Clinician programmer system and method for calculating volumes of activation for monopolar and bipolar electrode configurations

• US 20100049276A1
• Filed: 05/15/2009
• Published: 02/25/2010
• Est. Priority Date: 05/15/2008
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation), Medical College of Wisconsin Incorporated
• Original Assignee: IntElect Medical, Inc. (Boston Scientific Corporation), Medical College of Wisconsin Incorporated
• Inventors: Sparks, Troy, Blum, David Arthur, Carlton, Keith, Kokones, Scott, Greszler, Alan, Butson, Christopher
• Granted Patent: US 8,326,433 B2
• Time in Patent Office: Days
• US Class Current: 607/45
• CPC Class Codes: A61B 2034/104 Modelling the effect of the tool, e.g. the effect of an implanted prosthesis or for predicting the effect of ablation or burring
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2034/107 Visualisation of planned trajectories or target regions
• CPC Class Codes: A61B 2090/103 Cranial plugs for access to brain
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease
• CPC Class Codes: A61N 1/36128 Control systems
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration
• CPC Class Codes: A61N 1/37247 User interfaces, e.g. input or presentation means
• CPC Class Codes: G06V 40/10 Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
• CPC Class Codes: G16H 20/40 relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16H 50/50 for simulation or modelling of medical disorders
• CPC Class Codes: G16H 70/20 relating to practices or guidelines

Abstract

A system and method for providing a volume of activation (VOA) of a stimulation electrode leadwire may include a processor that calculates a VOA for each of a plurality of sets of parameter settings of the leadwire, stores in a database each of the calculated VOAs in association with the respective set of parameter settings for which it was calculated, performs a curve fitting on threshold values determined for a plurality of waveforms to obtain an equation, obtains a set of parameter settings of the leadwire for a stimulation, and determines a VOA for the obtained set of parameter settings based on the stored VOAs, for example, using the equation.

Claims

1. A method of a volume of activation (VOA) providing machine to provide a VOA of a stimulation electrode leadwire, comprising:

calculating, by a processor of the machine, a VOA for each of a plurality of sets of parameter settings of the leadwire;

storing in a database each of the calculated VOAs in association with the respective set of parameter settings for which it was calculated;

for a selected electrode configuration, plotting voltages at anatomical locations;

for each of a plurality of waveforms, determining an amplitude threshold for activation at various ones of the locations;

performing a curve fitting on the threshold values determined for the plurality of waveforms, the curve fitting resulting in a voltage threshold equation that provides a voltage threshold for a given pulse width, amplitude, and impedance;

obtaining a further set of parameter settings of the leadwire;

determining, by the processor, a VOA for the obtained set of parameter settings based on the stored VOAs; and

outputting, by the machine, the determined VOA;

wherein;

the obtained set of parameter settings includes an electrode configuration, a pulse width, and an amplitude; and

the determining of the VOA for the obtained set of parameter settings includes;

obtaining a voltage threshold for the pulse width and amplitude of the parameter settings using the function; and

applying the voltage threshold to voltages plotted for the obtained set of parameter settings.

2. The method of claim 1, wherein:

the performing of the curve fitting includes performing a first curve fitting to obtain a plurality of intermediary equations for a corresponding plurality of impedance levels and performing a second curve fitting on the intermediary equations to obtain the voltage threshold equation;

each intermediary equation is Volt=(C₁²*PW+C₂*PW+C₃)*Amp^{(C42*PW+C5*PW+C6)};

volt is a voltage threshold;

C₁ to C₆ are coefficients that fit a given leadwire type and impedance level;

PW is a given pulse width; and

Amp is a given amplitude.

3. The method of claim 2, wherein the selected electrode configuration is a monopolar electrode configuration.

4. A method of a volume of activation (VOA) providing machine to provide a VOA of a stimulation electrode leadwire, comprising:

calculating, by a processor of the machine, a VOA for each of a plurality of sets of parameter settings of the leadwire;

storing in a database each of the calculated VOAs in association with the respective set of parameter settings for which it was calculated;

for a selected monopolar electrode configuration, plotting voltages at anatomical locations;

for each of a plurality of waveforms;

determining an amplitude threshold for activation at various ones of the locations;

determining an electric field based on the plotted voltages;

obtaining a current density field based on the electric field; and

obtaining a charge density field based on the electric field and a pulse width of the waveform, the charge density field including charge density values at the locations in association with the determined amplitude thresholds;

performing a curve fitting on the threshold values determined for the plurality of waveforms, the curve fitting resulting in a charge density threshold equation that provides a charge density threshold for a given pulse width, amplitude, and impedance;

obtaining a further set of parameter settings of the leadwire;

determining, by the processor, a VOA for the obtained set of parameter settings based on the stored VOAs; and

outputting, by the machine, the determined VOA;

wherein;

the obtained set of parameter settings includes a bipolar electrode configuration, a pulse width, and an amplitude;

the determining of the VOA for the obtained set of parameter settings includes;

obtaining a charge density threshold for the pulse width and amplitude of the parameter settings using the function; and

applying the charge density threshold to charge density values plotted for the obtained set of parameter settings.

5. The method of claim 4, wherein the charge density values are plotted for the obtained set of parameter settings by:

recording voltage values at anatomical locations for the bipolar configuration;

thresholding the voltage values to one of scale down and remove anodic values; and

converting voltage values remaining after the thresholding into charge density values.

6. A method of a volume of activation (VOA) providing machine to provide a VOA of a stimulation electrode leadwire, comprising:

plotting, by a processor of the machine, voltage values at anatomical locations for a set of stimulation parameter settings;

determining, by the processor, one of a voltage threshold and a charge density threshold for the set of stimulation parameter settings by application of one of a voltage threshold function that outputs the voltage threshold and a charge density function that outputs the charge density threshold based on a pulse width, amplitude, and impedance of the stimulation parameter settings;

based on the determined one of voltage threshold and charge density threshold, determining, by the processor, a three dimensional surface of an area that includes one of (a) those of the voltage values that meet the voltage threshold and (b) charge density values corresponding to a subset of the voltage values and that meet the charge density threshold; and

outputting, by the machine, the area as a VOA.

7. The method of claim 6, wherein:

the voltage threshold is determined, the determination being by application of the voltage threshold function; and

the voltage threshold function is formed by, for a selected electrode configuration;

plotting voltages at anatomical locations;

for each of a plurality of waveforms, determining an amplitude threshold for activation at various ones of the locations; and

performing a curve fitting on the threshold values determined for the plurality of waveforms, the curve fitting resulting in a voltage threshold function that provides a voltage threshold for a given pulse width, amplitude, and impedance.

8. The method of claim 6, wherein:

the set of stimulation parameter settings includes a bipolar electrode configuration;

the charge density threshold is determined, the determination being by application of the charge density threshold function;

the processor determines the three dimensional surface of an area that includes the charge density values that meet the charge density threshold;

the charge density threshold function is formed by, for a selected monopolar electrode configuration;

plotting voltages at anatomical locations;

for each of a plurality of waveforms;

determining an amplitude threshold for activation at various ones of the locations;

determining an electric field based on the plotted voltages;

obtaining a current density field based on the electric field; and

obtaining a charge density field based on the electric field and a pulse width of the waveform, the charge density field including charge density values at the locations in association with the determined amplitude thresholds; and

performing a curve fitting on the threshold values determined for the plurality of waveforms, the curve fitting resulting in a charge density threshold equation that provides a charge density threshold for a given pulse width, amplitude, and impedance; and

the determining of the three dimensional surface includes;

recording voltage values at anatomical locations for the bipolar configuration;

thresholding the recorded voltage values to one of scale down and remove anodic values;

converting voltage values remaining after the thresholding into charge density values; and

applying the charge density threshold to the charge density values.

9. A volume of activation (VOA) providing system for providing a VOA of a stimulation electrode leadwire, comprising:

an input device, the system configured for obtaining a set of stimulation parameter settings via the input device;

a processor configured to;

plot voltage values at anatomical locations for the set of stimulation parameter settings;

determine one of a voltage threshold and a charge density threshold for the set of stimulation parameter settings by performing one of a voltage threshold function that outputs the voltage threshold and a charge density function that outputs the charge density threshold based on a pulse width, amplitude, and impedance of the stimulation parameter settings; and

based on the determined one of voltage threshold and charge density threshold, determine a three dimensional surface of a region that includes one of (a) those of the voltage values that meet the voltage threshold and (b) charge density values corresponding to a subset of the voltage values and that meet the charge density threshold; and

an output device, the system configured to output the region, via the output device, as a VOA.

10. A hardware computer-readable medium having stored thereon instructions, the instructions which, when executed, cause a processor to perform method to provide a volume of activation (VOA) of a stimulation electrode leadwire, the method comprising:

plotting, by a processor of the machine, voltage values at anatomical locations for a set of stimulation parameter settings;

determining, by the processor, one of a voltage threshold and a charge density threshold for the set of stimulation parameter settings by application of one of a voltage threshold function that outputs the voltage threshold and a charge density function that outputs the charge density threshold based on a pulse width, amplitude, and impedance of the stimulation parameter settings;

based on the determined one of voltage threshold and charge density threshold, determining, by the processor, a three dimensional surface of an area that includes one of (a) those of the voltage values that meet the voltage threshold and (b) charge density values corresponding to a subset of the voltage values and that meet the charge density threshold; and

outputting, by the machine, the area as a VOA.