Physicians can dramatically reduce
the radiation dose delivered to patients undergoing coronary CT angiography in a
“triple rule-out” protocol by simply using tube current modulation, according to
a study performed at Thomas
Jefferson University Hospital in Philadelphia, PA.
study included 172 patients who were evaluated using coronary CT angiography
without tube current modulation and 95 patients who were evaluated with tube
current modulation. The effective radiation dose ranged between 9.9 and 31.3 mSv
in patients without modulation; the dose ranged between 5.4 and 16.6 mSv in
patients with modulation. “Image quality was comparable to when we didn’t use
tube current modulation,” said Kevin M. Takakuwa, MD, lead author of the study.
the major criticisms of the triple rule out coronary CT angiography study is the
concern about the high amount of radiation given, which has been estimated by
some to be as high as 30-40 mSv. Our study demonstrates that the radiation is a
lot less, averaging less than 9 mSv when using tube current modulation. In
addition, it uses less radiation than a nuclear stress test, a common
alternative study to the triple rule-out cardiac CT,” he said.
“Cardiac CT in a “triple rule-out” protocol
allows us to look for coronary artery disease, aortic dissections and pulmonary
emboli. These are three potentially life-threatening causes of chest pain that
we cannot afford to miss in the emergency room. When we perform this test on
undifferentiated chest pain patients we are able to identify disease entities
that cannot be made with nuclear stress testing. For example, we have diagnosed
metastatic cancers, pulmonary embolism and pneumonia that would have been missed
by stress testing alone. Cardiac
CT is also much quicker than a stress test and can
save people from getting an invasive cardiac catheterization,” said Dr.
goal is to be able to perform cardiac CT using tube current modulation 24/7 and
as a means to be able to admit or discharge patients more rapidly,” he said.
— News release courtesy of The American
Roentgen Ray Society (ARRS)