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Chapter 7 as contrast-enhanced MR angiography techniques have a limited temporal imaging window due to the relatively fast passage and subsequent wash- out of the contrast agent from the vessels of interest. Secondly, because perforator branches course through the rectus abdominal muscles and the subcutaneous abdominal fat, it can be difficult to acquire sufficient contrast resolution between the perforator branches and the surrounding static tissues. Also, breathing and bowel motion may lead to seriously compromised image quality due to related image artifacts. Currently, best results with first-pass CE-MRA of the DIEA per- forator branches have been achieved at 3.0T, as this field strength allows to optimally balance spatial resolution, contrast resolution and acquisition time.6 We sought to investigate whether acquisition of equilibrium phase images with higher spatial resolution compared to imaging during first arterial passage resulted in better image quality and improved diagnostic accuracy in identifying the most suitable perforator branch. Diagnostic accuracy of equilibrium-phase high spatial resolution imaging In this study, we evaluated the diagnostic accuracy of CE-MRA at 1.5 T with gadofosveset trisodium as contrast agent, both for equilibrium-phase high spatial resolution and first-pass imaging. For both acquisitions a 3D gradient echo (FFE) sequence was used. For equilibrium-phase high spatial resolution imaging, there was 100% agreement between intraoperative and MR findings as far as the location of the single best perforator branch was concerned. In all cases there was no more than 1 cm difference in either craniocaudal or left-right direction between equilibrium-phase high spatial resolution MRA and intraoperative findings. This indicates that equilibrium-phase high spatial resolution MR angiography is a very accurate technique for identifying the location of the single best perforator branch in DIEP-procedures and can be a valuable tool for the surgeon to facilitate preoperative planning of the procedure. Equilibrium-phase versus first-pass CE-MRA Whereas equilibrium-phase high spatial resolution imaging was highly accurate, the opposite was true for first-pass imaging. In only 11 out of 36 DIEP flaps, first-pass imaging accurately determined the location of the single best perforator branch. In 10 patients (17 DIEP flaps), first-pass images were not able to identify any perforator branch (non-diagnostic image quality). Besides low accuracy in identifying the single best perforator branches, the total number of perforator branches determined with first-pass imaging was also significantly lower as compared to equilibrium-phase high 125


5. lay-out phd DEFINITIEF_digitaal2
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