Methods of determining catheter orientation
Inventors
Panescu, Dorin • Koblish, Josef Vincent • CHUN, Donghoon • Johnson, Jessi E. • Schultheis, Eric Andrew
Assignees
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Publication Number
US-12121291-B2
Publication Date
2024-10-22
Expiration Date
Abstract
Systems, devices and methods of determining orientation of a distal end of a medical instrument (e.g., electrode-tissue orientation of an RF ablation catheter) are described herein. One or more processors may be configured to receive temperature measurements from each of a plurality of temperature-measurement devices distributed along a length of the distal end of the medical instrument and determine the orientation from a group of two or more possible orientation options based on whether temperature measurement values or characteristics of temperature response determined from the temperature measurement values satisfy one or more orientation criteria.
Core Innovation
The invention relates to determining an orientation of a device configured to deliver energy with respect to a target region by using a medical device that includes a plurality of temperature sensors. Temperatures are determined for each temperature sensor during a first period of time at a first plurality of time points to establish initial temperature measurement values, and during a second period of time at a second plurality of time points to obtain additional temperature measurement values.
A rate of change is calculated for each temperature sensor based on the initial temperature measurement values and the temperature measurement values during the second plurality of time points. The calculating uses a moving average value of the determined temperature measurement values and compares that moving average value to the initial temperature measurement values with time elapsed from the first period of time to the second period of time. The rate of change is then used to determine the orientation of the medical device, including the distal portion of the medical device relative to the target region.
The orientation is determined based on a comparison of the calculated rate of change of at least two temperature sensors and whether the calculated rates of change satisfy one or more orientation criteria associated with a respective orientation. The orientation is determined from a plurality of orientation options including parallel, perpendicular, and oblique options, and the orientation criteria are different for each orientation option.
An RF energy ablation system is described that performs contact sensing and drift compensation using multi-frequency impedance and network parameter measurements between electrode members and surrounding tissue or blood. A processing device computes impedance magnitude at a first frequency and impedance magnitude plus phase at a second frequency, and uses these values to form a contact indication value, contact criterion, or contact state or level of contact.
Claims Coverage
The consolidated claims coverage identifies five inventive features. Across the claims, orientation is determined from temperature-sensor-derived rate-of-change information, and contact sensing is determined from multi-frequency impedance and network parameter measurements.
Two-period temperature measurement and moving-average rate-of-change calculation
Determining initial temperature measurement values for each temperature sensor at a first plurality of time points during a first period of time; determining temperature measurement values for each temperature sensor at a second plurality of time points during a second period of time; calculating a rate of change based on a moving average value of the determined temperature measurement values, the initial temperature measurement values, and a time elapsed from the first period of time to the second period of time.
Orientation determined from calculated per-sensor rate of change
Determining the orientation of the medical device relative to the target region based on the calculated rate of change; determining an orientation of the distal portion relative to the target region based on a comparison of the calculated rate of change of at least two temperature sensors.
Orientation options mapped to orientation criteria
Determining whether the calculated rates of change satisfy one or more orientation criteria associated with a respective orientation option; determining the orientation from one of a plurality of orientation options including parallel, perpendicular, and oblique options.
Multi-frequency contact indication value
Computing impedance magnitude at a first frequency and impedance magnitude plus phase at a second frequency to form a contact indication value, contact criterion, or contact state or level of contact.
Corrected bipolar impedance from network parameter measurements
Measuring network parameters at a network measurement circuit input and removing aggregate hardware component effects to obtain corrected bipolar impedance for a contact level assessment.
In the independent claims represented here, orientation is determined from temperature-sensor-derived rate-of-change information across two time periods using a moving average and elapsed time, with orientation decisions based on comparison across at least two sensors and orientation criteria mapped to discrete orientation options. The contact-sensing claims use multi-frequency impedance and network parameter measurements and corrected bipolar impedance for contact indication and contact level assessment.
Stated Advantages
Compensates drift in electrode-tissue contact impedance using reference impedance values and blood impedance change effects.
Generates a contact criterion, contact indication value, or contact state using multi-frequency impedance magnitude, impedance phase, and magnitude ratios across frequencies.
Obtains corrected bipolar impedance by measuring network parameters at the circuit input and removing aggregate hardware component effects.
Documented Applications
Contact sensing and contact state or level determination during RF energy ablation using electrode members and a processing device with multi-frequency impedance and network parameter measurements.
Lesion, orientation, and peak temperature estimation using multiple temperature sensors in an RF energy ablation system with composite electrodes.
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