阅读说明：本技术 血管内流动和压力测量结果 (Intravascular flow and pressure measurements ) 是由 A·范德霍斯特 A·K·贾殷 于 2018-03-30 设计创作，主要内容包括：本公开描述了生成身体结构的功能流动图的方法和系统。所述方法可以包括提供被配置用于插入到在跟踪场内的身体结构内的管腔内设备。所述管腔内设备可以包括被配置为获得一个或多个功能流动测量结果并且被配置为接收信号或引起所述跟踪场中的扰动的传感器。接收到的所述传感器的信号或扰动可以用来跟踪所述管腔内设备在所述身体结构内的一个或多个位置。所述传感器还可以用来获得所述跟踪位置处的所述功能流动测量结果。基于所述跟踪位置和所述功能流动测量结果,可以生成所述身体结构的所述功能流动图。(The present disclosure describes methods and systems for generating functional flowmaps of body structures. The method may include providing an intraluminal device configured for insertion into a body structure within a tracking field. The intraluminal device may include a sensor configured to obtain one or more functional flow measurements and configured to receive a signal or cause a perturbation in the tracking field. The received signals or disturbances of the sensor may be used to track one or more locations of the intraluminal device within the body structure. The sensor may also be used to obtain the functional flow measurements at the tracked location. Based on the tracked positions and the functional flow measurements, the functional flow map of the body structure may be generated.)

1. A method, comprising:

Providing an intraluminal device configured for insertion into a body structure within a tracking field, the intraluminal device comprising a sensor configured to obtain one or more functional flow measurements and configured to receive a signal or cause a disturbance in the tracking field;

Tracking one or more locations of the intraluminal device within the body structure using the received signals or the perturbation of the sensor;

Obtaining the functional flow measurements at the tracked locations using the sensors; and

generating a functional flow map of the body structure based on the tracked positions and the functional flow measurements.

2. The method of claim 1, wherein the functional flow measurements include at least one of blood pressure or blood flow velocity.

3. The method of claim 1, wherein the method is performed in real-time as the intraluminal device is moved through the tracking field.

4. The method of claim 1, wherein the tracking field is generated by transmitting ultrasound toward the sensor, wherein the sensor comprises an ultrasound receiver, and wherein using the received signals comprises performing unidirectional beamforming of the received signals.

5. The method of claim 1, further comprising providing a quality indication of the functional flow measurements obtained using the sensor, wherein the quality indication is based at least in part on the tracked position of the sensor relative to the tracking field.

6. The method of claim 5, wherein the tracked position comprises at least one of a proximity of the sensor to an inner lumen wall, an angle between the sensor and the inner lumen wall, or a level of movement of the sensor relative to the inner lumen wall.

7. The method of claim 1, wherein generating the functional flow map comprises rejecting measured blood pressure or measured blood flow velocity associated with a quality value below a threshold quality value.

8. The method of claim 2, wherein generating the functional flow map comprises combining blood pressure or blood flow velocity measurements obtained using the sensor with a flow velocity estimate derived from an external ultrasound system.

9. The method of claim 1, wherein obtaining the functional flow measurement using the sensor comprises transmitting and receiving an intraluminal ultrasound signal at the sensor.

10. The method according to claim 1, further comprising displaying an image comprising the functional flow map superimposed on an image of the body structure.

11. A system, comprising:

An intraluminal device configured for insertion into a body structure within a tracking field;

a sensor positioned on the intraluminal device, wherein the sensor is configured to obtain one or more functional flow measurements and is configured to receive a signal or cause a disturbance in the tracking field;

A tracking system communicatively coupled to the sensor to generate tracking data in response to the received signal or a disturbance caused by the sensor; and

One or more processors in communication with the sensors and the tracking system, the one or more processors configured to:

Tracking one or more locations of the intraluminal device within the body structure using the received signals or the perturbation of the sensor;

Obtaining the functional flow measurements at the tracked locations using the sensors; and is

Generating a functional flow map of the body structure based on the tracked positions and the functional flow measurements.

12. The system of claim 11, wherein the functional flow measurements include at least one of blood pressure or blood flow velocity.

13. The system according to claim 11, further comprising a display in communication with the one or more processors, wherein the one or more processors are configured to cause the display to display an image including the functional flow map superimposed on an image of the body structure.

14. The system of claim 12, wherein the one or more processors are configured to cause the display to display a quality indication of the blood pressure or blood flow velocity measurements obtained using the sensor, and wherein the quality indication of the blood pressure or blood flow velocity measurements is based at least in part on the tracked location.

15. The system of claim 12, wherein the one or more processors are configured to ignore blood pressure or blood flow velocity measurements associated with quality values below a threshold quality value when generating the functional flow map.

16. The system of claim 11, wherein the tracking system is an ultrasound tracking system comprising an ultrasound transmitter configured to transmit ultrasound towards the sensor, wherein the sensor comprises an ultrasound receiver, and wherein the ultrasound tracking system is configured to locate the position of the ultrasound receiver by performing unidirectional beamforming of signals received by the ultrasound receiver when placed within a field of view of the ultrasound transmitter.

17. The system of claim 16, wherein the tracking system is provided by an ultrasound array of an ultrasound imaging system configured to generate an ultrasound image comprising a B-mode image of the body structure superimposed with the functional flowgrams.

18. The system of claim 17, wherein the ultrasound imaging system is configured to generate an ultrasound image further comprising the tracked position of the sensor, the tracked position of the sensor being updated in real-time in the ultrasound image.

19. The system of claim 11, wherein the tracking system is an ultrasound system configured to generate color flow doppler or vector flow images, and wherein the one or more processors are configured to generate the functional flow map in combination with a flow velocity estimate derived by the ultrasound system using the one or more functional flow measurements obtained by the sensors.

20. The system of claim 11, wherein the tracking system is an Electromagnetic (EM) tracking system comprising a field generator configured to generate an EM field, wherein the sensor comprises one or more sensor coils, and wherein the EM tracking system is configured to locate the tracking position of the one or more sensor coils in response to a perturbation of the EM field caused by the one or more sensor coils when placed within the EM field.

Technical Field

The present invention relates to a system and method for obtaining hemodynamic measurements and mapping the measurements to specific locations within a body structure. More particularly, the present invention relates to ultrasound systems and methods for obtaining blood pressure and/or flow measurements using an intraluminal device and mapping the measurements to specific intraluminal locations using a tracking system to generate a functional flow map of a body structure.

Background

Assessing hemodynamic significance of cardiovascular and peripheral vascular disease from intravascular pressure and/or flow measurements has proven beneficial for guiding the treatment of atherosclerotic disease. For example, in the coronary arteries, obtaining intraluminal blood pressure measurements using pressure sensors mounted on a guidewire/catheter is currently a treatment standard for evaluating cardiovascular disease. However, according to such methods, the position of the pressure sensor must be co-registered with the intraluminal pressure readings, which can be difficult. Obtaining accurate intraluminal blood flow velocity using a catheter/guidewire can be more difficult because the velocity profile of a given vessel is typically dependent on the vessel anatomy. Furthermore, recognizing the position and/or orientation of the flow sensor relative to the vessel is crucial for obtaining reliable flow measurement data, especially using current ultrasound guidewires, which generally determine blood flow velocity in the direction of the wire rather than the direction of the vessel. Existing guidewires therefore often fail to provide accurate measurements of blood flow and blood pressure. Accordingly, techniques for more accurately and reliably measuring blood flow and blood pressure at localized locations within a blood vessel may be desirable.

Disclosure of Invention

Methods, systems, and devices are provided herein for obtaining hemodynamic measurements within a body structure (such as a lumen of a blood vessel) and mapping the measurements to specific intraluminal locations using an external tracking system. The tracking data collected by the external tracking system may be used to assess the quality of hemodynamic measurements obtained within the lumen of the tube, which may be obtained using one or more sensors included on the intraluminal device (e.g., a guidewire). In certain embodiments, the tracking data is acquired from the same sensor used for hemodynamic measurements. For example, certain measurements may be discarded based on the position and/or orientation of the sensor relative to the luminal inner wall of the body structure. One or more processors may be used to combine externally acquired tracking data with intraluminal hemodynamic data and create a functional flow map that overlays both data types. In some examples, a body structure containing the sensor may also be imaged and the resulting image(s) superimposed on the functional flow map, such that the intraluminal measurements are displayed on the image of the body structure at the location where the measurements were obtained. Hemodynamic data acquired within a body structure may include measurements of intraluminal blood pressure, blood flow velocity, and/or blood flow direction. Hemodynamic data can also be estimated using a tracking system (e.g., via doppler flow imaging) and used in conjunction with corresponding intraluminal measurements to adjust for inaccurate and/or misaligned measurements. Tracking systems that may be implemented to perform the methods described herein may include ultrasound and/or electromagnetic tracking systems, each configured to generate a tracking field in which the position and/or orientation of an intraluminal device may be monitored. In some embodiments, tracking is based on when the sensor receives a signal from the disturbance using time-of-flight measurements, e.g., tracking a location within the field is based on the time it takes for an external signal or disturbance to be received by the sensor.

According to some examples, a method may include providing an intraluminal device configured for insertion into a body structure within a tracking field. The intraluminal device may include one or more sensors, and at least one sensor is configured to obtain one or more functional flow measurements and to receive signals or cause disturbances in the tracking field. The method may further include tracking one or more locations of the intraluminal device within the body structure using the received signals or perturbations of the sensors, obtaining the functional flow measurements at the tracked locations using the sensors, and generating a functional flow map of the body structure based on the tracked locations and the functional flow measurements.

In some examples, the functional flow measurements may include at least one of blood pressure or blood flow velocity. In various embodiments, the method may be performed in real-time as the intraluminal device is moved through the tracking field. In some embodiments, the tracking field may be generated by transmitting ultrasound towards the sensor, wherein the sensor comprises an ultrasound receiver, and wherein using the received signals involves performing unidirectional beamforming of the received signals.

Some example methods may further include providing an indication of a quality of the functional flow measurements obtained using the sensor. The indication of quality may be based at least in part on the tracked position of the sensor relative to the tracking field. In some embodiments, the tracked position may include a proximity of the sensor to an inner lumen wall, an angle between the sensor and the inner lumen wall, and/or a level of movement of the sensor relative to the inner lumen wall.

In some embodiments, generating the functional flow graph may include rejecting measured blood pressure or measured blood flow velocity associated with a quality value below a threshold quality value. Additionally or alternatively, generating the functional flow map may include combining blood pressure or blood flow velocity measurements obtained using the sensor with a flow velocity estimate derived from an external ultrasound system. In some embodiments, obtaining the functional flow measurement using the sensor may include transmitting and receiving an intraluminal ultrasound signal at the sensor. The method may further comprise displaying an image comprising the functional flow map superimposed on an image of the body structure.

According to some examples, a system may include an intraluminal device that provides a body structure configured for insertion within a tracking field. One or more sensors may be positioned on the intraluminal device, with at least one sensor configured to obtain one or more functional flow measurements and configured to receive signals or cause disturbances in the tracking field. The system may further include a tracking system communicatively coupled to the sensor to generate tracking data in response to the received signal or a disturbance caused by the sensor. The system may further include one or more processors in communication with the sensors and the tracking system. The one or more processors may be configured to: tracking one or more locations of the intraluminal device within the body structure using the received signals or perturbations of the sensors; obtaining the functional flow measurements at the tracked locations using the sensors; and generating a functional flow map of the body structure based on the tracked position and the functional flow measurements. The functional flow measurements may include at least blood pressure and/or blood flow velocity. In some examples, the system may further include a display in communication with the one or more processors, wherein the one or more processors are configured to cause the display to display an image including the functional flow map superimposed on an image of the body structure. In some embodiments, the one or more processors are configured to cause the display to display an indication of a quality of the blood pressure or blood flow velocity measurements obtained using the sensor, wherein the indication of the quality of the blood pressure or blood flow velocity measurements is based at least in part on the tracked location. The one or more processors may be further configured to ignore blood pressure or blood flow velocity measurements associated with quality values below a threshold quality value when generating the functional flow map.

in some embodiments, the tracking system may comprise an ultrasound tracking system comprising an ultrasound transmitter configured to transmit ultrasound towards the sensor, wherein the sensor comprises an ultrasound receiver, and wherein the ultrasound tracking system is configured to locate the position of the ultrasound receiver by performing unidirectional beamforming of signals received by the ultrasound receiver when placed within a field of view of the ultrasound transmitter. In some examples, the tracking system may be provided by an ultrasound array of an ultrasound imaging system configured to generate an ultrasound image including a B-mode image of the body structure superimposed with the functional flow graph. The ultrasound imaging system may be configured to generate an ultrasound image further comprising the tracked position of the sensor, the tracked position of the sensor being updated in real-time in the ultrasound image. In some examples, the tracking system may be configured as an ultrasound system that generates color flow doppler or vector flow images, wherein the one or more processors are configured to generate the functional flow map using the one or more functional flow measurements obtained by the sensors in combination with a flow velocity estimate derived by the ultrasound system.

in additional or alternative embodiments, the tracking system may comprise an Electromagnetic (EM) tracking system comprising a field generator configured to generate an EM field, wherein the sensor comprises one or more sensor coils, and wherein the EM tracking system is configured to locate the tracking position of the one or more sensor coils in response to a perturbation of the EM field caused by the one or more sensor coils when placed within the EM field.

drawings

Fig. 1 is a block diagram of a flow diagram generation system according to the principles of the present disclosure.

Fig. 2 is an illustration of an intraluminal device equipped with a sensor positioned near the center of a vessel, according to the principles of the present disclosure.

Fig. 3 is an illustration of an intraluminal device equipped with a sensor positioned near the turning point of a blood vessel, according to the principles of the present disclosure.

Fig. 4 is an illustration of moving an intraluminal device of the aorta equipped with a sensor positioned near the center of the vessel according to the principles of the present disclosure.

Fig. 5 is a block diagram of another flow diagram generation system according to the principles of the present disclosure.

Fig. 6 is a block diagram of an ultrasound tracking system according to the principles of the present disclosure.

Fig. 7 is a block diagram of a flow diagram generation method according to the principles of the present disclosure.

Detailed Description

The following description of certain exemplary embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. In the detailed description of the embodiments of the present systems and methods, reference is made to the accompanying drawings (which form a part hereof), and in which is shown by way of illustration specific embodiments in which the described systems and methods may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the presently disclosed systems and methods, and it is to be understood that other embodiments may be utilized and that structural and logical changes may be made without departing from the spirit and scope of the present system. Furthermore, for the sake of brevity, where specific features are readily apparent to those of ordinary skill in the art, a detailed description of such features will not be discussed so as not to obscure the description of the present system. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present system is defined only by the claims.

Fig. 1 illustrates an example system 100 configured to generate a functional flow graph of a body structure according to this disclosure. As shown, the system 100 may include an intraluminal device 102, e.g., a catheter, microcatheter, or guidewire, the intraluminal device 102 configured for insertion into a bodily structure 104 (such as a blood vessel) defining an internal lumen 105. The intraluminal device 102 may include one or more sensors 106, the one or more sensors 106 configured to obtain various functional flow measurements in the form of hemodynamic intraluminal data 107, such as blood flow velocity and/or blood pressure. Functional flow measurements may be obtained within tracking field 108 generated by external tracking system 110. The at least one sensor 106 is also configured to receive signals or disturbances generated by the external tracking system 110. The tracking system 110 shown in fig. 1 includes a tracking field generator 111 and a tracking processor 112, both of which tracking field generator 111 and tracking processor 112 may be communicatively coupled to the sensor 106. Tracking system 110 may be configured to generate tracking data 114 in response to detected movement of sensor 106 (e.g., in response to a disturbance 118 caused by sensor 106 within tracking field 108). In other embodiments, the tracking system 110 may transmit a signal 116, such as an ultrasonic signal, toward the sensor 106, which sensor 106 may include an ultrasonic receiver. The sensor 106 may generate a signal in response to the detected ultrasound, and the signal may be transmitted (e.g., via a wired or wireless connection) to the tracking system 110 or the processor 126 (such as via a wired connection to transmit the intraluminal data 107). The tracking system 110 may generate tracking data 114, which tracking data 114 may be used to track the sensor 106 with respect to the body structure. For example, the tracking data 114 generated by the tracking system 110 may contain information about the location and/or orientation of the sensor 106, which may be collected in real-time as the intraluminal device 102 is moved through the body structure 104. In embodiments where the sensor 106 communicates the tracking signal directly to the processor 126, the processor 126 may be configured to determine the position and/or orientation of the sensor 106 relative to the body structure 104. For example, the processor may be configured to generate tracking data 114 based on signals from the sensors 106 and/or additional information transmitted from the tracking system 110 (e.g., information about ultrasound tracking pulses). Other arrangements of tracking sensors relative to the tracking system and/or the processor 126 may be used.

As further shown, the intraluminal device 102 may be coupled to a device system 120, which device system 120 may include a device controller 122 and a device processor 124, which device controller 122 and device processor 124 are configured to operate the intraluminal device 102 and process intraluminal data 107 it collects, respectively. Communicatively coupled to both the tracking processor 112 and the device processor 124 is an integrated processor 126. The integrated processor 126 may be configured to receive and process the tracking data 114 received from the tracking system 110 and the intraluminal data 107 received from the device system 120. By compiling data from two information sources, the integrated processor 126 may be configured to combine the position information of the sensor 106 with the functional flow measurements obtained within the lumen 105, thereby generating a functional flow map 128, the functional flow map 128 including functional flow measurements mapped to particular locations within the body structure 104. The system shown in fig. 1 also includes a display 130, which display 130 may be communicatively coupled with integrated processor 126 and may include an interactive user interface 131. The display 130 may be configured to display the functional flowsheet 128 superimposed on an image 132 (e.g., B-mode) of the body structure 104. In some examples, the display 130 may be further configured to display an indication of the quality 133 of the one or more functional flow measurements.

the integrated processor 126 may be configured to process data received from both the sensors 106 and the tracking system 110 in a variety of ways. The integrated processor 126 may be formed of one or more processors. For example, as set forth above, the integrated processor 126 may be configured to generate the functional flow graph 128. The functional flow map 128 may include various flow and/or pressure measurements collected from within the lumen 105 of the body structure 104, each measurement corresponding to a particular location at which the measurement was obtained. In one example, the functional flow map 128 may include blood flow velocity measurements mapped to one or more locations within the vessel. As the intraluminal device 102 is moved through the body structure 104, new velocity measurements collected by the sensors 106 may be added to the map 128 at discrete locations where they are detected. Additionally or alternatively, the functional flow graph 128 may contain blood pressure readings obtained by the sensor 106 at various locations within the blood vessel. In yet another example, blood flow direction data may be obtained by the sensor 106 and mapped to different locations within the functional flow map 128. Two or more different types of functional flow measurements may be included on the functional flow map 128 depending on the functionality of the sensors 106 or the number of sensors coupled to a particular intraluminal device 102. Such measurements may be displayed simultaneously or individually via display 130. Under control of the user, the display 130 may be configured to switch between multiple versions of the function flow graph 128. For example, a user wishing to view only data regarding blood flow velocity may select an option for viewing the functional flow graph 128 including such data, for example at the user interface 131. Another selectable option may include only blood pressure data, while another may include two or more data types.

Obtaining functional flow measurements via sensor 106 and mapping these measurements to specific intraluminal locations via tracking system 110 may facilitate improved data collection and interpretation. For example, blood pressure, fractional flow reserve ("FFR"), instantaneous wave-free ratio ("iFR"), blood flow velocity, direction of blood flow, volumetric blood flow, coronary flow reserve ("CFR"), flow resistance, and/or microcirculation, and other hemodynamic parameters may fluctuate at different locations within a blood vessel. The ability to measure these parameters using currently available guidewires/catheters also varies at different locations. For example, a sensor oriented parallel to the inner wall of the surrounding lumen may collect more accurate data about blood flow velocity than the same sensor oriented perpendicular to the inner wall of the lumen. Thus, by taking into account the functional flow measurements and the location at which the measurements were obtained, the quality or accuracy of the measurements can be evaluated. As discussed herein, the accuracy of the intraluminal data 107 may be corrected by combining such data with externally obtained tracking data 114. Additionally or alternatively, the intraluminal data 107 may be filtered based on tracking data 114 obtained via the tracking system 110.

The integrated processor 126 depicted in fig. 1 comprises a single component coupled with two separate processors, however, the configuration of the integrated processor 126 may vary. For example, the integrated processor 126 may include two or more processors. In some examples, integration of the intraluminal data 107 with the tracking data 114 may not be performed by distinct components. Alternatively, data integration may occur within the same processor that is used to process the tracking data 114 and/or the intraluminal data 107. Thus, in some examples, the device processor 124 and/or the tracking processor 112 may be configured to generate the function flow graph 128. In various embodiments, the different device processor 124 and the trace processor 112 may be omitted altogether, such that the integration processor 126 performs initial processing and final consolidation of data received from the trace system 110 and the device system 120.

The manner in which the integrated processor 126 is configured to process the various functional flow measurements (e.g., blood pressure and/or blood flow velocity) in series with the tracking data 114 may vary. In some embodiments, the integrated processor 126 may be configured to determine a quality indication 133 of one or more functional flow measurements obtained using the sensor 106. The quality indication 133 may be based at least in part on the tracked position of the sensor 106 and may be displayed on the display 130 in real-time as measurements are being collected. The quality indication 133 may be improved relative to a curved portion when the sensor 106 is positioned within a relatively straight portion of a vessel, such as a curved portion particularly near particularly tight corners, where the sensor 106 may be more likely to face the inner wall of the lumen. The quality indication 133 may be displayed in a binary manner such that a given functional flow measurement is considered "acceptable" or "unacceptable," or the quality indication 133 may be continuously adjusted on a relative scale from "high quality" to "low quality. According to such embodiments, when tracking data 114 and intraluminal data 107 are obtained, for example, via ultrasound, the quality measurements may be evaluated on a frame-by-frame basis

In some examples, the integration processor 126 may be configured to reject, ignore, or otherwise filter the functional flow measurements associated with quality values below a threshold quality value when generating the functional flow graph 128. In this manner, the functional flow map 128 may selectively include only functional flow measurements deemed to be of sufficient quality. Measurements that satisfy the quality threshold applied by the integrated processor 126 may be interpolated with data points corresponding to intervening intraluminal locations and/or time points excluded. Various parameters may be evaluated by the integrated processor 126 to determine whether the functional flow measurements satisfy a threshold quality value. For example, the tracked position of sensor 106 may include information about the proximity of sensor 106 to the inner wall of the lumen, the angle between sensor 106 and the inner wall of the lumen, and/or the level of movement of sensor 106 relative to the inner wall of the lumen. One or more of these parameters may affect the quality of the measurements obtained by the sensor 106. For example, the mass may decrease at a location closer to the inner wall of the lumen. In some embodiments, the integrated processor 126 may be configured to automatically determine, based on the tracking data 114 received from the tracking system 110, whether the distal tip portion of the intraluminal device 102 (which may be coupled with the sensors 106) is positioned in the radial center of the vessel, near the vessel wall, or somewhere in between. Functional flow measurements obtained when the sensor 106 is positioned near the wall may be rejected, while a location closer to or at the center may be accepted for further processing and/or included within the functional flow map 128. Similarly, the mass may be reduced if the sensor 106 is moving toward or away from the intraluminal wall, for example if the sensor is oscillating due to turbulent blood flow and/or the intraluminal device 102 is being propelled by a user.

example scenarios where functional flow measurements may be rejected or accepted by the integrated processor 126 are illustrated in fig. 2-4. Each figure depicts the intraluminal device 102 coupled to a sensor 106 positioned within a lumen 105 of a body structure 104, the lumen 105 of the body structure 104 being represented as a blood vessel. For purposes of explanation, vessel 104 is shown to include two parallel intraluminal walls 105a and 105b defining an intraluminal space 105; however, the blood vessel 104 comprises only one inner cylindrical lumen wall. In fig. 2, the sensor 106 is positioned near the center of the blood vessel 104, at approximately equal distances from the two lumen inner walls 105a, 105 b. Functional flow measurements collected from this position and orientation by the sensor 106 may be accepted by the integrated processor 126 and displayed on the functional flow graph 128. In contrast, fig. 3 is a scenario where functional flow measurements collected by the sensors 106 may be rejected by the integrated processor 126. Specifically, sensor 106 is facing inner lumen wall 105a and facing away from inner lumen wall 105 b. In this orientation, the sensor 106 may collect inaccurate measurements. Therefore, these measurements can be excluded from the functional flow graph 128. Fig. 4 depicts yet another scenario in which the integrated processor 126 may be configured to reject the intraluminal data 107 collected by the sensors 106. In fig. 4, sensor 106 is being moved vertically in the direction of the arrow toward lumen inner wall 105 b. Sensor 106 may be oscillating up and down to alternately approach lumen inner walls 105a and 105b in rapid succession. This movement of the sensor 106 may prevent it from obtaining accurate measurements, particularly with respect to flow rate. Therefore, the intraluminal data 107 obtained in this orientation may also be excluded.

Intraluminal data 107 relating to functional flow measurements obtained via the sensors 106 may be rejected or deemed of poor quality for a number of additional reasons. For example, certain locations within the body structure 104 may be preemptively avoided, and thus the intraluminal data 107 obtained in these locations may be automatically rejected by the integrated processor 126. The intraluminal data 107 may also be rejected if secondary flow is detected within the lumen 105 (which may occur particularly frequently near vessel bifurcations and/or stenoses). The secondary flow may be detected manually or automatically by the tracking system 110 and communicated to the integrated processor 126 to aid in data filtering.

The intraluminal device 102 and the sensor 106 may include various configurations and/or functionalities. Sensor 106 may be permanently attached, integrally formed, or reversibly coupled with intraluminal device 102. The window within which the sensor 106 obtains the intraluminal data 107 may be located and variable in size. For example, the measurement window size of the sensor 106 may range from about 1mm to about 15mm, from about 2mm to about 12mm, from about 3mm to about 9mm, from about 4 to about 8mm, or about 6 mm. As shown in fig. 1-4, in some embodiments, only one sensor 106 may be included on an individual intraluminal device 102. According to some examples, a single sensor 106 may be configured to alternate between different modes of operation. For example, the sensor 106 may include an ultrasound receiver communicatively coupled with an external ultrasound tracking system. In such an example, the sensor 106 may be configured to alternate between a receive mode and a transmit mode. In a receive mode, the sensor 106 may be operable to receive externally generated ultrasound signals, and in a transmit mode, the sensor 106 may be configured to transmit ultrasound signals in the lumen 105. Additionally or alternatively, the sensors 106 may be time-segmented to alternate between tracking and measurement modes. In the tracking mode, for example, the sensor 106 may transmit and/or receive ultrasound signals, while in the measurement mode, the sensor 106 may monitor the intraluminal blood pressure. Alternatively, two or more sensors 106 may be included on a single intraluminal device 102. Where two or more sensors are included on a single device, the sensors may be offset from each other by various distances along the length of the device. In some examples, each sensor may be configured to perform a distinct function, which may depend in part on the type of tracking system used. For example, the first sensor may be a tracking sensor configured to receive ultrasound signals transmitted from an external ultrasound transmitter towards the sensor, while the second sensor may be configured to determine one or more functional flow measurements within a lumen of the body structure, such as blood pressure.

in some embodiments, the sensor 106 may be configured to obtain intraluminal data 107 about blood flow. Such sensors 106 may include ultrasound transducers, e.g., lead zirconate titanate ("PZT") transducers, capacitive micromachined ultrasound transducers ("CMUTs"), or single crystal transducers, and may be configured to measure blood flow velocity, e.g., via doppler flow, by transmitting an ultrasound signal or beam 134 into the lumen 105 of the body structure 104 and receiving a signal 136 in response to the transmitted signal 134 (as shown in fig. 2-4). As described in more detail below with reference to fig. 5, the same sensor 106 may also be configured to receive ultrasound signals transmitted into the body structure 104 from an external ultrasound device.

In some embodiments, the sensor 106 may be configured to obtain intraluminal data 107 regarding blood pressure. Such sensors 106 may be configured to measure blood pressure within resultant lumen 105 via various techniques, including fractional flow reserve ("FFR") and/or instantaneous wave-free ratio FFR ("iFR"). The sensors configured to obtain pressure data may be pressure sensitive and capacitive, and may be used to locate the position of the sensors in an externally generated tracking field 108. The functional flow graph 128, which includes blood pressure measurements, may include different colors to represent different pressures measured at different locations. Sensors equipped to measure blood pressure may be used in accordance with various pullback measurement techniques, which may generally include detecting a pressure gradient within the body structure 104 as the intraluminal device 102, and thus the blood pressure sensor 106 coupled thereto, is moved through the body structure. Some embodiments may further include electrocardiographic gating of blood pressure measurements such that pressure readings are displayed as a function of cardiac cycle. According to such embodiments, pressure measurements may be obtained during systole and diastole, with intervening values being interpolated via one or more of the processors shown in fig. 1.

In some examples, the sensor 106 may be configured to facilitate tracking. For example, the sensors 106 may include one or more sensors, in some examples, an array of sensors, for receiving signals or disturbances transmitted through the body. The signals transmitted through the body may be ultrasonic, mechanical, electromechanical, etc. Particular embodiments may include a tracking sensor 106 such as described in U.S. patent publication No. US 2016/0317119(Maraghoosh), which is incorporated by reference herein in its entirety. According to such embodiments, the sensors 106 may include one or more sensors (e.g., ultrasonic sensors) responsive to signals generated from the external tracking system 110. An external tracking system may be operably associated with the intraluminal sensor 106 to track the location of the sensor 106. The tracking system 110 may include a processor, such as a tracking processor 112, that may be configured to determine the position and/or orientation of the sensor 106 from signals generated by the sensor 106 and received by the external tracking system 110. In some embodiments, the sensor 106 may be an ultrasonic receiver configured to detect ultrasonic waves. The sensor 106 may generate a signal in response to the detected waves, and the signal may be transmitted to a processor 112 of the tracking system for determining the relative position and/or orientation of the sensor 106 with respect to the source of ultrasonic waves. In such embodiments, unidirectional beamforming (e.g., reflecting unidirectional time of flight between the source and the sensor) may be used to determine the location of the sensor 106. In other embodiments, the sensor 106 may be an ultrasound transmitter configured to generate ultrasound toward an external receiver (e.g., an imaging array). The relative position and/or orientation of the sensor 106 with respect to the external receiver may thus be determined. According to examples of the present disclosure, the type of tissue surrounding the sensor 106 may also be classified in response to signals received at the sensor 106. In further embodiments, different arrangements of ultrasound tracking sensors (e.g., sensors 106) may be used, which may employ unidirectional or bidirectional beamforming to determine the position and/or orientation of the sensors at any given time. Moreover, in other examples, non-ultrasonic sensors (e.g., EM tracking sensors) may be used.

The intraluminal device 102 may include one or more sensors 106 configured to measure one or more hemodynamic characteristics, including blood flow velocity, blood pressure, and/or blood flow direction. Example intraluminal devices that may be implemented in system 100 include flowre, verata, and/or combowre of Koninklijke Philips Volcano ("Philips"). In some examples, the intraluminal device 102 may be configured for manual steering in the body structure 104. Movement of the device 102 may also be performed robotically, with image guidance provided by an ultrasound tracking system, for example.

in different embodiments, the type of tracking system 110 included in the system 100 may vary. For example, the tracking system 110 may include an electromagnetic tracking system. According to such an example, tracking field generator 111 may comprise an electromagnetic field generator configured to generate an electromagnetic field 108, the electromagnetic field 108 surrounding the body structure 104 containing the intraluminal device 102. The sensor 106 employed may include one or more sensor coils. In operation, the electromagnetic tracking system 110 may be configured to locate a tracking position of one or more sensor coils in response to a disturbance caused within the electromagnetic field by the one or more sensor coils when placed within the electromagnetic field. In some examples, the electromagnetic tracking system 110 may be used in conjunction with an imaging system (e.g., an ultrasound imaging system). Such examples may include at least two sensors 106 mounted at known locations on a single intraluminal device 102. The first sensor may comprise a coil configured to cause a perturbation in the electromagnetic field 108 generated by the tracking field generator 111, and the second sensor may comprise an array configured to receive ultrasound signals from an external ultrasound imaging system. The position of the second sensor may be registered to the position of the first sensor by the tracking system 110 and the imaging system to determine the position and/or orientation of the sensor on the intraluminal device, for example, in U.S. patent publication nos.: US2015/0269728(Parthasarathy), which is hereby incorporated by reference in its entirety. In further examples, EM tracking system 110 may not include an ultrasound sensor and may be configured to determine a location of an EM sensor that may be registered to an EM tracking field based on movement of the EM sensor within the tracking field.

The functionality of a given tracking system 110 may affect the degree of its input within the overall system 100. For example, the tracking system 110 may also include an ultrasound tracking system that may estimate blood flow characteristics from the external vantage point. Fig. 5 shows an example of such a system according to an embodiment of the present disclosure. Like the system 100 shown in fig. 1, the system 500 includes an intraluminal device 502 positioned within a bodily structure 504 (such as a blood vessel having a lumen 505). The intraluminal device 502 includes at least one sensor 506, the at least one sensor 506 including an ultrasound receiver 507. The sensor 506 may be configured to obtain various functional flow measurements (e.g., blood pressure and/or blood flow velocity) within a tracking field 508 generated by an external ultrasound tracking system 510. In this embodiment, the external ultrasound tracking system 510 includes an external ultrasound probe 512, a probe controller 514, and an ultrasound processor 516, each of which may be coupled within the tracking system. The probe 512 may include an ultrasound sensor array 518 configured to transmit ultrasound signals 520 into the body structure 104 and receive signals 522 in response to the transmitted signals. The ultrasound tracking processor 516 may be configured to generate tracking data 524 in response to the received signal 522. Tracking data 524 generated by the ultrasound tracking system 510 may contain information about the position and/or orientation of the sensor 506 as well as externally acquired functional flow data. As in the system 100, the intraluminal device 502 may be coupled to a device system 528, which device system 528 may include a device controller 530 and a device processor 532, the device controller 530 and the device processor 532 being configured to operate the intraluminal device 502 and process the intraluminal data 503 it collects, respectively. Communicatively coupled to both the ultrasound tracking processor 516 and the device processor 632 is an integrated processor 534, the integrated processor 534 configured to receive and process data from the ultrasound tracking system 510 and the device system 528. The system 500 may be coupled with a display 536, which display 536 may be configured to display an image 537 of the body structure, which image 537 may be incident with a functional flow graph 538 generated by the integrated processor 534. The user interface 539 and the indication of quality 540 may also be included and/or displayed by the display 536.

In the case of the ultrasound tracking system 510, tracking the position and/or orientation of the sensor 506 may also include imaging the sensor 506, and in some examples, one or more aspects of surrounding features of the body structure 504. In some embodiments, the ultrasound tracking system 510 may be configured to locate the position of the ultrasound receiver 507 by performing unidirectional beamforming of the signals received at the receiver 507 (i.e., the transmitted signals 520) when placed within the field of view of the ultrasound probe 512, for example as described in U.S. patent publication nos.: US 2013/0041252(Vignon), which is hereby incorporated by reference in its entirety. Such embodiments may include transmitting one or more ultrasound pulses from the external ultrasound tracking system 510. Each pulse may be received by an ultrasonic receiver 507 on the sensor 506. Based on the time of flight from the transmission of the pulse until its reception at the receiver 507, the distance of the receiver 507, and thus the sensor 506, from the external ultrasound tracking system 510 may be determined. In an embodiment, the ultrasound tracking system 510 may be provided by an ultrasound array of an ultrasound imaging system configured to generate an ultrasound image 537 of the body structure 504. The image 537 may be of many different types, such as B-mode, doppler, vector flow, and/or raw signal display, to name a few. One or more of these images 537 may be superimposed onto the functional flow map 538 generated by the integrated processor 534. Ultrasound image 537 may include the tracked position of sensor 506 and may be updated in real-time. In some examples, multiple image types may be integrated into the same functional flowgraph 538, such that the graph contains, for example, B-mode and doppler images superimposed on an FFR pullback graph. Possible ultrasound imaging systems may include, for example, mobile systems such as LUMIFY from Philips, or SPARQ and/or EPIQ, also produced by Philips.

Externally acquired tracking data 524, including functional flow data collected via the ultrasound tracking system 510, may be used to improve the accuracy of the intraluminal data 503 collected at the sensor 506. In particular, externally acquired functional flow data may be used to enrich the intraluminal data by correcting for mismatched data or otherwise combining the intraluminal data with externally acquired data. For example, in addition to collecting tracking data 524 regarding the position/orientation of sensor 506, ultrasound tracking system 510 may be configured to estimate a flow velocity and/or a flow direction of blood within body structure 504. In particular embodiments, the ultrasound tracking system 510 may be configured to generate color flow doppler or vector flow images. According to such embodiments, the integrated processor 534 may be configured to combine one or more functional flow measurements obtained using the sensor 506 with the flow estimate derived by the ultrasound tracking system 510. Such compiled data may be fused into function flow graph 538. In various embodiments, the ultrasound tracking system 510 may be configured to acquire information about the location of a blood vessel, the size of a blood vessel, doppler-based flow information, 3D information, and/or vector flow information. Any or all of these information types may be used to supplement and/or modify the intraluminal data 503 acquired at the sensors 506 to provide improved flow information for inclusion in the functional flow map.

In particular embodiments, the tracking data 524 collected from the ultrasound tracking system 510 may be integrated with the intraluminal data 503 as part of an improved flow calculation model. The flow computation model may feed local intraluminal data into external doppler and/or vector flow estimates, or vice versa. Different external imaging modes of the ultrasound tracking system may also be used to improve the accuracy of the external flow estimation. The cross-sectional area of the body structure at the location of the sensor may also be estimated and incorporated into the bulk flow estimate, which may generally be calculated by multiplying the cross-sectional area of a particular location within the body structure by the average velocity of the measurements at that location. In some examples, 3D volumetric flow calculations obtained via 3D ultrasound modalities may be used to further improve volumetric flow calculations.

Fig. 6 is a block diagram of an external ultrasound tracking system 610 configured to obtain ultrasound images in accordance with the principles of the present disclosure. The ultrasound tracking system 610 may be incorporated into a system for generating functional flow maps, such as the system 510. The images acquired via the ultrasound tracking system 610 may be combined with functional flow maps such that a variety of information (e.g., blood pressure and/or flow rate) obtained at a particular location within a vessel may be displayed on the image of the vessel at the location where the measurements were collected. The ultrasound tracking system 610 includes additional components not shown in fig. 5 that may be included within a tracking system configured to detect sensors coupled with the intraluminal device. For example, processing operations performed by one or more of the above-mentioned processors (such as the ultrasound processor 516, the device processor 532, and/or the integrated processor 534) may be implemented in and/or controlled by one or more of the processing components shown in fig. 6 (including, for example, the B-mode processor 628, the volume mapper 634, and/or the image processor 636). Additionally, one or more of the components shown in fig. 6 may be physically, operatively, and/or communicatively coupled with additional components of a system for generating functional flow graphs (including, for example, the integrated processor 534 and/or the display 536).

In the ultrasound tracking system 610 of fig. 6, the ultrasound probe 612 includes a transducer array 614 for transmitting ultrasound waves and receiving echo information at sensors on the intraluminal device. Various transducer arrays are well known in the art, such as linear arrays, convex arrays, or phased arrays. The transducer array 614 can comprise, for example, a two-dimensional array of transducer elements capable of scanning for 2D and/or 3D imaging in both the elevation and azimuth dimensions (as shown). The transducer array 614 is coupled to a beamformer 616 in the probe 612, the beamformer 616 controlling the transmission and reception of signals by the transducer elements in the array. In this example, the beamformer is coupled by the probe cable to a transmit/receive (T/R) switch 618, which switch 618 switches between transmit and receive and keeps the main beamformer 622 from high energy transmit signals. In some embodiments, the T/R switch 618 and other elements in the system can be included in the transducer probe rather than in a separate ultrasound system base. The transmission of ultrasound beams from the transducer array 614 under the control of the beamformer 616 is directed by a transmit controller 620 coupled to a T/R switch 618 and a beamformer 622, the transmit controller 620 receiving input from user operation of a user interface or control panel 624. One of the functions controlled by transmit controller 620 is the direction in which the beam is steered. The beams may be steered directly in front of (orthogonal to) the transducer array or at different angles for a wider field of view. The orientation may be changed in response to movement of the intraluminal device within the body structure, such as during implementation of a pullback method used to take blood pressure readings within a vessel. The partially beamformed signals produced by the beamformer 616 are coupled to a main beamformer 622, where the partially beamformed signals from individual patches of transducer elements are combined into a fully beamformed signal.

The beamformed signals are coupled to a signal processor 626. The signal processor 626 may process the received echo signals in various ways, such as bandpass filtering, decimation, I and Q component separation, and harmonic signal separation. The signal processor 626 may also perform additional signal enhancement such as ripple reduction, signal compounding, and noise cancellation. The processed signals are coupled to a B-mode processor 628, which B-mode processor 628 is capable of employing amplitude detection for imaging of structures in the body. The signals generated by the B-mode processor are coupled to a scan converter 630 and a multi-plane format converter 632. The scan converter 630 arranges the echo signals in the spatial relationship in which they are received in the desired image format. For example, the scan converter 630 may arrange the echo signals into a two-dimensional (2D) fan format or a pyramidal three-dimensional (3D) pattern. The multiplanar format converter 632 is capable of converting echoes received from points in a common plane in a volumetric region of the body into an ultrasound image of that plane, as described in U.S. patent No. US6443896 (Detmer). The volume mapper 634 converts the echo signals of the 3D data set into a projected 3D image as viewed from a given reference point, for example as described in US patent No. US6530885(Entrekin et al). From the scan converter 630, the multi-plane format converter 632, and the volume mapper 634, the 2D or 3D images are coupled to an image processor 636 for further enhancement, buffering, and temporary storage for display on the image display 638. The graphics processor 636 can generate a graphical overlay for display with the ultrasound images. These graphic overlays can contain, for example, standard identifying information such as patient name, date and time of the image, imaging parameters, and the like. For these purposes, the graphics processor receives input from the user interface 624, such as a typed patient name. The user interface can also be coupled to a multi-plane format converter 632 for selecting and controlling the display of a plurality of multi-plane format conversion (MPR) images.

Fig. 7 is a block diagram of a flow diagram generation method 700 according to the principles of the present disclosure. The example method 700 of fig. 7 illustrates steps that may be used by the systems and/or devices described herein in any order to generate functional flow maps and/or improve the accuracy of functional flow data obtained within a body structure, such as a blood vessel.

At block 710, the method involves "providing an intraluminal device configured for insertion within a body structure within a tracking field, the intraluminal device including a sensor configured to obtain one or more functional flow measurements and configured to receive a signal or cause a disturbance in the tracking field. In some examples, the functional flow measurements may include blood pressure and/or blood flow velocity.

At block 712, the method involves "tracking one or more locations of the intraluminal device within the body structure using the received signals or perturbations of the sensors. Depending on the tracking system used, the tracking field may comprise an electromagnetic field or a field generated by the transmitted ultrasound signal. Thus, the sensors may be tracked in different ways. When electromagnetic fields are employed, the sensors may cause field disturbances that are detected by the electromagnetic tracking system. In contrast, an ultrasound tracking system may track the position of a sensor by transmitting ultrasound signals at the sensor and receiving echoes in response to the transmitted signals.

at block 714, the method involves "using the sensor to obtain a functional flow measurement at the tracked location. The process used by the sensor to obtain functional flow measurements from within the body structure may vary. For example, the sensor may include a pressure sensor and/or a flow rate sensor. The flow rate sensor may be configured to transmit and receive ultrasound signals from within a tube lumen of the body structure, thereby obtaining velocity information via doppler flow. The number of sensors and their location on the intraluminal device may vary. In some examples, separate sensors may be configured to perform different functions. When multiple sensors are implemented, one or more may include an ultrasound receiver configured to receive ultrasound signals transmitted from an external ultrasound system.

At block 716, the method involves "generating a functional flow map of the body structure based on the tracked positions and the functional flow measurements". The functional flow map may comprise a plurality of measurements, each measurement corresponding to a discrete location within the body structure. Embodiments may include fusing location-specific measurements with doppler flow and/or B-mode images generated by an external ultrasound tracking system so that the measurements may be observed on an image of the body structure at the location where each measurement within the structure was obtained. In some examples, the functional flowgrams may be obtained in real-time, for example, as the intraluminal device is moved through a body structure. Real-time implementations may be reflected to the functional flow graph by automatic updates so that when measurements are obtained, images of the body structure are populated with functional flow measurements.

Of course, it should be understood that any of the examples, embodiments, or processes described herein may be combined with or separated from one or more other examples, embodiments, and/or processes and/or performed in accordance with the present systems, apparatus, and methods in separate apparatus or apparatus parts. The foregoing is intended to be merely illustrative of the present system and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments. Thus, while the present system has been described in particular detail with reference to exemplary embodiments, it should also be appreciated that numerous modifications and alternative embodiments may be devised by those having ordinary skill in the art without departing from the broader and intended spirit and scope of the present system as set forth in the claims that follow. Accordingly, the patent specification and drawings are to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.