seen. Under these conditions, the risk of experiencing a heart attack within the next two or five years is very poor.

Positive test :

Positive result indicates the CAD is present regardless of whether or not the patient shows any symptoms. Calcification—expressed as a calcium score—can help predict the probability of a myocardial infarction (heart attack) in the coming years and help the doctor or cardiologist determine if a patient may need to take preventive medication or take other steps, such as diet and exercise, to reduce the risk of a heart attack.

Calcium ScorePresence of CAD
0No evidence of CAD
1-10Minimal evidence of CAD
11-100Mild evidence of CAD
101-400Moderate evidence of CAD
Over 400Extensive evidence of CAD

Follow-up examinations could be required. If that is the case, the doctor will explain why. Often a follow-up examination is conducted when a possible abnormality demands further assessment with additional views or a special imaging procedure. A follow-up exam can also be performed to see if an abnormality has improved over time. Follow-up checks are also the only way to see if therapy is successful or if an abnormality is unchanged or has improved.

What are the benefits vs. risks?

Benefits

• Calcium cardiac CT is a safe and non-invasive way to determine whether you are at higher risk of heart disease.

• The test takes a brief time, induces no discomfort and does not require injection of contrast content.

• The EBCT scan takes less than 20 minutes and you can return to normal activities soon afterwards.

• There is no radiation left in the patient’s body following a CT test.

• The X-rays used in CT scans do not have any immediate side effects.

Risks

  • There is still a small risk of cancer due to prolonged exposure to radiation. The value of correct diagnosis, however, greatly outweighs the risk.The effective dosage of radiation for this treatment varies.
  • Women should always notify their doctor and x-ray or CT technologist whether they are expected to be pregnant.
  •  CT scanning is generally not recommended for pregnant women because it is fairly necessary due to a potential risk to the unborn child. A high calcium score may often be accompanied by other medical tests for heart disease, which may or may not have therapeutic benefit outcomes and may be correlated with side effects.

What are the limitations of Cardiac CT for Calcium Scoring?

Over weight:

A individual who is very big can not fit into the opening of a traditional CT scanner or be over the weight limit—usually 450 pounds—for a moving table.

Over aged:

CAD, particularly in people under 50 years of age, may be present without calcium (non-calcified plaque) and may not be detectable by this examination.

Health insurance plans:

Not all health care policies cover cardiac CT with calcium scores.

Uncertainty:

The precise manner in which your care or avoidance of heart problems can be adjusted according to your calcium score remains unclear

Few rows of detectors:

EBCT scanners have fewer rows of detectors and lack the spatial resolution of the latest generation CT scanners.

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