AMI - Advanced Medical Imaging

Exams and Preps > CT Scan > CT Cardiac

Cardiac CTA now covered by Medicare for some indications

Medicare now covers cardiac CTA for these scenarios:

the evalution of patients with acute chest pain present in an emergency room (or equivalent) when necessary to rapidly differentiate among reasonably probable aortic, pulmonary, and/or coronary etiologies;
the first line testing for coronary artery disease (CAD) in non-diabetic parients with intermediate risk factors presntingin an emergency room (or equivalent) with chest pain syndrome or other symptoms strongly suggestive of coronary disease and who have normal or borderline enzymes and EKGs, when negative negative findings will result in avoiding invasive coronary angiography;
the exclusion of coronary artery disease following an equivocal or suspected inaccurate stress (or stress imaging) test in patients with low to intermediate risk factors when a negative MDCT will result in avoiding invasive coronary angiography;
the assessment of surgical eligibility, or for the preoperative planning, in patients wth clinical findings that are either known to be due to or strongly suggestive of a congenital anomaly of the coronary vessels or great vessels.

Advanced Medical Imaging is pleased to offer cardiac CT scans on our new Philips 64 slice scanner. This state-of-the-art technology is installed at our Silverdale location in the Harlow Medical Building at Harrison Silverdale. Our AMI radiologists and the cardiologists from Kitsap Cardiology Consultants and Doctors Clinic, who will be reading the exams, are very excited to offer this service. This exam gives you a quick, non-invasive alternative for definitively assessing cardiovascular disease.

This new technology’s leap in acquisition speed makes advanced applications such as cardiovascular imaging and whole body CT angiography routine. According to Dr. Michael Cook, Medical Director for Advanced Medical Imaging, “We can obtain whole heart examinations in just seconds. With the speed and specialized software of this new scanner, we can now overcome the challenges that prevented us from being able to offer such definitive and non-invasive cardiovascular exams in the past”.

Cardiac CT can evaluate:

the heart muscle
the coronary arteries
the pulmonary veins
the thoracic aorta
the sac around the heart (pericardium)

Clinical Indications for Cardiac CT

Exclusion of coronary artery disease in the low to intermediate risk patient. It is the best test that is now available with a negative predictive value approaching 100%. It can visualize early disease before it is detectable on cardiac catheterization. It may be used to clear patients for surgery instead of stress testing. Screening is controversial and not supported by peer reviewed literature.
Evaluation for cardiac/pericardial anatomic abnormalities including masses, thrombus, etc.
Triple rule out study for chest pain and can evaluate for other causes of chest pain including musculoskeletal pathology.
Evaluate status of bypass grafts and stents – are they open? CT may not be able to fully assess in-stent stenosis and grafts with metal clip artifacts.
Evaluate wall motion and valve function – this information comes with extra reconstructions and post processing.
Detect anomalies including myocardial bridging.

Applications for Cardiac CT

CT Coronary Angiography – The most exciting application is the visualization of the coronary arteries. Previously invasive cardiac catheterization was necessary to assess cardiovascular disease. Cardiac CT can determine the severity of blockages as well as directly visualize the atherosclerotic plaque deposited in the vessel wall. It can identify the early stages of soft plaque formation even before it can be visualized on x-ray angiography images. It also visualizes calcified plaque, which occurs in more chronic coronary artery disease.

Patients who have already undergone revascularization procedures including stenting and bypass can now be imaged non-invasively.

Due to the rapid improvements in spatial and temporal resolution of the latest generation of CT scanners, there is inadequate scientific review of the state of the art in what is possible in patient diagnosis using this technology. It will undoubtedly change the paradigm of cardiac imaging forever and cardiac catheterization will become a primary therapeutic procedure. With the use of CTA and MRA this has already occurred in other vascular imaging of the body including the carotid arteries, intra-cranial vessels, torso and extremities.

Current research includes continuing improvements in data acquisition and visualization as well as trying to predict coronary events through the analysis of the type and distribution of the plaque on the CTA examinations.

Visualization of cardiac and other structures – Because the CT data is volumetric, exquisite structural detail in multiple planes is now possible. Post processing and advanced visualization algorithms allow the extraction of specific structures such as bones, lung tissue and soft tissue structures, which allows the physician to better understand complex anatomy. This can be invaluable to surgeons in the preoperative planning and very useful in training.

Visualization of wall and valve motion – Because the CT data is acquired synchronized to the cardiac cycle and the data is volumetric, slices in any arbitrary plane in three-dimensional space can be created during multiple phases of the cardiac cycle. The cardiac function can be assessed non-invasively (like echocardiography and MRI) from the data already acquired for the coronary artery visualization. The only cost is additional computer reconstruction and processing time as well as interpreting physician time. Precise quantitative calculation of ejection fraction can be obtained from these data sets as well as qualitative evaluation of wall motion and valve function. Cross sectional evaluation of valves to measure stenosis is possible.

How the procedure is performed

The patient will be asked a series of questions at the time of scheduling the appointment such as symptoms, prior history, cardiac arrhythmias and more, so that the exam can be tailored to answer referring physician concerns. At the time of appointment, the medical history will be reviewed prior to inserting an intravenous line into the patient’s arm to administer contrast (dye) and/or medication to slow the patient’s heart rate, which improves the image quality. The patient will lie on the scanning table with arms raised over the head for image acquisition, which takes about 15 minutes. The patient will be monitored for a short time after the exam before being discharged.

Advantages of a Cardiac CT

low risk procedure
quick and non-invasive
detailed image information displayed in the most appropriate format, including 3D images of the moving heart and great vessels
thinner slices improves the accuracy of the data for greater diagnostic confidence, enhancing your ability to catch disease earlier
gives accurate information of the coronary arteries including narrowing, type and degree of plaque
CTA can exclude coronary artery disease
can simultaneously visualize the pulmonary and systemic arteries of the chest, thereby excluding other dangerous causes of chest pain including pulmonary embolism and aortic dissection.

Patient should be well hydrated with water. No caffeine before exam. Do not eat any solid foods 4 hours prior to your exam. No exercise before exam. Your doctor may prescribe a medication to slow your heart rate prioer to the exam. Heart rate for this exam should be less than 65 beats per minute.