Magnetic resonance guided renal denervation using active tracking: first in vivo experience in Swine

Interventional cardiovascular magnetic resonance (iCMR) might evolve as a technique to improve procedural success rates in cardiovascular interventions by combining intraprocedural guidance and simultaneous lesion imaging. The objective of the present study was to prove feasibility and estimate safety of renal sympathetic denervation guided by real-time iCMR using active tracking. Six pigs were examined in a 1.5 T MRI-System (Achieva, Philips Healthcare, Best, Netherlands) equipped with non-invasive hemodynamic control and in-room monitors displaying an interventional software platform [Interventional MRI Suite (iSuite), Philips Research, Hamburg, Germany]. MR-guided renal denervation was performed using a MR conditional non-irrigated ablation catheter with active tracking (Imricor, Burnsville, MN, USA). Real-time imaging for device guidance was performed with a TFE sequence, vessel patency was assessed with a 3D non-contrast angiography and velocity encoded imaging. Oedema of the renal artery was visualized by a high-resolution T2 SPIR sequence. Renal sympathetic denervation was feasible in all cases with survival of all animals. Non-contrast angiography displayed renal artery patency accompanied by equal flow conditions before and after the ablation in all cases as measured by velocity encoded imaging. Oedema imaging displayed a significant increase in relative signal intensity at renal artery ablations sites pre and post intervention (p < 0.05). The histologic examination revealed no signs of perforation or bleeding, while sufficient ablation lesions could be depicted. MR-guided renal sympathetic denervation using active tracking is feasible and the initial data suggest safety of this procedure. MR-guided renal sympathetic denervation offers the inherent strength of high soft tissue contrast thereby providing target information without the use of iodinated contrast agents or radiation.