Recent decades have seen major advances in cardiovascular diagnostic imaging. The quantitative and qualitative information gained from cardiovascular diagnostic imaging have been of inestimable value to cardiology, allowing better risk analysis and allowing physicians to better assess the effects of medical or surgical efforts on cardiac function. Though there are a number of cardiac diagnostic imaging solutions, catheter based angiography is still considered a primary diagnostic procedure.
Catheter Based Angiography: Still the Gold Standard
Catheter based angiography allows visualization of the arteries, veins and chambers of the heart. Traditionally it is done by injecting a radio-opaque contrast agent into blood vessels and using x-ray techniques for visualization. Different arteries or veins are injected to allow visualization of the left side of the heart and arterial system, or the right side of the heart and venous system. The x-rays taken may be still or moving images. Catheter-based angiography allows physicians to see blockages or narrowing of cardiac blood vessels that indicate risk of heart disease or that are already blocking blood flow and causing pain. It is a very sensitive type of imaging that also allows for simultaneous treatment when significant disease is found.
What Is Cardiac CTA?
A newer technique in cardiac diagnostic imaging is coronary computed tomography angiography, or CTA. It is noninvasive and produces high-resolution, three-dimensional images of the moving heart and major blood vessels. Cardiac CTA can determine whether fatty or calcium deposits have accumulated in the coronary arteries. Contrast dye is injected into the patient’s arm to improve image quality, and in some cases medication to slow or stabilize heart rate may be given to help improve image quality. Sometimes newer dual source CT equipment is used. This equipment provides necessary detail while reducing radiation exposure compared with traditional CT equipment.
When Is Cardiac CTA a Good Option?
CTA is much faster than cardiac catheterization angiography, and is a more comfortable procedure for the patient. Coronary CTA is proving useful at ruling out significant narrowing of major coronary arteries, and can also detect softer fatty matter in coronary artery walls that has not yet calcified, but that could lead to future problems. Coronary CTA is useful in determining whether chest pain is caused by a coronary blockage.
It is also indicated for patients without symptoms but who have a family history of coronary artery disease or risk factors, and for whom the more invasive catheterization angiography is not warranted. Other patients who may be good candidates for CTA include those with inconclusive stress tests or echocardiograms, those with atypical chest pain, or those with unexplained shortness of breath that may be caused by coronary artery disease. CTA is also valuable in asymptomatic patients who require cardiac anatomical evaluation before having other procedures like valve surgery or pulmonary vein ablation.
When Is Cardiac CTA Not Ideal?
Cardiac CTA is not always the best cardiac imaging procedure, however. For patients at high risk of coronary artery disease, catheter based angiography is preferable due to its greater sensitivity and allowance for simultaneous treatment. Other patients for whom cardiac CTA is not appropriate include:
• Emergency patients with undiagnosed acute chest pain
• Patients who cannot tolerate prolonged supine position
• Pregnant women
• Patients with severe claustrophobia
• Patients with severe contrast reactions
• Multiple myeloma patients
• Patients with hypotension
• Patients with severe obesity
• Patients with certain types of arrhythmia
The Future: PET Plus CTA
Studies are being done on the value of positron emission tomography (PET) scanning combined with CTA for detection of heart disease. PET scanning requires a small dose of radioactive material to be injected into the patient before the test, and like CTA involves the patient being placed in a donut-shaped scanning device for acquisition of images. The hope is that the addition of PET imaging will allow radiologists and cardiologists to examine biological functions including blood flow and glucose metabolism of the heart as well as the heart shape and volume as shown on CTA images. This type of combined imaging is still very new, and more research is needed to determine whether and when it is appropriate for cardiac diagnostic imaging.
The right type of cardiac diagnostic imaging depends on several factors, and the knowledge and skill of an experienced cardiac radiologist can be invaluable in determining which technique will produce the best results for the individual patient. SteleRAD has over 40 years of experience in radiology, including the specialty of cardiac diagnostic imaging. Drs. Richard Spira, David Ring, Charles C. Cole, and Carl Raboi are cardiology subspecialty radiologists with SteleRAD who can bring their expertise to your hospital, physician group, or imaging center. To learn more about how SteleRAD can benefit your practice, contact us online or call 954-358-5250.