High Radiation Equivalent To Repeated Cardiac Imaging, Study.

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Cardiac imaging newsAccording to a retrospective, single-center study,about 40% of patients who wre subjected to myocardial perfusion imaging had repeated exams and were exposed to high doses of radiation.

Andrew Einstein, MD, PhD, of Columbia University Medical Center in New York City, at the American Heart Association annual meeting mentioned that the median estimated cumulative effective radiation dose that received over 1,000 consecutive patients in the study was 121 mSv.

Simultaneously, a paper published in the Journal of the American Medical Association by the fresearchers who reported that the level of radiation exposure has been associated with raised in cancer risks. But, Einstein and colleagues explained that the cancer risks that attributed with medical imaging, despite of concerning, cannot be considered in a vacuum .

They reported that the population of patients subjecting to myocardial perfusion imaging exams were older and had a much higher prevalence of known cardiac disease or related symptoms than showed among the Japanese cohort or the general U.S. population -- which shifts the risk-benefit ratio toward a benefit.

The researchers noted "In particular, myocardial perfusion imaging plays a critical role in risk stratification of patients with established coronary artery disease".They also said that efforts to decrease radiation exposure should be targeted toward patients subjecting to repeat myocardial perfusion imaging exams and another highly exposed populations. An attention must be given to radiation exposure from CT scans, In fact myocardial perfusion imaging is the medical exam that associates the highest radiation burden to the United States individuals accounting for 22% of cumulative effective doses from medical sources.

Conseqently, Einstein and colleagues viewed at the cumulative radiation exposure from all medical exams among 1,097 patients (mean age 62.2) who also subjected to myocardial perfusion imaging examing at Columbia University Medical Center-New York Presbyterian Hospital, over the former 100 days of 2006.

The researching team analyzed all previous medical imaging procedures using electronic health records going back to 1988, besides all subsequent procedures through June 2008. The median number of procedures including radiation exposure per patients was fifteen, 4 of which were high-dose procedures with exposures of at least 3 mSv -- equal to a year's worth of natural background radiation.The median number of myocardial perfusion imaging exams per patients was 1. However, approximately one-fifth of patients (18.2%) had at least 3 of the examss and 4.9% had at least 5.

The important reason for a myocardial perfusion screening study was chest pain, dyspnea, or both in about 2/3 of cases. Einstein and his colleagues mentioned that "The clear majority of myocardial perfusion imaging examinations were performed for reasons presently regarded as appropriate and with the potential to affect therapeutic management,".

The researchings offer information that may be useful to clinicians when considering whether to order a myocardial perfusion screening exam. The researchers noted "While current appropriate use criteria provide detailed guidance for myocardial perfusion imaging utilization in terms of an individual test, they do not yet simultaneously consider the appropriateness of other modalities that involve no ionizing radiation exposure, and only superficially address longitudinal management strategies, which have clear implications for both radiation dose and healthcare costs."