Abstract
When compared to most other high resolution imaging modalities (i.e. CT), magnetic resonance (MR) requires significantly more time for data acquisition. The average MR scan time ranges from 2 to 6 minutes. Cardiac and respiratory motion cause large artifacts and significantly reduce the resolution of internal structures. Thus, a method for gating MR acquisition with the respiratory cycle was developed. The respiratory cycle was followed via a pneumatic bellows placed around the patients chest, observing the change in pressure caused by motion of the chest with a transducer linked to the bellows by plastic tubing. The voltage output from the transducer was monitored by an electronic device which could be set to start and stop acquisition at any portion of the respiratory cycle. The authors have performed studies on 5 volunteers and 23 patients gating the acquisition of data to the end-expiratory portion of the respiratory cycle. Respiratory gating eliminated the gross motion artifacts normally present at 0.5 T and markedly improved visualization of hepatic vessels. In 2 patients one with a pheochromocytoma and one post splenic embolization, the tissue abnormalities could only be diagnosed with the use of respiratory gating. Gating of data acquisition by chest wall motion inmore » MR is feasible and significantly improves the diagnostic potential of MR imaging, particularly at higher field strengths where motion artifact is more severe.« less
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