Chapter 7 functional impairment compared to TRAM flaps.5,6 Disadvantages of the DIEP procedure, on the other hand, include difficulties in harvesting the flap, resulting in considerably longer dissection times, and the fact that long-term results depend heavily on the quality of the perforator branch supplying the flap. Preoperative evaluation of the DIEA perforator branches in the abdomen to identify adequate perforator branches facilitates surgical planning of the procedure and shortens dissection times.6,7,8,9,10 Currently, the most widely applied techniques in preoperative imaging and planning in DIEP flap procedures are Doppler ultrasound (DUS) and computed tomography angiography (CTA).5 Doppler, however, is associated with long imaging times, low accuracy and high interobserver variability.5,11 CTA, on the other hand, is highly accurate in demonstrating location, size and course of the perfo- rators, but suffers from exposure to ionizing radiation, which is an important drawback in the often (relatively) young patients.12,13,14 Recently, several authors have demonstrated that MR angiography can also be used in preoperative imaging of the perforator branches of the DIEA.5,6,8,15,16 Excellent soft-tissue contrast and the absence of ionizing radiation are important advantages of MRI. Nevertheless, experience with contrast- enhanced MR angiography (CE-MRA) in the preoperative workup of patients undergoing DIEP flap procedures is still scarce. Several studies have been performed using state-of-the-art 3T hardware, instead of the more widely available 1.5T magnetic resonance angiography (MRI) systems,5,6,8,15,16 and most of these studies have employed conventional extracellular contrast agents in combination with first-pass imaging to visualize DIEA perforator branches. Considering the small size of DIEA perforator branches we wondered whether it was possible to obtain high spatial resolution equilibrium-phase (EP) images with improved resolution compared to first-pass acquisitions using a recently described new intravascular contrast agent, gadofosveset trisodium.17,18 Blood pool agents have important benefits over conventional small-sized extracellular agents in CE-MRA, such as the lengthened imaging window and the relatively large R1,19 both allowing longer acquisition times, enabling data acquisition at a very high resolution and with very high accuracy. The aims of the current study were (I) to investigate the accuracy of equilibrium-phase high spatial resolution CE-MRA at 1.5T using a blood pool contrast agent in the preoperative evaluation of the DIEA perforator branches, and (II) to compare image quality of equilibrium-phase high spatial resolution imaging with conventional first-pass CE-MRA. 115
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