MIBG cardiac imaging compared to ejection fraction in evaluation of cardiotoxicity: a systematic review

Background: Advances in diagnosis and treatment of cancer has improved survival but resulted in increased cardiotoxic effects. The decrease in left ventricular ejection fraction (EF), one of the pillars of diagnosis of cardiotoxicity, seems to be a late process in the evolution of the disease, so ^123I-metaiodobenzylguanidine (MIBG) cardiac imaging has been proposed to detect early cardiac impairment. The aim of this systematic review was to evaluate the performance of MIBG cardiac scan in this scenario.

Methods and results: A systematic search was conducted in five international databases comparing MIBG parameters with EF for evaluation of cardiotoxicity. Twelve studies were included and separated in three groups. First, studies evaluating patients with established cardiotoxicity, in which EF was reduced and MIBG parameters were abnormal. Second, studies analyzing patients during or after treatment compared to controls, with MIBG parameters significantly different between groups in most studies, even when EF remained normal. Finally, studies analyzing anthracycline (ATC) dose-related changes, with alteration in MIBG parameters occurring even when EF was preserved.

Conclusion: Although studies had high methodological variability, cardiac sympathetic innervation imaging seems to be a promising tool for assessing early cardiotoxicity. Further studies are needed to analyze its diagnostic value in this scenario.