Detection of late radiation damage on left atrial fibrosis using cardiac late gadolinium enhancement magnetic resonance imaging

Abstract Purpose This is a proof-of-principle study investigating the feasibility of using late gadolinium enhancement magnetic resonance imaging (LGE-MRI) to detect left atrium (LA) radiation damage. Methods and materials LGE-MRI data were acquired for 7 patients with previous external beam radiation therapy (EBRT) histories. The enhancement in LA scar was delineated and fused to the computed tomography images used in dose calculation for radiation therapy. Dosimetric and normal tissue complication probability analyses were performed to investigate the relationship between LA scar enhancement and radiation doses. Results The average LA scar volume for the subjects was 2.5 cm3 (range, 1.2-4.1 cm3 ; median, 2.6 cm3 ). The overall average of the mean dose to the LA scar was 25.9 Gy (range, 5.8-49.2 Gy). Linear relationships were found between the amount of radiation dose (mean dose) (R2 = 0.8514, P = .03) to the LA scar-enhanced volume. The ratio of the cardiac tissue change (LA scar/LA wall) also demonstrated a linear relationship with the level of radiation received by the cardiac tissue (R2 = 0.9787, P