AUTHORS' ABSTRACT: Lancellotti et al. 2015 (IEEE #6158): BACKGROUND: Cardiac magnetic resonance (CMR) is increasingly used for the diagnosis and management of cardiac diseases. Recent studies have reported immediate post-CMR DNA double-strand breaks in T lymphocytes. We sought to evaluate CMR-induced DNA damage in lymphocytes, alterations of blood cells, and their temporal persistence.
METHODS AND RESULTS: In 20 prospectively enrolled healthy men (31.4±7.9 years), blood was drawn before and after (1-2 hours, 2 days, 1 month, and 1 year) unenhanced 1.5T CMR. Blood cell counts, cell death, and activation status of lymphocytes, monocytes, neutrophils, and platelets were evaluated. The first 2-hour post-CMR were characterized by a small increase of lymphocyte B and neutrophil counts and a transient drop of total lymphocytes because of a decrease in natural killer cells. Among blood cells, only neutrophils and monocytes displayed slight and transient activation. DNA double-strand breaks in lymphocytes were quantified through flow cytometric analysis of H2AX phosphorylation (³-H2AX). ³-H2AX intensity in T lymphocytes did not change early after CMR but increased significantly at day 2 d1 month before returning to baseline levels of 1-year post-CMR.
CONCLUSIONS: Unenhanced CMR is associated with minor but significant immediate blood cell alterations or activations figuring inflammatory response, as well as DNA damage in T lymphocytes observed from day 2 until the first month but disappearing at 1-year follow-up. Although further studies are required to definitely state whether CMR can be used safely, our findings already call for caution when it comes to repeat this examination within a month.
FROM AUTHOR'S EDITORIAL: Kaufmann 2015 (IEEE #6487): It is in this context that Lancellotti et al,26 in this issue of Circulation:
Cardiovascular Imaging, have studied an important aspect of the impact of CMR scanning on peripheral lymphocyte DNA integrity, namely the time course over 1 year. Their results are remarkable for several reasons. First, they studied CMR alone with no gadolinium-based contrast medium to avoid confounding effects from the genotoxic contrast medium. As the latter, however, is widely used off-label in the vast majority of clinical CMR scans,27 the findings may be even more relevant in the clinical setting. Second, they did not find any
DNA damage early after CMR but observed an increase in DSB from day 2 until the first month, which disappeared after 1 year. Third, they found that CMR was also associated with a minor but significant immediate blood cell alteration reflecting inflammatory response. This adds a new aspect to the knowledge of biological reactions to CMR exposure.