METHOD AND SYSTEM FOR DATA TRANSFER REDUCTION IN ULTRASOUND IMAGING

Abstract

The invention is directed to method for ultrasound (US) imaging using an ultrasound system comprising a US probe (10), wherein the US probe (10) is configured to insonify an imaging region, receive echo signals, digitize the received echo signals and transfer the digitized radiofrequency (RF) data (14) to a data processing unit adapted to beamform the RF data (14). The method comprises acquiring at least one scouting image (15) including an anatomical structure; selecting at least one region of interest (ROI) (16) within the scouting image (15), wherein the at least one ROI (16) includes a portion of the anatomical structure; setting a transmit (TX) scheme (46) and a receive (RX) scheme (48) for US imaging of the imaging region (18), in which the ROI (16) is insonified with different TX and RX settings than the imaging region (18) outside the ROI (16); and acquiring a plurality of US images (26) according to the TX and RX scheme. The US probe (10) is configured to transfer to the data processing unit only the received RF data (14) corresponding to a depth range of the at least one ROI (16) for at least some of the stipulated receive beams (24) reflected from the at least one ROI (16), and is configured to transfer the received RF data corresponding to the full depth of the imaging region (18) for at least some of the receive beams (24) reflected from the imaging region (18) outside the at least one ROI (16).

Claims

1. A method for ultrasound (US) imaging using an ultrasound system comprising a US probe having a transducer array and an analogue-to-digital converter (ADC) array, wherein the US probe is configured to insonify an imaging region, receive echo signals, digitize the received echo signals by the ADC array and transfer the digitized radiofrequency (RF) data to a data processing unit via a bandwidth-limited channel, wherein the data processing unit is adapted to beamform the RF data, the method comprising the following steps: acquiring at least one scouting image of the imaging region, the scouting image including an anatomical structure of interest; selecting at least one region of interest (ROI) within the scouting image, wherein the at least one ROI includes a portion of the anatomical structure; setting a transmit (TX) scheme and a receive (RX) scheme for US imaging of the imaging region, wherein the at least one ROI is insonified with different TX and RX settings than the imaging region outside the at least one ROI; acquiring a plurality of US images according to the TX scheme and the RX scheme; wherein the US probe is configured to transfer to the data processing unit only the received RF data corresponding to a depth range of the at least one ROI for at least some of the stipulated receive beams reflected from the at least one ROI, and is configured to transfer the received RF data corresponding to the full depth of the imaging region for at least some of the receive beams reflected from the imaging region outside the at least one ROI.

2. The method according to claim 1, wherein TX and RX schemes comprise insonifying the at least one ROI with a higher temporal resolution and/or with different types of transmit beams and/or with a different pulse-repetition rate than the imaging region outside the at least one ROI.

3. The method according to claim 1, wherein, in the TX scheme, the transmit power and/or the focusing scheme of transmit beams insonifying the at least one ROI are adapted to the at least one ROI, in particular to the location of the at least one ROI relative to the US probe.

4. The method according to claim 1, wherein the TX scheme and RX scheme comprise interleaving at least one ROI acquisition cycle, in which only the at least one ROI is insonified, between two full acquisition cycles, in which the entire imaging region of the US probe is insonified; and wherein according to the RX scheme, in a ROI acquisition cycle, the US probe is configured to transfer only the received RF data corresponding to a depth range of the at least one ROI for at least some of the stipulated receive beams reflected from the at least one ROI, and, in a full acquisition cycle, the US probe is configured to transfer the received RF data corresponding to the depth range of the entire imaging region of the US probe.

5. The method according to claim 1, wherein the US probe comprises an in-probe memory, wherein the in-probe memory is in particular integrated with the ADC array, the method further comprising the steps of: selecting the digitized RF data corresponding to a depth range of the at least one ROI for at least some of the stipulated receive beams reflected from the at least one ROI for transfer to the data processing unit; buffering at least some of the selected digitized RF data in the in-probe memory in order to delay the transfer of RF data from the US probe when a pre-determined maximum data rate is exceeded.

6. The method according to claim 1, wherein the digitized RF data are compressed, in particular via a discrete wavelet transform, before they are transferred to the data processing unit.

7. The method according to claim 6, wherein the digitized RF data reflected from the at least one ROI are compressed with a different bit depth, in particular a higher bit-depth, and/or with a different subsampling pattern and/or with a different wavelet compression than the digitized RF data reflected from the imaging region outside the at least one ROI.

8. The method according to claim 1, wherein the TX and RX scheme uses a wide transmit beam imaging mode with a plurality of transmit events to insonify the imaging region, wherein only a part of the plurality of transmit events insonifies the at least one ROI, and wherein the transmit events insonifying the at least one ROI are carried out at a higher temporal resolution.

9. The method according to claim 4, wherein the TX scheme uses a plurality of transmit events to insonify the imaging region, wherein a part of the plurality of transmit events insonifies the at least one ROI, wherein spatially equivalent transmit events are initiated at the same time offset in a at least one ROI acquisition cycle and a full acquisition cycle.

10. The method according to claim 1, wherein two or more regions of interest (ROIs) are selected within the scouting image, the two or more ROIs each including a portion of the anatomical structure, wherein in the TX scheme and the RX scheme, the two or more ROIs are insonified with different TX and RX settings than the imaging region outside the two or more ROIs, and wherein at least two different ROIs are insonified with different TX and RX settings with respect to each other.

11. The method according to claim 3, further comprising the following steps: reconstructing ROI images from the ROI acquisition cycle and full US images from the full acquisition cycles; temporally upsampling the full US images in order to achieve the same frame rate of full US images for the entire imaging region as for the ROI images; blending together the upsampled full US images with the ROI images.

12. The method according to claim 10, wherein upsampling is carried out using interpolation, and the interpolation takes into account motion between the at least one ROI and the remaining imaging region, in particular by using a trained neural network.

13. The method according to claim 1, wherein, in the TX scheme, the at least one ROI (16) and the imaging region outside the at least one ROI are insonified by overlapping transmit beams, wherein more transmit beams overlap in the at least one ROI than in the imaging region outside the at least one ROI.

14. The method according to claim 1, wherein the at least one ROI is detected and tracked automatically by a computer vision and/or an artificial intelligence algorithm on the at least one scouting image and/or on the plurality of ultrasound images.

15. An US imaging system adapted to carry out the method according to claim 1, the system comprising an US probe having a transducer array and an ADC array, wherein the US probe is configured to insonify an imaging region, receive echo signals, digitize the received echo signals and transfer the digitized RF data via an interface comprising a bandwidth-limited channel to a data processing unit, wherein the data processing unit is adapted to process and beamform the RF data.

Description

SHORT DESCRIPTION OF THE FIGURES

[0057] Useful embodiments of the invention shall now be described with reference to the attached figures. Similar elements or features are designated with the same reference signs in the figures. Different embodiments shown are explicitly allowed to be combined unless noted otherwise.

[0058] FIG. 1 schematically shows a full ultrasound (US) image with a marked region of interest,

[0059] FIG. 2 shows a schematic illustration of an angled plane wave imaging mode with a region of interest according an embodiment of the invention,

[0060] FIG. 3 shows a schematic view of an alternative angled plane wave imaging mode with a region of interest according an embodiment of the invention,

[0061] FIG. 4 shows an illustration of a receive scheme according to an embodiment of the invention,

[0062] FIG. 5 shows a flow diagram representing a method according to an embodiment of the invention,

[0063] FIG. 6 shows a schematic illustration of a system according to an embodiment of the invention,

[0064] FIGS. 7 and 8 show further flow diagrams of a method according to an embodiment of the invention,

[0065] FIG. 9 shows a concept of interleaving ROI acquisitions with full acquisitions according to an embodiment of the invention based on data taken with an imaging mode similar to that shown in FIG. 2,

[0066] FIG. 10 shows a concept of upsampling full US images to the same frame rate as the ROI frame rate based on data as it is shown in FIG. 9,

[0067] FIG. 11 shows a concept of interleaving ROI acquisitions with full acquisitions according to an embodiment of the invention based on data taken with an imaging mode shown in FIG. 3,

[0068] FIG. 12 shows another schematic representation of an ultrasound system according to an embodiment of the invention.

DESCRIPTION OF EMBODIMENTS

[0069] FIG. 1 schematically shows a full ultrasound (US) image 18a corresponding to the imaging region of an US probe. The US image 18a shows a 4-chamber-view of a human heart 30. Within this full US image 18a a region of interest (ROI) 16 is marked. Some parts of the heart, like the valves, move faster than other parts, like the ventricle 27 or atrial walls. In order to resolve the fast movement of the valve 28, it is necessary to apply a sufficiently fast imaging technique, e.g. ultrafast US imaging. On the other hand, other parts of the anatomical structure do not require such a fast imaging technique. Hence, after selecting an ROI 16, which in this example comprises the fast-moving valve 28, the region inside the ROI 16 may be imaged with a higher frame rate than the region outside the ROI 16. For the other parts of the organ 30, the corresponding transmissions of the US probe 10 are scheduled at larger intervals to match the speed of their (slower) movements. Consequently, there will be a slow-time and fast-time acquisition. Such an adaptive TX-RX scheme helps in reducing the radiofrequency (RF) data transfer load compared to a fixed TX-RX scheme, while still allowing to acquire data of the fast-moving valve 28 with a sufficiently high frame rate.

[0070] FIG. 2 shows a schematic illustration of an angled plane wave imaging mode according to the invention, wherein different transmit events, i.e. different transmit beams 22, numbered TX1, TX2, TX3, . . . , TX7, are directed in different directions, each transmit beam spanning e.g. 5° to 15° of the azimuth angle. In this embodiment the transmit beams 22 are propagating such that consecutive transmit beams 22 are adjacent to one another, and every sector of a predetermined area corresponding to the full imaging region 18 is covered by one transmit beam. In this example, only the transmit beams TX4, TX5 and TX6 are covering the ROI 16. Hence, only 3 out of 7 transmit beams 22 are required to image the ROI 16.

[0071] The transmit and receive parameters may be different for the insonification of the ROI than for the full imaging region. For example, the transmit power and/or the transmit focusing scheme may be adapted depending on the location of the ROI 16. Focused TX may help to do harmonic imaging in the ROI 16. Furthermore, the transmit beams 22 that cover the ROI 16 (TX4-TX6) may be transmitted with a higher frequency than the remaining transmit beams 22 of the imaging region 18.

[0072] FIG. 3 shows a schematic view of an alternative angled plane wave TX scheme according an embodiment of the invention. In this embodiment, there are three transmit events (TX1, TX2 and TX3) which overlap partially. This results in a much higher temporal resolution in the zone where all transmit beams 22 overlap, than at the edges, which are covered by only one transmit beam 22 (TX1 and TX3 respectively). By adjusting the transmit pattern to provide most overlap around the ROI 16 zone, an improved sampling of the ROI 16 is obtained. In this example, the central zone comprising the ROI 16 is imaged three times more often, namely by all three transmit beams 22 (TX1-TX3) than the two zones at the edges.

[0073] FIG. 4 shows an illustration of a receive scheme according to an embodiment of the invention. The receive scheme can be adjusted to only keep samples in the depth range corresponding to the ROI 16 of the stipulated transmit beams 22. In this illustration the full imaging region 18 is represented by a large cube, wherein the horizontal axis is a depth axis (also called fast-time axis), the vertical axis Tx corresponds to the transmit events and the third axis Rx corresponds to the receive elements. The ROI 16 is represented by a smaller cube within the larger cube. In order to reduce the RF data 14 that is forwarded to an analysis system 40 during an ROI acquisition cycle, only the RF data 14 corresponding to a certain depth range, in this case the range from d.sub.start to d.sub.stop is forwarded. Furthermore, RF data 14 is only forwarded when transmitting into certain transmit angles that cover the ROI 16. In FIG. 4, this range of transmit angles is between tx.sub.start and tx.sub.stop. Following this scheme, the amount of RF data 14 can be reduced by:

[00002]$R_{\mathrm{frame}}=\left(\frac{d_{\mathrm{stop}}-d_{\mathrm{start}}}{d_{\mathrm{full}}}\right)\left(\frac{{\mathrm{tx}}_{\mathrm{stop}}-{\mathrm{tx}}_{\mathrm{start}}}{{\mathrm{tx}}_{\mathrm{full}}}\right)$

[0074] FIG. 5 shows a diagram representing a method according to an embodiment of the invention. As a first step a scouting US image 15 of an anatomical structure of a patient, for example a heart, is acquired. In order to limit the data rates involved, the scouting US image 15 may have lower resolution or may support lower frame rates than images that are acquired later for the actual data analysis. As a next step, an ROI is selected 116 within the scouting US image 15. The ROI 16 may in particular cover a fast-moving portion of an anatomical structure like the valve 28 of a heart. The selection of the ROI 16 may for example be carried out manually by a user or it may be detected automatically by an AI.

[0075] Next, a transmit scheme and a receive scheme are adapted for the US imaging system 114 based on the location of the ROI 16 relative to a US probe 10 of the system. The transmit scheme may, for example, comprise insonifying the ROI with a higher temporal resolution, and/or with different types of transmit beams 22 than the imaging region 18 outside the ROI 16. On the other hand, the receive scheme may be according to the embodiment shown in FIG. 4, i.e. at predetermined time intervals corresponding to the transmit scheme only received RF data 14 corresponding to a depth range of the ROI 16 are processed. It is also conceivable to apply a different bit-depth in the ROI 16, e.g. 12-bit precision, than in the region outside the ROI 16, e.g. 8-bit precision, or to measure a Doppler shift within the ROI 16 but not outside of the ROI 16. The following steps are to acquire RF full frame data 118 and ROI frame data 120, wherein according to the transmit scheme, the ROI 16 may for example be insonified with a higher temporal resolution than the imaging region 18 outside the ROI 16. This may be realized by interleaving one or several ROI acquisition cycles, in which only the ROI 16 is insonified, between two full acquisition cycles, in which the entire imaging region 18 is insonified. Hence, for every acquired RF full frame dataset 118 at least one other dataset comprising only the ROI frame is also acquired 120. According to the receive scheme, in an ROI acquisition cycle the US probe 10 is, configured to transfer only the received RF signals corresponding to a depth range of the ROI 16 for the stipulated receive beams 24 reflected from the ROI 16 and in a full acquisition cycle the US probe 10 is configured to transfer the received RF signals corresponding to the entire imaging region 18.

[0076] The following steps are to beamform the full frame data 119 and the ROI frame data 121. The ROI images 16a and the full US images 18a are then blended together in a sequence of images to create a temporal sequence of the imaged region, i.e. a video. Thus, a series of US images 26 is created. Optionally, it is conceivable to use one or several of the blended images as a further scouting US image 15 in order to adjust the ROI 16 to accommodate relative movement between the US probe 10 and ROI 16. Accordingly, the steps of this method may be repeated in a cyclical manner, in order to create a plurality of images, wherein the position of the ROI 16 is constantly adjusted.

[0077] FIG. 6 shows a schematic illustration of a system according to an embodiment of the invention. The system is configured to acquire a scouting US image 15 of an anatomical structure and automatically or manually select an ROI 16, including a portion of the anatomical structure, within the scouting US image 15. Additionally, the system is configured to set a transmit and receive scheme based on the acquired scouting US image 15 and the selected ROI 16. The system comprises receive elements 34, which include a transducer array 8 that is adapted to emit transmit beams 22 and, as it is shown in FIG. 6, to detect receive beams 24.

[0078] Furthermore, an analogue-to-digital converter (ADC), or preferably an array of ADCs 32, one for each transducer element, is provided. The ADC is adapted to digitize the received echo signals and forward them as RF data 14 to the encoder 42. The encoder 42 may for example be an application specific integrated circuit (ASIC) that comprises an in-probe memory 50 which is adapted to temporarily store the relevant data, such as the RF data corresponding to the depth range of the ROI according to a receive scheme as described herein. The encoder 42 is configured to forward the selected RF data 14 via an interface 36 to an analysis system 40. According to the receive scheme set by the system, the encoder 42 is adapted to forward only the received RF data 14 corresponding to a depth range of the ROI 16 for at least some of the stipulated receive beams 24 reflected from the ROI 16, in particular those receive beams 24 corresponding to transmit beams 22 of a ROI acquisition cycle. The encoder 42 is further configured to transfer the received RF data 14 corresponding to the full depth of the imaging region 18 for at least some of the receive beams 24 reflected from the FOV outside the ROI 16, in particular those receive beams 24 corresponding to transmit beams 22 of a full acquisition cycle.

[0079] Since the interface 36 may have a limited capacity concerning the transfer of data, the encoder 42 is preferably adapted to use an in-probe memory 50 as a buffer, in order to control and equalize the data stream forwarded via the interface 36. For example, in case that the ROI 16 is imaged with a higher frequency than the region outside of the ROI 16, the amount of data to be transferred may vary depending on time and may be larger whenever the full imaging region 18 is imaged compared to when only the ROI 16 is imaged. In order to balance this out, the data may be buffered by holding data back, i.e. storing some of the generated RF data 14 on the in-probe memory 50, when a large amount of RF data 14 is generated, and forwarding the stored data, when an altogether lower amount of RF data 14 is generated, together with the lower amount of currently generated RF data 14. Thus, an even stream of data without any data peaks will be forwarded. Preferably, all the relevant data can be transferred within one complete cycle that comprises both at least one ROI acquisition cycle and one full acquisition cycle with a relatively constant data stream, wherein the data rate does in particular not exceed a predetermined threshold. Advantageously, the encoder 42 may further comprise means to compress RF data 14, e.g. wavelet compression, to achieve a further minimization of the forwarded data.

[0080] The system furthermore comprises an analysis system 40 including a decoder 44 that is configured to receive the transferred RF data 14, possibly decompress it, and provide it to a data processing unit 12 which includes a beamformer. By utilizing the data processing unit 12, the analysis system 40 is adapted to process the RF data 14 and create US images 26.

[0081] FIGS. 7 and 8 show another schematic representation of a method according to an embodiment of the invention. FIG. 7 represents the first stage, in which the ROI 16 is selected and corresponding TX and RX schemes are set. Therein, first a TX beamforming pattern 38a is transmitted to a transducer array 8. The transducer array 8 emits transmit beams 22 and detects corresponding receive beams 24, which are digitized and processed via RX beamforming 38b. Corresponding B-mode images 52 are then used to select an ROI 16. According to the selected ROI 16, corresponding TX and RX schemes 46, 48 are then selected 148 and redirected to the transducer array 8. As it is shown in FIG. 8 the TX scheme 46 is then used for TX beamforming 38a via the transducer array 8 and incoming signals received by the transducer array 8 are digitized and processed via RX beamforming 38b according to the set RX scheme 48. According to this RX scheme 48, one or several ROI images 16a and a full US image 18a of the imaging region 18 are generated. These images are then blended in the final step 122 in order to create a series of US images 26.

[0082] FIG. 9 shows a concept of interleaving ROI acquisitions with full acquisitions according to an embodiment of the invention. The concept is to take images of the ROI 16 at a higher frequency, i.e. take a larger number of ROI images 16a per time, while also keeping the full imaging region 18 imaged but with a lower frequency, i.e. by taking fewer full US images 18a per time. In this embodiment, there are three ROI images 16a for every full US image 18a. A time axis 145 shows the order, in which the images are taken. Hence, after each full US image 18a, three ROI images 16a are consecutively taken, before the next full US image 18a is taken. Preferably, the time offset between corresponding TX and RX events in each acquired image is constant. This makes it easier to blend the images together and achieve a smooth motion of a corresponding resulting video. Generally, by interlacing one full US image 18a and n−1 ROI images 16a and based on the reduction factor R.sub.frame introduced previously the total reduction of data rate may be described by the reduction factor R.sub.tot:

[00003]$R_{\mathrm{tot}}=\frac{\left(n-1\right)*R_{\mathrm{frame}}+1}{n}$

[0083] Hence, the total reduction of data rate in the example shown in FIG. 9 is R.sub.tot=(3R.sub.frame+1)/4. Dependent on the size of the specific ROI, a total data reduction factor R.sub.tot between 2 and 5 can thus be achieved.

[0084] FIG. 10 is based on data as it is shown in FIG. 9, wherein full US images 18a are upsampled to the same frame rate as the ROI frame rate. The hatched parts of the bars correspond to measured RF data 14, while the empty parts of the bars correspond to upsampled data. Upsampling of the full US images 18a may be achieved by a simple linear temporal interpolation method. Hence, interpolated full images 18b based on the previous and the following acquired full US image 18a are generated at time steps corresponding to the time steps of acquired ROI images 16a. Thus, the same number of full imaging region images, comprising interpolated full images 18b and originally measured full US images 18a, is created as there are ROI images 16a. The upsampled full frame images are then blended with the ROI images 16a in order to create a full video sequence of the imaging region 18. The resulting video will have a higher quality in the ROI 16 than in the region outside the ROI 16, i.e. it will be temporally more accurate. It is conceivable that during the interpolation of the images, the motion between the ROI 16 and the region outside of the ROI 16 is taken into account. This may be supported by utilizing a neural network. Furthermore, the blending might be either performed in the image domain as described above, i.e. pixel-based by adding or averaging intensities of two images, or it might also be performed in the RF domain before the actual images are created by using Gaussian intensity profiles, in particular weighted Gaussian intensity profiles. Blending in the image domain might be either done in polar coordinates, which are the natural coordinates that originate from the geometry of the ultrasound image taking system, or blending can be done in Cartesian coordinates that are calculated from the polar coordinates during a scan conversion.

[0085] The images as they are represented in FIGS. 9 and 10 may for example be acquired in diverging wave or in angled plane imaging mode similar to that shown in FIG. 2. When acquiring images according to an embodiment as shown in FIG. 3, wherein different transmit events overlap, an interleaving scheme as it is shown in FIG. 11 may be applied. Again, the hatched areas of the bars represent actually measured RF data 14 while the empty parts of the bars result from an interpolation of the images. In the central area close to the time axis 154, corresponding to the ROI 16, the image data resulting from all three different transmit beams 22 (TX1, TX2 and TX3) overlap, while on the upper part (TX3) and in the lower part (TX1) of the figure, corresponding to the area outside the ROI 16, only one transmit beam (TX1 and TX3, respectively) contributes to the actual image data. Similar to the embodiments shown in FIGS. 9 and 10, the remaining empty spaces may be filled by interpolation, thereby the images are upsampled to show the whole area at every time step. Again, the interpolated full images 18b are then blended together in order to create a video sequence, wherein the ROI 16 is represented temporally more accurate.

[0086] FIG. 12 shows a schematic representation of an ultrasound system 200 according to an embodiment of the invention and configured to perform the inventive method. It may in particular be configured to work as schematically shown in FIG. 5. The ultrasound system 200 includes a usual ultrasound hardware unit 202, comprising a CPU 204, GPU 206 and digital storage medium 208, for example a hard disc or solid-state disc. A computer program may be loaded into the hardware unit, from CD-ROM 210 or over the internet 212. The hardware unit 202 is connected to a user-interface 214, which comprises a keyboard 216 and optionally a touchpad 218. The touchpad 218 may also act as a display device for displaying imaging parameters. The hardware unit 202 is connected to a US probe 10, which includes a transducer array 8 and optionally an in-probe memory 50 (not shown). The US probe 10 is configured to insonify an imaging region, receive echo signals, digitize the received echo signals and transfer the digitized RF data to a data processing unit 12, wherein the data processing unit 12 may be part of the CPU 204 and/or the GPU 206. Acquired US images 26 are displayed on the screen 226, which may be any commercially available display unit, e.g. a screen, television set, flat screen, projector etc.

[0087] 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 invention, as set forth in the claims that follow. Accordingly, the specification and drawings are to be regarded as an illustrative manner and are not intended to limit the scope of the appended claims.

Reference Signs

[0088] 8 transducer array [0089] 10 US probe [0090] 12 data processing unit [0091] 14 RF data [0092] 15 scouting US image [0093] 16 ROI [0094] 16a ROI image [0095] 18 imaging region [0096] 18a Full US image [0097] 18b interpolated full image [0098] 22 transmit beam [0099] 24 receive beam [0100] 26 series of US images [0101] 27 ventricle [0102] 28 valve [0103] 30 heart [0104] 32 ADC array [0105] 34 receive elements [0106] 34a receive element axis [0107] 35a transmit event axis [0108] 36 interface [0109] 38 beamforming [0110] 38a TX beamforming [0111] 38b RX beamforming [0112] 40 analysis system [0113] 42 encoder [0114] 44 decoder [0115] 46 TX scheme [0116] 48 RX scheme [0117] 50 in-probe memory [0118] 52 B-mode [0119] 114 adapt TX/RX scheme [0120] 116 select ROI [0121] 118 acquire RF Full Frame [0122] 119 beamform Full Frame [0123] 120 acquire ROI frame [0124] 121 beamform ROI frame [0125] 122 video/image blending [0126] 148 select TX and RX scheme [0127] 154 time axis [0128] 200 ultrasound system [0129] 202 ultrasound hardware unit [0130] 204 CPU [0131] 206 GPU [0132] 208 digital storage medium [0133] 210 CD-ROM [0134] 212 internet [0135] 214 user-interface [0136] 216 keyboard [0137] 218 touchpad [0138] 226 screen