Optimised passive marker device visibility and automatic marker detection for 3-T MRI-guided endovascular interventions: a pulsatile flow phantom study

Abstract

Background Passive paramagnetic markers on magnetic resonance imaging (MRI)-compatible endovascular devices induce susceptibility artifacts, enabling MRI-visibility and real-time MRI-guidance. Optimised visibility is crucial for automatic detection and device tracking but depends on MRI technical parameters and marker characteristics. We assessed marker visibility and automatic detection robustness for varying MRI parameters and marker characteristics in a pulsatile flow phantom. Methods Guidewires with varying iron(II,III) oxide nanoparticle (IONP) concentration markers were imaged using gradient-echo (GRE) and balanced steady-state free precession (bSSFP) sequences at 3 T. Furthermore, echo time (TE), slice thickness (ST) and phase encoding direction (PED) were varied. Artifact width was measured and contrast-to-noise ratios were calculated. Marker visibility and image quality were scored by two MRI interventional radiologists. Additionally, a deep learning model for automatic marker detection was trained and the effects of the parameters on detection performance were evaluated. Two-tailed Wilcoxon signed-rank tests were used (significance level, p < 0.05). Results Medan artifact width (IQR) was larger in bSSFP compared to GRE images (12.7 mm (11.0–15.2) versus 8.4 mm (6.5–11.0)) (p < 0.001) and showed a positive relation with TE and IONP concentration. Switching PED and doubling ST had limited effect on artifact width. Image quality assessment scores were higher for GRE compared to bSSFP images. The deep learning model automatically detected the markers. However, the model performance was reduced after adjusting PED, TE, and IONP concentration. Conclusion Marker visibility was sufficient and a large range of artifact sizes was generated by adjusting TE and IONP concentration. Deep learning-based marker detection was feasible but performance decreased for altered MR parameters. These factors should be considered to optimise device visibility and ensure reliable automatic marker detectability in MRI-guided endovascular interventions.

MR-based navigation for robot-assisted endovascular procedures

“…There are very few other works in literature focusing on passive tracking of endovascular tools under MR guidance. Nijsink et al (2022b) developed a deep learning model for automatic passive detection of guidewire markers assessing its detection performance in terms of correctly and false positive detected markers. The detection accuracy of the algorithm was not evaluated.…”

Interventional device tracking under MRI via alternating current controlled inhomogeneities

“…8 As MRI continues to evolve into a more accessible and suitable imaging modality for interventional procedures, the design of visible and safe interventional tools remains a significant challenge in this field. 6 Several types of device markers have been proposed to enhance the MRI visibility of interventional medical devices: passive, [21][22][23][24] active, [25][26][27][28] and semi-active (resonant) markers. 29,30 Another approach generates local field disruption using tiny inductors, wherein a direct current (DC) is applied to the conductive wire wound around the device.…”

“…Several types of device markers have been proposed to enhance the MRI visibility of interventional medical devices: passive, 21–24 active, 25–28 and semi‐active (resonant) markers 29,30 . Another approach generates local field disruption using tiny inductors, wherein a direct current (DC) is applied to the conductive wire wound around the device 31 .…”