Patients who had a CT scan to check for build-up in the arteries around the heart had more surgeries, and more costly medical care, than those who had their hearts checked with basic stress tests, in a new study. While researchers couldn't tell if those extra costly procedures were really called for, they said the findings suggest that doctors may detect small changes in the arteries on CT scans that lead them to do more invasive, potentially unnecessary, surgeries. So-called CT angiography was developed as an alternative to coronary angiography, which requires doctors to thread a catheter through the blood vessels to check for blockages in patients with signs of heart disease.