| Popis: |
Ever since the introduction of contrast-enhanced MR angiography in the mid-1990s, there has been steady improvement in the technique. Early investigations identified a number of performance targets, including the desirability for high-spatial-resolution 3D imaging, need to synchronize the acquisition to the arterial phase of the contrast bolus passage, and desirability for minimal enhancement of the venous system. To a great extent, these were addressed with the development of short repetition time (TR) gradient echo pulse sequences, nonreal-time and real-time means for determination of accurate timing, and development of centric view orders which allowed extended acquisition times into the venous phase. |
