Real-Time MRI-Guided Catheter Tracking Using Hyperpolarized Silicon Particles

Abstract

Visualizing the movement of angiocatheters during endovascular interventions is typically accomplished using x-ray fluoroscopy. There are many potential advantages to developing magnetic resonance imaging-based approaches that will allow three-dimensional imaging of the tissue/vasculature interface while monitoring other physiologically-relevant criteria, without exposing the patient or clinician team to ionizing radiation. Here we introduce a proof-of-concept development of a magnetic resonance imaging-guided catheter tracking method that utilizes hyperpolarized silicon particles. The increased signal of the silicon particles is generated via low-temperature, solid-state dynamic nuclear polarization, and the particles retain their enhanced signal for ≥40 minutes—allowing imaging experiments over extended time durations. The particles are affixed to the tip of standard medical-grade catheters and are used to track passage under set distal and temporal points in phantoms and live mouse models. With continued development, this method has the potential to supplement x-ray fluoroscopy and other MRI-guided catheter tracking methods as a zero-background, positive contrast agent that does not require ionizing radiation.

Hyperpolarized Porous Silicon Nanoparticles: Potential Theragnostic Material for 29Si Magnetic Resonance Imaging

“…Because this enhanced spin polarization is relatively protected within the core of the particles, the effect is retained for significantly longer than most other hyperpolarized contrast agents in vivo . 29 Si hyperpolarization decay time constants ( T 1 ) have ranged from 10 minutes to over 40 minutes,, depending on the size of the particle; this is in comparison with the significantly shorter (e. g., 1–5 minute) T 1 values typically afforded to 13 C nanodiamonds that are hyperpolarized via DNP . This extended T 1 increases the imaging window and may enable the particles more time within the body to act as targeted molecular imaging agents .…”

Magnetic Resonance Imaging System–Driven Medical Robotics

“…This high‐intensity signal can be classified as passive, semiactive, or active positive contrast methods. The passive positive contrast methods use contrast agents such as 19 F, 13 C, and 29 Si as the source of the high‐intensity signal . Figure a shows 2D overlaid 1 H and 29 Si in vivo anatomical images of mouse intestines with hyperpolarized 29 Si particles attached to the tip of the catheter as a passive contrast agent.…”

“…Imaging and localization using MRI devices. a) Overlapped image of 1 H image and 29 Si image; the red region is the hyperpolarized 29 Si particles attached on the tip of the catheter . b) Catheter antenna image without sensitivity correction, where the antenna boosts the signal around the catheter .…”

“…f) Larmor frequency shifting profile of a magnetic bead and the corresponding 1D projection image . Panel (a): Reproduced under terms of the CC‐BY licence . Copyright 2015.…”

Toward a Versatile Robotic Platform for Fluoroscopy and MRI-Guided Endovascular Interventions: A Pre-Clinical Study

“…This limits use to pediatric patients. (5) Future directions are towards MRI-based interventions to reduce ionizing radiation exposure [15], [16]. MR-compatible devices are exclusively reported for cardiac cases with steerable catheters.…”