Method for tissue characterization by ultrasound wave attenuation measurements and ultrasound system for tissue characterization

A method for tissue characterization by ultrasound wave attenuation measurements is provided that comprises:      The disclosure relates also to an ultrasound system for carrying out the method.

BACKGROUND

Field

The present invention relates to a method for tissue characterization by ultrasound wave attenuation measurements, the said method comprising the steps of

a) transmitting at least an ultrasound pulse in a target body;

b) receiving the ultrasound waves reflected by the said target body and transforming the said reflected ultrasound pulses in RF reception signals and computing the propagation depth dependent attenuation coefficient of the tissues crossed by the ultrasound pulse in the target body as a function of the said RF reception signals.

Related Art

Attenuation in ultrasound is the reduction in amplitude of the ultrasound beam as a function of distance through the imaging medium. As the ultrasound beam travels through the body it loses energy. The intensity and amplitude of the sound wave decreases, and this process is known as attenuation. Attenuation coefficients are used to quantify different media according to how strongly the transmitted ultrasound amplitude decreases as a function of frequency. The amount of attenuation that occurs will depend on the type of tissue the sound wave is traveling through. Where the molecules of the tissue are densely packed (such as bone), attenuation will be much greater than in less densely packed tissue (such as fat). Different tissues have different attenuation coefficients depending on the amount of attenuation occurring in the beam of sound. The attenuation coefficient (a) can be used to determine total attenuation in dB in the medium. Attenuation is linearly dependent on the medium length and attenuation coefficient, and also on the frequency of the incident ultrasound beam for biological tissue. The higher the frequency, the greater the amount of attenuation that will occur in any given tissue. Attenuation coefficients vary widely for different media. In biomedical ultrasound imaging however, biological materials and water are the most commonly used media. Attenuation will occur not only in the beam of sound produced by the transducer as it propagates through tissue, but also in the returning echoes as they travel back to the transducer.

Absorption is the main factor causing attenuation of the ultrasound beam. The higher the frequency of the sound wave, the greater the amount of absorption that will occur. Energy is transferred from the sound wave into the medium through which it is traveling.

Ultrasound attenuation parameters are gaining increasing clinical importance. In particular in relation to steatosis. Steatosis is the most frequent liver disease, with both alcoholic (ALFD) and nonalcoholic (NALFD) etiology. NALFD affects up to 30% of adult western population. If not treated liver steatosis can lead to more severe illness such as fibrosis, cirrhosis and liver cancer. Liver steatosis is mainly symptomless, therefore patients are not motivated to undergo liver biopsy. Tissue attenuation is a parameter strongly correlated with liver fat content. Attenuation measurement and imaging by medical ultrasound can provide a powerful, not-invasive, diagnostic tool for liver steatosis staging.

Different methods for carrying out measurements of attenuation coefficients in tissues are known.

Document Jpn. Pat. Appln. KOKAI Publication No. 3-24868 discloses a technique of divisionally transmitting and receiving ultrasonic pulses in different frequency bands twice in the same direction. Based on the fact that the tissue attenuation amount varies depending on the frequency, this technique infers the attenuation constant of a medium by comparing the attenuation amounts of two pulses. Jpn. Pat. Appln. KOKAI Publication No. 3-24868 also discloses a technique of adding attenuation information to a conventional tomogram by extracting two different frequency band components contained in a reception signal upon performing transmission/reception once in the same direction, and weighting and adding the respective signals. This technique can be easily implemented by one transmission/reception cycle.

Document US20100249590 discloses an ultrasonic diagnostic apparatus comprising: a transmission unit which transmits a composite ultrasonic wave obtained by combining at least a first ultrasonic wave having a first center frequency with a second ultrasonic wave having a second center frequency different from the first center frequency at least twice in each of a plurality of directions in an object while modulating a phase; an ultrasonic reception unit which receives, from the object, an echo signal corresponding to each of the at least two transmissions in each of the plurality of directions; a signal extraction unit which extracts a first echo signal corresponding to the first ultrasonic wave and a second echo signal corresponding to the second ultrasonic wave after canceling out harmonics by performing subtraction processing between the echo signals respectively corresponding to the at least two transmissions in each of the plurality of directions; and an image generating unit which generates an attenuation image representing attenuation of an ultrasonic wave propagating in the object by using the first echo signal and the second echo signal.

US2014114189 discloses a method for estimating the amount of attenuation by calculating the signal intensity of a received signal. Several conventional methods are disclosed therein. One of these methods provides for estimating the amount of attenuation specific to a subject by transmitting multiple ultrasound pulses each having a different center frequency and by comparing the received signals that are acquired with regards to how much the intensity of the received signals changes in the depth direction. Another method disclosed therein comprises the steps of comparing multiple frequency signals with regards to the change in their intensity and utilizing the characteristic that the amount of attenuation of ultrasound waves in a living body depends on the frequency.

SUMMARY

Example embodiments of the present invention aim to provide for a method and a system for tissue characterization by ultrasound wave attenuation measurements improving the drawbacks of the method according to the state of the art.

According to a first aspect of the present invention, a method for tissue characterization by ultrasound wave attenuation measurements is provided, the said method comprising the steps of

a) transmitting at least an ultrasound pulse in a target body;

b) receiving the ultrasound pulses reflected by the said target body and transforming the said reflected ultrasound pulses in RF reception signals;

c) extracting the envelope of the received RF signals;

d) carrying out a logarithmic compression of the said extracted envelope and

e) computing the propagation depth dependent attenuation coefficient of the tissues crossed by the ultrasound pulse in the target body as the slope of the line fitting the said logarithmic compressed envelope data along the penetration depth of the ultrasound pulse in the said target body.

In an embodiment the transmitted ultrasound pulse is a wide-frequency band pulse or a multifrequency pulse comprising frequency components with frequencies within a predetermined frequency band, the step of determining RF signal components with frequencies within a sub range of the predetermined frequency band by filter-bank filtering is carried out before the step c) of extracting the envelope of the RF reception signal,

the said envelope extraction being carried out separately for each frequency sub-band component of the RF reception signal,

the said step d) of logarithmic extraction and the said step e) being carried out attenuation coefficient for each frequency sub-band component of the RF reception signal,

f) for each propagation depth of the ultrasound pulse the attenuation coefficient being determined as the mean or median value of the attenuation coefficients calculated for each frequency sub-band component of the RF reception signal.

According to a further embodiment, a sequence of several ultrasound pulses is transmitted into the target body and a sequence of reception signals is acquired from the sequence of the reflected ultrasound pulses, the said steps c) to e) and optionally the step f) being carried out for each of the reception signals of the sequence of reception signals and

g) the attenuation coefficient at a propagation depth is computed as the mean or the median value of the attenuation coefficients at the said penetration depth of the attenuation coefficients computed from each of the reception signals of the sequence of reception signals.

The envelope of the RF reception signals may be expressed by the following equation:
s(f,z)=exp(−αfz)scat(f,z)

In which

s(f,z) is the frequency and depth dependent envelope of the RF reception signal;

Exp(−αfz) is the attenuation term

α is the slope of a line fitting the logarithm of the data envelope;

f is the frequency;

z is the propagation depth of the ultrasound pulse;

scat(f,z) is a function describing the speckle.

Compressing the above envelope by a logarithmic compression, is described by the following equation:
ln(s(f,z))=−αfz+ln(scat(f,z))

According to a further aspect the invention aims to overcome the drawbacks of low signal to noise ratio regions or losses in signal to noise ratio.

According to an embodiment, in the case the at least one ultrasound pulse transmitted into the target body is a wide frequency pulse which is filtered in reception of the reflected pulses by a filter-bank, the loss in signal to Noise Ratio is compensated by repeating the transmission of the said ultrasound pulse and combining the receipt signals generated by the corresponding reflected pulses.

According to a variant embodiment, different signal parameters may be used for estimating the attenuation coefficient such as one or more of the parameters listed in the following list:

Signal intensity, spectral shape of the received signals, out of range attenuation slope along the propagation depth.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Elasticity of soft biological tissues has been used for evaluating possible pathological conditions since the dawning of medicine. The use of manual palpations for evaluating the health condition of the tissues is still used commonly in routine medical examinations. For example the presence of rigid masses found during routine breast examinations is often an early indication of breast cancer. Manual palpation methods however are relatively little objective and are limited to surface anatomical structures.

The methods for quantifying the elasticity or for the comparative measurement of biological tissues by ultrasounds allow deep-tissue elasticity to be measured in the body under examination, are reliable and therefore are used in clinical practice.

Unlike the traditional ultrasound imaging, such as for example B-mode, that allows images to be acquired where tissues with different acoustic properties are distinguished, the methods measuring the elasticity allow tissues with different mechanical properties to be distinguished. To do this, such methods carry out an excitation of the tissues and monitor the strain response, which is related to tissue elasticity.

A type of elasticity measurement methods provides to use transverse waves, or shear waves, generated after an excitation, and are defined as Shear Wave Elasticity Imaging (SWEI). These methods provide to generate shear waves in the tissue following an acoustic disturbance, called as shock disturbance, of the first excitation point applied by the ultrasound probe, and consequently to monitor the shear waves in the regions of interest placed outside the area or the point of excitation. By measuring the displacements over time of the image or of the pixels of the image or of the pixels of a Line of Sight at a plurality of lateral positions separated by a known distance from the excitation source, it is possible to estimate the shear wave speed.

Actually the measurement is indirect since the method detects the propagation speed of the shear wave in a direction substantially orthogonal to the acoustic shock disturbance of the excitation point.

The relation between speed of such shear wave and the elasticity is approximate and it depends on some assumptions about the density of the tissue under examination.

The tissue elasticity is proportional to the propagation speed ρ of the shear wave Vs, according to the following formula:
E≈3ρVs2
wherein it is assumed that p″, namely that tissue density is unit quantity.

The document U.S. Pat. No. 5,606,971 describes a SWE method, that uses a focused ultrasound transducer which induces shear waves in a tissue by sending modulated ultrasonic pulses. The shear wave of the frequency of the modulating signal is detected. The mechanical properties of tissues under examination are evaluated on the basis of the measured values of speed and attenuation of shear waves.

A subset of such methods is the one defined as pSWE (Point Shear Wave Elasticity), where, instead of an image, a point measurement generally averaged in the region of interest is generated.

A problem of the known methods derives from the possibility of the probe and/or patient moving during the examination. Such movements during acquisition can be substantially considered of two different types: transversal, i.e. along the direction of propagation of the transversal wave, due, for example, due to a translation or shift of the probe on skin of the patient or a rotation of the probe by small angles on the plane of the image or longitudinal, i.e. along the direction of propagation of the ultrasound beam, caused, for example, by a different relative position of the probe with reference to the patient due to a different pressure of the hand holding the probe or patient breathing.

In both cases the measurement is altered: in presence of a transversal movement the wave is detected slightly beforehand or slightly later, depending on the direction of rotation or of translation of the probe; in presence of a longitudinal movement the reconstructed signal contains also the effect of such movement consisting in an erroneous ramp trend superimposed on the wave. This leads to a calculation of the shear wave propagation speed not corresponding to reality, and therefore to a distorted estimation of tissue elasticity.

A further method for carrying out elasticity measurements is described in WO2016108178. According to this method the elasticity parameter is measured by estimating the velocity of a shear wave according to a sequence of reference ultrasound pulses transmitted in a target body followed by a shock wave for generating the shear wave and then the displacements of the reflectors is measured by a sequence of tracking ultrasound pulses which are transmitted focused along lines which are laterally staggered one form the other with reference to the origin of the shear wave.

The method disclosed in WO2016108178 therefore allows a reliable measurement of the elasticity of the material under examination to be obtained, particularly of the biological tissues under examination, by correcting anomalies due to the movement, in particular due to the mutual rotation of the probe with respect to the patient or vice versa on the image plane. The fact of providing two excitation points on two opposite sides of the region of interest, allows movement errors to be compensated since, if the detection of the shear wave is anticipated for the measurement corresponding to the first excitation point, it is delayed for the measurement corresponding to the second excitation point and vice versa. This is obviously valid for movements of the probe and/or of the patient that are small and always having the same direction during the examination.

The method disclosed in the above document allows to carry out the measurement of the elasticity of any biological tissue involved by the cardiac movement, and it is particularly advantageous in relation to the measurement on the liver.

Tissue elasticity and tissue ultrasound attenuation may provide complementary diagnostic information about correlated diseases. For example, liver fibrosis is often occurring together with liver steatosis.

Standard medical ultrasound devices provide elasticity and attenuation imaging modalities where B-mode is overlapped to a color-coded measurement map. The two imaging modalities are separate modalities and need to perform two separate examination. This causes additional time, cost and patient discomfort also considering that the patient is many times is not collaborative.

According to a further aspect of the present invention, the method for tissue characterization by ultrasound wave attenuation measurements is provided in combination with the steps of estimating shear wave velocity coefficient.

According to an embodiment, the said combined method for tissue characterization and elasticity measurements by ultrasound comprises the following steps:

a1) acquiring an ultrasound image (3);

b1) defining a region of interest (2) in the image (3), the region of interest including image pixels;

transmitting an acoustic disturbance ultrasound beam (10) directed at an excitation point (1), the acoustic disturbance ultrasound beam configured to produce a shear wave (11) that has a direction of propagation extending laterally from a direction of propagation of the acoustic disturbance ultrasound beam (10);

c1) measuring displacements of the image pixels induced by the shear wave (11) by transmitting a sequence of ultrasound tracking pulses which are laterally staggered at different lateral positions relatively to the said excitation point and receiving the corresponding reception signals;

d1) assessing the propagation speed of the shear wave in the direction of the lateral displacement of the tracking pulses and/or the stiffness value of tissue in the region of interest (2) based on the displacements measured at step c1).

at least some of the reception signals generated by the reflection of the one or more of the said tracking pulses being as reception signals for computing the attenuation coefficient at predetermined propagation depths.

at least some of the tracking pulses are transmitted at least twice, the received signals due to the reflected pulse of one of the at least two transmitted tracking pulses being used for computing the shear wave velocity while the received signals due to the reflected pulse of the second of the at least two transmitted tracking pulses being used for computing the attenuation coefficient.

According to a further embodiment, before transmitting the shear wave generating pulse or the shear wave generating pulses at least one or a sequence of ultrasound reference pulses is transmitted in the region of interest (2) defined at step b1), at least some of the reception signals generated by the reflection of the one or more of the said reference pulses being used as reception signals for computing the attenuation coefficient at predetermined propagation depths.

According to still a further embodiment, at least some of the reference pulses are transmitted at least twice, the received signals due to the reflected pulse of one of the at least two transmitted reference pulses being used for computing the shear wave velocity while the received signals due to the reflected pulse of the second of the at least two transmitted reference pulses being used for computing the attenuation coefficient.

Thanks to the above embodiments, both the attenuation and the elasticity maps are obtained with a single examination.

The two possible alternative embodiments providing two transmit-receive sequences carried out in sequence one for determining the elasticity parameters and the other for determining the attenuation coefficients or providing only one transmit-receive sequence which is used for both modalities, namely for determining the elasticity parameters and for determining the attenuation coefficients, may be implemented as a choice in combination.

A user interface may allow the operator to select one of these two alternative embodiments and to start the selected one.

FIG.1shows the interface of the method according to the present invention, which interface shows a B-mode ultrasound image3. On the B-mode image3the user defines a region of interest2through a gate, in which region of interest the attenuation coefficients of the tissue have to be measured.

The region of interest2may have any shape, preferably a rectangular shape or as a section of an annulus, and preferably it has a predetermined size for the end user. The user can place the region of interest2where he/she desires, preferably only in one portion of the image defined in the development step, such to avoid areas not suitable for the measurement, such as for example areas of the image that are too deep or too superficial.

During the dedicated acquisition, the B-mode image is still, or “frozen”, and it can be removed from such condition only after producing the numerical result.

According to a variant embodiment the B-mode data acquisition is interleaved with the acquisition of the data for determining elasticity and for determining the attenuation parameters. Thanks to this variant embodiment data stream of B-mode image data and elasticity and attenuation data are acquired and the elasticity data and the attenuation data are refreshed in real time with the B-mode image data.

Therefore the user, once defining the region of interest2, starts the measurement; the image is made as still, and the special insonification/acquisition is carried out for estimating the shear wave. Once such step has ended, the data are processed and the obtained result is displayed on the monitor.

Once a measurement has ended, the image can be “unfrozen” such to allow a new shot and a new acquisition, till leaving the mode.

Once the region of interest2is defined.

One or more ultrasound pulses or one or more sequences of ultrasound pulses are transmitted in the ROI2of the target body along at least one scan line12. In the present example several scanlines which are laterally staggered one from the other are provided and along each one of which scanlines at least an ultrasound pulse or a sequence of ultrasound pulses is transmitted in the ROI2.

The ultrasound pulse is focused along the corresponding scan line12at different positions corresponding to different depth of propagation of the pulse inside the body.

The reflected pulses are then collected and transformed by the transducer of a probe in RF reception signals.

According to the present method the envelope of the RF reception signals is generated.

Equation (1) describes the said envelope
s(f,z)=exp(−αft)scat(f,z)

In this equation

s(f,z) is the frequency and depth dependent envelope of the RF reception signal;

exp(−αfz) is the attenuation term

α is the slope of a line fitting the logarithm of the data envelope;

f is the frequency;

z is the propagation depth of the ultrasound pulse;

scat(f,z) is a function describing the speckle.

Equation (2) describes the logarithmic compression of the envelope:
ln(s(f,z))=−αfz+ln(scat(f,z))

Here the term a represents the slope of the line fitting the envelope at a certain depth range.

To improve robustness, attenuation can be computed over multiple frequency bands taking the mean or median value of the attenuation parameters computed at a certain depth range for each of two or more frequency sub bands of the multiple frequency band.

FIG.3is an example showing the envelope function at different depths z and the line fitting the said envelope for each of four depth ranges.

At the different depth ranges corresponding or centered at the different focal points along the scan corresponding scan line12the logarithm of the envelope is approximated by fitting the data with a linear function. The attenuation of the tissue at the said depth range is computed as the slope of the said linear function.

The above attenuation imaging can be combined with a tissue elasticity imaging.

In this case a first excitation point1is defined within the acquired B-mode image3.

For carrying out the measurements of the elasticity parameters of the tissue in the region of interest (ROI) a focused ultrasonic beam10is generated for the acoustic disturbance of one target point1, to generate a shear wave11. The shear wave11originates in the first excitation point1and has a propagation direction substantially perpendicular to the direction of propagation of the ultrasonic beam10, in the two opposite departing directions denoted by the arrows in the figure. The first excitation point1is placed such that the shear wave11passes through the region of interest2.

The generated shear wave11is measured at a plurality of lines of sight placed inside the region of interest2at different predetermined distances from the first excitation point1. The figure shows the line of sight under examination, while the other lines of sight are broken lines.

By the measurement of the passage of the shear wave on all the lines of sight the propagation speed of the measured shear wave is calculated.

As it will be described with further details in the following description with reference toFIG.4, a further step may be carried out prior to transmitting the shear wave excitation pulse11. In this step one reference pulse or a sequence of reference pulses which may be also transmitted along lines being laterally staggered one from the other and from the excitation point1are transmitted into the target body.

Combining the attenuation imaging steps with the elasticity imaging can be carried out in different ways.

One or more of the reference pulses and/or one or more of the tracking pulses transmitted into the ROI for carrying out elasticity imaging scans can be used also for computing the attenuation coefficients along each of the scanlines corresponding to one or more of the said reference or tracking pulses.

In one embodiment the reflected echoes of the transmitted ultrasound pulses of one or more of the reference pulses or of one or more of the tracking pulses can be used for carrying out the attenuation coefficient calculation and the elasticity evaluation along the corresponding scanline and at the corresponding depth.

In an alternative embodiment at least some or all the transmitted reference pulses and/o the transmitted tracking pulses can be repeated, and the corresponding echoes are used respectively for the attenuation coefficient calculation and for the elasticity estimation.

FIG.2adds more details to the representation ofFIG.1and is related to the case of combining attenuation imaging and elasticity imaging of the tissue in the ROI2.

For simplicity sake the reference pulses are not shown in this example, but it is clear for the skilled person how to integrate the presentFIG.2in order to show also the reference pulses, particularly when consideringFIG.4representing a sequence of transmission pulses comprising reference and tracking pulses and, in between the said reference and tracking pulses, the shear wave generation shock pulse is transmitted.

Here the probe20is represented diagrammatically as a linear array of transducers220. The arrow10represents the tracking pulse focused at an excitation point or region along a certain line adjacent to the region of interest. The shear wave11is represented by the arrow and has a certain width in the depth direction i.e. in the direction of propagation of the tracking beams T1, T2, T3, T4and T5and the direction of propagation of the shear wave is indicated by the arrow like shape. The tracking beams T1to T5are focused each one along a line of sight of a plurality of lines of sight which are distributed over the extension of the region of interest. The term lateral means here in the direction of propagation of the shear wave11.

Along each tracking line the corresponding tracking beam is focused at a certain number of tracking focal points FP1to FP6which are positioned at different depth in the region of interest.

Ultrasound tracking beams are repeatedly transmitted focused along the tracking lines and the received data are processed for determining the displacements of the tissue in the region of interest caused by the propagation of the shear wave.

The displacement is a mean displacement since it is averaged in the space, by grouping the displacement measurement between near pixels. On each tracking line, and at each tracking point along the corresponding tracking line the measurement of the displacement is repeated over time to form a sample curve representing the passage of the shear wave.

According to an embodiment such curve may be filtered by a moving mean such to eliminate noise.

For each tracking line and at each tracking focal point at the different depth the measured curve shows the displacement at the corresponding focal point as a function of time.

According to the present embodiment, the peak of the measured displacement is defined to find the shear wave propagation speed: the peak instant on each line of sight and at each tracking focal point FP1to FP6related to the known distance of the lines of sight from each other allows the propagation speed to be calculated.

Identifying the peak is the most simple and advantageous operation, but as an alternative it is possible to consider other significant points of the curve such as for example the maximum slope point or the correlation between the curves or the difference between curves.

According to the above process, the displacements inside the region of interest along each of the tracking lines and at the different depth of the tracking focal points are considered, such to reconstruct the shear wave propagation pattern by the measurement of all the tracking lines and the shear wave speed obtained from the said propagation pattern may be processed for calculating the distribution of the elasticity parameter along the region of interest.

According to an embodiment the examination may be structured in repeated acquisition sequences, and each sequence comprises the transmission of an acoustic excitation pulse at the excitation point and a measurement of the displacements at the tracking focal points of a single tracking line or of a plurality of tracking lines acquired in parallel.

When the measurement of the displacements induced by the propagation of the shear wave occurs line by line it is necessary to transmit an excitation pulse for each of the measurements on the different lines of sight acquired individually or in parallel.

For example, it is possible to acquire one line of sight a time or two or four lines of sight a time in parallel, with standard B-mode imaging techniques.

Tracking of the displacement data along two or more of the tracking lines can also be carried out in an interleaved manner for the two or more tracking lines relatively to each shear wave generation event after a shear wave excitation pulse of a sequence of excitation pulses.

According to an embodiment such sequence of excitation pulses has a limited number of excitation pulses transmitted with a certain repetition frequency and each series of excitation pulses is interrupted for a certain period by a cooling period before being carried out again. The B-mode image acquisition and the corresponding image may be frozen for the time during which a series of excitation pulses is being transmitted and the B-mode image may be refreshed by a new image acquisition during the cooling period between the repetition sequences of excitation pulses.

Such feature has also the advantage of allowing hardware to be prepared to perform a new transmission series of excitation pulses, and at the same time of allowing the probe and the tissues to cool.

In a further embodiment for each tracking line, before the transmission of the shear wave excitation pulse, one or more reference measurements on the line of sight under examination are carried out. Thus, the displacement at each of the tracking points can be measured in relation to a reference condition where the tissue in the region of interest is not disturbed by the passage of the shear wave.

According to a further embodiment, the data detected by the measurement of the shear wave are processed for filtering possible artefacts. Preferably such processing is carried out before the calculation of the displacement on each line of sight and the following calculation of the shear wave propagation speed.

In one embodiment, an ECG signal is recorded and the generation of ultrasound beams and the measurement of the displacement of pixels in the image induced by the shear wave passing through the region of interest are synchronized with the ECG signal.

Thus, the method can perform a triggering on the heartbeat, in order to try to suppress as much as possible the movement-related artefacts, for which the shear wave imaging is very sensitive.

This embodiment can be used for the measurement of the elasticity of any biological tissue involved by the cardiac movement, and it is particularly advantageous in relation to the measurement on the left part of the liver, that is the liver part affected by the heartbeat.

The processing of the acquired data for determining the elasticity data substantially is divided in the following macro-steps:

I. Processing all the repetitions of the acquisition of a line of sight to obtain the extraction of the pattern over time of the displacements of the tissue on such line of sight at each tracking focal point within the region of interest2;

II. Processing the whole set of results deriving from the previous steps in order to obtain the shear wave speed distribution in the region of interest and out of these data the one or more elasticity parameters in different sub regions of the region of interest.

III. Generating a graphic representation of the calculated values of the elasticity parameter distribution in the region of interest in the form of an elasticity image by applying to the image pixels representing the corresponding sub region of the region of interest appearance features as a function of the said elasticity parameters.

IV. combining this elasticity image to the anatomical image of the region of interest, i.e. the B-mode image of the region of interest by maintaining the same scaling and the same topological relation of the sub regions in the elasticity image with the anatomical structure in the region of interest.

As already disclosed above with a more generic case, the RF reception signals corresponding to the reflected echoes of the transmitted pulses can be used also for calculating the attenuation coefficients of the tissue at the different depths ranges which are indicated by the geometric symbols.

The envelope of the reception signals obtained by the reflected echoes on one or more of the said tracking lines is subjected to processing for calculating the attenuation coefficient according to the steps already disclosed above and according to one of the two alternative embodiments.

The embodiment described inFIGS.1and2can be used for the measurement of the attenuation map of any biological tissue and it is particularly advantageous in relation to the measurement on the liver.

The processing of the acquired data for determining the attenuation data substantially is divided in the following macro-steps:

I. Processing all the repetitions of the acquisition of a line of sight to obtain the extraction of the pattern over time of the attenuation coefficients of the tissue on such line of sight at each tracking focal point within the region of interest2;

II. Processing the whole set of results deriving from the previous steps in order to obtain the attenuation coefficient distribution in the region of interest and out of these data the one or more attenuation parameters in different sub regions of the region of interest.

III. Generating a graphic representation of the calculated values of the attenuation parameter distribution in the region of interest in the form of an attenuation coefficient or parameter image by applying to the image pixels representing the corresponding sub region of the region of interest appearance features as a function of the said attenuation parameters.

IV. Combining this attenuation image to the anatomical image of the region of interest, i.e. the B-mode image of the region of interest by maintaining the same scaling and the same topological relation of the sub regions in the attenuation image and/or in the elasticity image with the anatomical structure in the region of interest.

In a further embodiment the elasticity image can be also displayed in an overlapped manner or side by side, or it can be displayed alternatively to the attenuation image by simple commands.

According to a further variant embodiment the combined B-mode and elasticity data and the combined B-mode and attenuation data are displayed with two different images placed one beside the other on a display. One image showing elasticity data overlapped to the B-mode data and the other image showing attenuation data overlapped to the B-mode data.

On the graph ofFIG.2, the abscissa shows the propagation time and the ordinate the space, that is the position of the lines of sight. For each line of sight the maximum of the mean displacement along the line of sight, that corresponds to the wave peak, is identified and drawn in the graph.

FIG.4show a sequence of reference shock and tracking pulses which is typically applied for elasticity imaging and which can be used also for obtaining the data for calculating the attenuation image of a ROI.

FIG.5shows an example of an attenuation map along a scan line which is overlapped on a B-mode image of the same ROI of the attenuation map.

The geometric symbols correspond to the ones inFIG.2and maintain a relation with the depth ranges ofFIG.2showing where on the image map the said depth ranges are located.

FIG.6illustrates a high-level block diagram of an ultrasound system. Portions of the system (as defined by various functional blocks) may be implemented with dedicated hardware, such as transmit/receive (TX/RX) driving/preamp and power switching circuitry, which may utilize analog components. Digital components, DSPs and/or FPGAs, may be utilized to implement the sequencer controller and the timing generator.

The ultrasound system ofFIG.6includes one or more ultrasound probes601,620. The probe601may include various transducer array configurations, such as a one-dimensional array, a two-dimensional array, a linear array, a convex array and the like. The transducers of the array may be managed to operate as a 1D array, 1.25D array, 1.5D array, 1.75D array, 2D array, 3D array, 4D array, etc.

The ultrasound probe601is coupled over a wired or wireless link to a beamformer603. The beamformer603includes a transmit (TX) beamformer and a receive (RX) beamformer that are jointly represented by TX/RX beamformer603. The beamformer603supplies transmit signals to the probe601and performs beamforming of “echo” signals that are received by the probe601.

A TX waveform generator602is coupled to the beamformer603and generates the transmit signals that are supplied from the beamformer603to the probe601. The transmit signals may represent various types of ultrasound TX signals such as used in connection with B-mode imaging, colour Doppler imaging, pulse-inversion transmit techniques, contrast-based imaging, M-mode imaging and the like. In accordance with embodiments herein, the transmit signals include acoustic disturbance ultrasound (ACU) beam that are directed at select excitation points or regions (1inFIG.1A). The ACU beams are configured to generate shear waves as described herein.

The beamformer603performs beamforming upon received echo signals to form beamformed echo signals in connection pixel locations distributed across the region of interest. For example, in accordance with certain embodiments, the transducer elements generate raw analog receive signals that are supplied to the beamformer. The beamformer adjusts the delays to focus the receive signal along a select receive beam and at a select depth within the ROI. The beamformer adjusts the weighting of the receive signals to obtain a desired apodization and profile. The beamformer sums the delayed, weighted receive signals to form RF beamformed signals. The RF beamformed signals are digitized at a select sampling rate by the RX preamp and A/D converter604. The RF beamformed signals are converted to I,Q data pairs.

The TX waveform generator602, TX/RX beamformer603and A/D converter604cooperate to generate the acoustic disturbance ultrasound beams10directed at the excitation point1. The acoustic disturbance ultrasound beams are configured to produce shear waves11that have directions of propagation extending laterally from the directions of propagation of the acoustic disturbance ultrasound beams10. The I,Q data pairs are saved as image pixels in the line of sight (LOS) memory. For example, the LOS memory may include LOS memory portions associated with each line of sight through the ROI. The I,Q data pairs, defining the image pixels for corresponding individual ROI locations along a corresponding LOS, are saved in the corresponding LOS memory portion. A collection of image pixels (e.g., I,Q data pairs) are collected over time and saved in the LOS memory605. The image pixels correspond to tissue and other anatomy within the ROI. As the ROI experiences the shear waves, the tissue and other anatomy in the ROI moves in response to the shear waves. The collection of image pixels captures the movement of tissue other anatomy within the ROI.

In embodiments, a dedicated sequencer/timing controller610may be programmed to manage acquisition timing which can be generalized as a sequence of firings aimed to locally generate shear waves aside the measurement box followed by tracking firings to monitor transition of the shear waves through the acquisition lines (LOS) in the measurement box (corresponding to the ROI). Optionally, idle phases can be added to control heating of the probe and manage compliance with safety emission regulations. According to a further option also reference pulses can be generated and transmitted along corresponding reference lines.

A sequence controller610manages operation of the TX/RX beamformer603and the A/D converter604in connection with transmitting ADU beams and measuring image pixels at individual LOS locations along the lines of sight. The sequence controller610manages collection of reference measurements and shear-wave induced measurements. The sequence controller610provides a pause period between a last measurement along one tracking line coincident with one line of sight and a first measurement along a following tracking line coincident with a following line of sight.

One or more processors perform various processing operations as described herein. The CPU612may perform one or more of the operations described herein in connection with generation of shear waves, measurement of displacement, calculation of displacement speed, calculation of stiffness values and the like.

Among other things, the processor and/or CPU612analyze the image pixels to measure displacement of the image pixels or controls an optional dedicated shear wave tracking data processor626. The processor and/or the CPU612and or the optional shear wave data processor measure the displacement at image pixels for the plurality of lines of sight placed in the region of interest. The lines of sight are located at different predetermined laterally staggered distances from the excitation point (1), (4).

The processor606and/or CPU612or optionally a dedicated shear wave tracking data processor626also calculates a stiffness value based on the speed of the shear wave according to one or more of the examples describe above.

As explained herein, the processor and/or CPU612or the dedicated processor626obtaining one or more reference measurements for a plurality of lines of sight in the region of interest, prior to generating the first and second shear waves. According to an embodiment, the processor and/or CPU612or the optional dedicated processor626measure the shear waves11include measuring mean displacement over time of the tissue along a plurality of line of sights and identifying a peak of the mean displacements.

For example, the measurements by the processor and/or CPU612or the optional dedicated processor626may include calculating a cross-correlation between the measurements associated with the shear waves and a reference measurement obtained independent of the shear waves. The processor and/or CPU612or the optional dedicated processor626measure displacement over time of the tissue along a plurality of line of sights and calculates speeds of the shear waves11based, in part, on distances of the corresponding lines of sight from the excitation point1.

The processor and/or CPU612also performs conventional ultrasound operations. For example, the processor executes a B/W module to generate B-mode images. The processor and/or CPU612executes a Doppler module to generate Doppler images. The processor executes a Color flow module (CFM) to generate colour flow images. The processor and/or CPU612may implement additional ultrasound imaging and measurement operations. Optionally, the processor and/or CPU612may filter the displacements to eliminate movement-related artifacts.

An image scan converter607performs scan conversion on the image pixels to convert the format of the image pixels from the coordinate system of the ultrasound acquisition signal path (e.g., the beamformer, etc.) and the coordinate system of the display. For example, the scan converter607may convert the image pixels from polar coordinates to Cartesian coordinates for image frames.

A cine memory608stores a collection of image frames over time. The image frames may be stored formatted in polar coordinates, Cartesian coordinates or another coordinate system.

An image display609displays various ultrasound information, such as the image frames and information measured in accordance with embodiments herein. For example, the image display609displays the stiffness values, displacement measurements, displacement speeds, and other information calculated in accordance with embodiments herein. The stiffness values, displacement measurements, displacement speeds, and other information may be displayed as image information, as numeric values, graphical information and the like. The display609displays the ultrasound image with the region of interest shown. Optionally, the display609may display indicia indicating the excitation points (1), where the indicia are overlaid on the ultrasound image and/or presented along opposite sides of the ultrasound image.

Optionally, the system ofFIG.6may include an ECG monitor not shown in detail that couples an ECG sensor to the patient and records an ECG signal indicative of the patient's heart rate. The processor and/or sequence controller610synchronize the generation of acoustic disturbance ultrasound beams10and the measurement of the first and second displacements of the image pixels induced by the first and second shear waves11with the ECG signal.

According to the present invention the embodiment ofFIG.6shows an envelope extractor614which generates the envelope of the RF reception signals corresponding to the received echoes along one or more of the reference and tracking scan lines. The envelope generated in the extractor614is subjected to logarithmic compression in615. A slope detector616computes the slope of lines fitting the logarithm of the envelope at different depths as already disclosed in relation to method in the present description and in the preceding paragraphs.

A map is generated in which an attenuation coefficient calculated for a certain depth range and along a certain scan line is represented by a color hue scale and in the position corresponding to the pixel or voxel at the said depth range and along the said scan line.

The blocks/modules illustrated inFIG.6can be implemented with dedicated hardware (DPSs, FPGAs, memories) and/or in software with one or more processors.

A control CPU module612is configured to perform various tasks such as implementing the user/interface and overall system configuration/control. In case of fully software implementation of the ultrasound signal path, the processing node usually hosts also the functions of the control CPU.

A power supply circuit611is provided to supply power to the various circuits, modules, processors, memory components, and the like. The power front-end may be an A.C. power source and/or a battery power source (e.g., in connection with portable operation).

Optionally, in point Shear Wave acquisition, the RX tracking lines (line of sights—LOSs) may be temporarily stored, either as pure RF or as I/Q data, in the front-end local memories. The processing may be implemented by a dedicated processor module and/or a CPU612. Processed data may be formatted as shear wave speed measurements or stiffness values. These are then added to the ancillary data of the field-of-view under scan and properly reported as an overlay to the image displayed on system's monitor.

According to a further feature, an image combination unit627may be present in which the B-mode image data of at least of a region of interest and the corresponding graphic representation as an image of the velocity of the shear wave or of the elasticity parameter determined from said velocity data and/or the attenuation data is combined for the superimposed display of the B-mode image and of the image representing the shear wave velocity and/or the elasticity features determined for the corresponding pixels in the B-mode image. The representation as an image of the velocity or of the corresponding elasticity parameter values and the representation of the attenuation coefficients and the combination of this image with the B-mode image can be carried out according to one of the previously disclosed methods.

FIG.7illustrates a block diagram of an ultrasound system formed in accordance with an alternative embodiment. The system ofFIG.7implements the operations described herein in connection with various embodiments. By way of example, one or more circuits/processors within the system implement the operations of any processes illustrated in connection with the figures and/or described herein. The system includes a probe interconnect board702that includes one or more probe connection ports704. The connection ports704may support various numbers of signal channels (e.g., 128, 192, 256, etc.). The connector ports704may be configured to be used with different types of probe arrays (e.g., phased array, linear array, curved array, 1D, 1.25D, 1.5D, 1.75D, 2D array, etc.). The probes may be configured for different types of applications, such as abdominal, cardiac, maternity, gynecological, urological and cerebrovascular examination, breast examination and the like.

One or more of the connection ports704may support acquisition of 2D image data and/or one or more of the connection ports704may support 3D image data. By way of example only, the 3D image data may be acquired through physical movement (e.g., mechanically sweeping or physician movement) of the probe and/or by a probe that electrically or mechanically steers the transducer array.

The probe interconnect board (PIB)702includes a switching circuit706to select between the connection ports704. The switching circuit706may be manually managed based on user inputs. For example, a user may designate a connection port704by selecting a button, switch or other input on the system. Optionally, the user may select a connection port704by entering a selection through a user interface on the system.

Optionally, the switching circuit706may automatically switch to one of the connection ports704in response to detecting a presence of a mating connection of a probe. For example, the switching circuit706may receive a “connect” signal indicating that a probe has been connected to a selected one of the connection ports704. The connect signal may be generated by the probe when power is initially supplied to the probe when coupled to the connection port704. Additionally, or alternatively, each connection port704may include a sensor705that detects when a mating connection on a cable of a probe has been interconnected with the corresponding connection port704. The sensor705provides signal to the switching circuit706, and in response thereto, the switching circuit706couples the corresponding connection port704to PIB outputs708. Optionally, the sensor705may be constructed as a circuit with contacts provided at the connection ports704. The circuit remains open when no mating connected is joined to the corresponding connection port704. The circuit is closed when the mating connector of a probe is joined to the connection port704.

A control line724conveys control signals between the probe interconnection board702and a digital processing board724. A power supply line736provides power from a power supply740to the various components of the system, including but not limited to, the probe interconnection board (PIB)702, digital front-end boards (DFB)710, digital processing board (DPB)726, the master processing board (M PB)744, and a user interface control board (UI CB)746. A temporary control bus738interconnects, and provides temporary control signals between, the power supply740and the boards702,710,726,744and746. The power supply740includes a cable to be coupled to an external AC power supply. Optionally, the power supply740may include one or more power storage devices (e.g. batteries) that provide power when the AC power supply is interrupted or disconnected. The power supply740includes a controller742that manages operation of the power supply740including operation of the storage devices.

Additionally, or alternatively, the power supply740may include alternative power sources, such as solar panels and the like. One or more fans743are coupled to the power supply740and are managed by the controller742to be turned on and off based on operating parameters (e.g. temperature) of the various circuit boards and electronic components within the overall system (e.g. to prevent overheating of the various electronics).

The digital front-end boards710providing analog interface to and from probes connected to the probe interconnection board702. The DFB710also provides pulse or control and drive signals, manages analog gains, includes analog to digital converters in connection with each receive channel, provides transmit beamforming management and receive beamforming management and vector composition (associated with focusing during receive operations).

The digital front-end boards710include transmit driver circuits712that generate transmit signals that are passed over corresponding channels to the corresponding transducers in connection with ultrasound transmit firing operations. The transmit driver circuits712provide pulse or control for each drive signal and transmit beamforming management to steer firing operations to points of interest within the region of interest. By way of example, a separate transmit driver circuits712may be provided in connection with each individual channel, or a common transmit driver circuits712may be utilized to drive multiple channels. The transmit driver circuits712cooperate to focus transmit beams to one or more select points within the region of interest. The transmit driver circuits712may implement single line transmit, encoded firing sequences, multiline transmitter operations, generation of shear wave inducing ultrasound beams as well as other forms of ultrasound transmission techniques.

The digital front-end boards710include receive beamformer circuits714that received echo/receive signals and perform various analog and digital processing thereon, as well as phase shifting, time delaying and other operations in connection with beamforming. The beam former circuits714may implement various types of beamforming, such as single-line acquisition, multiline acquisition as well as other ultrasound beamforming techniques.

The digital front-end boards716include continuous wave Doppler processing circuits716configured to perform continuous wave Doppler processing upon received echo signals. Optionally, the continuous wave Doppler circuits716may also generate continuous wave Doppler transmit signals.

The digital front-end boards710are coupled to the digital processing board726through various buses and control lines, such as control lines722, synchronization lines720and one or more data bus718. The control lines722and synchronization lines720provide control information and data, as well as synchronization signals, to the transmit drive circuits712, receive beamforming circuits714and continuous wave Doppler circuits716. The data bus718conveys RF ultrasound data from the digital front-end boards710to the digital processing board726. Optionally, the digital front-end boards710may convert the RF ultrasound data to I,Q data pairs which are then passed to the digital processing board726.

The digital processing board726includes an RF and imaging module728, a colour flow processing module730, an RF processing and Doppler module732and a PCI link module734. The digital processing board726performs RF filtering and processing, processing of black and white image information, processing in connection with colour flow, Doppler mode processing (e.g. in connection with polls wise and continuous wave Doppler). The digital processing board726also provides image filtering (e.g. speckle reduction) and scanner timing control. The digital processing board726may include other modules based upon the ultrasound image processing functionality afforded by the system.

The modules728-734comprise one or more processors, DSPs, and/or FPGAs, and memory storing program instructions to direct the processors, DSPs, and/or FPGAs to perform various ultrasound image processing operations. The RF and imaging module728perform various ultrasound related imaging, such as B mode related image processing of the RF data. The RF processing and Doppler module732convert incoming RF data to I,Q data pairs, and performs Doppler related processing on the I, Q data pairs. Optionally, the imaging module728may perform B mode related image processing upon I, Q data pairs. The CFM processing module730performs colour flow related image processing upon the ultrasound RF data and/or the I, Q data pairs. The PCI link734manages transfer of ultrasound data, control data and other information, over a PCI express bus748, between the digital processing board726and the master processing board744.

The master processing board744includes memory750(e.g. serial ATA solid-state devices, serial ATA hard disk drives, etc.), a VGA board752that includes one or more graphic processing unit (GPUs), one or more transceivers760one or more CPUs752and memory754. The master processing board (also referred to as a PC board) provides user interface management, scan conversion and cine loop management. The master processing board744may be connected to one or more external devices, such as a DVD player756, and one or more displays758. The master processing board includes communications interfaces, such as one or more USB ports762and one or more ports764configured to be coupled to peripheral devices. The master processing board744is configured to maintain communication with various types of network devices766and various network servers768, such as over wireless links through the transceiver760and/or through a network connection (e.g. via USB connector762and/or peripheral connector764).

The network devices766may represent portable or desktop devices, such as smart phones, personal digital assistants, tablet devices, laptop computers, desktop computers, smart watches, ECG monitors, patient monitors, and the like. The master processing board744conveys ultrasound images, ultrasound data, patient data and other information and content to the network devices for presentation to the user. The master processing board744receives, from the network devices766, inputs, requests, data entry and the like.

The network server768may represent part of a medical network, such as a hospital, a healthcare network, a third-party healthcare service provider, a medical equipment maintenance service, a medical equipment manufacturer, a government healthcare service and the like. The communications link to the network server768may be over the Internet, a private intranet, a local area network, a wide-area network, and the like.

The master processing board744is connected, via a communications link770with a user interface control board746. The communications link770conveys data and information between the user interface and the master processing board744. The user interface control board746includes one or more processors772, one or more audio/video components774(e.g. speakers, a display, etc.). The user interface control board746is coupled to one or more user interface input/output devices, such as an LCD touch panel776, a trackball778, a keyboard780and the like. The processor772manages operation of the LCD touch panel776, as well as collecting user inputs via the touch panel776, trackball778and keyboard780, where such user inputs are conveyed to the master processing board744in connection with implementing embodiments herein.

FIG.8illustrates a block diagram of a portion of the digital front-end boards710formed in accordance with embodiments herein. A group of diplexers802receive the ultrasound signals for the individual channels over the PIB output808. The ultrasound signals are passed along a standard processing circuit805or to a continuous wave processing circuit812, based upon the type of probing utilized. When processed by the standard processing circuit805, a preamplifier and variable gain amplifier804process the incoming ultrasound receive signals that are then provided to an anti-aliasing filter806which performs anti-aliasing filtering.

According to an embodiment the retrospective transmit beam focusing according to the present invention may be applied to the RF data directly acquired by the system or to transformed data according to different transformations as for example as a phase/quadrature (I/Q) transformation, or similar.

In the embodiment ofFIG.8an example of the said transformation of the RF data is disclosed According to this example, the output of the filter806is provided to an A/D converter808that digitizes the incoming analog ultrasound receive signals. When a continuous wave (CW) probe is utilized, the signals therefrom are provided to a continuous wave phase shifter, demodulator and summer810which converts the analog RF reception signals to I,Q data pairs. The CW I,Q data pairs are summed, filtered and digitized by a continuous wave processing circuit812. Outputs from the standard or continuous wave processing circuits805,812are then passed to beam forming circuits820which utilize one or more FPGAs to perform filtering, delaying and summing the incoming digitized receive signals before passing the RF data to the digital processing board826(FIG.7). The FPGAs receive focalization data from memories828. The focalization data is utilized to manage the filters, delays and summing operations performed by the FPGAs in connection with beamforming. The beamformed RF or I/Q data is passed between the beamforming circuits820and ultimately to the digital processing board726.

The digital front-end boards710also include transmit modules822that provide transmit drive signals to corresponding transducers of the ultrasound probe. The beamforming circuits820include memory that stores transmit waveforms. The transmit modules822receive transmit waveforms over line824from the beamforming circuits820.

FIG.9illustrates a block diagram of the digital processing board726implemented in accordance with embodiments herein. The digital processing board726includes various processors952-959to perform different operations under the control of program instructions saved within corresponding memories see962-969. A master controller950manages operation of the digital processing board726and the processors952-959. By way of example, one or more processors as the952may perform filtering, the modulation, compression and other operations, while another processor953performs colour flow processing. The master controller provides probe control signals, timing control signals, communications control and the like. The master controller950provides real-time configuration information and synchronization signals in connection with each channel to the digital front-end board710.

FIG.10is a flowchart of an embodiment of the present method. Particularly example ofFIG.10relates to the case in which a transmitted pulse of multifrequency band is generated and transmitted into the ROI.

Step500provides for the transmission of at least one ultrasound pulse in a ROI of a target body. The received echoes of the said pulse at step501are transformed by the probe in RF reception signals at step502. The RF reception signals are subjected to filtering with a filter-bank for determining signal components of the RF signals with frequencies within n sub-bands of a frequency band as illustrated at step503.

Step504provides for calculating the envelope of the corresponding RF signal for each of the n frequency subbands and for each penetration depth of the ultrasound pulse in a target body.

In step505for each of the n frequency subbands the logarithm of the envelope of the corresponding RF signal is calculated and in step506the slope of the logarithm of the envelope of the corresponding RF signal is calculated for each of the n frequency subbands.

Step507provides for setting the attenuation coefficient of the ultrasound wave equal to the slope of the logarithm of the envelope of the corresponding RF signal for each of the n frequency subbands.

In step508the attenuation coefficient of the ultrasound wave is set equal to the mean value or the median value of the slopes of the logarithm of the envelope of the corresponding RF signal for each of the n frequency subbands.

FIG.11show a flowchart relating to the embodiment of the present invention according to which the attenuation imaging is combined with the elasticity imaging within one image acquisition process.

AT step510one or a sequence of ultrasound reference pulses is transmitted into a target body. The echoes of the said transmit signals is received at step511and transformed in RF reception signals at step512.

According to the one embodiment of the present invention the RF reception signals are used for carrying out the attenuation coefficient extraction process and graphically representing an attenuation coefficient map as indicated by steps520and521and also for carrying out the elasticity coefficient determination process and graphically representing an elasticity coefficient map as indicated by the steps530and531.

Further embodiments which are already disclosed can be easily derived from the present flow chart. In the case the tracking pulses are used instead of the reference pulses or the said tracking pulses are used in combination with the said reference pulses and also in the case in which the said reference or tracking pulses are transmitted twice one time for carrying out the attenuation imaging modality and the other for carrying out the elasticity imaging modality.

It should be clearly understood that the various arrangements and processes broadly described and illustrated with respect to the figures, and/or one or more individual components or elements of such arrangements and/or one or more process operations associated of such processes, can be employed independently from or together with one or more other components, elements and/or process operations described and illustrated herein. Accordingly, while various arrangements and processes are broadly contemplated, described and illustrated herein, it should be understood that they are provided merely in illustrative and non-restrictive fashion, and furthermore can be regarded as but mere examples of possible working environments in which one or more arrangements or processes may function or operate.

Aspects are described herein with reference to the figures, which illustrate example methods, devices and program products according to various example embodiments. These program instructions may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing device or information handling device to produce a machine, such that the instructions, which execute via a processor of the device implement the functions/acts specified. The program instructions may also be stored in a device readable medium that can direct a device to function in a particular manner, such that the instructions stored in the device readable medium produce an article of manufacture including instructions which implement the function/act specified. The program instructions may also be loaded onto a device to cause a series of operational steps to be performed on the device to produce a device implemented process such that the instructions which execute on the device provide processes for implementing the functions/acts specified.

One or more of the operations described above in connection with the methods may be performed using one or more processors. The different devices in the systems described herein may represent one or more processors, and two or more of these devices may include at least one of the same processors. In one embodiment, the operations described herein may represent actions performed when one or more processors (e.g., of the devices described herein) execute program instructions stored in memory (for example, software stored on a tangible and non-transitory computer readable storage medium, such as a computer hard drive, ROM, RAM, or the like).

The processor(s) may execute a set of instructions that are stored in one or more storage elements, in order to process data. The storage elements may also store data or other information as desired or needed. The storage element may be in the form of an information source or a physical memory element within the controllers and the controller device. The set of instructions may include various commands that instruct the controllers and the controller device to perform specific operations such as the methods and processes of the various embodiments of the subject matter described herein. The set of instructions may be in the form of a software program. The software may be in various forms such as system software or application software. Further, the software may be in the form of a collection of separate programs or modules, a program module within a larger program or a portion of a program module. The software also may include modular programming in the form of object-oriented programming. The processing of input data by the processing machine may be in response to user commands, or in response to results of previous processing, or in response to a request made by another processing machine.

The controller may include any processor-based or microprocessor-based system including systems using microcontrollers, reduced instruction set computers (RISC), application specific integrated circuitry (ASICs), field-programmable gate arrays (FPGAs), logic circuitry, and any other circuit or processor capable of executing the functions described herein. When processor-based, the controller executes program instructions stored in memory to perform the corresponding operations. Additionally, or alternatively, the controllers and the controller device may represent circuitry that may be implemented as hardware. The above examples are exemplary only, and are thus not intended to limit in any way the definition and/or meaning of the term “controller.”

Optionally, aspects of the processes described herein may be performed over one or more networks one a network server. The network may support communications using any of a variety of commercially-available protocols, such as Transmission Control Protocol/Internet Protocol (“TCP/IP”), User Datagram Protocol (“UDP”), protocols operating in various layers of the Open System Interconnection (“OSI”) model, File Transfer Protocol (“FTP”), Universal Plug and Play (“UpnP”), Network File System (“NFS”), Common Internet File System (“CIFS”) and AppleTalk. The network can be, for example, a local area network, a wide-area network, a virtual private network, the Internet, an intranet, an extranet, a public switched telephone network, an infrared network, a wireless network, a satellite network and any combination thereof.