磁共振心脏门控成象研究

On MR Cardiac Gating Imaging

本文首先简要讨伦磁共振成象(MRI)系统在心脏成象中产生伪影的原因及消除伪影的方法,然后着重论述MRI心脏成象门控仪的设计原则和工作原理.临床实验结果表明,心脏成象门控仪的应用使心脏MRI图象具有较高的诊断价值.

Magnetic Resonance Imaging (MRI) is useful for cardiovascular system examination. In conventional MRI techniques several minutes are needed to sample and produce an image. Consequently, when imaging sequences are made, as the data are sampled at random from systolic and diastolic phases of the cardiac cycle, motion artifacts and edge unsharpress occurs in moving structures of the image. An electrocardiograph (ECG) sensing and gating device has been developed to sense the ECG signal and generate a sequence of triggering pulses to synchronize the imaging sequence with a specific phase of the cardiac cycle. Noises and artifacts induced by the radio-frequency pulse and gradient magnetic fields inherent in MRI are electrically suppressed with a floating-earth amplifier and a fibre-optic cable to amplify and transmit the ECG signal. This device is currently satisfactorily used for medical examination in Beijing Cancer Hospital.