Abstract: An automatic method of categorizing the contact force of a catheter tip against a portion of a patient's heart based on motion of the catheter tip, the method comprising (a) capturing a series of 3D-coordinate data points of the catheter tip as a function of discrete times with a 3D medical imaging system, the 3D coordinates corresponding to an orthogonal 3-axis spatial coordinate system, (b) using a programmable computing system, computing a set of measures based on the series of 3D-coordinate data points, (c) categorizing each measure by a respective set of predetermined threshold values; and (d) combining the categorized measures to yield a relative quality of the contact force.

Abstract: A method of determining respiratory phase of a living body from a sequence of digitized fluoroscopic images of a living-body region exhibiting respiratory displacement, the method employing programmable computing apparatus and comprising the steps of: (a) in each living-body-region image in the sequence, defining one or more zones with each image having identical image-to-image zone locations, sizes, and shapes; (b) for each image, computing an average pixel intensity for each zone to form a sequence thereof for each zone; (c) for each zone, modifying the average pixel intensities by (i) computing the mean value of the sequence of average pixel intensities for such zone, and (ii) subtracting the mean from each average pixel intensity in the zone; (d) for each zone sequence, computing a figure-of-merit; (e) selecting the zone having the highest figure-of-merit; and (f) using the sequence of pixel intensities of the selected zone to determine respiratory phase.

Abstract: A method for automatically determining the 3D position and orientation of a radio-opaque medical object in a living body using single-plane fluoroscopy comprising: (a) capturing a stream of digitized 2D images from a single-plane fluoroscope; (b) detecting an image of the medical object in a subset of the digital 2D images; (c) applying to the digital 2D images calculations which preserve original pixel intensity values and permit statistical calculations thereon, using (i) multiple sequential determinations of a midline of the medical object image, (ii) a plurality of unfiltered raw-data cross-sectional intensity profiles perpendicular to each sequentially-determined midline, (iii) removal of outlier profiles from each plurality of profiles, and (iv) statistically combining each plurality of profiles to estimate image dimensions; (d) applying conical projection and radial elongation corrections to the image measurements; and (e) calculating the 3D position and orientation of the medical object from the corre

Abstract: An automatic method of categorizing the contact force of a catheter tip against a portion of a patient's heart based on motion of the catheter tip, the method comprising (a) capturing a series of 3D-coordinate data points of the catheter tip as a function of discrete times with a 3D medical imaging system, the 3D coordinates corresponding to an orthogonal 3-axis spatial coordinate system, (b) using a programmable computing system, computing a set of measures based on the series of 3D-coordinate data points, (c) categorizing each measure by a respective set of predetermined threshold values; and (d) combining the categorized measures to yield a relative quality of the contact force.

Abstract: The present invention is a method for generating and displaying a 3D visualization of a cardiac-ablation balloon in a region of a living heart within a predefined 3D space. The method comprises: placing, inflating and positioning the balloon into the region; generating a 3D image of the region using a 3D medical imaging system; determining 3D location and orientation of the balloon in the region; based on the determined location and orientation, inserting a 3D balloon model into the predefined space to generate the 3D visualization; and displaying the 3D visualization on a display device. The method enables a user to visualize where cardiac ablation was applied within the region after the balloon has been moved from where the ablation occurred.

Abstract: A method for determining the 3D location of a catheter distal end portion in a patient's body, the distal end portion including an electrode, the method comprising: (a) placing first and second body-surface patches on the patient in positions such that body region of interest is therebetween; (b) driving an alternating current between the patches; (c) measuring the voltage at the electrode and substantially contemporaneously capturing a 2D fluoroscopic image of the region of interest; and (d) determining the 3D location of the catheter distal end portion from the image and the measured voltage. A primary application of this method is 3D navigation during cardiac interventional procedures.

Abstract: A method of determining respiratory phase of a living body from a sequence of digitized fluoroscopic images of a living-body region exhibiting respiratory displacement, the method employing programmable computing apparatus and comprising the steps of: (a) in each living-body-region image in the sequence, defining one or more zones with each image having identical image-to-image zone locations, sizes, and shapes; (b) for each image, computing an average pixel intensity for each zone to form a sequence thereof for each zone; (c) for each zone, modifying the average pixel intensities by (i) computing the mean value of the sequence of average pixel intensities for such zone, and (ii) subtracting the mean from each average pixel intensity in the zone; (d) for each zone sequence, computing a figure-of-merit; (e) selecting the zone having the highest figure-of-merit; and (f) using the sequence of pixel intensities of the selected zone to determine respiratory phase.

Abstract: A method for generating and displaying a 3D visualization of a cardiac-ablation balloon with a location marker and central catheter portion in a heart, the method using single-plane fluoroscopic images and comprising: placing, inflating and positioning the balloon; capturing a first burst of images from a first angle; capturing a burst of images from a second (different) angle; selecting an image from each burst to minimize cardio-respiratory phase differences therebetween; identifying the location marker in each image; placing first and second orientation markers in two images where the central catheter portion intersects a projected balloon image farthest from the location marker; associating the second-view location and orientation markers in the selected second-view image with the first-view location orientation markers; determining balloon 3D location and orientation of the balloon using the selected images and associated orientation markers; and inserting a balloon model into the 3D visualization for di

Abstract: A method of determining respiratory phase of a living body from a sequence of digitized fluoroscopic images of a living-body region exhibiting respiratory displacement.

Abstract: A method of determining respiratory phase of a living body from a sequence of digitized fluoroscopic images of a living-body region exhibiting respiratory displacement.

Abstract: An automatic method of determining local activation time (LAT) from at least three multi-channel cardiac electrogram signals including a mapping channel and a plurality of reference channels. The method comprises (a) storing the cardiac channel signals, (b) using the mapping-channel signal and a first reference-channel signal to compute LAT values at a plurality of mapping-channel locations, (c) monitoring the timing stability of the first reference-channel signal, and (d) if the timing stability of the monitored signal falls below a stability standard, using the signal of a second reference channel to determine LAT values. Substantial loss of LAT values is avoided in spite of loss of timing stability.

Abstract: A method for generating a 3D map of a cardiac parameter in a region of a living heart, the method using single-plane fluoroscopic images and comprising: (a) placing a plurality of catheters each having one or more radio-opaque sensors into the region such that the locations of the sensors geometrically span the region; (b) capturing a first-view digitized 2D image of the region from a first fluoroscope positioned at a first angle; (c) identifying each of the plurality of sensors in the first-view image; (d) capturing a second-view digitized 2D image of the region from a second fluoroscope positioned at a second angle which is different from the first angle; (e) identifying each of the plurality of sensors in the second-view image; (f) associating each of the plurality of identified sensors in the second-view image with its corresponding identified sensor in the first-view image; (g) sensing and storing values of the cardiac parameter with each of the plurality of sensors; (h) determining the 3D location of ea

Abstract: A method for generating and displaying a 3D visualization of a cardiac-ablation balloon in a region of a living heart within a predefined 3D space, the method using single-plane fluoroscopic images and comprising: (1) placing, inflating and positioning the balloon into the region, the balloon having a radio-opaque location marker and central catheter portion; (2) capturing a burst of first-view digitized 2D images of the region from a fluoroscope positioned at a first angle; (3) capturing a burst of second-view digitized 2D images of the region from the fluoroscope positioned at a second angle different from the first angle; (4) selecting first-view and second-view images from the bursts such that the difference between measures of the cardio-respiratory phases of the selected first-view and second-view images is minimized; (5) identifying the location marker in each of the two selected images; (6) placing first and second orientation markers in the selected first-view and second view images, respectively, wh

Abstract: A method for automatically determining the 3D position and orientation of a radio-opaque medical object in a living body using single-plane fluoroscopy comprising: (a) capturing a stream of digitized 2D images from a single-plane fluoroscope; (b) detecting an image of the medical object in a subset of the digital 2D images; (c) applying to the digital 2D images calculations which preserve original pixel intensity values and permit statistical calculations thereon, using (i) multiple sequential determinations of a midline of the medical object image, (ii) a plurality of unfiltered raw-data cross-sectional intensity profiles perpendicular to each sequentially-determined midline, (iii) removal of outlier profiles from each plurality of profiles, and (iv) statistically combining each plurality of profiles to estimate image dimensions, thereby to measure the medical-object image from a final estimation of image dimensions; (d) applying conical projection and radial elongation corrections to the image measurements;

Abstract: A method for generating a 3D map of a cardiac parameter in a region of a living heart, the method using single-plane fluoroscopic images and comprising: (a) placing a plurality of catheters each having one or more radio-opaque sensors into the region such that the locations of the sensors geometrically span the region; (b) capturing a first-view digitized 2D image of the region from a first fluoroscope positioned at a first angle; (c) identifying each of the plurality of sensors in the first-view image; (d) capturing a second-view digitized 2D image of the region from a second fluoroscope positioned at a second angle which is different from the first angle; (e) identifying each of the plurality of sensors in the second-view image; (f) associating each of the plurality of identified sensors in the second-view image with its corresponding identified sensor in the first-view image; (g) sensing and storing values of the cardiac parameter with each of the plurality of sensors; (h) determining the 3D location of ea

Abstract: A method for detecting a stimulus pulse by using two or more electrical signals derived from a living body, the method comprising the following steps: (a) for each electrical signal, digitizing the signal with an analog-to-digital converter to produce a sampled signal Sk; (b) for each signal Sk at a sample time ti, computing a primary difference ?kp(ti)=abs[Sk(ti)?Sk(ti?p)]; (c) determining the minimum value of all of the computed differences, such minimum being a detector output D(ti); (d) comparing the detector output D(ti) with a detection threshold; and (e) indicating that a stimulus pulse has been detected when the detector output D(ti) is above the detection threshold.

Abstract: A method for automatically determining the 3D position and orientation of a radio-opaque medical object in a living body using single-plane fluoroscopy comprising capturing a stream of digitized 2D images from a single-plane fluoroscope (10), detecting the image of the medical object in a subset of the digital 2D images, applying pixel-level geometric calculations to measure the medical-object image, applying conical projection and radial elongation corrections (31) to the image measurements, and calculating the 3D position and orientation of the medical object from the corrected 2D image measurements.

Abstract: An automatic method of determining local activation time (LAT) from at least three multi-channel cardiac electrogram signals including a mapping channel and a plurality of reference channels. The method comprises (a) storing the cardiac channel signals, (b) using the mapping-channel signal and a first reference-channel signal to compute LAT values at a plurality of mapping-channel locations, (c) monitoring the timing stability of the first reference-channel signal, and (d) if the timing stability of the monitored signal falls below a stability standard, using the signal of a second reference channel to determine LAT values. Substantial loss of LAT values is avoided in spite of loss of timing stability.

Abstract: An automatic method of determining local activation time (LAT) from at least four multi-channel cardiac electrogram signals including a ventricular channel, a mapping channel and a plurality of reference channels. The method comprises (a) storing the cardiac channel signals, (b) using the ventricular and mapping channel signals and a first reference channel signal to compute LAT values at a plurality of mapping-channel locations, (c) monitoring the timing stability of the first reference channel signal, and (d) if the timing stability of the monitored signal falls below a stability standard, using the signal of a second reference channel to determine LAT values. Substantial loss of LAT values is avoided in spite of loss of timing stability.

Abstract: An automatic method of determining local activation time (LAT) from at least four multi-channel cardiac electrogram signals including a ventricular channel, a mapping channel and a plurality of reference channels. The method comprises (a) storing the cardiac channel signals, (b) using the ventricular and mapping channel signals and a first reference channel signal to compute LAT values at a plurality of mapping-channel locations, (c) monitoring the timing stability of the first reference channel signal, and (d) if the timing stability of the monitored signal falls below a stability standard, using the signal of a second reference channel to determine LAT values. Substantial loss of LAT values is avoided in spite of loss of timing stability.