Excitation schemes for low-cost transducer arrays

Technical field of excitation scheme for low-cost transducer array

[0001] The present invention relates to an excitation scheme for a transducer array, and in particular to a scheme for operating the array for imaging.

Background technique

[0002] Assessing the health of the fetus is a very important clinical practice in health care during pregnancy. At present, the most popular way for doctors to assess the health of the fetus is to use a cardiograph (CTG) to analyze the fetal heart rate and to use Doppler ultrasound to assess the vascular flow of the mother and fetus. Ultrasound Doppler waveform analysis of the specific blood flow of the fetus and mother is part of established medical practice, as well as for high-risk pregnancy (maternal type 2 diabetes, hypertension and preeclampsia, and fetal IUGR-intrauterine growth The standard recommendations in various clinical guidelines for diagnosis and evaluation. One of the main purposes of routine prenatal care is to identify "at risk" fetuses for clinical intervention, thereby reducing the incidence of perinatal morbidity and death. Some blood vessels useful in the assessment of fetal health are: umbilical artery, middle cerebral artery, venous catheter, and (left and right) uterine artery and umbilical vein.

[0003] Ultrasound scanners have become indispensable in pregnancy monitoring worldwide. They currently provide the best option for monitoring the growth and development of the fetus. The dual ultrasound scanner provides ultrasound pulse wave Doppler in addition to regular scanning. Color and power Doppler are newer additions to the range of scanners used to provide vascular imaging. Color Doppler, especially the one usually provided, gets what is usually called a "triple" scanner.

[0004] Doppler examinations typically require a great degree of skill in order to obtain clinically useful measurements. For example, the correct orientation of the probe relative to the vessel is critical to ensure that the beam angle is less than 60 degrees. When an angle greater than 60 degrees is used in the determination of the speed, the error in the measurement result is released. The standard workflow of a clinical ultrasound scanner allows the sonographer to use the standard B-mode and color flow display to determine the orientation of the probe relative to the vessel. Then obtain the spectral Doppler measurement results, thereby ensuring that the measured velocity is correct.

[0005] The use of ultrasound in vascular applications to perform Doppler velocimetry requires the availability of technicians.

Summary of the invention

[0006] In emerging market countries such as India, the shortage of specialist doctors limits the availability and use of ultrasound. Therefore, an automated method of acquiring and evaluating Doppler signals for clinical diagnosis (without the need for the user to interpret ultrasound scan images) will be useful to non-radiologists (such as OB/GYN or cardiologists) who are the main treatment providers.

[0007] In addition, low-cost systems are essential to provide attractive solutions in emerging market environments. The currently available devices in the market for prenatal examinations and delivery are ultrasound and CTG machines. However, both types of equipment are relatively expensive.

[0008] There is a need to provide a low-cost, easy-to-use solution for Doppler velocimetry for screening and monitoring high-risk pregnancies.

[0009] A commonly assigned patent application entitled Automated Doppler Velocimetry Using a Low-Cost Transducer discloses a handheld, free-standing, Doppler-based ultrasound probe whose inspection surface is less finely divided into individual The transducer element is divided into relatively few independent elements. As mentioned in it, the probe has no

Need to explain the visual display of the anatomical structure for automatic operation.

[0010] This patent application is directed to a novel excitation scheme for an array of transducer elements, specifically applied to the probe referred to immediately above.

[0011] According to the present invention, a device is designed to use the transducer elements of the current group in parallel in time and to sequentially image in time in groups. The groups are arranged spatially relative to each other such that the individual elements are interleaved with each other.

[0012] In an aspect of the present invention, the device is configured not to use any of the elements of the group in common to focus or steer the beam used in the imaging.

[0013] In one embodiment, the device includes the elements of the group.

[0014] In another aspect, the device is further configured to change the grouping.

[0015] In the sub-aspect, the change is based on an input indicative of blood vessel size and/or blood vessel depth.

[0016] In an optional sub-aspect, the change includes switching between one and the other of the at least two interval states. At least one of the states is characterized by the smallest, non-zero element-to-element non-adjacency between the elements of a group.

[0017] In an optional sub-aspect, the device is configured to automatically transition in response to an input indicating the size and/or depth of the blood vessel.

[0018] In a specific aspect, the elements of the current group have respective faces, and the respective faces have corresponding geometric centers. The device is configured to have a minimum, non-zero element-to-element non-contiguous degree between the elements of the current group. The minimum represents the minimum distance between the geometric centers.

[0019] In the sub-aspect, the minimum distance for one or more pairs of the elements of the current group is sufficient to allow a certain element of the other group to be inserted between the pairs, wherein The corresponding geometric centers are collinear.

[0020] In the second sub-aspect, the minimum distance, for the one or more pairs of the elements of the current group, is sufficient to allow certain two elements of the other or more of the groups Insert between the pairs, where the corresponding geometric centers are collinear.

[0021] In a related aspect, the elements of the current group are separated pair by pair by at least one respective insert element in the other group.

[0022] In one other aspect, the groups are mutually exclusive element by element.

[0023] In a different aspect, the elements of the group are arranged collectively in a multi-dimensional array.

[0024] In yet another aspect, the using includes simultaneously firing the elements of the current group.

[0025] In yet another aspect, the imaging includes medical imaging.

[0026] In an additional aspect, the imaging utilizes fluid flow analysis techniques.

[0027] In yet another aspect, the device is included in a handheld stand-alone diagnostic device.

[0028] In one version, the device is configured as one or more integrated circuits.

[0029] In yet another different aspect, a device is configured to perform volume imaging by operating transducer elements in parallel in time, and is configured to not use any of the elements in common to focus or manipulate The beam used in the imaging.

[0030] In a sub-aspect, the imaging includes performing fluid flow analysis.

[0031] The novel device and the details of its excitation scheme are further explained below with the aid of drawings (which are not drawn to scale).

Description of the drawings

[0032] FIG. 1 is a schematic diagram showing by way of example an ultrasound probe, a volume of interest including blood vessels, blood flow waveforms, and respective clinical Doppler indices;

[0033] FIG. 2 is a conceptual flowchart of exemplary signal processing;

[0034] FIGS. 3A and 3B are flowcharts showing examples of probe operation;

[0035] FIGS. 4A to 4C are schematic diagrams of some possible interval states and excitation schemes for the transducer array;

[0036] FIG. 5 is a flowchart of an exemplary incentive scheme; and

[0037] FIG. 6 is a flowchart of an exemplary interval state initialization.

Detailed ways

[0038] Before describing the content proposed in this article for the transducer excitation scheme, it is mainly a review of the Doppler-based probe disclosed in the patent application Automated Doppler Velocimetry Using a Low-Cost Transducer. The discussion of the invention will then begin to focus particularly on the present invention in connection with FIG. 4 and subsequent drawings.

[0039] FIG. 1 depicts by way of an exemplary and non-limiting example an ultrasound probe 100 and a volume or "volume of interest" 106 including blood vessels 108, 110.112. The blood flow, or "spectroscopic Doppler ultrasound" waveform 114, and the respective clinical Doppler indices 116, 118 are also depicted.

[0040] The probe 100 may be implemented as an automatic, handheld, stand-alone, self-contained ultrasound inspection device. It has a transducer housing 120 and a handle 122.

[0041] In the transducer housing 120, the non-phased two-dimensional transducer array 134 is composed of transducer elements 126, and the number of elements is determined by the scanning volume and anatomical structure. Data collection is performed independently by element 126, but, as discussed in more detail further below, the elements can work in parallel to shorten the overall collection time period.

[0042] As seen in FIG. 1, the number of elements 126 is 32 by way of example. Therefore, with an element size of 110nm, it covers a volume of approximately 6cm x 6cm. Flush with the front surface 130 of the housing 120 is the ultrasound receiving surface 132 of the transducer element 136, and the same surface also emits, that is, sends out ultrasound.

[0043] A total of only 32 elements 126 is in sharp contrast to the much larger number of elements that would be required to cover the same 6cm x 6cm volume in conventional medical imaging.

[0044] In this regard, electronic focusing for medical imaging, such as the use of phased array transducers, requires 1/2 wavelength (ie 1/2 λ) or smaller inter-element spacing. Doppler ultrasound used for imaging can typically range from 2×10 per second⁶The range between to 4x10° cycles (2 to 4 MHζ). Ultrasound travels through the soft tissue at a speed of approximately 1540 m/s. The wavelength, the person, is equal to the speed divided by the frequency. Here, this is 1540m/s divided by roughly 2x10° cycle/s=0. 8mm. Medical ultrasound imaging for display will therefore require an inter-element spacing of less than 0.4mm, and less than (0. 4mm)² (Less than 0.2mm²) The surface area of the component. Therefore, with a small component size on the order of 1/2 person, thousands of components 126 will be required to create a reduced 2D array as shown in Figure 1, covering a volume of 6 cm by 6 cm.

[0045] The spacing (size) of the elements in FIG. 1 is lOrnm. As discussed above, it will generally be larger than the 12λ of ultrasound used in the examination of the volume of interest 106 for the existing blood vessels 108, 110, 112. _o

[0046] More generally, according to what is proposed herein, the elements 126 are separated by more than 1/2 person, although as discussed above, the inter-element spacing can be λ>2λ or more. The area of surface 132 is correspondingly at least 0.6 square millimeters (mm²), and can be larger, such as 10mm in Figure 1² >2 5mm², Or 100mm² □

[0047] Advantageously, the automatic ultrasound device 100 does not rely on the display of medical images to make a diagnosis;

The next feature is an array composed of fewer transducer elements and therefore fewer channels. Therefore, the production cost is low, and at the same time, the reliability is maintained by virtue of the automatic operation. When medical examinations must be performed at a faster pace, reliability can even be improved. The automatic operation also tends to reduce the inspection time, thereby reducing the workload and making the inspection more convenient.

[0048] During Doppler data acquisition, the elements 126 are fired either sequentially or in one or more groups, noting that the acoustic signal from one element does not significantly affect other elements that are simultaneously excited. For each element 126, the receiving cycle lags the transmitting cycle. In the receiving period, the Doppler receiving gate is positioned accordingly, so as to enable sampling from the corresponding depth within the volume of interest 106.

[0049] On the back surface 134 of the housing 120, facing the user are a number of user interfaces, input and output panels, which include a top panel 136, a left panel 138, and a right panel 140. The on-off switch 142 and the audio speaker surface 144 are provided in the top panel 136. The left panel 138 frames the functional navigation/actuation button 146, the display 148, the Doppler power detection indicator 150, the fetus dagger, the beat collection indicator 152, the maternal heartbeat collection indicator 154, the normal blood flow indicator 156, and Abnormal blood flow indicator 158. The right panel 140 includes three initialization parameter input feedback windows 160, 162, 164.

[0050] The elements 126 of the array 124 are all operated to independently image.

[0051] This is in contrast to phased arrays, which, for example, collectively use multiple independent transducer elements to image or manipulate beams. In a phased array, the operation and focusing are performed by appropriately delaying the input and/or output of an element relative to other elements.

[0052] According to the content proposed in this article, a set of transducer elements are simultaneously excited. The group of elements continues to be imaged in parallel, and element by element independently, until the data collection time period of the group expires.

[0053] The apparatus for grouping imaging is configured not to use any of the elements 126 in common to focus or steer the beam used in imaging. By way of illustration, the transducer elements 166, 168, 170, 172 in FIG. 1 each have their respective signals 174, 176, 178, 180. The signals 174, 180 being transmitted lag behind the transmission signals 176, 178, thereby resulting in focusing and/or manipulation of the resulting ultrasonic beam. The probe is not implemented for this protocol, as indicated by "X" 182 in Figure 1. Similarly, when receiving, no delay is applied differently to the elements 166, 168, 170, 172.

[0054] Clinical Doppler indexes, such as pulsation index (PI) 116 and resistance index (RI) 118 are Doppler angle-dependent measures of blood pulsation. The symbols S, D, and A labeled with the blood flow waveform 114 in FIG. 1 represent the peak frequency shift during systole, the end diastolic frequency shift and one cardiac cycle, respectively. The blood flow waveform 114 is a Doppler frequency and thus a graph of blood flow velocity versus time.

[0055] In identifying blood vessels and in assessing the normality of blood flow, the probe 100 can use both indexes PI and RI.

[0056] FIG. 2 shows by way of example a blood vessel to be found in the volume of interest 106 by the probe 100

108-112 performs the signal processing involved in the classification.

[0057] The blood vessel classifier 200 may be implemented as a k-nearest neighbor (Κ-NN) classifier, where, for example, K=3.

[0058] The classifier is first used to predict whether the blood vessels 108-112 are veins or arteries. Using various feature inputs to the classifier 200, such as the PI, each of the M input types corresponds to one dimension in the M-dimensional feature space. Another type of input to the classifier is training examples. Each training example corresponds to an actual clinical situation, and includes M feature inputs for this situation, and the example is limited to a specific point in the M-dimensional space, that is, "example point". Among them, depending on whether the training example actually belongs to a vein or an artery, each example point is associated with a respective result of "vein" or "artery". After the classifier 200 has been initialized with the training example, the feature input derived for the blood vessels 108-112 currently being classified is used to form points in the M-dimensional space. For Κ=3, identify the 3 nearest (example) points. Each proximity will have the value "artery" or "vein" as its result. The majority vote wins. Since 3 is an odd number, never

There will be no draw.

[0059] If the blood vessel is classified as an artery, the classifier 200 then uses the same nearest neighbor algorithm to determine whether it is a mother or a fetus. If the blood vessel is the mother's artery, a determination is made as to whether it is a uterine artery. If, on the other hand, the blood vessel is an artery of a fetus, a determination is made as to whether it is an umbilical artery. The latter two determinations use the same nearest neighbor algorithm.

[0060] The nearest neighbor classifier enjoys simple benefits, although other alternative methods can also be used instead, such as neural networks, or support vector machines (SVM).

[0061] The classifier input from the user includes gestational age 204, and a rough approximate location 208 of the probe on the mother's abdomen. A blood vessel model 212 in the form of a training example of the classifier 200 is also provided.

[0062] The other input directly or indirectly comes from the pulse echo information from the received ultrasound 216.

[0063] Directly from the ultrasound 216, the average reflection index estimate 218 is made for the tissue surrounding the probe 100. The index is compared with a list of predefined reflectance indices to determine the position of the probe 100 on the mother's body.

[0064] To form an indirect input, the received ultrasound is demodulated in the demodulator 220 to extract the ultrasound Doppler signal 224 from the carrier frequency. A Fast Fourier Transform (FFT) 228 is performed on the Doppler signal 224 to generate a spectrogram, or "FFT-based acoustic wave diagram" 230. From the spectrogram 230, one or more relevant spectral contours 232 are extracted. The term "spectral profile" refers to the portion of the acoustic image 230 that corresponds to the blood flow through the artery or vein. The spectral profile 232 can be approximated as the area between the curves corresponding to the maximum and minimum spectral velocities (or spectral frequencies). Estimated The spectral width 236 of the extracted spectral profile 232 is provided to the classifier 200. From the spectral profile(s) 232, a curve 240 corresponding to the peak (or alternatively, average) spectral velocity is extracted. Also Specific temporal features 248 are extracted from the spectral profile(s) 232. These features include, for example, the presence of a notch immediately before the pulse in the blood flow waveform 114 of the uterine artery. For blood vessels that are about to undergo classification 252 The PI and RI are also extracted. In the initialization procedure (which precedes the inspection of the current volume of interest 106), it is performed based on the spectral profile(s) 232 and then the pulse cycle time estimate 256 is extracted.

[0065] Operationally, and as shown in FIGS. 3A and 3B, the user-which can be a clinician, midwife, general practitioner, obstetrician/gynecologist or fetal radiologist, input (as an initialization Part of the procedure) the target vessel used for inspection, such as the left uterine artery (which falls into the "uterine artery" vascular physiology category); gestational age; and a rough description of the position, the probe will be described at the end of the beam initialization an examination. Specifically, after the on/off switch 142 is actuated, the user presses the function navigation actuation button 146 twice in rapid succession. In response, the first vessel selection appears in display 148. If the selection that appears is not the target vessel for examination, the button 146 is pressed once to provide a new selection in the display 148. Repeat this operation until the displayed selection is the one used for selection. Then the button 148 is kept pressed, and the selection is echoed in the initialization parameter input feedback window 160. What appears in the display 148 is a selection for gestational age, measured in months or weeks. In a similar manner, the user navigates to the correct age and keeps pressing the button 146 to echo the selection to the window 162. In order to complete the initialization parameter input, the same procedure is performed for the probe position, and the selected position is shown in the window 164. Optionally, more than one target blood vessel can be specified. Can use them These are processed in the order found, or a specific order can be specified during this initialization (step S304).

[0066] The user now continues the initialization for the pulse cycle time estimation 256 by placing the probe on the mother's abdomen. The user presses the function navigation/actuation button 146 to start the ultrasound Doppler operation. The transducer will scan the depth at each element location to detect blood movement, that is, Doppler power. If the Doppler power detection indicator 150 lights up, the Doppler power representing blood flow in the 300-1000HZ frequency band is detected, which has a sufficient amplitude to obtain the following

In conclusion, the heartbeat of the fetus or pregnant woman can be measured reliably from the arterial blood flow. The mother's heart rate is usually lower than that of the fetus. In addition to the indicator 150, a short beep can be emitted from the speaker 144 to alert the user to start the detection of Doppler power. Alternatively or additionally, the acoustic feedback to the Doppler signal may be emitted from the speaker 144. Hold the probe 100 in the proper position for a few seconds; if not, the Doppler power drops and the indicator light 150 must be turned on again. If the fetal heartbeat or the pregnant woman's heartbeat is not detected at the end of the beam of a few seconds, the user can move the probe to another position on the mother's abdomen, and can repeat this until the detection result appears. If the heartbeat of the fetus or pregnant woman is detected through the signal processing route 220-232.240.256, that is, the body blood vessels and especially the arteries are found, the corresponding fetal heartbeat collection indicator 152 or the pregnant woman heartbeat collection indicator 154 is lit ( Step S308)_oThe user repeatedly moves the probe 100 to the next position on the mothers abdomen until both indicators 152 and 152 are lit (step S312), indicating the pulse cycle time and clinical Doppler parameters, It has been collected and extracted for both the mother and the fetus.

[0067] The user now places the probe to check the normal/abnormal blood flow in the corresponding pregnant or fetal blood vessel in the target blood vessel (step S316)_OIf the Doppler power detection indicator 150 is not lit (step S320), then no Doppler power is detected in the 300-1000 Hz frequency band representing blood flow, or the Doppler power amplitude is not sufficient to find one or more A blood vessel. In this case, the user moves or tilts the probe 100 (step S324) until the pointer 150 is illuminated.

[0068] Once the indicator is illuminated, the probe 100 is held in place to process the volume of interest 106. Each element 126 will fire for several heartbeats, 3 to 5 seconds in total, to obtain Doppler information within its range. If 32 elements 126 are operated one by one, this requires about 2 to 3 minutes of volume data collection. In order to reduce the overall time period, operate the elements 126 in one or more groups, paying attention to the acoustic beams of the respective elements 126 not to significantly interfere with and weaken the received data. Minimizing the overall acquisition time reduces the possibility of errors due to movement of the patient or examiner during the acquisition period (step S328). The possible groupings are discussed in more detail further below.

[0069] Advantageously, said volume data collection occurs automatically and without user intervention. Since there is no need to display images of blood vessels, there is no need for electronic focusing of ultrasound. The device is thus simplified and cost-effective.

[0070] The result of the processing may be the green light of the normal blood flow indicator 156, the red light of the abnormal blood flow indicator 158, or two types of light if the blood vessel currently being inspected does not match the target blood vessel. nothing. If the indicators 156, 158 are not lit (step S332), the process returns to step S324.

[0071] An example of the processing in step S328 is provided in FIG. 3B. The volume of interest 106 (which may change every time the probe 100 is moved or tilted, but which is fixed when the user holds the probe stably) is subjected to inspection for the presence of blood vessels. In particular, the Doppler power in the frequency band of 300-1000HZ is calculated. This generates a 3-dimensional (3D) representation of the blood vessels 108-112 in the scan volume. The continuity criterion is used to identify the total number of blood vessels in the scan volume. For example, needle 8 adjacent pixels, that is, 4 lateral and 4 diagonal pixels, assuming that the adjacent pixels for the blood flow are detected as representing the same blood vessel. However, the blood vessel can also be drawn in 3D, because the transducer receiving gate can be set for different depths. In 3D, a line fitting algorithm based on least squares is used to find a straight line connecting the identified points using the continuity criterion. The angle of the straight line from the ultrasonic receiving surface 132 of the transducer element 126 is then calculated. This results in a 3D map from which individual blood vessels and their respective orientations can be identified. Recognizing the orientation, the spatial characteristics can be determined from the map. For example, in a uterine artery scan, the Doppler sample volume is typically located at the pseudo-intersection of the uterine artery and the iliac artery. The intersection is determined as the position where the sum of the squares of the distances between pixels on the blood vessel is the smallest (step S336)_OOptionally, the adjacency checked for the continuity standard may be 26 adjacent pixels in 3D,

Instead of 8 adjacent pixels in 2D.

[0072] If the blood vessel diagram does not contain 108-112 (step S340), the processing of the current volume of interest 106 is completed, no diagnosis is presented, and control continues to step S332.

[0073] Otherwise, if the blood vessels 108-112 are selected, the blood vessels among those found in the volume of interest 106 are selected for fluid flow analysis and as candidates for matching the target blood vessel (step S344). Any criteria can be used for the selection, because the selection of candidates will not end until the target vessel is found or all of the vessels 108-112 in the volume of interest 106 have been processed.

[0074] Generate information specifically for the selected blood vessel, as seen in FIG. 2 (step S348). The information includes, for example, spectral Doppler waveform characteristics (average frequency estimation, cycle time-time interval between two consecutive peaks, spectral width-the width between the maximum and minimum frequency envelopes at peaks and troughs) ), peak time, holder defects, and clinical Doppler indicators (such as S/D.PI and RI).

[0075] Based on the generated information and its analysis, the blood vessel classifier 200 classifies the selected blood vessel (step

S352)_O

[0076] If the classification does not match the target vessel (step S356), and there is no next vessel among those found in the volume of interest 106 (step S360), then control continues to step S332.

[0077] Otherwise, if the classification does not match the target blood vessel, but the next blood vessel does exist, the control branch returns to step S344, where the next blood vessel serves as the selected blood vessel (step S364)_O

[0078] On the other hand, if the classification matches the target blood vessel, the probe 100 draws a conclusion about the normal state of blood flow in the target (ie, selected) blood vessel. In particular and by way of example, the Doppler parameters are compared with a nomogram (ie, a table representing the range of the expected Doppler index depending on the gestational age) to determine whether the flow profile is normal or abnormal. Optionally, before drawing a conclusion about the normal state of blood flow, the acquisition of Doppler data may also occur (step S368)_O

[0079] Based on the conclusion, the green light of the normal blood flow indicator 156 or the red light of the abnormal blood flow indicator 158 provides an indication of the normal state of the blood flow in the selected blood vessel (step S372)_O

[0080] FIGS. 4A to 4C illustrate exemplary interval states 404, 408, 412, and excitation schemes 416, 420, 424 for the transducer array 124.

[0081] In the first spaced state 404 shown in FIG. 4A, the number of transducers 126 inserted between elements of the same group is zero. In particular, there is only a single group, and the elements 126 of the group are arranged directly adjacent in the array 124. Therefore, the element-to-element non-adjacent degree in the group is zero. The element 126, although imaging independently, operates simultaneously as a single group during imaging to generate a blood vessel map. The time period required to collect the data used to create the graph is therefore relatively short, ie 3-5 seconds for each element and therefore 3-5 seconds overall. As mentioned above, this is advantageous because there are fewer opportunities for imaging errors due to patient or examiner movement.

[0082] The first interval state 404 is not always feasible. Undesirable acoustic crosstalk between elements 126 increases as the element-to-element proximity in the array 124 increases. In particular, there is a possibility that the amount of ultrasound received by the element 126 and emitted by an adjacent element is unacceptable.

[0083] However, the amount of crosstalk decreases as blood vessels become shallower. It also decreases as the blood vessel becomes smaller, that is, the interference effect depends on the size of the blood vessel being imaged and the size of the element 126.

[0084] In the second spaced state 408 shown in FIG. 4B, the number of transducer elements 126 inserted between the elements of a group is at least one. In other words, at least two elements in a group are separated from each other by at least one respective element. in

The eight elements 126 designated by the number "1" in FIG. 4B are in the same group, which will be referred to as the first group 428 for the second interval state 408 hereinafter. The second group 432 for the second interval state 408 is composed of eight elements 126 designated by the number "2". Similarly, the third group 436 and the fourth group 440 of the second interval state 408 each consist of eight elements 126 designated by the numbers "3" and "4", respectively. The groups 428, 432, 436, and 440 overlap in space, but remain different from element to element.

[0085] In the first group 428 (but the same principle applies to the other groups 432, 436, 440 of the interval state 408), any two adjacent elements 444.448 in the group are separated by at least a minimum predetermined distance 452 .

[0086] This distance is indicated by a broken line in FIG. 4B. The minimum distance 452, in some embodiments, is the distance between

408 The associated non-zero element-to-element non-adjacent degree within the group.

[0087] This can be distinguished from element-to-element non-adjacency within the zero group. An example of the latter would be a strict two-group checkerboard pattern. This pattern will have zero abutment because the corners of the component elements meet. However, it should be noted that due to the feature that the groups 428, 432, 436, and 440 are interlaced with each other element by element, this pattern will still fall within the intended scope of the present invention.

[0088] The element-to-element distance can be measured from the corresponding geometric center 456,460. The geometric center of the element surface 132 can be calculated as follows. Conceptually, the face 132 is packed (usually like this) in a grid of fine equal cells in two or three dimensions. For each grid coordinate, such as "X" or "y", the arithmetic average of all cells that coincide with each surface 132 is taken.

[0089] The minimum distance 452 from the non-zero element-to-element non-adjacency indicating a non-zero group may be sufficient to allow a certain element in another group 432, 436>440 to be inserted between the pair of elements 444>448 in the first group, where The corresponding geometric centers 456 and 460.464 are collinear. Here, the inserted component 454 belongs to the second group 432: although if it is assumed that all components are of equal size in this example, any component of the group other than the first group 428 can be selected instead. The minimum distance 452 of the same value applies to all pairs of elements in the first group 428.

[0090] The said non-adjacency for some or most of the element pairs of a group may be greater than the minimum degree of the group. In this example, this is based on, for example, the case of element pairs 448,468. As seen in Figure 4B, the distance 470 here is measurable between the geometric centers 460,476 of the faces 132 of the respective elements 448,468. Hypothetically, by appropriately moving the insertion element 466 to the right, its geometric center 482 can be collinear with those of the sandwich element 448>468, showing that the minimum distance 452 is sufficient. Optionally, the insertion element 483 can be moved imaginary to the left to similarly achieve collinearity of the geometric center. The minimum non-adjacent degree is obtained by observing the entire group (ie, the first group 428)±. For the second spaced state 408, the elements of a given group are separated pair by pair by at least one respective insertion element of another group. Since there are all interval states 404.408.412, at any given time, only one group 428, 432, 436, 440 works in the second interval state 408.

[0091] As mentioned above, imaging uses the current set of transducer elements in parallel in time, and occurs sequentially in groups in time. Therefore, during the data acquisition cycle, the elements 126 of the first group 428 work in parallel. The parallel work then switches to subsequent groups after each cycle, namely to the second group 432, then the third group 436, and then the fourth group 440.

[0092] In the second spacing state 408, due to the spacing between elements of the same group in the array 124, the acoustic crosstalk is significantly smaller than the acoustic crosstalk that would occur in the first spacing state 404. As a compromise, compared with a single group in the first interval state 404, since there are four groups 428, 432, 436, 440, the total blood vessel map acquisition time is four times. However, this is still 1/8o of the time required in the case of sequential acquisition at the component level (ie for each of the 32 components 126)

[0093] Under some conditions, even if the interval provided by the second interval state 408 may even cause greater crosstalk, it can be tolerated without sacrificing clinical utility and accuracy. Therefore, a third spacing state 412 may be required, which has a greater spacing between elements within the group.

[0094] In the third spacing state 412 shown in FIG. 4C, for one or more pairs of elements 125 in the current group, the minimum distance is sufficient to allow certain two elements in another one or more groups They are inserted together between the pairs, where the corresponding geometric centers are collinear. Thus, for example, two elements 484, 486 are inserted between the pair 488, 490, each element in the pair is the same group, and the same group is the first group for the third interval state 412. The distance between the elements of the pair of 488.490 is the minimum distance, that is, for the third spacing state 412, the minimum non-zero element-to-element non-adjacency between the elements of the first group. Similarly, two elements 492, 494 are inserted between a pair of 486, 496 elements in the same group, the same group is the third group here; however, here, the insertion element will imaginarily require conversion, That is, to the left and right, respectively, to align the four geometric centers. Therefore, as seen in Figure 4C, the distance between the pair of elements 486.496 is greater than the minimum distance.

[0095] Compared with the first and second spacing states 404.408, the element-to-element non-adjacent degree of the third spacing state is higher further alleviates or reduces the possibility of any acoustic crosstalk between the elements 126. There are nine groups in the third interval state 412, which still provide a substantial improvement in total data collection time relative to the purely sequential overall scheme.

[0096] From FIGS. 4B and 4C, it can be seen that the groups are mutually exclusive element by element, in that no element belongs to more than one group of a given interval state 404, 408, 412.

[0097] It is also seen that the groups are arranged spatially relative to each other such that the individual elements are interleaved with each other. Their elements 126 collectively form a grid. As a result, the amount of purity required in the Doppler signal is achieved, and at the same time, the ultrasound interface "real estate" is effectively managed, thus operating in the entire process. Although in the above-discussed embodiment, there is no spacing state requiring element-to-element separation in groups of more than two elements, this larger non-adjacency can also be implemented, especially where the array has relatively many elements. In designing which components 126 are allocated to which groups 428, 432, 436, 440, the criteria for placing components in the respective groups can be based on Euclidean distance or a combination algorithm, such as an n-wise algorithm, for example, AETG/Jenny TM. The use of this standard in the design of the grouping can occur before the probe is working. Alternatively, it may occur sequentially during the operation of the probe, for example, to work around a fault detected in the element 126. The probe may be configured as a single interval state 404.408.412 or as a transition 498 between two or more of them.

[0098] In the above embodiment, the elements 126 are in a two-dimensional matrix array 124, but the array may have fewer or more dimensions. Moreover, the array need not be in a matrix arrangement.

[0099] The element surface 132 is not limited to any specific shape or size. The element faces 132 need not all be laterally the same in size, which is also within the intent of the present invention. Therefore, even if the selected element 126 is required to be suitable for a particular orientation, that is, to be inserted, the sufficiency criterion for the distance between elements of a group can be satisfied.

[0100] Within the probe 100, a control circuit (not shown), which serves as the device of claims 1, 19, 21, 22, may take the form of one or more integrated circuits (ICs). One or more ICs according to claim 1, 19, 21 or 22 may optionally be configured to be installed into existing devices (for example, ultrasonic dual scanners).

[0101] More generally, the device of claim 1, 19, 21, or 22 can be implemented as one or more integrated circuits, a control circuit for the array 124, or by another example, implemented as including The control circuit and the device of the array 124, such as the probe 100ο

[0102] According to the technology proposed herein, the signal for operating the array 124 can be formed by changing the line input applied to the array, or the current applied to the wireless transmission of the signal and the reception by the probe 100. .

[0103] FIG. 5 is a sample incentive scheme. In order to start volume imaging (step S510), the elements 126 of the current group are excited at the same time (step S520)_oThere is no need to use element 126 collectively to focus or steer the beam, while imaging continues (step S530)_oWhen the number

When the data collection period expires (step S540), if the next group for the current interval status 404, 408, 412, or the near interval status exists (step S550), the next group is made the current group (step S560), and the process returns to Step S520. Otherwise, if there is no next group (step S550), the volume imaging is now complete (step S570).

[0104] In some implementations of the probe 100, only a single interval state is provided. For example, if the probe 100 is to be used on a specific part of an anatomical structure, the blood vessel size and depth may be known or relatively constant. Therefore, it can be found that the specific interval state is optimal based on experience.

[0105] In other implementations, the grouping 428, 432, 436, 440 of the element 126 may be changed, which requires a transition 498 to the new interval state 404, 408, 412. Regrouping can be automatic, based on preliminary data indicative of vessel size and/or vessel state. Or, it can occur in response to the clinician actuating the control.

[0106] FIG. 6 provides an example of the interval state initialization of the device 100, for which the groups 428, 432, 436, 440 can be changed.

[0107] The clinician inputs an indication of the overall acquisition time (step S610) as part of the initialization in step S304. Optionally, the input may indicate blood vessel size (step S620) and/or blood vessel depth (step S630), wherein the input only selects the target blood vessel used for the examination in step S304, or, conversely, involves inputting the blood vessel size And/or the value of blood vessel depth.

[0108] According to the input, a suitable group is determined (step S640).

[0109] If the current group matches the group determined (by the default or last used group) (step S650), the volume acquisition of the Doppler signal starts (step S660), which is consistent with step S510.

[0110] Otherwise, if there is no match (step S650), proceed to the transition 498 corresponding to the interval status 404, 408, 412 of the determined packet (step S670). In one configuration, 32 transducer elements 126 are connected to 32 separate transmit/receive channels. Only the elements 126 of the current group are turned on. All other elements in the array 124 are cut off. Optionally, the number of channels in the probe 100 can be reduced to the maximum number of the elements 126 of the groups 428, 432, 436, 440 in all groups. For the first interval state 408 in FIG. 4B, each of the groups 428, 432, 436, 440 has the same number of elements 126, that is, eight; therefore, the maximum number of elements 126 is eight. For interval status 404.408. Each change of 412 switches the eight channels to the connection of the respective element 126. This can be achieved through the use of cross-point switching operated by a Field Programmable Gate Array (FPGA). These devices are discussed in jointly assigned patent US5997479 by Savord et al. entitled "Phased Array Acoustic Systems With Intra-Group Processors, and jointly assigned patent application US2010/0277305 by Garner et al. entitled Wireless Ultrasound Probe Asset Tracking. The control program (for example, in software or firmware) can set up the appropriate connection between the channel and the transducer element 126 for a given group according to a pre-loaded scan sequence look-up table. Once it is done, it is determined The transition 498 of the interval states 404, 408, and 412 can start volume acquisition in step S510. [0111] The novel excitation scheme proposed herein reduces the length of the examination time, thereby avoiding errors that may otherwise occur due to the movement of the patient or clinician. In addition, the number of receive/transmit channels can be reduced to the maximum element count of any group. This reduces the production cost, which is also used to create a relatively small number of transducer elements 126 One of the driving factors for the simple self-contained device 100. Through the wise choice of the spacing scheme, the adverse effects of crosstalk can be eliminated or reduced; in addition, the interleaving of component groups makes effective use of the "real estate" of the probe surface, resulting in a small form factor. By not implementing electronic focusing or manipulation, the device 100 is further simplified and cost-effective. The automatic Doppler analysis alleviates the need for displayable images and personnel trained to interpret such displays. The automatic nature preserves reliability and may even improve reliability. By making the inspection faster, the workload is reduced. Due to medical diagnosis

The device 100 is relatively inexpensive and can be used more widely.

[0112] The device uses a set of transducer elements to image in parallel in time. In some embodiments, the elements belong to the current group, and the imaging is group-sequential in time. The groups may be spatially arranged relative to each other to be interleaved element by element. The imaging may include volume imaging. The device may be configured to focus or steer the beam used in the imaging without using any of the elements in common. The device can be operated to transition between spaced states, at least one of the spaced states having the smallest non-zero element-to-element non-adjacency feature within the group, or can be fixed in a spaced state. The transformation may be automatic in response to an input indicating the size and/or depth of the blood vessel.

[0113] Although the method of the present invention can be advantageously applied to provide medical diagnosis for human or animal subjects, the scope of the present invention is not limited thereto. More broadly, the technology disclosed in this article points to the effective search and analysis of fluid flow in human tissues through the receptors, in vitro, or indirectly in vivo.

[0114] The content proposed herein relates to a transducer element excitation scheme for an automatic Doppler device, which is used to draw a clinical diagnosis based on the analysis result of analyzing the characteristics of the spectral Doppler waveform. In addition to fetal health assessment, applications include carotid and renal artery screening, ABI measurement for detecting peripheral arterial disease (PAD), and transcranial hemorrhage detection in trauma or other bleeding.

[0115] Although the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description should be regarded as exemplary or exemplary, and not restrictive; the present invention is not limited to The disclosed embodiment.

[0116] For example, in a given interval state, the minimum distance between geometric centers can be changed in groups. Likewise, although the novel excitation scheme is described for a two-dimensional array of transducers, the array can also be multi-dimensional or in a specific geometric arrangement.

[0117] When practicing the claimed invention, those skilled in the art can understand and implement other modifications to the disclosed embodiments based on the study of the drawings, the disclosure and the claims. In the claims, the word "comprising" does not exclude other elements or steps, and the attributive "a" or "an" does not exclude a plural number. Any reference signs in the claims should not be construed as limiting the scope.

[0118] The computer program may be stored on a suitable computer-readable medium, such as an optical storage medium or a solid-state medium, temporarily, temporarily, or for a longer period of time. Such media is only permanent in the sense of not being a transient, propagating signal, but also includes other forms of computer-readable media, such as register memory, processor cache, and RAM.

[0119] A single processor or other unit can fulfill the functions of several items recited in the claims. Although certain measures are recited in mutually different dependent claims, this does not indicate that these measures cannot be combined to advantage.