The effect of 1.5T cardiac magnetic resonance on human circulating leukocytes

Aims: Investigators have proposed that cardiovascular magnetic resonance (CMR) should have restrictions similar to those of ionizing imaging techniques. We aimed to investigate the acute effect of 1.5T CMR on leukocyte DNA integrity, cell counts and function in vitro, and in a large cohort of patients in vivo.

Methods and Results: In vitro study: Peripheral blood mononuclear cells (PBMC) were isolated from healthy volunteers and histone H2AX phosphorylation (γ-H2AX) expression, leukocyte counts and functional parameters were quantified using flow cytometry under the following conditions: 1) immediately following PBMC isolation, 2) after standing on the benchside as a temperature and time control, 3) after a standard CMR scan. In vivo study: Blood samples were taken from 64 consecutive consenting patients immediately before and after a standard clinical scan. Samples were analysed for γ-H2AX expression and leukocyte counts.

CMR was not associated with a significant change in γ-H2AX expression in vitro or in vivo, although there were significant inter-patient variations. In vitro cell integrity and function did not change with CMR. There was a significant reduction in circulating T cells in vivo following CMR.

Conclusion: 1.5T CMR was not associated with DNA damage in vitro or in vivo. γ-H2AX expression varied markedly between individuals, therefore small studies using γ-H2AX as a marker of DNA damage should be interpreted with caution. CMR was not associated with loss of leukocyte viability or function in vitro. CMR was associated with a statistically significant reduction in viable leukocytes in vivo.