Increased radiation doses to the heart base and apex were associated with moderate-to-large and mild deteriorations in myocardial strain at 6 months, with left coronary regions more affected.
Observational (n=12)
No
Does regional cardiac radiation dose affect magnetic resonance imaging myocardial contractility parameters in thoracic cancer patients?
Regional cardiac radiation dose is associated with heterogeneous changes in myocardial strain on MRI, with the left coronary artery territory showing greater vulnerability to radiation-induced cardiotoxicity.
Background/Objectives: Magnetic resonance imaging (MRI) provides a non-invasive means for a comprehensive assessment of the effect of radiation therapy (RT) on heart function. This study aims to determine RT induced cardiotoxicity in thoracic cancer patients using cardiac MRI. Methods: Cardiac MRI was performed at baseline and at six months post-treatment in patients undergoing standard-of-care RT for lung or esophageal cancers at a single institution. Parameters included regional myocardial strain in the longitudinal, circumferential, and radial directions as well as myocardium T1, T2, and extracellular-volume (ECV) maps. Cardiac segmental doses were extracted from the RT planning scans. The relationship between changes in segmental MRI parameters at six months and segmental heart RT dose were investigated. Results: Twelve patients underwent baseline MRI and four completed the follow-up MRI. Five of the segmental strain parameters showed notable changes between baseline and six-month follow-up. Increased doses in the heart base and apex were associated with moderate-to-large and mild deteriorations, respectively, in strain for all regions. Increased doses in the mid-ventricular regions were associated with improved strain in all regions. The segmental analysis revealed that myocardial regions nurtured by the left coronary artery are more negatively affected by radiation compared to those nurtured by the right coronary artery. Conclusions: Alterations in regional tissue and strain parameters on MRI vary according to local myocardial RT dose, suggesting there may be heterogeneity of radiation sensitivity for the heart substructures and regions. Changes in segmental strain parameters may reflect post-RT cardiac remodeling, but larger confirmatory studies are required.
Ibrahim et al. (Tue,) conducted a observational in Lung or esophageal cancer (n=12). Standard-of-care radiation therapy was evaluated on Changes in segmental MRI parameters (myocardial strain, T1, T2, and ECV maps) at six months. Increased radiation doses to the heart base and apex were associated with moderate-to-large and mild deteriorations in myocardial strain at 6 months, with left coronary regions more affected.
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