Myocardial perfusion damage after mediastinal irradiation for Hodgkin's disease: a thallium-201 single photon emission tomography study

Conflicting data have been reported on the incidence of myocardial abnormalities after mediastinal irradiation for Hodgkin's disease. We studied myocardial perfusion in 31 clinically asymptomatic patients (13 male, 18 female, mean age 35 years) 7 years (range 3–11 years) after mantle field radiotherapy. Thallium-201 tomoscintigraphic data were obtained after exercise, 4 h later and at rest (8–15 days later). Images were analysed visually and quantitatively (sectorial quantification of ²⁰¹T1 uptake on the bull's eye images of the short-axis slices) compared with those of 35 subjects with a low likelihood of coronary artery disease. Twenty-five tomographic data sets were available. Images were visually abnormal in 21 patients (84%) showing an heterogeneous ²⁰¹Tl uptake. In 68%, the sectorial ²⁰¹Tl uptake was lower than the mean ²⁰¹Tl uptake value minus 2 standard deviations measured in subjects with a low likelihood of coronary artery disease. Significant redistribution (quantitatively assessed 10%) was present in 10 patients (40%). In most of the patients, the location and the shape of the defect(s) could not be anatomically related to an epicardial coronary vessel disease. These results indicate that after mediastinal irradiation the ²⁰¹Tl myocardial uptake is frequently abnormal. The observed patterns suggest a disease of the small coronary vessels and/or the existence of a myocardial fibrosis rather than epicardial coronary artery disease.