A MONITORING, FEEDBACK, AND TRIGGERING SYSTEM FOR REPRODUCIBLE BREATH-HOLD MR-IMAGING

A technique is described that Provides improved reproducibility of bre ath-holding for MR image acquisition by monitoring the superior-inferi or (S/I) position of the diaphragm. The method incorporates detection of the level of inspiration using an MR signal, rapid display to the p atient of diaphragm position to enable breath-hold adjustment, and tri ggering of image data acquisition once appropriate position is attaine d. The response time of the system is short, approximately 10 ms. Stud ies in six volunteers using this method demonstrate a considerable dec rease in the S/I range of diaphragm position over 10 consecutive perio ds of suspended respiration. The mean range is 1.3 mm with the system, while it is 8.3 mm without using it. It is expected that this method will be of assistance in many abdominal and cardiothoracic studies tha t use breath-hold techniques.