New-Generation Laser-lithographed Dual-Axis Magnetically Assisted Remote-controlled Endovascular Catheter for Interventional MR Imaging: In Vitro Multiplanar Navigation at 1.5 T and 3 T versus X-ray Fluoroscopy

Abstract

).q RSNA, 2015 Purpose:To assess the feasibility of multiplanar vascular navigation with a new magnetically assisted remote-controlled (MARC) catheter with real-time magnetic resonance (MR) imaging at 1.5 T and 3 T and to compare it with standard x-ray guidance in simulated endovascular catheterization procedures. Materials andMethods:A 1.6-mm-diameter custom clinical-grade microcatheter prototype with lithographed double-saddle coils at the distal tip was deflected with real-time MR imaging. Two inexperienced operators and two experienced operators catheterized anteroposterior (celiac, superior mesenteric, and inferior mesenteric arteries) and mediolateral (renal arteries) branch vessels in a cryogel abdominal aortic phantom. This was repeated with conventional x-ray fluoroscopy by using clinical catheters and guidewires. Mean procedure times and percentage success data were analyzed with linear mixed-effects regression. Results:The MARC catheter tip was visible at 1.5 T and 3 T. Among inexperienced operators, MARC MR imaging guidance was not statistically different from x-ray guidance at 1.5 T (67% successful vessel selection turns with MR imaging vs 76% with x-ray guidance, P = .157) and at 3 T (75% successful turns with MR imaging vs 76% with x-ray guidance, P = .869). Experienced operators were more successful in catheterizing vessels with x-ray guidance (98% success within 60 seconds) than with 1.5-T (65%, P , .001) or 3-T (75%) MR imaging. Among inexperienced operators, mean procedure time was nearly equivalent by using MR imaging (31 seconds) and x-ray guidance (34 seconds, P = .436). Among experienced operators, catheterization was faster with x-ray guidance (20 seconds) compared with 1.5-T MR imaging (42 seconds, P , .001), but MARC guidance improved at 3 T (31 seconds). MARC MR imaging guidance at 3 T was not significantly different from x-ray guidance for the celiac (P = .755), superior mesenteric (P = .358), and inferior mesenteric (P = .065) arteries. Conclusion:Multiplanar navigation with a new MARC catheter with real-time MR imaging at 1.5 T and 3 T is feasible and comparable to x-ray guidance for anteroposterior vessels at 3 T in a vascular phantom.q RSNA, 2015

Intra-Arterial MR Perfusion Imaging of Meningiomas: Comparison to Digital Subtraction Angiography and Intravenous MR Perfusion Imaging

“…As such, it could serve as an adjunct to DSA in evaluation of tumor supply by providing physiologic data in current practice and could be an important component of tumor evaluation during completely MRI-guided tumor embolization if interventional MRI supplants x-ray guided embolization in the future[17]. …”

Magnetic Resonance Imaging System–Driven Medical Robotics

“…Such a given torque is used to deform the flexible body to control the catheter tip orientation . In terms of catheter coil design, generally one or more sets of coils, referred to as “saddle” or “axial” depending upon the design, are wound, 3D‐printed, or cut using laser lithography at the tip of the catheter . A Lorentz torque is generated on the tip when current flows through these coils, allowing direct user control of the catheter tip.…”

Endovascular MR-guided Renal Embolization by Using a Magnetically Assisted Remote-controlled Catheter System

“…The saddle design was composed of two virtually identical coil patterns, with one pattern on each side of the cylindrical tip fabricated by laser lithography (P.V.L.L), as previously described (29,30). Electrical connections to the microcoil were made by using a pair of 0.125-mm-diameter copper wires embedded in the catheter wall (P.V.L.).…”

“…to allow the interventionalist control, via foot pedals, value, and polarity of the current delivered to the microcoil tip (30,31). Additionally, the interventionalist was able to turn the current on and off with the foot pedal actuator.…”