Accuracy considerations in image-guided cardiac interventions: experience and lessons learned

Abstract

Motivation Medical imaging and its application in interventional guidance has revolutionized the development of minimally invasive surgical procedures leading to reduced patient trauma, fewer risks, and shorter recovery times. However, a frequently posed question with regards to an image guidance system is “how accurate is it?” On one hand, the accuracy challenge can be posed in terms of the tolerable clinical error associated with the procedure; on the other hand, accuracy is bound by the limitations of the system’s components, including modeling, patient registration, and surgical instrument tracking, all of which ultimately impact the overall targeting capabilities of the system. Methods While these processes are not unique to any interventional specialty, this paper discusses them in the context of two different cardiac image-guidance platforms: a model-enhanced ultrasound platform for intracardiac interventions and a prototype system for advanced visualization in image-guided cardiac ablation therapy. Results Pre-operative modeling techniques involving manual, semi-automatic and registration-based segmentation are discussed. The performance and limitations of clinically feasible approaches for patient registration evaluated both in the laboratory and operating room are presented. Our experience with two different magnetic tracking systems for instrument and ultrasound transducer localization is reported. Ultimately, the overall accuracy of the systems is discussed based on both in vitro and preliminary in vivo experience. Conclusion While clinical accuracy is specific to a particular patient and procedure and vastly dependent on the surgeon’s experience, the system’s engineering limitations are critical to determine whether the clinical requirements can be met.

Electromagnetic Tracking in Medicine—A Review of Technology, Validation, and Applications

“…However, most of the recent studies on catheter applications with EM tracking do not track guidewires, but track catheters without guidewires, which offer a larger diameter to include sensors. Most studies deal with catheterizations into the heart to perform cardiac mapping or ablation [97]. It should be noted that the frequently used term Magnetic Navigation may be misleading in this relation.…”

“…This system relies on the relative accuracy between the position of an instrument and the imaging ultrasound transducer. Also, because it is concerned only with the safe navigation of the instrument to the site where image-guided repair will take place, (rather than guiding the entire procedure, including the action on the target that is achieved under local real-time ultrasound guidance) the accuracy of instrument positioning relative to the US image needs only to be in the range of 3-5mm [97].…”

Using a low-amplitude RF pulse at echo time (LARFET) for device localization in MRI

“…Taking the size of the coil into account (Ø = 2 mm, l = 3 mm), an error of 0.8 mm (≤1 pixel) is acceptable. This is also far better than required accuracies for many interventional procedures and comparable to error ranges of similar active tracking systems [15,23]. Reducing the image resolution within the same FoV can result in a broader spatial coverage of the center pixel, and the location found by the system may fall in it rather than the neighbor pixel, thus virtually increasing the accuracy of image guidance.…”

An Adaptive 6-DOF Tracking Method by Hybrid Sensing for Ultrasonic Endoscopes

“…Compared with accuracy reported by other groups [32,33], the accuracy of 0.3 cm is a bit lower, but it is still small and within acceptable limits [34,35]. On the other hand, in contrast with their large array which contains dozens of coils and specialized high-speed circuits, our system structure is much more simplified, and only requires a low-cost integrated sensor, regular coils and basic hardware.…”