From April to May 2010, DSCT.com – the expert
community for dual-source CT in radiology and cardiology – asked the
website’s visitors at what dose level they would consider a CTA to be a viable
option for early detection of coronary artery disease. 363 participants took a
vote showing a clear result: 42 % gave a figure of less than 1 mSV (see fig.
1).
DSCT experts’ voices
DSCT.com also asked Prof. Joseph Schoepf (University of South Carolina, USA) and Prof. Stephan Achenbach (University of Erlangen, Germany) to comment on these results. Here are their opinions:
Prof. U. Joseph Schoepf:
One of the prerequisites of a successful screening test is low invasiveness, since, by definition, screening is directed at asymptomatic, a priori healthy individuals. Accordingly, the relatively high radiation dose which was associated with coronary CT angiography in the past naturally precluded the application of this test for early disease detection in asymptomatic individuals.
Now we have CT systems that enable accurate, non-invasive interrogation of the coronary arteries with minimal radiation, so that for the first time the use of coronary CT angiography for primary disease prevention has moved into the realm of the conceivable. Having successfully cleared the radiation hurdle, work needs to be done now to investigate whether low-radiation-dose coronary CT angiography also lives up to the remainder of the requirements that define a successful screening test. Large-scale population-based studies will be needed to create the evidence to support this use.
I am personally confident that this test will have a role in primary disease prevention in high-risk, yet asymptomatic individuals. Accordingly, since the advent of second-generation dual-source CT at our institution, we have added low-radiation dose coronary CT angiography to the tests we offer within the framework of our preventive cardiology programs.
Prof. Stephan Achenbach:
The majority of participants has indicated that a coronary CT scan performed for early detection of disease should be of a very low dose, preferrably less than one mSv. It is certainly important to keep the dose low, but we must bear in mind that a low dose – as important as it may be – is unfortunately not the only requirement. Scans also need to be of extremely high quality in order to avoid false positive findings and to miss any positive findings. So we are looking for a combination of very low doses and highest image quality.
It seems that high-pitch spiral acquisition puts the technical possibilities to achieve that in reach, at least with certain patients. It may offer a technical basis for early detection, but the clinical data to back such applications need to be generated as soon as possible.
About DSCT.com, the dual-source CT community
DSCT.com is a non-commercial platform launched in 2007 for the exchange of scientific knowledge regarding the medical value of the latest innovations in computed tomography: dual-source CT. The website represents an international community of medical experts, especially radiologists and cardiologists dedicated to research on DSCT, and provides a global discussion forum for medical experts to talk about its potential use in patient care. The website is run and operated by Spirit Link Medical, based in Erlangen, Germany, with Siemens AG as a partner.
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