Jekic Mihaela, Foster Eric L, Ballinger Michelle R, Raman Subha V, Simonetti Orlando P
Dorothy M, Davis Heart and Lung Research Institute, 473 W 12th Ave, Columbus, OH43210, USA.
J Cardiovasc Magn Reson. 2008 Jan 15;10(1):3. doi: 10.1186/1532-429X-10-3.
Treadmill exercise stress testing is an essential tool in the prevention, detection, and treatment of a broad spectrum of cardiovascular disease. After maximal exercise, cardiac images at peak stress are typically acquired using nuclear scintigraphy or echocardiography, both of which have inherent limitations. Although CMR offers superior image quality, the lack of MRI-compatible exercise and monitoring equipment has prevented the realization of treadmill exercise CMR. It is critical to commence imaging as quickly as possible after exercise to capture exercise-induced cardiac wall motion abnormalities. We modified a commercial treadmill such that it could be safely positioned inside the MRI room to minimize the distance between the treadmill and the scan table. We optimized the treadmill exercise CMR protocol in 20 healthy volunteers and successfully imaged cardiac function and myocardial perfusion at peak stress, followed by viability imaging at rest. Imaging commenced an average of 30 seconds after maximal exercise. Real-time cine of seven slices with no breath-hold and no ECG-gating was completed within 45 seconds of exercise, immediately followed by stress perfusion imaging of three short-axis slices which showed an average time to peak enhancement within 57 seconds of exercise. We observed a 3.1-fold increase in cardiac output and a myocardial perfusion reserve index of 1.9, which agree with reported values for healthy subjects at peak stress. This study successfully demonstrates in-room treadmill exercise CMR in healthy volunteers, but confirmation of feasibility in patients with heart disease is still needed.
跑步机运动负荷试验是预防、检测和治疗多种心血管疾病的重要工具。在最大运动后，通常使用核闪烁扫描或超声心动图获取峰值负荷时的心脏图像，这两种方法都有其固有的局限性。尽管心脏磁共振成像（CMR）提供了卓越的图像质量，但缺乏与磁共振兼容的运动和监测设备阻碍了跑步机运动CMR的实现。在运动后尽快开始成像以捕捉运动诱发的心脏壁运动异常至关重要。我们对一台商用跑步机进行了改装，使其能够安全地放置在磁共振成像室内，以尽量缩短跑步机与扫描台之间的距离。我们在20名健康志愿者中优化了跑步机运动CMR方案，并成功地在峰值负荷时对心脏功能和心肌灌注进行了成像，随后在静息状态下进行了心肌存活成像。成像在最大运动后平均30秒开始。在运动后45秒内完成了七层面无屏气和无心电图门控的实时电影成像，紧接着对三个短轴层面进行了负荷灌注成像，显示运动后平均峰值增强时间在57秒内。我们观察到心输出量增加了3.1倍，心肌灌注储备指数为1.9，这与报道的健康受试者在峰值负荷时的值相符。本研究成功地在健康志愿者中展示了室内跑步机运动CMR，但仍需要证实其在心脏病患者中的可行性。
