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."