P-004 solid organ embolizationin vivousing a magnetically assisted remote controlled catheter under real-time mri guidance

Abstract

<h3>Purpose</h3> Using real-time MRI for solid organ embolization provides physiologic and structural information. Current embolization under x-ray guidance only visualizes the vessels and lacks a quantifiable endpoint, which could be overcome by using MRI. The purpose of this study was to use a magnetically assisted remote controlled (MARC) catheter under real-time endovascular MRI to navigate into the renal arteries, embolize with &nbsp;gadolinium (Gd) impregnated microspheres, and measure the reduction in flow. <h3>Method and materials</h3> The catheter device was constructed using 4.1Fr custom copper braided catheter (Penumbra Inc., Alameda, CA) with copper wires in the wall connected to a laser-lithographed saddle coil at the distal tip (Figure 1). The copper wires were connected to an in-room MRI compatible cart via an SFTP cable. A foot pedal actuator was used to deliver ± 450mA to deflect the catheter. <i>In vivo</i> navigation was tested in four farm pigs (40–45 kg). The renal arteries were catheterized under a real-time b-SSFP sequence at 1.5T. Embolization was visualized under a real-time contrast enhanced angiographic sequence. Renal artery blood flow rates were assessed with ECG gated velocity-encoded MR imaging before and after embolization with Gd-impregnated microspheres (100–300 μm). Workflow is diagrammed in Figure 2. Statistical analysis was performed and data were presented as mean ± SD. <h3>Results</h3> The catheter tip was clearly visible under MRI guidance. Three (75%) out of four renal arteries were successfully catheterized. Overall mean catheterization time was (956 s). The MR signal from the Gd-impregnated spheres was observed under real-time MRI (Figure 3). Flow rate was significantly different (P = 0.025) between pre and post embolization (2.20 ± 0.20 vs. 0.14 ± 0.03 mL/min/kg), accounting for a 94 percent reduction in flow. <h3>Conclusion</h3> Using a MARC catheter for renal artery catheterization and embolization under real-time MRI is feasible. The MARC catheter system provides a novel opportunity to perform endovascular procedures in interventional MRI environment. Future work will focus on developing more flexible catheters that can be used for head, neck, and brain embolization applications. <h3>Disclosures</h3> S. Hetts: 1; C; NIH-NIBIB, NIH-NCI, Penumbra, Siemens, Stryker, MicroVention Terumo. 2; C; Stryker, Penumbra, Silk Road Medical, Medina Medical. 4; C; Medina Medical. 5; C; UCSF. A. Losey: None. P. Lillaney: None. D. Cooke: None. B. Thorne: None. J. Yang: None. L. Sze: None. L. Do: None. A. Martin: None. M. Saeed: None. M. Wilson: None.