Impact of an abdominal belt on breathing patterns and scan efficiency in whole-heart coronary magnetic resonance angiography: comparison between the UK and Japan

Background: Long acquisition times and complex breathing motion patterns lead to suboptimal image quality in whole heart coronary magnetic resonance angiography (WHCMRA). To overcome this problem, an abdominal belt (BELT) has been suggested by a Japanese group. However, its applicability in a Western population has not been previously demonstrated. The purpose of this study was to investigate 1) how the application of a BELT alters breathing patterns during MR scanning and 2) whether the BELT has a similar impact on breathing patterns in UK and Japanese patient populations. Methods: 30 patients (15 in the UK and 15 in Japan) were studied at 1.5 Tesla (Achieva, Philips Healthcare). Real time navigator positioned through the right diaphragm in cranio-caudal direction was evaluated. Measurements were performed in the supine position with free breathing for one minute before and after a tight-fitting BELT was positioned around the patient's abdomen. End expiratory position (EEP), end inspiratory position (EIP), end expiratory duration (EED) for the right diaphragm and respiratory rate (RR) were obtained. Scan efficiency (SE) was calculated as follows; SE = [the duration within 5 mm gating window per minutes]/[RR interval]/[heart rate]. Results: Height and weight of UK patients were significantly larger than in the Japanese population (171.2 +/- 10.8 cm vs 160.8 +/- 8.5 cm, p = 0.007; 80.5 +/- 22.5 kg vs 59.9 +/- 7.7 kg, p = 0.004). After fitting the BELT, EEP-EIP decreased (all patients, 14.9 +/- 6.2 mm to 9.4 +/- 3.8 mm, p <0.001; UK patients, 15.9 +/- 6.0 mm to 9.7 +/- 3.1 mm, p = 0.001; Japanese patients, 14.0 +/- 6.4 mm to 9.1 +/- 4.6 mm, p = 0.001), RR increased (all patients, 10.0 +/- 3.1 min(-1) to 11.2 +/- 3.0 min(-1), p = 0.003; UK patients, 9.5 +/- 2.8 min(-1) to 10.7 +/- 2.8 min(-1), p = 0.038; Japanese patients, 10.4 +/- 3.5 min(-1) to 11.8 +/- 3.1 min(-1), p = 0.036), and calculated scan efficiency increased (all patients, 45.3 +/- 11.4% to 58.6 +/- 17.0%, p <0.001; UK patients, 44.2 +/- 10.8% to 55.7 +/- 16.7%, p = 0.004; Japanese patients, 46.3 +/- 32.2% to 61.0 +/- 17.6%, p = 0.001). No significant differences were found between UK and Japanese patients before and after administration of the BELT. Conclusion: Using a BELT significantly increases whole-heart coronary MR angiography scan efficiency in both UK and Japanese patients.