Anthracycline chemotherapies (e.g. doxorubicin, daunorubicin) are commonly given to treat pediatric cancer, and carry a risk of cardiotoxicity. Over the long term, children who receive these therapies have an increased risk of heart failure and early cardiovascular death. However, current strategies for identifying patients who are at risk prior to the development of significant changes in heart function are limited. This study will focus on imaging markers of cardiac injury and dysfunction with the goal of developing improved diagnostic tests and treatment strategies.