Improved catheter tracking during cardiovascular magnetic resonance-guided cardiac catheterization using overlay visualization

Abstract

Introduction Cardiovascular magnetic resonance (CMR)-guided cardiac catheterization is becoming more widespread due to the ability to acquire both functional CMR measurements and diagnostic catheterization data without exposing patients to ionizing radiation. However, the real-time imaging sequences used for catheter guidance during these procedures are limited in resolution and the anatomical detail they can provide. In this study, we propose a passive catheter tracking approach which simultaneously improves catheter tracking and visualization of the anatomy. Methods 60 patients with congenital heart disease underwent CMR-guided cardiac catheterization on a 1.5T CMR scanner (Ingenia, Philips Healthcare, Best the Netherlands) using the Philips iSuite system. The proposed T1-overlay technique uses a commercially available heavily T1-weighted sequence to image the catheter, and overlays it on a high-resolution 3D dataset within iSuite in real-time. Suppressed tissue in the real-time images enables the use of a thick imaging slab to assist in tracking of the catheter. Improvement in catheter visualization time was compared between T1-overlay and the conventional invasive CMR (iCMR) balanced steady state free precession (bSSFP) sequence. This technique also enabled selective angiography visualization for real-time evaluation of blood flow dynamics (such as pulmonary transit time), similar to direct contrast injection under standard fluoroscopy. Estimates of pulmonary transit time using iCMR were validated using x-ray fluoroscopy in 16 patients. Results The T1-overlay approach significantly increased the time that the catheter tip was kept in view by the technologist compared to the bSSFP sequence conventionally used for iCMR. The resulting images received higher ratings for blood/balloon contrast, anatomy visualization, and overall suitability for iCMR guidance by three cardiologists. iCMR selective angiography using T1-overlay also provided accurate estimates of pulmonary transit time that agreed well with x-ray fluoroscopy. Conclusion We demonstrate a new passive catheter tracking technique using the iSuite platform that improves visualization of the catheter and cardiac anatomy. These improvements significantly increase the time that the catheter tip is seen throughout the procedure. We also demonstrate the feasibility of iCMR selective angiography for the measurement of pulmonary transit time.

Silent active device tracking for MR‐guided interventional procedures

“…We quantified the sound pressure level (SPL) by means of a predictive model, as well as representative measurements with a sound level meter, and compared the results with previously used "conventional" tracking 3,8 as well as real-time imaging. 1,2,4,5,9 Most importantly, we validated the performance of the "silent" MR catheter tracking sequence in terms of signal quality and tracking accuracy in phantoms, and during in vivo conditions in 12 patients undergoing an MR-guided interventional ablation procedure for atrial flutter.…”

“…Furthermore, the catheter tip is also shown against the native bright-blood balanced SSFP (bSSFP) contrast in three other orientations, two of which are shown in (B) and (C) within a single-session examination using a single imaging modality. [1][2][3][4][5] The combination of measurable parameters and inherent co-registration holds the promise for improved outcomes and reduced recurrences. 6 A typical workflow 3 for the MR intervention used here is sketched in Figure S1.…”

“…We quantified the sound pressure level (SPL) by means of a predictive model, as well as representative measurements with a sound level meter, and compared the results with previously used “conventional” tracking 3,8 as well as real‐time imaging 1,2,4,5,9 …”

“…Magnetic resonance imaging offers excellent 3D soft tissue and lesion visualization, arrhythmic substrate identification, and allows conducting invasive cardiovascular procedures, including localization and tracking of interventional devices and postprocedural follow‐up, within a single‐session examination using a single imaging modality 1–5 . The combination of measurable parameters and inherent co‐registration holds the promise for improved outcomes and reduced recurrences 6 …”

“…Alternative workflows 1,2,4,5,9 include (additional) real‐time MRI for frequent updates of the catheter tip and surrounding tissue. Both approaches have specific assets and drawbacks.…”