Chapter 7 brium-phase and first-pass imaging. First-pass imaging was performed during a single breath-hold, while patients were freely breathing during equili- brium-phase imaging, as the acquisition time of the equilibrium-phase sequence was approximately 5 minutes. Yet, image distortion due to breathing turned out to be much less severe in equilibrium-phase imaging as compared to first-pass imaging. This is mainly inherent to the imaging technique and the inability of many patients to hold their breath for the requested 33 seconds in first-pass imaging. Study limitations Both equilibrium-phase, but especially first-pass imaging, suffered from motion artifacts, reducing image quality. The influence of breathing may be reduced by imaging patients in prone rather than supine position. Initial findings in our hospital show that abdominal movement is greatly reduced this way, however, drawbacks of this method are distortion of the abdominal wall in prone position and, especially for obese patients, this position is much less comfortable. Fat suppression might result in an even better contrast resolution and thereby improve image quality. However, use of fat suppression in most cases results in a prolonged acquisition time, which is undesirable for first-pass imaging. For equilibrium-phase imaging image quality already was sufficient, but it is likely that the use of fat suppression will result in even higher VNR and VBR values. Determining the influence of CE-MRA upon the dissection time of the DIEP flap during surgery was beyond the scope of this study. However, an important next step would be to determine the actual additional value of CE-MRA in both facilitating the preoperative planning of the procedure and the influence upon the dissection time during surgery. This, however, is quite complicated, as many factors are responsible for the dissection time, amongst others the experience and preferences of the surgeon and the between- subject differences in quality and course of the single best perforator branches of the DIEA. CONCLUSION Equilibrium-phase high spatial resolution CE-MRA of the DIEA per- forator branches in the preoperative evaluation of patients undergoing a DIEP flap reconstruction procedure is highly accurate in identifying the single best perforator branch at 1.5T, when using a blood pool contrast agent. Besides accuracy, image quality of equilibrium-phase high spatial resolution imaging proved superior to conventional first-pass CE-MRA. 127
5. lay-out phd DEFINITIEF_digitaal2
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