1999 Volume 55 Issue 12 Pages 1247-1251
We have pointed out a number of problems with the Smart Prep technique as used in initial clinical practice. A number of measures to solve these problems were evaluated and applied to clinical practice to determine their effectiveness, (1) In cases in which scan start timing was too early, the cause was assumed to be the monitoring of a signal other than the target vessel. The tracking volume was set for the ascending aorta to counter the problem. In addition, two to three continuous scans were performed during one breath hold. Good MRA images were obtained in all cases as a result of this modification. (2) In cases in which scan start timing was too late, the cause was assumed to be deviation of the tracking volume from the target vessel. In order to solve this problem, the average scan start time of the target vessel was calculated, and this value was used to set the fail-limit time. Good quality MRA images were obtained in cases for which the scan time was started at the fail-limit time when operation was not triggered by the Smart Prep technique.
