PET/MRI Assessment of Acute Cardiac Inflammation 1 Month After Left-Sided Breast Cancer Radiation Therapy

Abstract

Our purpose was to investigate the utility of 18 F-FDG PET/MRI and serial blood work to detect early inflammatory responses and cardiac functionality changes at 1 mo after radiation therapy (RT) in patients with left-sided breast cancer. Methods: Fifteen left-sided breast cancer patients who enrolled in the RICT-BREAST study underwent cardiac PET/MRI at baseline and 1 mo after standard RT. Eleven patients received deep-inspiration breath-hold RT, whereas the others received free-breathing RT. A list-mode 18 F-FDG PET scan with glucose suppression was acquired. Myocardial inflammation was quantified by the change in 18 F-FDG SUV mean (based on body weight) and analyzed on the basis of the myocardial tissue associated with the left anterior descending, left circumflex, or right coronary artery territories. MRI assessments, including left ventricular functional and extracellular volumes (ECVs), were extracted from T1 (before and during a constant infusion of gadolinium) and cine images, respectively, acquired simultaneously during the PET acquisition. Cardiac injury and inflammation biomarker measurements of high-sensitivity troponin T, high-sensitivity C-reactive protein, and erythrocyte sedimentation rate were measured at the 1-mo follow-up and compared with preirradiation values. Results: At the 1-mo follow-up, a significant increase (10%) in myocardial SUV mean in left anterior descending segments (P 5 0.04) and ECVs in slices at the apex (6%) and base (5%) was detected (P # 0.02). Further, a significant reduction in left ventricular stroke volume (27%) was seen (P , 0.02). No significant changes in any circulating biomarkers were seen at follow-up. Conclusion: Myocardial 18 F-FDG uptake and functional MRI, including stroke volume and ECVs, were sensitive to changes at 1 mo after breast cancer RT, with findings suggesting an acute cardiac inflammatory response to RT.

Advances in Screening for Radiation-Associated Cardiotoxicity in Cancer Patients

“…Increased ECV in the apical and basal segments (6% and 5%, respectively) was also noted on cMRI at 1 month post-left-sided RT in 15 patients with breast cancer ( p < 0.02). This same study also noted a 7% reduction in LV stroke volume ( p < 0.02) [ 39 ]. Another small study similarly noted higher T1 values after RT at 6-year follow-up in patients who received higher MHD for breast cancer [ 40 ].…”