Clinical Radiologists, S.C. is pleased to have added a 64 row CT scanner to multiple service locations, including Memorial Medical Center in Springfield, Illini Community Hospital in Pittsfield, Passavant Area Hospital in Jacksonville, Blessing Hospital in Quincy, and St. Mary’s Hospital in Decatur. This is the first scanner of its type in the state of Illinois. The greatest strength of this new equipment is its ability to perform coronary CT angiography. We would like to provide you with answers to some of the commonly asked questions by clinicians and patients about this new technology.

This is a 3D view of the heart from a Coronary CT angiogram. These coronary arteries are normal without plaque or blockage. (LAD = left anterior descending coronary artery. LCX = Left circumflex coronary artery).

WHAT IS A CORONARY CT ANGIOGRAM (CTA)?

A coronary CTA is a CT scan of the heart to assess the coronary arteries. IV contrast is given and very rapid images of the heart and coronary arteries are obtained. Computer processing of the data is then performed and 3 dimensional angiographic images of the coronary arteries are created.

WHAT CAN YOU DETECT WITH A CORONARY CTA?

This study detects the presence of coronary artery disease (CAD) and can determine the severity of the disease. Anatomic variants of the coronary arteries can also be assessed. This study can also determine if a bypass graft or stent is open and functioning or blocked.

WHAT PATIENTS MIGHT BENEFIT FROM CORONARY CTA?

Studies have shown that coronary CTA has a very high (97%) negative predictive value for CAD. This means that a normal result means you do not have the disease when compared with catheter angiography. For this reason one of the most common uses of coronary CTA is to rule out or rule in CAD in young or middle age patients with one or two risk factors. This exam can also be used in patients with atypical chest pain. Coronary CTA can also be used to determine if a bypass graft or stent is open and functioning or blocked.

An example would be a 45 year old male with high cholesterol and a strong family history of CAD. A coronary CTA could be performed to determine if that patient had CAD. That information could be used to help plan medical therapies and guide risk factor modification.

WHERE CAN I GET THIS EXAM?

The Radiology Departments of Memorial Medical Center in Springfield, Illini Community Hospital in Pittsfield, Passavant Area Hospital in Jacksonville, Blessing Hospital in Quincy, and St. Mary’s Hospital in Decatur are currently the only facilities in the State of Illinois that provides coronary CTA on a 64 row scanner.

WHAT PATIENTS SHOULD NOT HAVE THIS TEST?

We do not recommend this exam in patients with acute coronary syndrome or classic angina symptoms as a first line approach until the test is validated by research in these settings. We do not recommend this exam in patients with an irregular heart rhythm as this can cause motion artifact.

WHAT ARE THE WEAKNESSES OF THE EXAM?

The presence of a large amount of coronary artery calcification can make it difficult to estimate the degree of stenosis with coronary CTA.

WHAT ARE THE RISKS OF THE STUDY?

This is a noninvasive exam and is very safe. The patients will receive an IV injection of a standard does (approximately 100cc) of contrast. This has a small risk of allergic reaction and should not be used in patients with decreased renal function. The radiation exposure is similar to that which is received with a catheter angiography.

DO YOU GIVE MEDICATION DURING THE EXAM?

Ideally we would like the patient to have a slow heart rate during the exam and we may administer a beta blocker (a medicine used to lower the heart rate) prior to the study. In some cases we also give the patient sublingual nitroglycerin to dilate the coronary arteries during the exam.

HOW IS THIS DIFFERENT THAN A CORONARY CALCIUM SCORING OR EBCT EXAM?

A coronary calcium scoring exam with EBCT is a CT of the heart without IV contrast used to determine the presence of coronary artery calcification or “hard plague”. A coronary CTA with a 64 row scanner is a study with IV contrast that allows you to obtain angiographic images of the coronary arteries and detect calcified (hard) plaque as well as uncalcified (soft) plaque. Most investigators believe it is the soft plague that is the most vulnerable plaque that can rupture and cause acute coronary artery obstruction and a myocardial infarct. The degree of coronary artery stenosis can also be estimated with coronary CTA, which cannot be done with calcium scoring.

WHAT IS THE COST OF THE EXAM?

The exam costs about the same as a chest CT without and with IV contrast.

WHAT WOULD A PATIENT EXPECT IF THEY WERE TO HAVE A CORONARY CT ANGIOGRAM IN THE RADIOLOGY DEPARTMENT AT MMC?

First the exam would have to be ordered by a physician. The patient would then check in to the department of radiology. They would be taken to the CT scanner.

The prep times takes about 15-30 minutes. During this time an IV is placed in the forearm. EKG leads would then be positioned on the chest to synchronize the images we take with the patients heart beat. The patient may be given some medications during this time to slow and steady the heart rate and to dilate the coronary arteries. A set of initial images are obtained to set up the exam.

The next part of the exam the actual CT images of the heart and coronary arteries are obtained. This takes about 10-15 seconds. It is done in one breath hold. The exam is then complete.

After this the patient is observed in the department for 10-30 minutes.

The exam is then interpreted and the results are available for the ordering physician in the next 24-48 hours.

HOW LONG DOES THE EXAM TAKE?

The scan itself takes about 10-20 seconds. The entire exam takes one hour or less. After the exam the patient leaves the department with a band-aid on the forearm and can return to work or normal activities. If betablocker medication is used during the exam the patient should refrain from heavy physical activity for the remainder of the day.

For more information please contact:
Dr. Andrew D. Sherrick, Clinical Radiologists, S.C., at 217-788-7021.

This is a 2D view of a coronary artery from a coronary CT angiogram. The coronary artery shown contains hard or calcified plaque. The hard plaque appears bright white and is marked with arrow heads. Hard plaque is more stable than soft plaque.

This is a 2D view of a coronary artery from a coronary CT angiogram. The coronary artery shown contains soft or uncalcified plaque. The soft plaque appears gray and is marked with an arrow. Soft plaque is more vulnerable to rupture and cause a heart attack than hard plaque.

This is a 2D view of a coronary artery from a coronary CT angiogram. The coronary artery shown contains a stent and some plaque before the stent. The stent is open and working well. The soft (uncalcified) plaque is gray and is marked with an arrow, there is also some adjacent Hard (calcified )plaque.