News | May 17, 2010

CT Benefits Outweigh Radiation Risks

May 17, 2010 – When patients present with chest pain or other high-risk symptoms of heart problems, doctors increasingly rely on nuclear imaging and computed tomography (CT) to find evidence of heart disease. Results of these procedures can help guide life-saving prevention and treatment options.

However, despite their widespread use and efforts by the cardiac imaging community to reduce exposure to ionizing radiation, concerns over the potential cancer-causing effects of these diagnostic tests continue to dominate discussions. This may lead to imbalanced decision-making and heighten consumers’ fear of these tests, according to experts writing in the May 2010 issue of the Journal of the American College of Cardiology (JACC): Cardiovascular Imaging. This special issue explores the challenges of cardiac imaging, including how to effectively measure the radiation doses of different tests, as well as the lack of standard guidelines to evaluate risks and benefits of using such imaging tests.

“These tests are so widely applied now, the concern is that there is some potential of increased cancer risk associated with their use,” said Jagat Narula, M.D., Ph.D., division of cardiology, University of California, Irvine, and editor-in-chief of JACC: Cardiovascular Imaging. “The problem is that most estimates of radiation exposure stem from an extrapolation of studies on World War II Hiroshima survivors, and the radiation exposure from imaging tests may not necessarily be the same.”

As with anything in medicine, a careful analysis of the risks and benefits of cardiac imaging is warranted, and experts agree these tests should only be used when the clinical benefit is expected to exceed the potential harm.

“Because most patients undergoing cardiac imaging are symptomatic, the risk of heart disease is high, so the radiation risk is far less than the benefits gained,” said Leslee Shaw, Ph.D., professor of medicine, Emory University School of Medicine, Atlanta, Ga., and an author of the editorial. “If we can identify appropriate patients for testing, then we can provide more intensive treatment and the patient will likely have better outcomes. And, importantly, the radiation exposure is far less than the benefit gained from targeting treatment for heart disease.”

Of course, there are also some cases in which use of these tests may not afford the greatest benefit, according to authors. For example, the risk of exposing a 38-year-old woman of childbearing age who reports one episode of stabbing chest pain to radiation might be far greater than any benefit because her risk of coronary artery disease is so low. Other procedures, such as a routine treadmill test or electrocardiogram could be used to help rule out heart problems. In other cases, cardiac imaging can help rule out heart problems and redirect clinical care as needed.

“There has also been a tendency to play up the fears of radiation and we don’t want patients to be afraid of these tests,” Shaw explains, adding there have been some instances in which very sick patients refuse imaging procedures when the test would have been valuable in terms of their medical management and follow up. “We should encourage patients and doctors to talk about whether a test is needed, why it is being ordered and what it will show. Dialogue about the benefits of testing and the risks of radiation exposure is an essential part of the patient and physician decision making.”

Clinicians should educate patients about these tests and encourage them to be informed participants in decision making by asking themselves: “Am I going to gain more information by having this test, and am I willing to accept a small dose [of radiation] to find out?”

What is needed moving forward?
Recent advances in limiting radiation dose levels through quality imaging, technological advances and guidelines, such as the American College of Cardiology’s Appropriate Use Criteria, as well as keeping doses as low as reasonably appropriate (referred to as ALARA), are making a difference.

Authors stress there is a need for standardized measures for radiation exposure, long-term follow up of patients to better understand the safety profile in term of estimating cancer risk and cardiac benefits, especially among those with an elevated cancer risk, more comparative effectiveness studies that include radiation exposure as a primary safety endpoint, promotion of low-dose imaging protocols which can reduce radiation dose by more than half, new imaging techniques and equipment that reduce radiation exposure, and improved patient education programs about the risks and benefits of cardiac imaging.

For more information: www.acc.org

Related Content

The Philips Lumify point-of-care ultrasound (POCUS) system assessing a patient in the emergency room combined with telehealth to enable real-time collaboration with other physicians.

The Philips Lumify point-of-care ultrasound (POCUS) system assessing a patient in the emergency room combined with telehealth to enable real-time collaboration with other physicians.

News | Coronavirus (COVID-19) | May 26, 2020
May 26, 2020  — Philips Healthcare recently received 510(k) clearance from the U.S.
An example of DiA'a automated ejection fraction AI software on the GE vScan POCUS system at RSNA 2019.

An example of DiA'a automated ejection fraction AI software on the GE vScan POCUS system at RSNA 2019. Photo by Dave Fornell.

News | Ultrasound Imaging | May 26, 2020
May 12, 2020 — DiA Imaging Analysis, a provider of AI based ultrasound analysis solutions, said it received a governm
Examples of chest CT images of COVID-19 (+) patients and visualization of features correlated to COVID-19 positivity. For each pair of images, the left image is a CT image showing the segmented lung used as input for the CNN (convolutional neural network algorithm) model trained on CT images only, and the right image shows the heatmap of pixels that the CNN model classified as having SARS-CoV-2 infection (red indicates higher probability). (a) A 51-year-old female with fever and history of exposure to SARS-

Figure 1: Examples of chest CT images of COVID-19 (+) patients and visualization of features correlated to COVID-19 positivity. For each pair of images, the left image is a CT image showing the segmented lung used as input for the CNN (convolutional neural network algorithm) model trained on CT images only, and the right image shows the heatmap of pixels that the CNN model classified as having SARS-CoV-2 infection (red indicates higher probability). (a) A 51-year-old female with fever and history of exposure to SARS-CoV-2. The CNN model identified abnormal features in the right lower lobe (white color), whereas the two radiologists labeled this CT as negative. (b) A 52-year-old female who had a history of exposure to SARS-CoV-2 and presented with fever and productive cough. Bilateral peripheral ground-glass opacities (arrows) were labeled by the radiologists, and the CNN model predicted positivity based on features in matching areas. (c) A 72-year-old female with exposure history to the animal market in Wuhan presented with fever and productive cough. The segmented CT image shows ground-glass opacity in the anterior aspect of the right lung (arrow), whereas the CNN model labeled this CT as negative. (d) A 59-year-old female with cough and exposure history. The segmented CT image shows no evidence of pneumonia, and the CNN model also labeled this CT as negative.  

News | Coronavirus (COVID-19) | May 19, 2020
May 19, 2020 — Mount Sinai researchers are the first in the country to use...
Advanced imaging data exchange is now live in Colorado due to the partnership of Health Images and the Colorado Regional Health Information Organization

Getty Images

News | Radiology Business | May 18, 2020
May 18, 2020 — 
Radiologists from Shanghai discuss modifying exam process and disinfecting exam room, while outlining personal protection measures during the coronavirus disease outbreak

(HIS = hospital information system, RIS = radiology information system) Image courtesy of American Journal of Roentgenology (AJR)

News | Coronavirus (COVID-19) | May 18, 2020
May 18, 2020 — In an open-access article published ahead-of-print
Now a research team — led by Tohoku University Professor, Wataru Yashiro — has developed a new method using intense synchrotron radiation that produces higher quality images within milliseconds.

How the bent crystal changes the direction of the X-rays. Image courtesy of Tohoku University

News | Computed Tomography (CT) | May 15, 2020
May 15, 2020 — Many will undergo a computed tomogr...
In today’s challenging healthcare environment, radiology departments are often faced with the difficult decision of how to safely image patients who are suspected of being positive with infectious disease. To help hospitals and institutions effectively utilize computed tomography (CT) with these conditions, Canon Medical Systems USA, Inc. introduces a deployable CT with a rapid decontamination solution.
News | Computed Tomography (CT) | May 11, 2020
May 11, 2020 — In today’s challenging healthcare environment, radiology departments are often faced with the difficul
Axial (A) and coronal (B) CT of the abdomen and pelvis with IV contrast in a 57-year-old man with a high clinical suspicion for bowel ischemia. There was generalized small bowel distension and segmental thickening (arrows), with adjacent mesenteric congestion (thin arrow in B), and a small volume of ascites (* in B). Findings are nonspecific but suggestive of early ischemia or infection.

Axial (A) and coronal (B) CT of the abdomen and pelvis with IV contrast in a 57-year-old man with a high clinical suspicion for bowel ischemia. There was generalized small bowel distension and segmental thickening (arrows), with adjacent mesenteric congestion (thin arrow in B), and a small volume of ascites (* in B). Findings are nonspecific but suggestive of early ischemia or infection. Image courtesy of RSNA

News | Coronavirus (COVID-19) | May 11, 2020
May 11, 2020 — Patients with COVID-19 can have b