Cardiac CT, Ultrasound, MRI and More: Which Tests Are Used When for CAD?Specialties Article 5 Minute Read GE Healthcare Global
Major advances in cardiac imaging technology have dramatically improved physicians’ ability to detect heart disease and improve patient care, especially with coronary artery disease (CAD), the most common type of heart disease in the United States, which is responsible for over 370,000 deaths a year.1,2
CAD occurs when fatty deposits called plaque build up in the blood vessels or arteries that supply blood in or to the heart.2 Over time, the plaque build-up narrows the arteries and blocks blood flow to the heart; that blockage can result in chest pain, which could increase the risk of heart attack and other serious heart-related complications.3 The symptoms of CAD typically include chest pain and trouble breathing, especially when you are active; although for some individuals, the first symptom of CAD may be a fatal heart attack.4 The risk factors for developing CAD include age over 60, smoking, high blood pressure, being overweight or obese, diabetes, high cholesterol, and a family history of heart disease.4 While chest pain is usually the first signpost that you may have heart disease, it’s estimated that almost half a million people die each year in the U.S. of an unexpected heart attack, emphasizing the importance of early and accurate diagnosis of CAD in order to reduce life-threatening events.5
Diagnosis and Assessment of Coronary Artery Disease
Because chest pain is such a common complaint, the guidelines of the American College of Cardiology and the American Heart Association (ACC/AHA) recommend that as a first step in evaluating chest pain and making a diagnosis of CAD, a baseline examination be performed.6 This examination includes a medical history, physical examination, and an electrocardiogram (ECG); a five to 10-minute test that measures the electrical activity of your heart by placing electrodes on the skin.6 This basic test can be performed in your primary care physician’s office or in an outpatient hospital setting. Because the exam and ECG, may not always provide enough information to rule out more serious forms of CAD, the guidelines suggest that patients with possibly more serious disease, as well as some low-risk patients, undergo an exercise ECG, such as a treadmill stress test.7 Exercise stress tests have the advantage of revealing problems in how well the heart is functioning that are not noticeable when you are at rest.4,7
While the exercise stress test is a useful diagnostic tool and relatively easy to perform, it’s not always as sensitive as other tests in detecting the degree of your CAD and heart attack risk.8 An echocardiogram, or ultrasound of the heart, uses high-frequency sound waves to provide more detailed moving pictures of the heart, including how well the blood is flowing through your arteries.9 Echocardiograms can also be performed while you exercise (stress echocardiogram) and offer the advantage of being a noninvasive test with no radiation exposure.10 Advances in ultrasound technology have included the development of portable ultrasound machines that can be used in hospital emergency departments, or at a patient’s bedside.
Increasingly, cardiac magnetic resonance (CMR) is considered the new “gold standard” in assessing warning signs of blockages by looking at both the structure and functioning of the heart.12 The extremely detailed images produced by the CMR are regarded as superior in quality to echocardiograms and can also be used as a “second opinion” in situations where the diagnosis of CAD is unclear.13 However, currently, CMR imaging is not available in many hospitals and specific skills are needed to perform and interpret the test results.12
Increasingly, coronary computed tomographic angiography (CCTA), or a CT scan of the heart, is being more widely used in patients who have a low to intermediate risk of having CAD. CCTA has the advantage of being a noninvasive test that produces highly detailed images of the structure of the heart, providing excellent accuracy in assessing patients who are not at high risk for serious CAD.13,14,15
If a patient’s testing or symptoms indicate intermediate or more serious risk factors for a heart attack, a test called an invasive coronary angiography (ICA) may be recommended.15,16,17 The ICA has traditionally been considered the “gold standard” for assessing the extent of the narrowing of the coronary arteries and blockages.17 As its name suggests, an ICA is an invasive procedure in which the patient lies down on an examination table while the technician inserts a small catheter through the skin into an artery in the groin or arm. A contrast solution is injected into each coronary artery and a special type of x-ray called a fluoroscopy is used to visualize the location and severity of the blockages.16 The results can help determine the degree of blockage within the arteries and the types of treatments the patient may need, which can range from medication therapy to coronary bypass surgery.
Other Options in Noninvasive Cardiac Testing
Patients who have established CAD, or have had heart attacks, may also undergo nuclear imaging testing that uses radioactive tracers to evaluate blood flow to the heart.13 Cardiac positron emission tomography (PET) is another imaging test that can be combined with other tests to detect CAD, although it’s used less frequently than nuclear imaging and stress echocardiography.12
As these advanced imaging technologies become more widespread, they offer physicians many more choices for diagnosing and assessing CAD—and vastly improved outcomes for patients who may be at risk for heart attack and other serious complications of CAD.
- The future of cardiovascular imaging. Circulation. https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.116.023511. Accessed May 11, 2018.
- Atherosclerosis and cholesterol. American Heart Association. http://www.heart.org/HEARTORG/Conditions/Cholesterol/AboutCholesterol/Atherosclerosis_UCM_305564_Article.jsp#.WvRUyKQvzIU. Accessed May 11, 2018.
- Heart Disease Facts. Centers for Disease Control. https://www.cdc.gov/heartdisease/facts.htm. Accessed April 17, 2018.
- Screening strategies for cardiovascular disease inasymptomatic adults. Primary Care. https://jamanetwork.com/journals/jama/fullarticle/1899206, Accessed April 17, 2018.
- State-Specific Mortality from Sudden Cardiac Death — United States. Centers for Disease Control. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5106a3.htm, Accessed April 18, 2018.
- Testing of low-risk patients presenting to the emergency department with chest pain: a scientific statement from the American Heart Association. https://www.ncbi.nlm.nih.gov/pubmed/20660809. Circulation. Accessed April 18, 2018.
- Diagnostic Imaging to Exclude Acute Coronary Syndrome. Current Emergency and Hospital Medicine Reports. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4958724/. Accessed May 11, 2018.
- Acute coronary syndrome: diagnostic evaluation. American Family Physician Journal. https://www.aafp.org/afp/2017/0201/p170.html. Accessed May 11, 2018.
- Should I have an exercise stress test? Journal of the American Medical Association: Cardiology. https://jamanetwork.com/journals/jamacardiology/fullarticle/2575503. Accessed May 13, 2018.
- Echocardiogram. American Heart Association. http://www.heart.org/HEARTORG/Conditions/HeartAttack/DiagnosingaHeartAttack/Echocardiogram—Echo_UCM_451485_Article.jsp#.WvYRFKQvzIU. Accessed May 13, 2018.
- The Use of Cardiac Magnetic Resonance in Patients with Suspected Coronary Artery Disease: A Clinical Practice Perspective. Journal of Cardiovascular Ultrasound. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4925404/. Accessed May 13, 2018.
- Coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR) imaging in the assessment of patients presenting with chest pain suspected for acute coronary syndrome. Annals of Translational Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4958724/. Accessed May 13, 2018.
- Efficacy of noninvasive cardiac imaging tests in diagnosis and management of stable coronary artery disease. Vascular Health and Risk Management. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5701553/. Accessed April,18, 2018.
- CT as gatekeeper of invasive coronary angiography in patients with suspected CAD. Cardiovascular Diagnostic Therapy. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5422839/. Accessed April 17, 2018.
- Non-invasive assessment of low- and intermediate-risk patients with chest pain. Trends in Cardiovascular Medicine. https://www.ncbi.nlm.nih.gov/pubmed/27717538. Accessed April 18, 2018.
- 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation. https://www.ncbi.nlm.nih.gov/pubmed/23166210. Accessed April 18, 2018.
- Stop invasive coronary angiography as the gold standard for the diagnosis of stable angine. Interventional Cardiology. http://www.openaccessjournals.com/articles/stop-invasive-coronary-angiography-as-the-gold-standard-for-the-diagnosis-of-stable-angina.html Accessed April 18, 2018.
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