MRI findings of radiation-induced myocardial damage in patients with oesophageal cancer

Aim To evaluate radiation-induced myocardial damage after mediastinal radiotherapy using MRI. Materials and methods Between May 2010 and April 2011, delayed contrast-enhanced MRI was performed for patients who had maintained a complete response to curative radiotherapy for oesophageal cancer for more than 6 months. The patients received radiotherapy with a median total dose of 66 Gy (60–70 Gy) for the primary tumour and metastatic lymph nodes. Images of MRI were analysed by a 17-segment method recommended by the American Heart Association. A segment included mainly in the 40 Gy dose line was defined as Segment 40 Gy, a segment included mainly in the 60 Gy dose line as Segment 60 Gy, and a segment out of the radiation fields as Segment OUT. The percentage of late gadolinium enhancement (LGE) was examined in those categories. The layer in which LGE was predominantly distributed was evaluated for each patient. Results Four hundred and eight segments in 24 patients were analysed. The median interval from completion of radiotherapy to MRI was 23.5 months (range 6–88 months). LGE was detected in 12 of the 24 patients. LGE was detected in 15.38% of Segment 40 Gy cases, 21.21% of Segment 60 Gy cases, and 0% of Segment OUT cases. LGE in mid-myocardial and subendocardial layers was detected in 11 patients and one patient, respectively. Conclusion LGE suggesting radiation induced myocardial fibrosis was observed by performing delayed contrast-enhanced MRI. Care should be taken when planning radiotherapy to avoid late cardiac damage.