Nonholonomic catheter path reconstruction using electromagnetic tracking

Abstract

Purpose: Catheter path reconstruction is a necessary step in many clinical procedures, such as cardiovascular interventions and high-dose-rate brachytherapy. To overcome limitations of standard imaging modalities, electromagnetic tracking has been employed to reconstruct catheter paths. However, tracking errors pose a challenge in accurate path reconstructions. We address this challenge by means of a filtering technique incorporating the electromagnetic measurements with the nonholonomic motion constraints of the sensor inside a catheter.Methods: The nonholonomic motion model of the sensor within the catheter and the electromagnetic measurement data were integrated using an extended Kalman filter. The performance of our proposed approach was experimentally evaluated using the Ascension's 3D Guidance trakStar electromagnetic tracker. Sensor measurements were recorded during insertions of an electromagnetic sensor (model 55) along ten predefined ground truth paths. Our method was implemented in MATLAB and applied to the measurement data. Our reconstruction results were compared to raw measurements as well as filtered measurements provided by the manufacturer.Results: The mean of the root-mean-square (RMS) errors along the ten paths was 3.7 mm for the raw measurements, and 3.3 mm with manufacturer's filters. Our approach effectively reduced the mean RMS error to 2.7 mm.Conclusion: Compared to other filtering methods, our approach successfully improved the path reconstruction accuracy by exploiting the sensor's nonholonomic motion constraints in its formulation. Our approach seems promising for a variety of clinical procedures involving reconstruction of a catheter path.

Simultaneous Electromagnetic Tracking and Calibration for Dynamic Field Distortion Compensation

“…First, the sensor size, number of redundant sensors, and the spacing between the sensors can be all reduced, depending on the required tracking precision. For example, two Model 55 sensors (0.55 mm outer diameter) can be placed inside a tiny 16 Gauge catheter [29]. The SLAM method can also be implemented for smaller instruments, such as needles, where a larger sensor is installed on the base of the instrument, while a smaller sensor is placed at the instrument's tip [28].…”

“…It only serves as a platform to investigate the effectiveness of the method under a controlled environment, while placing known field distorting objects at known locations. The clinical environment, however, involves various sources of EM field distortion commonly present in a prostate brachytherapy suite [28], [29], such as the surgical table, stepper stabilizer, ultrasound machine, stepper, probe, and template.…”

Field distortion compensation for electromagnetic tracking of ultrasound probes with application in high-dose-rate prostate brachytherapy

“…To overcome limitations of standard imaging techniques, complementary electromagnetic (EM) tracking has been proposed [20][21][22][23][24][25][26][27][28]. This alternative approach consists of simultaneously tracking TRUS scan planes and catheters; in turn, the reconstructed catheter paths can be overlaid on the TRUS images to enable thorough roadmaps of catheters' trajectory with respect to the well-defined images of the prostate gland.…”

Simultaneous localization and calibration for electromagnetic tracking systems

“…While random tracking errors (jitter) can be reduced with signal processing , systematic tracking errors (bias) are exceptionally difficult to compensate. The existing approaches employed to compensate for the field distortion rely on pre‐calibration and fusion .…”