Cardiac Magnetic Resonance for Early Detection of Radiation Therapy-Induced Cardiotoxicity in a Small Animal Model. JACC CardioOncol 2021 Mar;3(1):113-130
Date
04/30/2021Pubmed ID
33912843Pubmed Central ID
PMC8078846DOI
10.1016/j.jaccao.2020.12.006Scopus ID
2-s2.0-85102143842 (requires institutional sign-in at Scopus site) 12 CitationsAbstract
BACKGROUND: Over half of all cancer patients receive radiation therapy (RT). However, radiation exposure to the heart can cause cardiotoxicity. Nevertheless, there is a paucity of data on RT-induced cardiac damage, with limited understanding of safe regional RT doses, early detection, prevention and management. A common initial feature of cardiotoxicity is asymptomatic dysfunction, which if left untreated may progress to heart failure. The current paradigm for cardiotoxicity detection and management relies primarily upon assessment of ejection fraction (EF). However, cardiac injury can occur without a clear change in EF.
OBJECTIVES: To identify magnetic resonance imaging (MRI) markers of early RT-induced cardiac dysfunction.
METHODS: We investigated the effect of RT on global and regional cardiac function and myocardial T1/T2 values at two timepoints post-RT using cardiac MRI in a rat model of localized cardiac RT. Rats who received image-guided whole-heart radiation of 24Gy were compared to sham-treated rats.
RESULTS: The rats maintained normal global cardiac function post-RT. However, a deterioration in strain was particularly notable at 10-weeks post RT, and changes in circumferential strain were larger than changes in radial or longitudinal strain. Compared to sham, circumferential strain changes occurred at the basal, mid-ventricular and apical levels (p<0.05 for all at both 8-weeks and 10-weeks post-RT), most of the radial strain changes occurred at the mid-ventricular (p=0.044 at 8-weeks post-RT) and basal (p=0.018 at 10-weeks post-RT) levels, and most of the longitudinal strain changes occurred at the apical (p=0.002 at 8-weeks post-RT) and basal (p=0.035 at 10-weeks post-RT) levels. Regionally, lateral myocardial segments showed the greatest worsening in strain measurements, and histologic changes supported these findings. Despite worsened myocardial strain post-RT, myocardial tissue displacement measures were maintained, or even increased. T1/T2 measurements showed small non-significant changes post-RT compared to values in non-irradiated rats.
CONCLUSIONS: Our findings suggest MRI regional myocardial strain is a sensitive imaging biomarker for detecting RT-induced subclinical cardiac dysfunction prior to compromise of global cardiac function.
Author List
Ibrahim EH, Baruah D, Croisille P, Stojanovska J, Rubenstein JC, Frei A, Schlaak RA, Lin CY, Pipke JL, Lemke A, Xu Z, Klaas A, Brehler M, Flister MJ, Laviolette PS, Gore EM, Bergom CAuthors
Elizabeth M. Gore MD Professor in the Radiation Oncology department at Medical College of WisconsinPeter LaViolette PhD Professor in the Radiology department at Medical College of Wisconsin
Jason C. Rubenstein MD Associate Professor in the Medicine department at Medical College of Wisconsin
