Biological Effects of Cardiac Magnetic Resonance on Human Blood Cells

Abstract

The study was approved by the local Institutional Human Research Committee and conducted according to the ethical guidelines and principles of the international Helsinki declaration. After informed consent, 20 healthy male subjects ≥20 years (31.4±7.9 years) with normal physical cardiac examination (with no systolic nor diastolic murmur), normal ECG, without history of any cardiovascular disease or history of current smoking, no chronic excessive alcohol consumption, not currently on medical therapy with cardio-active drugs were prospectively recruited. Every volunteer was asked not to practice 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 (γ-H2AX). γ-H2AX intensity in T lymphocytes did not change early after CMR but increased significantly at day 2 ≤1 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. (Circ Cardiovasc Imaging. 2015;8:e003697.

Cardiac Magnetic Resonance Imaging

“…Another key finding in the study by Lancellotti et al, 26 which supports a causal relationship between DNA damage and CMR is the strong and impressive correlation between the augmentation of γ-H2AX levels at 1 month and the specific absorption rate values. This dose-response relation in the clinical setting was the final missing link closing the causal gap of knowledge about DSB induction and CMR scanning.…”

“…Estimations of the increased risk of cancer after low-dose radiation are based on extrapolations from population cohorts exposed to larger radiation doses, 16 such as atomic bomb survivors (who were also exposed to a nuclear electromagnetic pulse). Although the results by Lancellotti et al 26 may not answer all questions, they do increase the awareness of potential hazards of CMR. We need to be aware of the potential association of any type of radiation (ionizing or nonionizing) with cancer 32 because one cannot predict the risk in individual patients, and because clinically significant consequences may not become evident for many years.…”

“…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.…”

“…This dose-response relation in the clinical setting was the final missing link closing the causal gap of knowledge about DSB induction and CMR scanning. Despite the important information provided by the study of Lancellotti et al, 26 many questions remain unanswered. As the vast majority of CMR scans involve gadolinium-based contrast application more information on the interaction of gadolinium with CMR with regard to DNA damage and its time course would be of great clinical interest.…”

Diagnostic usefulness of myocardial perfusion imaging in patients reluctant to undergo angiography

“…63 In addition, while generally considered safe, there is some controversy that the magnetic and radiofrequency field generated during CMR may cause blood cell alterations and DNA damage in the short term; however, this finding has not been consistently replicated and its clinical relevance is unknown. 64,65 Unfortunately, certain patients are generally excluded from undergoing stress CMR. These may include patients with significant claustrophobia, patients unable to cooperate with breath holds, patients with advanced renal disease who are at risk for nephrogenic systemic fibrosis, and patients with some implanted metal devices (such as certain pacemakers or defibrillators;…”