Rethinking Healthcare

Non-invasive, low-radiation CT scans as good as gold standard

Posting in Cancer

Low dose radiation CT scans rule out heart problems as well as higher radiation standard tests.

People about to be scanned for suspected heart disease may want to consider a non-invasive, low dose radiation alternative.

Low-radiation computed tomography (CT) scans are just as good at ruling out heart problems as the current gold standard, catheter coronary angiography.

This standard test requires an x-ray while injecting fluid into the heart though a catheter, which has to be threaded into the heart though a blood vessel. This has sometimes caused bleeding and even death; so to get around those risks, some patients have opted for a CT scan instead.

But CT scans expose people to more x-rays than the catheter method, increasing the cancer risk: around one cancer per 1,000 scans. (More than 2 million CT heart scans are done a year in the US.)

In this new review of 16 studies comparing CT scans with the catheter procedure, researchers looked at the performance of low-radiation CT scans – called prospectively gated CT.

These scans cut the radiation dosage to less than 3 millisieverts – that’s about the same as yearly background radiation from natural sources. The standard CT scan gives out 12 millisieverts, and the catheter test gives out 7-9 millisieverts.

And as the review reveals, the low-radiation CT scans rule out heart problems just as effectively.

"They have a lot to offer because they are less invasive and expose patients to less radiation," says study researcher Moritz Wyler von Ballmoos of the Children's Hospital Boston. "I think it is a very reasonable option for patients."

The researchers aren't arguing for using those heart scans in patients without symptoms though. It's not a test for the general population who don't have chest pains, von Ballmoos says. "It is a diagnostic test, not a screening test."

From “Study suggests alternative to invasive heart test” [Reuters]. The study was published in the Annals of Internal Medicine yesterday.

Image: KidsHealth

Share this

Janet Fang

Contributing Editor

Janet Fang has written for Nature, Discover and the Point Reyes Light. She is currently a lab technician at Lamont-Doherty Earth Observatory. She holds degrees from the University of California, Berkeley and Columbia University. She is based in New York. Follow her on Twitter. Disclosure