WO2010125485A1

WO2010125485A1 - Acoustic medical imaging system and method of operation thereof

Info

Publication number: WO2010125485A1
Application number: PCT/IB2010/051574
Authority: WO
Inventors: Christianus Martinus Van Heesch; Emiel Peeters; Dirk Jan Broer
Original assignee: Koninklijke Philips Electronics, N.V.; U.S. Philips Corporation
Priority date: 2009-05-01
Filing date: 2010-04-12
Publication date: 2010-11-04

Abstract

A medical imaging system (600) and method including generating a force in a biological mass using high-intensity focused ultrasound (HIFU) beams, deflecting tissue contained in the biological mass using the force, and determining a physical quality of the deflected tissue. The physical quality of the deflected tissue may include one or more of rigidity and strength of the deflected tissue.

Description

ACOUSTIC MEDICAL IMAGING SYSTEM AND METHOD OF OPERATION

THEREOF

The present system relates generally to medical imaging systems and, more particularly, to an audio-frequency imaging system that uses vibro-acoustography to determine the structural and/or strength characteristics of tissue, and a method of operation thereof.

Recently, the medical profession has embraced regenerative medicine (RM) to repair or replace damaged and/or diseased tissue using healthy cells from a patent's body. Typically, to repair and/or replace damaged and/or diseased tissues or organs, a biodegradable scaffold is seeded with cells and implanted so that the cells may grow on the scaffold in vivo. For example, a polymer scaffold for the regeneration of structural and/or functional tissue can be implanted in a patient at a site of interest. The scaffold may be populated prior to implantation with cells such as appropriated stem cells or progenitor cells. Alternatively, the scaffold may be populated with cells after implantation either by capturing progenitor cells from circulation or by in-growth of cells from neighboring (healthy) tissue. Subsequently, the scaffold and the surrounding tissue provide the right cues to trigger production of an extracellular matrix and hence the formation and remodeling of newly-formed tissue. Simultaneous with the formation of newly formed (structural) tissue, the scaffold should degrade, since the structural support as originally provided by the scaffold is now obsolete as the newly formed tissue should be self- supporting.

RM may be used to repair and/or replace tissue for many parts of a body. For example, RM can be used to repair blood vessels, nerves, cartilage, bones, esophaguses, tracheas, pancreas, kidneys, livers, hearts, uteruses, bladders, etc. Additionally, RM may be used to repair and/or replace various parts of organs such as heart valves.

To repair a heart valve using RM, the diseased heart valve is typically removed, in whole or in part, and replaced with a new (replacement) valve that biologically generates in vivo. Accordingly, the new valve may be formed using a porous scaffold comprised of a non- woven fibrous polymer structure (scaffold polymer) that is pre-shaped in the form of a heart valve. This new valve may be surgically implanted in the heart where it functions in the same capacity as the original valve. The replacement valve (or other anatomical feature) may be surgically inserted using any suitable method. For example, the valve may be inserted using any suitable surgical technique. Further, as the replacement valve may "grow" once in place, it may have a scaffold that may be smaller than a conventional replacement valve and may, thus, be inserted in a patient using, for example, a less invasive surgical technique than conventional open-heart surgical techniques. Accordingly, the replacement valve may be inserted with a catheter that is inserted in, for example, a leg or a groin of a patient. Then, when in a location of interest, the scaffold of the replacement valve may be unfolded (e.g., by itself) and/or attached to a desired tissue. After implantation, cells may populate the scaffold polymer and form their own extracellular matrix as the cells grow on/in the scaffold polymer while, at the same time, the scaffold polymer degrades. Accordingly, the structural function of the scaffold polymer to support tissue formed by the cell population is gradually taken over by newly- formed cellular tissue that forms its own structure. As this growth process occurs in vivo and may take several months, the formation of the new tissue and the degradation of the polymer must be balanced relative to each other so that the mechanical characteristics of the new valve remain stable and do not deviate from a normal valve. The stability of the new valve is important to assure that the patient receiving the new heart valve does not suffer any flow irregularities that may be caused by sudden changes in the mechanical behavior of the heart valve. A change in the mechanical behavior of the heart valve may lead to medical complications or even death. Unfortunately, using current medical devices and methods, it is difficult if not impossible to obtain information that may be used to determine the mechanical characteristics of a new biological heart valve.

Further, with regard to conventional imaging techniques such as imaging catheters, etc., these techniques can only provide an image of the replacement heart valve (or other tissue) and do not provide information on physical (mechanical) characteristics such as rigidity, scaffold degradation, etc. Moreover, because, imaging catheters must be inserted into a conduit of a body such as an artery to visualize a heart valve, they can inadvertently contact the valve and, thus, damage the valve. Moreover, catheter imaging is invasive (e.g., requires a surgical procedure, such as an incision for insertion of the catheter and/or requires insertion of the catheter into the body cavity), and may cause complications and/or discomfort to a patient.

Accordingly, it is desirable to non-invasively (e.g., without contact) analyze a replacement valve in situ (and in vivo) to determine various structural aspects of the replacement valve and to assure that the formation of the new tissue relative to the degradation of the polymer matrix is balanced during the growth-process. These structural aspects may include, for example, size, stiffness, strength, rate-of-growth, and/or growing progress.

Further, there is need for a system and a method that can non-invasively analyze a replacement valve so that a proper analysis of the growth of the replacement valve may be determined using the image information. Further, there is a need for a system and method that can determine whether various structural aspects of the replacement valve are within guidelines and/or determine that the formation of the new tissue with respect to the degradation of a polymer support matrix is properly balanced based upon the image information. Moreover, there is a need for a method which can impart a predetermined force upon biological tissue to determine characteristics of the tissue such as tissue strength.

Accordingly, it is an object of the present system to non-invasively analyze a replacement heart valve (or other physiological structure) in situ and/or in vivo and acquire information that may be used to analyze the condition of the replacement heart valve. Further, it is another object of the present system to determine that various structural aspects of the replacement heart valve are within predefined guidelines and/or determine that the formation of new tissue with respect to the degradation of a polymer support matrix of the replacement valve is balanced.

One object of the present systems, methods, apparatuses, and devices (hereinafter system unless context indicates otherwise) is to overcome the disadvantages of conventional systems and devices.

According to one illustrative embodiment, there is disclosed a medical imaging method which may be performed by a medical imaging system, the method may include one or more acts of: generating a force in a biological mass using high-intensity focused ultrasound (HIFU) beams; deflecting tissue contained in the biological mass using the force; and determining a physical quality of the deflected tissue, the physical quality comprising one or more of rigidity and strength of the deflected tissue. The deflected tissue may include tissue such as, for example, a heart valve, an artery implant (e.g., vascular grafts) to replace and/or secure blood vessels and/or other tissue. The physical quality may include one or more of speed of the tissue (e.g., rate of movement of a valve, opening and/or closing), velocity of the tissue (e.g., speed and direction of travel), tissue strength recovery, stiffness, rigidity, strength, etc. Accordingly, the present system may determine strength of replacement tissues, organs, etc.

The method may further include an act of receiving an acoustic wave generated as a result of an interaction of the force with the tissue. Moreover, the method may further include an act of varying the force by varying a frequency of one of the HIFU beams relative to the other of the HIFU beams. The method may further include an act of determining a magnitude of the force. Further, the deflected tissue may include a scaffold polymer that may be populated with biological cells.

The method may further include an act of determining an amount of degradation of the scaffold polymer and/or an act of determining mechanical properties comprising one or more of strength and elasticity modulus of newly formed cellular tissue. The method may also include an act of storing information related to the determined physical quality of the deflected tissue.

According to a further embodiment, there is disclosed a medical imaging system including a controller which drives at least one transducer array to generate high-intensity focused ultrasound (HIFU) beams that are focused to produce a force in a biological mass, and deflect tissue contained in the biological mass using the force, and determines a physical quality of the deflected tissue, the physical quality may include one or more of rigidity and strength of the deflected tissue. Further, the deflected tissue may include a heart valve. The physical quality determined by the controller may include one or more of speed of the tissue, velocity of the tissue, tissue strength recovery, stiffness, etc. Moreover, the deflected tissue may include tissue such as, for example, artery implants (e.g., vascular grafts) to replace and/or secure blood vessels and/or other tissue (e.g., circulatory tissue), etc.

The system may also include a receiver which receives an acoustic wave generated as a result of an interaction of the force with the tissue. This acoustic wave may be processed and represented by a corresponding analog signal (e.g., Voltage) and/or a digital signal. The controller may vary the force by changing a frequency of one of the HIFU beams relative to the other of the HIFU beams. Further, the controller may determine a magnitude of the force. Further, the controller may determine a degradation of the scaffold polymer and represent the determined degradation as a percentage, etc. According to the system, the controller may determine mechanical properties including one or more of strength and elasticity modulus of newly formed cellular tissue.

Further, the system include a memory which stores information related to the determined physical quality of the deflected tissue.

The tissue may comprise a scaffold polymer that may be populated with cells (e.g., biological cells).

According to yet a further embodiment, there is disclosed a computer program stored on a computer readable memory medium, the computer program configured to obtain image information using high-intensity focused ultrasound (HIFU), the computer program may include a program portion configured to control a controller to drive at least one transducer array to generate HIFU beams that are focused to produce a force in a biological mass, and deflect tissue contained in the biological mass using the force. The program portion may determine a physical quality of the deflected tissue, the physical quality may include one or more of rigidity and strength of the deflected tissue. The deflected tissue may include a valve of a heart. Further, the deflected tissue may include tissue such as, for example, artery implants (e.g., vascular grafts) to replace and/or secure blood vessels and/or other tissue.

The program portion may further include a program portion configured to determine one or more of speed, velocity, percent recovery, stiffness, rigidity, and strength of the tissue, etc. Further, the program portion may also include a program portion configured to actuate a receiver to receive an acoustic wave generated as a result of an interaction of the force with the tissue.

Moreover, the program portion may further include a program portion configured to control the controller to vary the force by changing a frequency of one of the HIFU beams relative to the other of the HIFU beams. Further, the program portion may include a program portion configured to control the controller to determine the magnitude of the force. The program portion may further be configured to determine mechanical properties including one or more of strength and elasticity modulus of a scaffold polymer that is populated with cells of the tissue. Further, the program portion may be configured to control the controller to determine a degradation of the scaffold polymer.

Further, the computer program may include a program portion configured to control the controller to determine mechanical properties which may include one or more of strength and elasticity modulus of newly formed cellular tissue. The tissue may include a polymer matrix and a biological cellular population. Further, the program portion may include a program portion configured to control a memory to store information related to the determined physical quality of the deflected tissue.

These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings where:

FIG. 1 is a diagram of an imaging system according to an embodiment of the present system;

FIG. 2 shows measurement data obtained according to an embodiment of the present system; FIG. 3 is a graph indicating amplitude and phase as a function of the frequency difference according to another embodiment of the present system;

FIG. 4 is a flowchart illustrating a process performed by an embodiment of the present system;

FIG. 5 is a flowchart corresponding to a process performed by an embodiment of the present system; and FIG. 6 shows a system in accordance with yet another embodiment of the present system.

FIG. 7 shows a screen shot of an output screen according to an embodiment of the present system; FIG. 8 is a flow chart corresponding to a process performed by a further embodiment of the present system; FIG. 9 is a graph which illustrates tissue strength as a function of time according to an embodiment of the present system; and

FIG. 10 shows a diagram of an imaging system according to a further embodiment of the present system. The following description of certain exemplary embodiments is merely exemplary in nature and is in no way intended to limit the invention or its applications or uses. In the following detailed description of embodiments of the present systems and methods, reference is made to the accompanying drawings which form a part hereof, and in which are 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.

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 appended claims. Moreover, for the purpose of clarity, detailed descriptions of certain features will not be discussed when they would be apparent to those with skill in the art so as not to obscure the description of the present system.

In one embodiment, there is provided system, apparatus, device, and/or method which may generate a force in a biological mass using high-intensity focused ultrasound

(HIFU) beams; deflect tissue contained in the biological mass using the force; and/or determine a physical quality of the deflected tissue. The physical quality may include one or more of rigidity and strength of the deflected tissue. The deflected tissue may include a heart valve, etc. The physical quality may include one or more of speed (e.g., rate of movement of a valve, opening and/or closing), velocity (e.g., speed and direction of travel), percent recovery, stiffness, rigidity, and strength of the tissue. Accordingly, medical costs and operating time may be reduced, and quality of care and quality of life may be enhanced.

The present system uses a vibro-acoustography technique to monitor and detect physical properties of various objects such as heart valve tissue and scaffold material

(hereinafter both of which will be referred to as tissue unless context indicates otherwise) of a replacement heart valve, such as in vivo. Since a heart valve operating in a beating heart may be considered to be in "motion" at certain times, an acoustic frequency (f) that is applied to the heart valve will have a corresponding reflected signal (i.e., a reflected acoustic signal) with a frequency that is Doppler shifted (e.g., by Δf) in relation to the acoustic frequency (f). The Doppler shift (Δf) is dependent upon the motion of the tissue of the heart valve and may be positive or negative, depending on the direction of motion of the tissue of the heart valve at the time that the frequency (f) is applied to the heart valve. Thus, the tissue of a heart valve in motion will shift an acoustic frequency (f) that is applied to it by an amount equal to Δf, representing a Doppler shift that is positive or negative, depending on the direction of motion of the heart valve at the time that the frequency (f) is applied to the heart valve.

A vibro-acoustography technique according to the present system may obtain image and/or physical information using audio-frequency harmonic vibrations induced in the object by a radiation force of focused ultrasound. The image information obtained by the present system may have sufficient resolution to indicate the manifestation of various tissue structures and/or calcifications. As is typical with vibro-acoustography, the image and/or physical information may be obtained using, for example, a 3 MHz ultrasound transducer operating at a frequency of between 50 and 60 kHz to render soft tissue structures, tissue borders, micro-calcifications, etc., with high contrast, high resolution, and with little or no speckle. A suitable imaging probe may include a PHILIPS™ D5009V Cardiac Avascular non-imaging probe or the like.

The present system is ideal for monitoring the growth of replacement tissue grown using RM. The present system may subject the tissue such as, the replacement tissue, to a predetermined force and response information indicative of the tissue's response to the force may be received. The response information may be processed to determine the physical information which may indicate physical properties of the tissue such as strength, rigidity, etc. The strength and rigidity of replacement tissue may be used to determine an amplitude of vibration such as resonant vibration, when a modulating force with a similar frequency originating from high-intensity-focused-ultrasound (HIFU) emitter is applied to the replacement tissue. An index of strength (a) may be expressed as shown in Equation 1 below.

With reference to equation 1 , βy is a frequency where an intensity is maximum for healthy or normal tissue, f_t is the resonance frequency of the tissue being measured (e.g., which may be determined by detecting a maximum intensity (pressure)), and fo is a frequency of replacement tissue where the intensity is at its maximum. The intensity may include, for example, a normalized pressure which may be measured using any suitable method such as, for example, a hydrophone which may convert pressure into, for example, a value such as voltage, etc. However, it is also envisioned that other analog or digital values may be used. As the recovery strength (e.g., % recovery) of, for example, replacement tissue approaches the strength of healthy or normal tissue, a may approach 0. Accordingly, a may be used to determine the strength of replacement tissue. Thus, by monitoring variables such as, for example, a, the strength of a replacement tissue may be determined. This may be better illustrated with reference to FIG. 9 which is a graph which illustrates tissue strength as a function of time according to an embodiment of the present system. The system may monitor replacement tissue such as a heart valve whose performance may be tracked as shown by the graph in FIG. 9 in which the dotted line depicts an index of strength (e.g., .expressed as a percentage, in time). Due to a small inbalance between the degradation of the scaffold polymer and the speed of ingrowth of cells and the formation of reinforcing extracellular matrix in the present valve, the mechanical performance after around 20 days reaches a minimum. Information on the mechanical behavior of the heart valve (or other replacement tissue) may then be reported to professionals such as, for example, doctors, surgeons, etc. for further analysis. Thus, this information may be used to analyze the state of replacement tissue such as, for example, the heart valve and/or to determine a course of treatment such as, for example, medication and/or surgery. As degradation may be conveniently determined, valuable time may be saved if surgery is required. For example, medication may be administered to slow down scaffold degradation and/or enhance cell growth.Further, the response information may be processed to yield image information that may be rendered by the present system on, for example, a display.

A description of a technique to monitor and/or analyze a replacement heart valve will now be provided. However, the present system may also be used to analyze other types of tissue and/or organs such as, for example, vascular grafts for artery repair and/or replacement.

The present system may non-invasively monitor and/or analyze a replacement heart valve (hereinafter heart valve) in situ and in vivo while the heart is beating. As heart valves periodically open and close during a cardiac cycle, the valves, or parts thereof, may be considered to be "in motion." More particularly, that cusps or leaves of a heart valve may deflect during a cardiac cycle.

The present system uses a vibro-acoustography imaging technique that may have a scanning focus point formed by two overlapping ultrasound beams operating at different frequencies. The difference in frequency (Δω) of the ultrasound beams should be sufficiently small and may typically fall in a range of between 100 Hz and 1 MHz. However, it is also envisioned that other ranges of (Δω) may also be used. The two overlapping ultrasonic beams may intersect at a focus point and, as a result of interaction with tissue, generate a complex acoustic reflectance (or reflected acoustic signal (RAS)) By detecting the RAS at one or more focal points, image information of tissue being analyzed may be collected, processed, and/or rendered.

According to one embodiment of the present system, the focal point of the two overlapping ultrasound beams may be static and cover a large volume. This volume may include for example, an entire heart valve or parts thereof, while the heart valve is in motion. The location and/or volume of a focal point may be controlled by the system. A receiver (e.g., a microphone (MIC)) may receive an RAS of the volume (or parts thereof) giving relatively no positional information. The information of position (resolution of an image) may be determined by the focus area. Further, although a focal point as large as an entire heart valve may be too large for imaging the heart valve according to conventional imaging techniques, this large focal point may be used by the present system to determine an average elasticity of the heart (or parts thereof). Accordingly, using the RAS, as a function of time, a distinct frequency (f(t)), amplitude (A(t)) and phase (φ(t)) modulation of the RAS may be recorded as the heart beats. The recorded RAS may then be processed by the system and the results used to monitor and/or analyze the heart and one or more of its valves (or parts thereof). According to an embodiment of the present system, the RAS may be processed to monitor and/or analyze the heart valve. For example, a Doppler shift of the RAS may be detected and used to determine the speed of tissue of the heart valve which may be used to determine the speed of the heart valve opening and closing. The stiffness of tissue of the heart valve may be resolved from the phase and amplitude of the RAS at several values of Δω. By comparing the RAS at equal Doppler shifts Δf (or at zero Doppler shift i.e., Δf = 0), the influence of the applied force (e.g., due to the two overlapping ultrasound beams) on the tissue may be utilized to determine the stiffness of the tissue independent of motion of the heart (e.g., motion of the heart that is independent of ferees caused by the present system), during one or more cardiac cycles. A diagram of an imaging system 100 according to an embodiment of the present system is shown in FIG. 1. The imaging system 100 may include one or more transducers such as first and second HIFU emitters 102-1 and 102-2, respectively, and an acoustic wave detection device such as a microphone 106.

The HIFU emitter 102-1 emits an output waveform or beam 104-1 having a frequency /i and the HIFU emitter 102-2 emits an output waveform or beam 104-2 having a frequency /2 • The HIFU emitters 102-1 and 102-2 are configured so that their respective output beams 104-1 and 104-2 may be focused in an area or volume (i.e., a focus point) as illustrated by a moving standing wave 108. At the focus point, the output beams 104-1 and 104-2 interfere with each other and generate an interference pattern with a periodicity that is based upon, for example, differences in the wavelengths (e.g.,/i and^) of the emitted beams 104-1 and 104-2 and/or an angle between the emitted beams 104-1 and 104-2. The periodicity of the interference pattern may be static (i.e., unchanging) when the output beams 104-1 and 104-2 each have the same frequency (i.e., Z₁

and thus, Δω = 0). Further, by detuning one of the HIFUs so that/i does not equal/j, the interference pattern may move or form a moving interference pattern as opposed to a static interference pattern that may be formed when two waves of the same frequency interfere with each other. In other words, the resulting interference pattern may move and/or modulate at lower (e.g. acoustic) frequencies due to a frequency difference Δω between the frequencies/i and fi of the beams 104-1 and 104-2, respectively. Thus, high and low areas of an interference pattern formed by interfering waves (e.g., beams 104-1 and 104-2) of dissimilar frequencies may appear to move in a grating direction (e.g., the sum of the waves result in a shift of high and low intensities over time).

The reflectance of an acoustic wave (AW) from a boundary in a medium (e.g. from a heart valve) may be determined by the acoustic impedance (R) as defined in Equation 2 below.

R = Z - Z0 / (Z + Z0), ...(Eq. 2) where

Z = p / (vS), Z0 = pc ...(Eq. 3)

With reference to equations 2 and 3, p is the pressure (e.g., in Pa), v is a velocity of the heart valve relative to the acoustic wave, S is a surface area of the boundary (e.g. area of heart valve or an area of a focus point), p is the density of a medium enclosed by the surface (e.g. blood or average of blood and tissue average, etc.), c is the speed of sound in the medium (e.g. blood or average of blood and tissue) and may lie in the range of, for example, 1510 m/s +/- 50 m/s however other ranges are also envisioned, and Z is an acoustic impedance of the medium. Thus, the reflection of the acoustic wave may generate a force on the boundary that may have a direction that is opposite to the direction of the reflection. Further, the magnitude of the force (FMag) depends on the pressure p, surface area S, and acoustic impedance R. The present system, in accordance with an embodiment o the present system, may, for example, operate in one of two modes: (1) a continuous sweep mode; and (2) a frequency modulation mode.

Continuous Sweep Mode In the continuous sweep mode, the frequency difference (Δω) of the output beams

104-1 and 104-2 emitted by the HIFUs 102-1 and 102-2, respectively, may be swept, for example, once either linearly or exponentially. Thus, (Δω) may be swept over an entire spectrum (e.g., 0 -frequency HIFU/10, where the frequency HIFU may be equal to 1 MHz) or at one or more other frequencies of interest (e.g., audio = 0.5 - 22 kHz, etc.). The force (e.g., F_Mag) that may be impressed upon, for example, the examined tissue (e.g., the heart valve tissue) in this case is almost constant and slowly varying.

Typical measurement data obtained using a continuous sweep mode according to the present system will now be explained with reference to FIG. 2 which shows measurement data obtained according to an embodiment of the present system. With reference to FIG. 2, in graph (I), a schematic representation of the displacement (L(m)) where L(m) is a distance of a point on the heart valve from a reference point (e.g. a fixed or almost fixed point on the heart wall)) of a heart valve during three heartbeats is shown. In graph (II), a schematic representation of the frequency of a resulting reflected acoustic wave (Δω' or RAS) as a function of (Δω) is shown. In graph (HI), an amplitude (A) of the reflected wave as a function of the frequency difference (Δω) is shown. In graph (IV), the phase (φ) of the reflected wave as a function of the frequency difference (Δω) is shown.

Frequency Mode In the frequency modulation mode, the frequency difference (Δω) may be modulated between two fixed frequency differences (e.g., from Δωi to Δω₂). By sweeping the speed of this modulation, a modulating force (F_M) may act on the tissue (at the boundaries) being scanned (e.g., the heart valve). Similarly to a rheometer, the elastic properties of the tissue may be determined from a response of the modulating force (F_M). However instead of measuring phase delay and amplitude of rotational motion, as is typically measured by a rheometer, according to the present system, the phase delay and amplitude of a RAS is recorded. Resonance and/or anti-resonance frequencies may be monitored and tracked over time and may be used to determine development of the tissue growth. The resonance and anti-resonance frequencies may be used to obtain an indirect measure of tissue stiffness. For example, soft tissue may typically have a resonance frequency of about 20 Hz. At this frequency, minimum damping may occur. Conversely, at an anti-resonance frequency, maximum damping may occur. This is illustrated with reference to FIG. 3 in which a graph indicating amplitude (A) and phase (φ) as a function of the frequency difference (Δω) of a RAS in a scan of a replacement tissue according to an embodiment of the present system. The system may determine one or more resonance points and corresponding maximum amplitudes (A) at each of these resonance points. Then, using for example, Equation 1 , a may be determined. The system may use a to determine one or more mechanical characteristics, properties, etc., of the tissue such as, for example, strength, elasticity modulus. For example, the same or similar values of α may indicate the same strength or similar tissue strength, mechanical characteristics, properties, etc. For example, as stated above, as α approaches 0, it may be assumed that the recovery strength (e.g., mechanical characteristics, properties, etc.) of, for example, replacement tissue approaches the strength of healthy or normal tissue. Accordingly, by monitoring (and/or determining) values of α over time, the system may determine (and/or indicate, such as render) a percent of tissue strength recovery of the replacement tissue with respect to healthy or normal tissue. According to an embodiment of the present system, values of healthy tissue may obtained by using any suitable method such as, for example, by measuring nearby healthy tissue, using reference values, etc. A process to determine tissue strength recovery will be explained below with respect to FIG. 8. FIG. 4 shows a flow diagram that illustrates a process 400 in accordance with an embodiment of the present system. The process 400 may be performed using one more computers communicating over a network. The process 400 may include one of more of the following acts. Further, one or more of these acts may be combined and/or separated into sub-acts, if desired. In operation, the process may start during act 402 and then proceed to act 404. During act 404, the process may drive one or more transducer arrays to produce output beams. The output beams may have a common focus point. The one or more transducer arrays may be driven according to one or more modes (e.g., a frequency mode and/or a continuous sweep mode). After completing act 404, the process may continue to act 406.

During act 406, the process may receive an RAS. The RAS may be recorded in a memory of the system. After completing act 406, the process may continue to act 408.

During act 408, the RAS may be processed to determine response information which may include one or more of an amplitude of the RAS, a frequency of the RAS, a phase delay of the RAS, and displacement of a valve L(m). The process may also determine resonance and/or anti-resonance information. The process may also form image information based upon the response information. After completing act 408, the process may continue to act 410.

During act 410, the process may render results of the processing during act 408 on, for example, a display. After completing act 410, the process may continue to act 412.

During act 412, the process may save the response information or parts thereof. The response information may be compiled into a report which may include one or more of day, date, time, user identification (ID), center (e.g., hospital) identification, image acquisition information (e.g., settings, calibrations, etc.), image information, rate-of-change (e.g., change in growth, decay, strength, rigidity, etc. of the matrix and/or tissue). This information may be saved by the process in a memory of the system. After completing act 412, the process may continue to act 414, during which, the process may end.

The process may also include an act of determining whether a previous report has been saved in association with the same patient and, in the affirmative, load the previous report. The process may then include an act of comparing the previous report with a current report and determine whether changes exist. For example, the process may determine whether tissue strength has increased and/or decreased, whether a polymer matrix has decayed and if so, a rate of decay /time, etc. This information may then be rendered for the user's convenience and saved by the system for later use. A process 500 for capturing images according to another embodiment of the present system will now be described. A flow chart corresponding to the process 500 performed by an embodiment of the present system is shown in FIG. 5. The process 500 may be controlled by one more computers communicating directly and/or over a network. The process 500 may include one or more of the following steps, acts or operations.

Further, one or more of these steps, acts, or operations may be combined and/or separated into sub-steps, sub-acts, or sub-operations, if desired. During act 502, a heart valve monitoring automation process begins and proceeds to act 504.

During act 504, it is determined whether previous response information (which may include image information, etc.) exists. If it is determined that previous response information exists, the process continues to act 506. However, if it is determined that previous response information does not exist, the process continues to act 530. The previous response information may correspond with response information which was previously generated (e.g., and saved in a previous report). The process may determine whether previous response information exists by retrieving data related to a patient's identification (ID) such as, for example, an alpha/numeric code or biometric information.

During act 506, the process loads previous response information from, for example, a database (e.g., a remote storage device, such as a computer memory). After completing act 506, the process may continue to act 508. During act 508, the process may set data acquisition parameters such that response information may be correlated with previous response information. For example, the process may set image acquisition parameters for images to be captured so that the parameters match corresponding parameters in the previous response information. Parameters that may set or matched may include an operating frequency of one or more of the emitters (e.g., emitters 102-1, 102-2 shown in FIG. 1), angle of emission, frequency difference Δω between the emission frequencies, focus point, size of focus point, etc. The emitters, after having the operating parameters set, are set to emit in accordance with the operating parameters. After completing act 508, the process may continue to act 510.

During act 510, the process may acquire current response information as described herein. After completing act 510, the process may continue to act 514. During act 514, the process may determine image contour information and/or physical (mechanical) characteristic information such as rigidity, polymer matrix strength, etc. This information may be calculated for the current and/or previous response information. The image contour information may be obtained using a digital signal processing (DSP) routine as is known in the art. After completing act 514, the process may continue to act 516.

During act 516, the process may correlate the physical (mechanical) characteristic information and/or the image contour information corresponding with the current response information to similar information obtained from previous response information. After completing act 516, the process may continue to act 518.

During act 518, the process may compare the correlated information. The comparison may include information that is the same, similar, and/or has changed (e.g., by a certain amount (e.g., >5% difference, etc.) from the previous response information. These changes may then be recorded, saved, rendered, (e.g., displayed), etc. For example, the process may determine that the valve has changed in size by 5%, the strength of tissue on a valve has increase by a certain amount and that a polymer matrix has decreased in strength by a certain amount. After completing act 518, the process may continue to act 520.

During act 520, the process may provide a visual indication (e.g., highlight) of information that has changed by more that a given amount from the previous response information. For example, the process may determine that the size of a valve has changed (e.g., increased or decreased) by, for example, more than a predetermined amount (e.g., 2% change), is outside a predetermined range (e.g., outside 1-2% change) and accordingly, an embodiment of the present system may highlight (e.g., a red frame, border, background, text, etc.) may be displayed with the response (e.g., image information) related to the valve. Similarly, any changes/deviations may be highlighted by the system for review by the user. The highlight information may also include arrows or other information that may be used to draw a user's attention to the changed information. The highlight information may facilitate reviewing of the changed medical examination information when it is rendered. The highlight information may be saved together with the medical examination information or may be saved in a separate file that is associated with the medical examination information. After completing act 520, the process may continue to act 522.

During act 522, information related to the response information is rendered (e.g., on a display) for a user's convenience. The rendered information may include image information and/or information related to physical strength of the valve. After completing act 522, the process may continue to act 524.

During act 524, the process may generate a report including information generated by the system such as response information, image information, etc. The report may also include information such as day, date, time, user information, patient information, device/apparatus information (e.g., make of transducer arrays, etc.). The generated report may also include information related to the previous report information. After completing act 524, the process may continue to act 526.

During act 526, the process may save the generated report, for example in a local and/or remote memory. The remote memory may include proprietary and/or a national medical database. After completing act 526, the process may continue to act 528 where the process ends.

During act 530, the process may set parameters according to a default setting. This default setting, or parts thereof, may be set by the system and/or the user. This act may be similar to act 508, however, the parameters may not be set in accordance with previous parameter information. Parameter settings may include operating frequencies of the emitters, angle of emission, frequency difference Δω between the emission frequencies, focus point, size of focus point, etc. The emitters, after having the operating parameters set, are set to emit in accordance with the operating parameters. After completing act 530, the process may continue to act 532. During act 532, the process may acquire current response information as described during act 510. After completing act 532, the process may continue to act 534.

During act 534, the process may determine current response information, such as image contour information and/or physical (mechanical) characteristic information such as rigidity, polymer matrix strength, etc. The image contour information may be determined using a digital signal processing (DSP) routine as is known in the art. After completing act 534, the process may continue to act 536.

During act 536, information related to the response information is rendered (e.g., on a display) for a user's convenience. The rendered information may include image information and/or information related to physical strength of the valve. After completing act 536, the process may continue to act 538.

During act 538, the process may generate a report including information generated by the system such as response information, image information, etc. The report may also include information such as day, date, time, user information, patient information, device/apparatus information (e.g., make of transducer arrays, etc.). After completing act 538, the process may continue to act 526 and thereafter, end during act 528 as shown and previously discussed. Visibility in ultrasound imaging can be enhanced when the scaffold material has significantly different acoustic impedance compared to the surrounding (newly formed) tissue. The acoustic impedance of most body tissues lies in the range of about 1.3 x 10⁶ kgrrfV¹ for fatty tissue to about 1.65 x 10⁶ kgrrfV¹ for muscle and liver, with the exception of bone (7.7 x 10⁶ kgm²s). In general, the acoustic impedance of most polymeric materials is slightly higher (in the range from ~1.7-3.5^χ10⁶ kgrrfV¹). Contrast can be improved either by inclusion of (nano) particles with higher acoustic impedances (e.g., crystals, glass, ceramics (10-2OxIO⁶ kgmV) or metals (15-10OxIO⁶ kgm^'V¹)) or by the inclusion of gases that have a significantly lower acoustic impedance (~3 ^x 10² kgrrfV ^l). Alternatively liquid perfluorocarbons or fluorinated polymers can be included that, in general, have an acoustic impedance in the order of 0.8-1.3^χ10⁶ kgm^'V¹.

FIG. 6 shows a system 600 in accordance with yet another embodiment of the present system. The system 600 includes a user device 690 that has a processor 610 operationally coupled to a memory 620, a rendering device 630, such as one or more of a display, speaker, etc., a user input device 670, transducers 640, a receiver such as a microphone 650, and a data server 680 operationally coupled to the user device 690. The memory 620 may be any type of device for storing application data as well as other data, such as response information, image information, operating programs, graph data, heuristic information, user information, patient information, default settings, user settings, patient data, application data, other data, etc. The application data and other data are received by the processor 610 for configuring the processor 610 to perform operation acts in accordance with the present system. The operation acts include controlling at least one of the rendering device 630 to render one or more of the GUIs, render operating parameters, response data, etc. Further, the operation acts may include controlling at least the transducers 640 to output one or more beams having predetermined frequencies, shapes, beam angles, focus points, focus size, beam forming, beam direction, etc. Further, the operation acts may include receiving from the microphone information corresponding to response information. The user input 670 may include a keyboard, mouse, trackball or other devices, including touch sensitive displays, which may be stand alone or be a part of a system, such as part of a personal computer, personal digital assistant, mobile phone, converged device, or other rendering device for communicating with the processor 610 via any type of link, such as a wired or wireless link. The user input device 670 is operable for interacting with the processor 610 including interaction within a paradigm of a GUI and/or other elements of the present system, such as to enable web browsing, a change in operating parameter, data selection, etc., such as provided by left and right clicking on a device, a mouse-over, pop-up menu, etc., such as provided by user interaction with a computer mouse, etc., as may be readily appreciated by a person of ordinary skill in the art. In accordance with an embodiment of the present system, the rendering device 630 may operate as a touch sensitive display for communicating with the processor 610 (e.g., providing selection of a web browser, a Uniform Resource Locator (URL), portions of web pages, etc.) and thereby, the rendering device 630 may also operate as a user input device. In this way, a user may interact with the processor 610 including interaction within a paradigm of a UI, such as to support data selection, etc. Clearly the user device 690, the processor 610, memory 620, rendering device 630 and/or user input device 670 may all or partly be portions of a computer system or other device, and/or be embedded in a portable device, personal computer (PC), etc.

The system and method described herein address problems in prior art systems. In accordance with an embodiment of the present system, the user device 690, corresponding user interfaces and other portions of the system 600 are provided for displaying response information which may include image information, browsing data, selecting data, providing user inputs, etc., and for transferring this and/or other information, between the user device 690 and the data server 680.

The methods of the present system are particularly suited to be carried out by a computer software program, such program containing modules corresponding to one or more of the individual steps or acts described and/or envisioned by the present system. Such program may of course be embodied in a computer-readable medium, such as an integrated chip, a peripheral device or memory, such as the memory 620 or other memory coupled to the processor 610. The computer-readable medium and/or memory 620 may be any recordable medium (e.g., RAM, ROM, removable memory, CD-ROM, hard drives, DVD, floppy disks or memory cards) or may be a transmission medium utilizing one or more of radio frequency (RF) coupling, Bluetooth coupling, infrared coupling etc. Any medium known or developed that can store and/or transmit information suitable for use with a computer system may be used as the computer-readable medium and/or memory 620. The memories may be distributed (e.g., such as a portion of the data server 680) or local and the processor 610, where additional processors may be provided, may also be distributed or may be singular. The memories may be implemented as electrical, magnetic or optical memory, or any combination of these or other types of storage devices. Moreover, the term "memory" should be construed broadly enough to encompass any information able to be read from or written to an address in the addressable space accessed by a processor. With this definition, information on a network is still within memory 620, for instance, because the processor 610 may retrieve the information from the network (e.g., a LAN, WAN, the Internet, an intranet, a proprietary network, a system bus, etc.) for operation in accordance with the present system. For example, a portion of the memory as understood herein may reside as a portion of the data server 680. The one or more memories may be accessible via a UI such as a web-browser or other suitable application. Further, the data server 680 should be understood to include further network connections to other devices, systems (e.g., servers), etc. While not shown for purposes of simplifying the following description, it is readily appreciated that the data server 680 may include processors, memories, displays and user inputs similar as shown for the user device 690, as well as other networked servers, etc. Accordingly, while the description contained herein focuses on details of interaction within components of the user devices 690, it should be understood to similarly apply to interactions of components of the data server 680. These memories configure processor 610 to implement the methods, operational acts, and functions disclosed herein. The operation acts may include controlling the rendering device 630 to render elements in a form of a UI and/or controlling the rendering device 630 to render other information in accordance with the present system.

The processor 610 is capable of providing control signals and/or performing operations in response to input signals from the user input device 670 and executing instructions stored in the memory 620. The processor 610 may be an application- specific or general-use integrated circuit(s). Further, the processor 610 may be a dedicated processor for performing in accordance with the present system or may be a general- purpose processor wherein only one of many functions operates for performing in accordance with the present system. The processor 610 may operate utilizing a program portion, multiple program segments, or may be a hardware device utilizing a dedicated or multi-purpose integrated circuit.

The transducers 640 may include one more transducer arrays such as for example, HIFUs 102-1 and 102-2. The HIFUs may include commercially available units such as, for example, a JR60/20 from Dongfang Jinrong Ultrasonic Equipment Co., Ltd. or a M165D25 atomizer from Pro-Wave Electronics Corp.

The microphone (MIC) 650 may include any suitable device for receiving one or more desired signals such as, for example, a reflected acoustic signal of the present system.

Thus, according to the present system, an accurate, convenient, low-cost, upgradeable, reliable, and standardized imaging system is provided.

FIG. 7 shows a screen shot of an output screen according to an embodiment of the present system. The screen shot may include one or more parts which may be displayed on one or more displays. For example, the screen shot may include a screen 700 which may include one or more frames such as, for example, frames 702, 704, 706, and 708. Each frame may display desired information. For example, frame 702 may display ultrasound information corresponding with scanned tissue of interest (e.g., a heart valve). Frame 704 may include corresponding stiffness information such as, for example, stiffness 714 and a scale 710. Frame 706 may include a table 716 which may include patient information, current information (e.g., from the current examination), previous information (e.g., corresponding information from a previous examination), change information (e.g., a % change in the variables from the previous and current examinations), range information (e.g., expected and/or allowed ranges), and/or required action information. Highlight information such as, for example, colors (e.g., red, green, etc.), flashing, flags (e.g., flag 712) may be displayed to provide an alert of certain information such as, for example, abnormal information. Accordingly, a medical professional (e.g., a doctor) may quickly and conveniently be alerted and may pursue an appropriate course of action. Frame 708 may include various graphs such as, for example, a graph of L(m)/( Δω).

FIG. 8 is a flow chart corresponding to a process for capturing images in accordance with a further embodiment of the present system. The process 800 may be controlled by one more computers communicating directly and/or over a network. The process 800 may include one or more of the following steps, acts or operations. Further, one or more of these steps, acts, or operations may be combined and/or separated into sub- steps, sub-acts, or sub-operations, if desired. During act 802, a heart valve monitoring automation process begins and proceeds to act 804.

During act 804, the process may set image acquisition parameters. These parameters may be set in accordance with previous image information for a given patient, sample, etc. as desired, may be related to a statistical sample (e.g., typical for a given tissue type) and/or may be set/altered as desired. The parameters may be set/altered in accordance with response information (which may include image information, etc.) that may be downloaded from a memory such as for example, a database, etc., and may be related to a patient's identification (ID). The previous image information may include, for example, one or more of patient information, previous image information, data related to a patient, a patient's ID, etc., that may correspond with one or more previous reports. The image acquisition parameters may also correspond with a default setting, if desired. During act 806, the process may scan the replacement tissue and obtain image information (i.e., current image information) which may include response information as described elsewhere. For example, the process may determine amplitude (A) and/or phase (φ) as a function of the frequency difference (Δω) of a RAS in a scan of a replacement tissue as shown in FIG. 3.

During act 810, the process may analyze the information related to amplitude (A) and/or phase (φ) as a function of the frequency difference (Δω) of a RAS, and determine one or more resonance points for the current (and/or previous e.g., most recent) image information. During act 811 , the process may determine a corresponding maximum amplitude

(A) at each of these resonance points for the current and/or past image information. During act 812, the process may determine α using any suitable method such as, for example, Equation 1. During act 814, the process may determine whether α is within a predetermined value of zero. This value may be set by the user and/or the system. Thus, the process may determine when α approaches or is equal to 0. Accordingly, if the process determines that α is within a predetermined value of zero, the process may continue to step 816. However, if the process determines that α is not within a predetermined value of zero, the process may continue to act 818.

During act 818, the process may determine that tissue strength (e.g., of the replacement tissue) has not recovered and/or may determine a % of tissue strength that has been recovered (e.g., as compared with original tissue strength or a default tissue strength), and thereafter, the process may continue to act 820.

During act 816, the process may determine that tissue strength of the replacement tissue has recovered (e.g., as compared with original tissue strength or a default tissue strength, and thereafter, the process may continue to act 820.

During act 820, the process may render (e.g., via a display, a speaker, etc.) results of the current process for the user's convenience. The process, during act 822, may form and/or update one or more reports which may include current and/or previous image information, results of the present process, etc. The process may save the one or more reports in a memory of the system (e.g.., a database, etc.). The process may then end during act 824.

FIG. 10 shows a diagram of an imaging system 1000 according to a further embodiment of the present system. The imaging system 1000 may include command/control/display components 1002 which may be used to scan the tissue (e.g., replacement tissue such as, for example, valves, organs, etc.) of a biological body 1004 and obtain desired information such as, for example, image information (i.e., current image information) which may include response information as described elsewhere. This information may be displayed on one or more displays. A user may enter information using one or more input devices such as, for example, a keyboard, a touch screen, a mouse, a trackball, etc. The system may include one or more remote devices such as, for example, displays, controllers, input devices, etc. which may communicate via a suitable pathways such as, for example, a network.

Although the present system has been described with reference to an ultrasonic imaging system, it is also envisioned that the present system can be extended to other imaging systems. Accordingly, the present system may be used to obtain and/or record information related to tissue growth of, for example, a repaired and/or replaced organ, as well as other imaging applications. Further, the present system may also include a program which may be used with conventional imaging systems so that they may provide features and advantages of the present system. For example, conventional ultrasonic imaging systems and/or image analysis systems may be modified to incorporate various features and advantages of the present system.

Certain additional advantages and features of this invention may be apparent to those skilled in the art upon studying the disclosure, or may be experienced by persons employing the novel system and method of the present invention, chief of which is that a more reliable image acquisition system and method of operation thereof is provided. Another advantage of the present systems and devices is that conventional medical image systems can be easily upgraded to incorporate the features and advantages of the present systems and devices. Of course, it is to be appreciated that any one of the above embodiments or processes may be combined with one or more other embodiments and/or processes or be separated and/or performed amongst separate devices or device portions in accordance with the present systems, devices and methods. Finally, the above-discussion 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 specification and drawings are to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.

In interpreting the appended claims, it should be understood that: a) the word "comprising" does not exclude the presence of elements or acts other than those listed in a given claim; b) the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements; c) any reference signs in the claims do not limit their scope; d) several "means" may be represented by the same item or by the same hardware- or software -implemented structure or function; e) any of the disclosed elements may be comprised of hardware portions (e.g., including discrete and integrated electronic circuitry), software portions (e.g., computer programs), and any combination thereof; f) hardware portions may be comprised of one or both of analog and digital portions; g) any of the disclosed devices or portions thereof may be combined or separated into further portions unless specifically stated otherwise; h) no specific sequence of acts or steps is intended to be required including an order of acts depicted in flow diagrams unless specifically indicated; and i) the term "plurality of an element includes two or more of the claimed element, and does not imply any particular range or number of elements; that is, a plurality of elements may be as few as two elements, and may include an immeasurable number of elements.

Claims

What is claimed is:

1. A medical imaging method comprising acts of: generating a force in a biological mass using high-intensity focused ultrasound (HIFU) beams; deflecting tissue contained in the biological mass using the force; and determining a physical quality of the deflected tissue, the physical quality comprising one or more of rigidity and strength of the deflected tissue.

2. The imaging method of claim 1, wherein the deflected tissue comprises one of a valve of a heart and an artery implant.

3. The imaging method of claim 1, wherein the physical quality further comprises one or more of speed, velocity, percent recovery, stiffness, rigidity, and strength of the tissue.

4. The imaging method of claim 1, further comprising an act of receiving an acoustic wave generated as a result of an interaction of the force with the tissue.

5. The imaging method of claim 4, further comprising an act of varying the force by varying a frequency of one of the HIFU beams relative to the other of the HIFU beams.

6. The imaging method of claim 1, further comprising determining a magnitude of the force.

7. The method of claim 1 , wherein the tissue comprises a scaffold polymer that is populated with cells.

8. The imaging method of claim 7, further comprising an act of determining an amount of degradation of the scaffold polymer.

9. The imaging method of claim 1, further comprising an act of determining mechanical properties comprising one or more of strength and elasticity modulus of newly formed cellular tissue.

10. The imaging method of claim 1, further comprising storing information related to the determined physical quality of the deflected tissue.

11. A medical imaging system (600) comprising a controller (610) which drives at least one transducer array (640) to generate high-intensity focused ultrasound (HIFU) beams that are focused to produce a force in a biological mass, and deflect tissue contained in the biological mass using the force, and determines a physical quality of the deflected tissue, the physical quality comprising one or more of rigidity and strength of the deflected tissue.

12. The imaging system (600) of claim 11, wherein the deflected tissue comprises one of a valve of a heart and an artery implant.

13. The imaging system (600) of claim 11, wherein the physical quality determined by the controller (610) comprises one or more of speed, velocity, percent recovery, stiffness, rigidity, and strength of the tissue.

14. The imaging system (600) of claim 11, further comprising a receiver which receives an acoustic wave generated as a result of an interaction of the force with the tissue.

15. The imaging system (600) of claim 14, wherein the controller (610) varies the force by changing a frequency of one of the HIFU beams relative to the other of the HIFU beams.

16. The imaging system (600) of claim 11, wherein the controller (610) determines the magnitude of the force.

17. The imaging system (600) of claim 11, wherein the tissue comprises a scaffold polymer that is populated with cells.

18. The imaging system (600) of claim 17, wherein the controller (610) determines a degradation of the scaffold polymer.

19. The imaging system (600) of claim 11, wherein the controller (610) determines mechanical properties comprising one or more of strength and elasticity modulus of newly formed cellular tissue.

20. The imaging system (600) of claim 1, further comprising a memory (620) which stores information related to the determined physical quality of the deflected tissue.

21. A computer program stored on a computer readable memory medium (620), the computer program configured to obtain image information using high-intensity focused ultrasound (HIFU), the computer program comprising: a program portion configured to control a controller (610) to drive at least one transducer array (640) to generate HIFU beams that are focused to produce a force in a biological mass, and deflect tissue contained in the biological mass using the force, and determine a physical quality of the deflected tissue, the physical quality comprising one or more of rigidity and strength of the deflected tissue.

22. The computer program of claim 21, wherein the deflected tissue comprises one or more of a valve of a heart and an artery implant.

23. The computer program of claim 21 , further comprising a program portion configured to determine one or more of speed, velocity, percent recovery, stiffness, rigidity, and strength of the tissue.

24. The computer program of claim 21 , further comprising a program portion configured to actuate a receiver (650) to receive an acoustic wave generated as a result of an interaction of the force with the tissue.

25. The computer program of claim 24, further comprising a program portion configured to control the controller (610) to vary the force by changing a frequency of one of the HIFU beams relative to the other of the HIFU beams.

26. The computer program of claim 21, further comprising a program portion configured to control the controller (610) to determine the magnitude of the force.

27. The computer program of claim 21, further comprising a program portion configured to determine mechanical properties comprising one or more of strength and elasticity modulus of a scaffold polymer that is populated with cells of the tissue.

28. The computer program of claim 27, further comprising a program portion configured to control the controller (610) to determine a degradation of the scaffold polymer.

29. The computer program of claim 21, further comprising a program portion configured to control the controller (600) to determine mechanical properties comprising one or more of strength and elasticity modulus of newly formed cellular tissue comprising a polymer matrix and a biological cellular population.

30. The computer program of claim 21, further comprising a program portion configured to control a memory (620) to store information related to the determined physical quality of the deflected tissue.