PEPconnect

ACUSON Sequoia™ Ultrasound System Virtual Touch Elastography | VA25 Software Release

This web-based course helps the clinician, sonographer, radiographer, nurse, or student understand the access and use of the Virtual Touch feature on the ACUSON Sequoia system with the VA25 software. 

Continue Button HOOD05162003212823 | Effective Date: 10-Aug-2021 Master Template HOOD05162003052540 | Effective Date: 26-Nov-2019 ? ACUSON Sequoia™ Ultrasound System Virtual Touch Elastography | VA25 Software Online Training This eLearning provides you with relevant information to enhance and improve your knowledge of Virtual Touch technologies available on the ACUSON Sequoia system. Explain Virtual Touch (VT) technologies 1 Compare 2D shear wave elastography in the liver and small parts applications 4 Describe point shear wave elastography in liver applications 3 Demonstrate strain imaging controls and techniques 2 Welcome No audio web site: https://360.articulate.com/review/content/c59dd306-3a63-40d3-9efa-adfee222f183/feedback password: vt ? Tap or click the video to learn about Virtual Touch technologies on the ACUSON Sequoia ultrasound system. Upon completion of the video select Next to proceed. VT Technology VT Technology Audio script: Page 1: Welcome to the Virtual Touch elastography technology tutorial. Elastography provides a new dimension of diagnostic information to the ultrasound exam. With B-mode imaging, a diagnosis is based on the anatomical appearance of tissue in levels of gray and the presence of clinical markers, such as shadowing or enhancement. Doppler provides information on the presence or absence, speed and direction of vascular flow. Elastography allows us to assess the mechanical stiffness of tissue, providing additional information towards the clinical diagnosis and care of the patient. Page 2: Elastography provides information on tissue stiffness. To obtain this information, the tissue needs to be deformed. Since elastography is based on Hooke’s Law, let’s go over the basic process of Hooke’s Law. Here we have a structure, let’s say it’s tissue, with a length of L0. We deform the tissue with an applied force to stress the tissue. Now the tissue has a length of L1. Next, we compare the before and after lengths of the tissue by dividing the change in length from the original length to calculate the strain, or the variation in tissue deformation, which is the relative change in shape or size of the tissue after it is stressed. Page 3: Now let’s go over how we display the result as an elastogram on ultrasound. Here we have a column of tissue elements that might appear identical on the B-mode image. When a stress is applied, the tissue elements can behave differently. The middle tissue element experiences almost no deformation because it is hard but the elements at the periphery of the column experience more deformation because they are soft. Using the difference between the original and stressed image, the original image can now be labelled and displayed with stiffness information. We look to the grayscale or color bar that is displayed next to the image and, by convention, a dark shade is used to indicate stiff or hard tissue and lighter shades are used to indicate softer tissue. If a color map is selected, the color bar indicates which color represents soft or hard tissues. These gray or color shades are then used to assign and display the relative stiffness of tissue on the elastogram. Page 4: Now let’s discuss the two methods used to deform the tissue. The manual compression technique has traditionally been described as Strain imaging. Using manual compression, stress is created by the user applying minimal compression with the transducer. With this technique, we are not always able to generate enough stress to the deeper tissue elements. This challenge led to Acoustic Radiation Force Impulse imaging, or ARFI. ARFI uses a “push pulse” produced by the transducer to deform tissue. Using ARFI, we can now penetrate deeper tissues than we could with the manual compression technique. Page 5: So where do shear waves fit in to all of this? Shear waves are transverse mechanical waves generated from the ARFI push pulse. Shear waves move at different speeds through different kinds of tissue, for example, if a pebble is tossed into a puddle of water and then into a puddle of syrup, the waves created will move at different speeds. Shear waves travel at much slower speeds than longitudinal waves. This slower travel time allows us to track and measure the speed of the waves using conventional ultrasound beams for detection. The shear wave speed can be measured to give quantifiable measurements of tissue stiffness, something manual compression elastography alone has never been able to do. Select “Next” to continue. Page 6: The ACUSON Sequoia system has a comprehensive suite of Virtual Touch applications including Strain imaging, point shear wave elastography and 2D shear wave elastography. Strain imaging uses manual compression to produce an elastogram image based on displacement of the tissue and relative tissue stiffness. Point shear wave elastography and 2D shear wave elastography use ARFI to deform tissue and quantitative shear wave measurements can be made. Page 7: Strain imaging creates a displacement correlation image, mapping relative stiffness, which can be qualitatively assessed. Notice that the gray or color bar next to the strain image indicates hard or soft and has no numerical values. Point shear wave elastography displays only the B-mode image along with a shear wave measurement in units of meters per second and kilopascal; hence, it can be quantitatively assessed. 2D shear wave elastography creates a color-coded shear wave velocity, or elasticity, image that can be both qualitatively and quantitatively assessed in units of meters per second and kilopascal. Page 8: Strain imaging provides a visual assessment of tissue stiffness and can, for example, allow a subtle lesion in soft tissue to be more clearly visualized and assessed. When uniform stress is applied each tissue type will deform differently. The resulting mapping of these different degrees of deformation clearly illustrates relative tissue stiffness. When Strain imaging is activated the B-mode image will display side-by-side with the elastogram and the region of interest box can be resized and repositioned over the desired area. Using real time correlation methods, the system continuously estimates the degree of tissue deformation and displays the relative stiffness in either a gray scale or colorized elastogram. Page 9: When using Strain imaging, it is important to understand what the gray shades and color shades indicate on the elastogram in terms of “relative stiffness”. The qualitative gray map and color map in these two images indicates that the lesion is stiffer, or harder, relative to the surrounding tissue. As shown in the image on the top, the gray bar located next to the image indicates that tissue displayed in darker gray shades are “harder” while lighter gray shades are “softer”. In the image on the bottom, the color bar located next to the image indicates that tissue displayed in redder colors are “harder” while pinker colors are “softer”. Page 10: Point Shear wave elastography applies multiple push pulses on both sides of the region of interest producing shear waves that are propagated perpendicular to the push pulse throughout the tissue and in the region of interest. Multiple detection pulses are sent through the region of interest to monitor the speed of the shear wave. The speed correlates to the tissue stiffness. The quantitative result is instantly displayed next to the image in meters per second and kilopascal along with the depth of the region of interest. Page 11: 2D shear wave elastography applies high density push pulses sequentially across the region of interest causing shear waves to propagate across the region of interest. A series of ultrasound detection pulses follow in a quick push pulse, detect pulse, push pulse sequence. Shear wave speed estimates are then calculated for each pixel at exceptional color-coded resolution. Measurement region of interests can then be placed at precise locations to measure tissue stiffness in meters per second or kilopascal. PEPconnect video ID: 17512 Embed code: https://pep.siemens-info.com/stream/e4e60385-c709-4680-9d96-31564a87877b Folder name: 001-sequoia-va25-vt-technology; File names: sequoia-va25-vt-technology.story; sequoia-va25-vt-technology-v1.cptx; sequoia-va25-vt-technology-v1.mp4; sequolia-va25-vt-technolgy-001-v1.vtt ? Tap or click the video to learn about Strain Imaging on the ACUSON Sequoia ultrasound system. Upon completion of the video select Next to proceed. Strain Imaging Strain Imaging Strain Voice Over Script Page 1: Welcome to the Virtual Touch elastography Strain imaging tutorial. Strain imaging can be used to qualitatively assess relative tissue stiffness. It has been widely used in the breast and in thyroid lesions and is still relevant today as a highly sensitive indicator of relative tissue stiffness. To enter the Virtual Touch elastography mode, you would first select a compatible transducer and exam preset and then press the control labeled “VT” on the control panel. Page 2: Virtual Touch elastography mode will display the dedicated elastography applications that are available for the selected transducer and exam preset. Each application has its own dedicated tab folder containing the controls that can be used to perform the application. If needed, you would select the “Strain” tab to activate Strain imaging and display its controls on the touch screen Page 3: When Strain imaging is activated, the B-mode image and elastogram display in a live, dual format as shown here in the image of a breast mass. Let’s go over the touch screen controls that are available when Strain imaging is activated. “Live Dual” is highlighted in blue which indicates that it is currently activated. Page 4: When “Live Dual” is deactivated, a full screen strain image will display as shown here in the image of a breast mass. “Live Dual” can be deactivated or reactivated on a live or frozen image. By default, “Live Dual” is active upon entering Strain imaging. Page 5: Use best practice techniques when performing Strain imaging for reliable and repeatable results. First, you would optimize the scan direction by positioning the patient to obtain as much of a perpendicular plane to skin surface for good axial motion. Then, you would apply minimal compression. The natural compressions generated by a patient’s respirations and cardiac motion may be sufficient to generate the elastogram. If you see a gray overlay on the elastogram, as seen in this image, it indicates one of the following conditions: Too much lateral movement or rocking motion, too little pressure, or too much pressure which causes the lesion to slip in and out of the plane. The system also displays a real-time Quality Factor score. Maintain a Quality Factor greater than 50 for optimal results. Optimize the elastogram and then press Freeze on the control panel. At this point, you would review the cine to obtain desired frames and then choose a frame that contains several consecutive frames with the same Quality Factor score. Page 6: It is important to utilize proper scan technique to minimize the effect of precompression. If too much pressure is applied with the transducer, elastographic results can substantially change. Fat can appear to have the same elasticity as cancer when too much pressure is applied. In this image of a breast mass, the soft tissue in the near field appears to show an increase in stiffness due to the effect of precompression. Also note that the quality factor is 37, indicating a less than optimal result. Precompression is a substantial factor in obtaining accurate results with elastography. Precompression should be minimized when obtaining clinical images. Page 7: Page 7: Strain ratio compares the relative stiffness of tissue within two regions of interest. The strain ratio is the result of dividing region of interest 1 by region of interest 2. In this example, it has been used to compare the average strain of a breast lesion with the average strain of the surrounding tissue. When the first region of interest is placed in the surrounding tissue and the second region of interest is placed in the lesion, a strain ratio greater than 1 indicates that the lesion is harder than the surrounding tissue. A strain ratio less than or equal to 1 indicates that the lesion is softer or the same as the surrounding tissue. The strain ratio and the average strain percentage for both regions of interest are displayed in the measured results. In this image, the strain ratio of 3.47 indicates that the breast lesion is much harder than the surrounding tissue. Page 8: One of the most sensitive indicators for the likelihood of breast lesion malignancy is the ratio of the lesion size in the elastogram compared to the lesion size in the B-mode image. Research has shown that suspicious breast lesions appear measurably larger with elasticity imaging than versus B-mode imaging. It is hypothesized that this is due to detection of tentacle formation and/or desmoplasia, which is the growth of fibrous or connective tissue. When the ratio is greater than 1, the probability of malignancy is increased. Both the elasticity to imaging B-mode diameter and area measurements are available on the ACUSON Sequoia system, when scanning in the breast exam preset. In this example the elasticity to B-mode ratio diameter measurement has been used to compare the size of the lesion visualized on the elastogram, with the size of the lesion visualized on the B-mode image. The ratio of the elastogram measurement divided by the B-mode measurement is displayed as 1.26 in the measured results. This value is greater than 1, indicating that the lesion is measuring larger in the elastogram than in the B-mode image. Page 9: A characteristic of Strain imaging is the “bull’s-eye” appearance in cysts. As shown in this image of a breast cyst, the “bull’s-eye” appears as a dark ring surrounding a bright, echogenic center, with a posterior white spot. The bull’s-eye occurs from decorrelation between images caused by fluid movement in the cyst. It is a useful clinical marker for cysts in any organ imaged with Strain imaging. Page 10: Complicated cysts contain low level internal echoes or internal debris which may produce an appearance similar to that of a solid mass or a complex cyst with both solid and cystic components. It is important to differentiate a complicated cyst from a complex cyst or a solid mass to best assess lesion management for follow-up, aspiration or biopsy. Strain imaging can be used to support the differential diagnosis between a solid mass, complex cyst or a complicated cyst. In this example, the B-mode image on the left shows a lesion with internal echoes; however, in the elastogram, the lesion has a “bulls-eye” appearance, indicating that it is a complicated cyst. Page 11: In this example, the B-mode image displays acoustic shadowing, characterized by the loss of signal around the lateral and posterior borders of a thyroid lesion due to strong absorption or reflection of the ultrasound waves. Shadowing makes it difficult to distinguish or measure the borders of this lesion. Notice how shadowing does not affect the elastogram. The borders of the lesion can be identified, and the size of the lesion can be determined with greater confidence. PEPconnect ID: 17513 Embed Code: https://pep.siemens-info.com/stream/85a5b87e-c351-40f1-a1cd-9ae39de74139 Folder name: 002-sequia-va25-strain; File names: sequoia-va25-strain-v1.cptx; sequoia-va25-strain-v1.story; sequoia-va25-strain-overview-v1.mp4; sequoia-va25-strain-overview-v1.vtt ? Tap or click the video to view and example of Live Dual Strain Imaging on the ACUSON Sequoia ultrasound system. Upon completion of the video select Next to proceed. Features Features Audio script When Strain imaging is activated, the B-mode image and elastogram display in live, dual format. Minimal compression is used. After pressing freeze, the cine is reviewed to obtain a desired frame that has a Quality Factor greater than 50. The image can be “Zoomed” before or after it is frozen. If desired, select a different Map Index” or a “Color” map can be selected. A “Shadow” measurement can be performed for a comparison of lesion size and location. PEPconnect ID: 17423 Embed Code: https://pep.siemens-info.com/stream/7ca482d4-6ddf-4236-90ed-b182136c7889 Folder name: 003-sequoia-va25-strain-example; File names: sequoia-va25-strain-example.story; sequoia-va25-strain-example.mp4; sequoia-va25-strain-example.vtt ? Soft Keys There is no audio on the tab pages. The strain imaging soft keys, located at the bottom of the Touch Screen, allow adjustment of the transmit frequency, color maps and the map index. Select the tab arrows to learn more about using the soft keys during strain imaging. Frequency Color Map Index Soft Keys No audio. Frequency graphic: sequoia-strain-001.jpg; sequoia-strain-002.jpg Color graphic: sequoia-strain-001.jpg; sequoia-strain-003.jpg; sequoia-strain-004.jpg Map Index graphic: sequoia-strain-001.jpg; sequoia-strain-005.jpg; sequoia-strain-006.jpg Folder: 002-sequoia-va25-strain Map Index The Map Index soft key control rotates for adjustment of the Map Index. Available settings are: 0: Standard default map 1: Normalized map to compensate for non-uniform stress applied with the transducer 2: Inverted map Color Rotate the Color soft key to change the Color Map. Available settings are: Color 0: Grayscale only Color 1: Soft pink to soft red shades Color 2: Vibrant red to vibrant blue shades Frequency Rotate the Frequency soft key control to adjust the transmit frequency. Available settings vary with the selected transducer, mode, and feature: Res improves resolution High indicates a high frequency Mid denotes a mid-level frequency as shown on this image Low specifies a low frequency Pen improves penetration Activating Harmonic imaging results in the display of an H to the left of the transmit frequency setting. ? Tap or click the video to learn about point shear wave elastography (pSWE) in liver applications. Upon completion of the video select Next to proceed. pSWE | Liver pSWE | Liver Audio script: Page 1: Welcome to the Virtual Touch point shear wave elastography tutorial. Point shear wave elastography offers a highly reproducible technique using Acoustic Radiation Force Impulses to correlate liver stiffness with shear wave quantification. To enter the point shear wave elastography mode, you would first select a compatible transducer and exam preset and then press the control labeled “VT” on the control panel. Page 2: Virtual Touch elastography mode will display the dedicated applications that are available for the selected transducer and exam preset. Each application has its own dedicated tab folder containing the controls that can be used to perform the application. Point shear wave elastography is the default application and “Site 1” is the default measurement label. Page 3: Shown here are the “Site” measurement label options. If desired, select an alternate label. If “No Label’ is selected, the measurements will appear next to the image but will not be sent to the report or added to the overall statistics. Page 4: Select “Liver Segment” outlined in orange to view the “Liver Segment” measurement label options. Page 5: Take a moment to look over the “Liver Segment” measurement label options displayed here. Page 6: Select “Mass” outlined in orange to view the “Mass” measurement label options. Page 7: Take a moment to look over the “Mass” measurement label options displayed here. Page 8: Now let’s go through the steps and controls used during point shear wave elastography measurement acquisition in the liver. Use the default region of interest depth whenever possible for optimal results. If needed, the trackball can be used to reposition the region of interest. To begin the acquisition, you would press “Update” on the control panel. When the acquisition is complete, the system automatically freezes, emits one audible “beep” and displays the shear wave measurement and region of interest depth next to the image. To enter the measurement into the report, you would press “Image” to store the image or, press the right or left “Set” key. You would then unfreeze to make additional measurements and repeat the acquisition steps. When the acquisitions are complete, you would then select “Report” located on the left side of the touch screen to view, delete, store, print, or transfer shear wave measurements. Page 9: Displayed here is the liver assessment report containing each of the measurements along with the statistical data. It includes the Interquartile Range, which is the range of the spread of values in a repeated data set, from the 25th to 75th percentile. It is sometimes referred to as the “middle fifty.” It removes outlying measurements to represent more accurately the spread of values in a data set. The median shear wave velocity is used with the Interquartile Range to calculate the Interquartile Range to Median ratio. An Interquartile Range to Median ratio of less than or equal to 0.3 indicates that the variability of measurements lies within a reasonable variability range. It is the recommended quality control measure for adequate technical quality. A higher ratio indicates significant variability in the shear wave measurements, decreasing the reliability of measurement results. The Interquartile Range will be higher with advancing fibrosis; since the Interquartile Range to Median ratio normalizes for this increase, it is an important indicator of technical accuracy. Page 10: The shear wave measurement unit that is displayed in the report is a global system setting. The default is “Velocity” in meters per second. To customize the shear wave measurement unit displayed in the report, select “Measurement & Report” in the System Configuration menu and then select either “Velocity in meters per second” or “Elasticity in kilopascal” for the shear wave measurement unit that will display in the report. Both meters per second and kilopascal will still display next to the image. Page 11: Use best practice techniques when performing point shear wave elastography for reliable and repeatable results. In the non-fasting state, the liver can have falsely increased elastography values; therefore, the recommendation is to have the patient fast for four to six hours prior to the exam. Optimal patient positioning is supine or slight 30-degree left lateral decubitus with the right arm elevated above the head to improve intercostal access. Use ample gel so that the transducer surface is in continuous contact with the skin surface. In general, use a transducer angle of 90 degrees to the skin surface for the highest measurement accuracy. An out-of-plane transducer angle less than 50 degrees to the skin surface, can result in artificially low shear wave measurements due to the loss of transducer contact with the flat scanning surface. To obtain reproducible results in the liver and to avoid cardiac motion, take measurements in the right lobe of the liver in either segment five or eight, using an intercostal scanning approach. Page 12: Use best practice techniques when placing the measurement region of interest for reliable and repeatable results. Maintain a measurement region of interest depth between three to six centimeters. The default region of interest depth best represents the transducer-specific lens focus for that transducer; therefore, the best measurements are in this region. Although the default region of interest depth setting for each transducer is the recommended depth it may need to be repositioned for larger patients. Avoid increased subcapsular reverberation by placing the region of interest perpendicular to, and at least one to two centimeters below, the liver capsule. Scan parallel to the ribs in an intercostal space to avoid rib artifacts. Optimize the B-mode image so that the liver parenchyma is bright and large vessels, bile ducts and rib shadows are avoided. As shown here, the image on the left displays poor technique and invalid measurements due to poor propagation of the push pulse through the ribs. The image on the right displays proper technique and valid measurements. Page 13: When taking measurements, advise the patient to breathe normally and then to momentarily stop breathing during acquisition. Avoid taking measurements during Valsalva or deep inspiration and breath hold to avoid an undesired increase in central venous pressure. Elevated central venous pressure can falsely elevate shear wave measurements. When the acquisition is complete, the system automatically emits one audible “beep”. The patient may resume normal breathing when the audible “beep” is heard. At least 10 measurements should be taken in the same location to aid in measurement repeatability with the median shear wave measurement value representing the most reliable single measure when there are measurement outliers. At least six of the 10 measurements should be valid. This is tabulated at the bottom of the imaging screen as “Number Valid to Number Total”. Maintain an Interquartile Range to Median ratio less than or equal to 0.3 for adequate technical quality and to ensure that the variability of measurements lies within a reasonable variability range. Page 14: If the system displays the shear wave measurement as an invalid “X” value, the confidence interval threshold for measurement quality was not reached. You will need to repeat the acquisition until the system displays a numerical value. Most commonly, this results from a low shear wave signal-to-noise ratio due to either a high tissue stiffness, a large patient body habitus or a thick sono-opaque adipose layer. The push pulse cannot generate enough shear wave magnitude and is grossly attenuated. Invalid “X” values can also be caused by the proximity of the region of interest to a rib shadow, due to poor technique. It can also display if the measurements exceed the current maximum displayable value. Excessive motion in the tissue that disrupts the shear wave measurement estimate may also produce invalid results. Page 15: Patient factors can also result in abnormal shear wave measurement values. These factors should be checked before performing liver stiffness measurements in order to avoid overestimation and should be considered when interpreting the results. Aminotransferase levels or aspartate aminotransferase are blood tests that check for liver damage. When they are significantly elevated above the normal limit, they can indicate liver inflammation as shown here in the table on the right. Underlying disorders or diseases such as obstructive cholestasis, liver congestion, acute hepatitis and infiltrative liver disease can also result in overestimation of liver stiffness. Be aware of the patient’s medical history prior to performing a shear wave examination. Page 16: Liver assessment using gray scale ultrasound findings alone can be difficult. One of the reasons point shear wave elastography has become quite useful is the correlation between the progression of liver stiffness with quantitative tissue stiffness values. In the first two examples shown here, the B-mode image is similar overall but notice how the shear wave measurements differ. In the third example, a small liver presents with ascites and a higher shear wave measurement value. Research reports that shear wave measurements increase proportionally to the degree of liver stiffness. Page 17: Studies have shown point shear wave elastography to be rapid, reliable and reproducible in the measurement of shear waves in the liver. As a software option on the ACUSON Sequoia system, it is easy and convenient to use in conjunction with a standard abdominal ultrasound exam. As shown here, the Society of Radiologists in Ultrasound “Consensus Statement” also discusses the possible advantages of point shear wave elastography during assessment of liver fibrosis. Point shear wave elastography may also be preferred over 2D shear wave elastography for its rapid acquisition and ability to measure up to 14 centimeters when using the Deep Abdominal transducer. PEPconnect ID: 17514 Embed Code: https://pep.siemens-info.com/stream/afaafe87-29ad-4e30-8273-152ae0ce3351 Folder: 004-sequoia-va25-2d-liver; File names: sequoia-va25-pswe-liver-v1.mp4; sequoia-va25-pswe-liver-v1.vtt ? Tap or click the video to learn about a pSWE aquisition. Upon completion of the video select Next to proceed. pSWE | Liver pSWE | Liver Audio script: A compatible transducer is positioned perpendicular to the skin surface, and liver segment five or eight is scanned using an intercostal approach. The transducer is positioned parallel to the ribs, to avoid artifacts. The B-mode image is optimized so that the liver parenchyma is bright and large vessels, bile ducts and rib shadows are avoided. Point shear wave elastography is activated and the transducer is repositioned so that the region of interest is perpendicular to the liver capsule. In this patient the default region of interest depth can be used because it lies is between three to six centimeters deep and is at least one to two centimeters below the liver capsule. One acquisition per breath pause is performed. Ten acquisitions are performed in the same location. The report is entered to review the measurements and check that the Interquartile Range to Median ratio is less than or equal to 0.3. PEPconnect ID: 17476 Embed Code: https://pep.siemens-info.com/stream/ee5b3f3f-7c39-4da9-ada6-ea9ea68e2945 Folder: 005-sequoia-va25-pswe-example; File names: sequoia-va25-pswe-example.story; sequoia-va25-pswe-example.mp4; sequoia-va25-pswe-example.vtt ? Important No Audio accompanies this slide. Measurement values for shear waves and other image display settings are relative indices intended only for the purpose of comparison with other measurements performed using the ACUSON Sequoia system. Absolute values for shear wave measurements may vary among different manufacturers due to multiple system-dependent factors, including shear wave frequency, excitation beam (push beam) frequency, shear wave detection techniques, and shear wave measurement estimation methods. Important No audio. ? Tap or click the video to learn about 2D shear wave elastography (2D SWE) in the liver applications. Upon completion of the video select Next to proceed. 2D SWE | Liver 2D SWE | Liver Audio script: Page 1: Welcome to the Virtual Touch 2D shear wave elastography liver tutorial. The ACUSON Sequoia system offers flexibility for user preference in Virtual Touch liver applications. 2D shear wave elastography displays an image of stiffness that can be used to assess stiffness heterogeneity in the liver. It can also assist in guiding the user in placing the measurement region of interest in a homogeneous region of the liver. This added guidance can help the user avoid potential sources of artifact or, areas not visualized on the B-mode image, for less measurement variability and greater measurement reliability. To enter the 2D shear wave elastography mode, you would first select a compatible transducer and exam preset and then press the control labeled “VT” on the control panel. Page 2: When the 2D shear wave elastography tab folder is selected, the system activates the region of interest in a full-screen format. If desired, “Live Dual” can be selected before or after the acquisition and can be saved to a user-defined preset. Whenever possible, use the default region of interest depth and size. If needed, the trackball can be used to reposition the region of interest. The “Set” key and trackball can be used to resize the region of interest. Page 3: To begin the acquisition, you would press “Update” on the control panel. The system acquires a single image frame and then freezes the image, emits one audible “beep” and applies the “Velocity” or “Elasticity” shear wave display mode in the region of interest. During system freeze, a timer indicates the remaining time, in seconds, until the transducer is available for image acquisition. Cooling time duration is typically a few seconds depending on the transducer and region of interest size and depth. Page 4: You can rotate the “Min” or “Max” “Velocity” or “Elasticity” soft key controls to adjust the range of measurements displayed in the region of interest. The system updates the shear wave display in the region of interest and on the color bar to depict the selected range. If needed, the range can be decreased for better visualization of stiffness differences. The range can be increased if the measured value exceeds the range and displays “High” in the measurement display area. In this image, the “Max Elasticity” is set at 50. Select “Max Elasticity” outlined in orange to decrease the “Max Elasticity”. Page 5: The “Max Elasticity” has been decreased from 50 to 30 in these two images as displayed on the color bar and on the touch screen controls. Notice the improvement in visualization of stiffness variability in the image on the right. Page 6: Select the “Shear Wave” soft key outlined in orange to view the 2D shear wave display modes. Page 7: There are three shear wave display modes for 2D shear wave elastography. Each of these modes provides additional information for evaluating and interpreting the 2D shear wave image. The first display mode, as shown in the image on the left, is a color-coded display of shear wave values in “Velocity” or “Elasticity”. Refer to the color bar to determine which colors indicate higher values and which colors indicate lower values. Shear wave values are lower in soft tissue and higher in stiff tissue. The second display mode, as shown in the image in the middle, is the “Quality” map. The “Quality” map differentiates where the shear wave measurement estimate is accurate and where it is poor. Refer to the color bar next to determine which colors indicate high quality and which colors indicate low quality. The third display mode, as shown in the image on the right, is the “Displacement” map. The “Displacement” map indicates the relative stiffness in tissue. Refer to the color bar to determine which colors indicate higher tissue displacement and which colors indicate lower tissue displacement. Displacement is higher in soft tissue and lower in hard tissue. Page 8: There are several ways to assess the B-mode reference image during 2D shear wave elastography. You can select “Shear Wave Elastography Display” to hide the 2D shear wave image or you can select “Live Dual” to display the B-mode image on the left and the 2D shear wave image on the right. Select “Live Dual” outlined in orange to view the image in this format. Page 9: This image is displayed in the “Live Dual” format. You can rotate the “Virtual Touch” control located on the control panel to change the transparency of the 2D shear wave image in “Live Dual” or in any of the other display modes. In this image, the transparency has been changed from 60% to 20%. Changing the transparency in the region of interest can be helpful when placing a measurement caliper or, when assessing the margins of a focal lesion, as shown here. Page 10: Shear wave measurements can be performed or viewed in the “Velocity” or “Elasticity”, “Quality” or “Displacement” maps. To measure, you would first press “Caliper” on the control panel and then select the desired measurement label type. Then you would select the same measurement label for each measurement taken at the same site. At this point, you would position the measurement region of interest in the shear wave display. The default measurement region of interest size of 10 mm is the recommended diameter for liver assessment as it best compares to the region of interest size used in point shear wave elastography. The shear wave measurements and diameter are displayed next to the image. To enter a measurement into the report, you would press “Image” to store the image or, press the right or left “Set” key. To make additional measurements, you would “unfreeze” and repeat the acquisition and measurement steps. You would select “Report” on the left side of the touch screen to view, delete, store, print, or transfer shear wave measurements. Page 11: Displayed here is the 2D shear wave liver assessment report containing each of the measurements along with the statistical data. It includes the Interquartile Range, which is the range of the spread of values in a repeated data set, from the 25thto 75th percentile. It is sometimes referred to as the “middle fifty.” It removes outlying measurements to represent more accurately the spread of values in a data set. The median shear wave velocity is used with the Interquartile Range to calculate the Interquartile Range to Median ratio. An Interquartile Range to Median ratio of less than or equal to 0.3 indicates that the variability of measurements lies within a reasonable variability range. It is the recommended quality control measure for adequate technical quality. A higher ratio indicates significant variability in the shear wave measurements, decreasing the reliability of measurement results. The Interquartile Range will be higher with advancing fibrosis; since the Interquartile Range to Median ratio normalizes for this increase, it is an important indicator of technical accuracy. Page 12: The shear wave measurement unit that is displayed in the report is a global system setting. The default is “Velocity” in meters per second. To customize the shear wave measurement unit displayed in the report, select “Measurement & Report” in the System Configuration menu and then select either Velocity in meters per second” or “Elasticity in kilopascal” for the shear wave measurement unit that will display in the report. Both meters per second and kilopascal will still display next to the image. Page 13: Use best practice techniques when performing 2D shear wave elastography for reliable and repeatable results. In the non-fasting state, the liver can have falsely increased elastography values; therefore, the recommendation is to have the patient fast for four to six hours prior to the exam. Optimal patient positioning is supine or slight 30-degree left lateral decubitus with the right arm elevated above the head to improve intercostal access. Use ample gel so that the transducer surface is in continuous contact with the skin surface. In general, use a transducer angle of 90 degrees to the skin surface for the highest measurement accuracy. An out-of-plane transducer angle less than 50 degrees to the skin surface can result in artificially low shear wave measurements due to the loss of transducer contact with the flat scanning surface. To obtain reproducible results in the liver and to avoid cardiac motion, take measurements in the right lobe of the liver in either segment five or eight, using an intercostal scanning approach. Page 14: Use best practice techniques when placing the 2D shear wave region of interest and the measurement region of interest for reliable and repeatable results. Maintain a measurement region of interest depth between three to six centimeters. The default 2D shear wave region of interest depth best represents the transducer-specific lens focus for that transducer; therefore, the best measurements are in this region. Although the default depth setting for each transducer is the recommended depth, it may need to be repositioned for larger patients. Avoid increased subcapsular reverberation by placing the 2D shear wave region of interest perpendicular to, and at least one to two centimeters below, the liver capsule. Scan parallel to the ribs in an intercostal space to avoid rib artifacts. Optimize the B-mode image so that the liver parenchyma is bright and large vessels, bile ducts, and rib shadows are avoided. The image on the right displays proper technique. Page 15: Advise the patient to breathe normally and then to momentarily stop breathing during acquisition. Avoid acquisition during Valsalva or deep inspiration and breath hold to avoid an undesired increase in central venous pressure. Elevated central venous pressure can falsely elevate shear wave measurements. When the acquisition is complete, the system automatically emits an audible “beep”. The patient may resume normal breathing when the audible “beep” is heard. At least 10 measurements should be taken in the same location to aid in measurement repeatability with the median shear wave measurement value representing the most reliable single measure when there are measurement outliers. At least six of the 10 measurements should be valid. This is tabulated at the bottom of the imaging screen as “Number Valid to Number Total”. Maintain an Interquartile Range to Median ratio less than or equal to 0.3 for adequate technical quality and to ensure that the variability of measurements lie within a reasonable variability range. Page 16: If the shear wave measurement exceeds the current maximum measurement setting, the measured results display HIGH for the shear wave measurement value. If the measurement is lower than the current minimum measurement setting, the measured results display LOW. The measured results will display an invalid “X” value if the shear wave was not detected within the region of interest or if a measurement was performed outside of the region of interest. Page 17: Patient factors can also result in abnormal shear wave measurement values. These factors should be checked before performing liver stiffness measurements in order to avoid overestimation and should be considered when interpreting the results. Aminotransferase levels or aspartate aminotransferase are blood tests that check for liver damage. When they are significantly elevated above the normal limit, they can indicate liver inflammation as shown here in the table on the right. Underlying disorders or diseases such as obstructive cholestasis, liver congestion, acute hepatitis and infiltrative liver disease can also result in overestimation of liver stiffness. Be aware of the patient’s medical history prior to performing a shear wave examination. PEPconnect ID: 17504 Embed Code: https://pep.siemens-info.com/stream/7378ed7e-47fa-4732-881d-4b1ded775b4e Folder name: 006-sequoia-va25-2d-swe-liver; File names: sequoia-va25-2d-swe-liver-v1.story, sequoia-va25-2d-swe-liver-v1.cptx, sequoia-va25_2d_swe_liver-v1.mp4; sequoia-va25_2d_swe_liver-v1.vtt ? Tap or click the video to learn about the 2D SWE acquisition in the liver. Upon completion of the video select Next to proceed. 2D SWE | Liver Example 2D SWE | Liver Audio script: 2D shear wave elastography is activated and the transducer is repositioned so that the region of interest is perpendicular to the liver capsule. If possible, use the default region of interest depth or adjust as needed so that the region of interest is between three to six centimeters deep and at least one to two centimeters below the liver capsule. The acquisition is performed during the suspended respiration. When the acquisition is complete, the system displays the “Velocity” or “Elasticity” map. Check the “Quality” map for reliable measurement areas. Then, check the “Displacement” map to identify potential artifacts. The measurement region of interest is activated and a measurement label is selected. The measurement region of interest is positioned within the 2D shear wave region of interest and the measurement is entered into the report. Shear wave measurements can also be performed or viewed in the “Quality” or “Displacement” maps. A separate acquisition for each measurement should be performed. After 10 acquisitions have been performed, the report is entered to review the measurements and check that the Interquartile Range to median ratio is less than or equal to 0.3. PEPconnect ID: 17502 Embed Code: https://pep.siemens-info.com/stream/80dc30c6-f799-415b-8c71-bed77dd1b9f8 Folder name: 007-sequoia-va25-swe-liver-example; File names: sequoia-va25-2d-swe-liver-example.story; sequoia-va25-2d-swe-liver-example.mp4; sequoia-va25-2d-swe-liver-example.vtt ? Tap or click the video to learn about 2D shear wave elastography (2D SWE) in small parts applications Upon completion of the video select Next to proceed 2D SWE | Small Parts 2D SWE | Small Parts Voice Over Script Page 1: Welcome to the Virtual Touch 2D shear wave elastography small parts tutorial. The ACUSON Sequoia ultrasound system offers complimentary Virtual Touch Strain imaging and 2D shear wave elastography applications for breast and thyroid. Advantages of one application can be the challenge of the other. The combination increases the sensitivity and specificity of the exam, increasing confidence in the diagnosis. To enter the 2D shear wave elastography mode, you would first select a compatible transducer and exam preset and then press the control labeled “VT” on the control panel. Page 2: The shear wave elastography tab is selected by default and the system activates a live dual format and the region of interest. If desired, “Live Dual” can be selected before or after the acquisition and can be saved to a user-defined preset. You can roll the trackball to reposition the region of interest. You can press the right or left “Set” key and roll the trackball to resize the region of interest. To begin the acquisition, you would press “Update” on the control panel. When the acquisition is complete, the system automatically freezes, emits one audible “beep” and applies the “Velocity” or “Elasticity” display mode in the region of interest. Page 3: You can rotate the “Min or Max Velocity or Elasticity” soft key controls to adjust the range of measurements displayed in the region of interest. The system updates the shear wave display in the region of interest and on the color bar to depict the selected range. If needed, the range can be decreased for better visualization of stiffness differences. The range can be increased if the measured value exceeds the range and displays “High” in the measurement display area. The maximum velocity has been decreased from 7.5 to 4.0 in these two images as displayed on the color bar. Notice the improvement in visualization of stiffness variability in the image on the right. Select the “Shear Wave” soft key outlined in orange to view the 2D shear wave display modes. Page 4: There are three shear wave display modes for 2D shear wave elastography. Each of these modes provides additional information for evaluating and interpreting the 2D shear wave image. The first display mode, as shown in the image on the left, is a color-coded display of shear wave values in “Velocity” or “Elasticity”. Refer to the color bar to determine which colors indicate higher values and which colors indicate lower values. Shear wave values are lower in soft tissue and higher in stiff tissue. The second display mode, as shown in the image in the middle, is the “Quality” map. The “Quality” map differentiates where the shear wave measurement estimate is accurate and where it is poor. Refer to the color bar next to determine which colors indicate high quality and which colors indicate low quality. The third display mode, as shown in the image on the right, is the “Displacement” map. The “Displacement” map indicates the relative stiffness in tissue. Refer to the color bar next to the image which colors indicate higher tissue displacement and which colors indicate lower tissue displacement. Displacement is higher in soft tissue and lower in hard tissue. Page 5: There are several ways to assess the image during 2D shear wave elastography. You can turn “Live Dual” off to display the shear wave image in the full screen format, or you can select “Shear Wave Elastography” to hide the 2D shear wave image and then turn it back on. You can rotate the “Virtual Touch” control located on the control panel to change the transparency of the 2D shear wave image. In this image, the transparency has been changed from 20% to 100%. Changing the transparency in the region of interest can be helpful when placing a caliper or when assessing the margins of a lesion. Page 6: You can select “Unit” to display the 2D shear wave image as a shear wave velocity image in meters per second, or as a shear wave elasticity image in kilopascals. Both meters per second and kilopascal unit values still display next to the image and in the report. However, the image display is determined by the unit selected on the touch screen. This is a global system setting which is not preset dependent. Page 7: Shear wave measurements can be performed or viewed in the “Velocity” or “Elasticity”, “Quality” or “Displacement” maps. To measure, you would first press “Caliper” on the control panel. The system activates the “Shear Velocity” or “Shear Elasticity” measurement tool. Next, you would position the measurement region of interest in the shear wave display and adjust its size anywhere from 3-20 millimeters in diameter as needed. In “Live Dual”, the “Shadow” control is activated as a default. When “Shadow” is activated, the measurement is duplicated and displayed on the adjacent image for a comparison of lesion size and/or location. The shear wave measurements, depth and diameter are displayed near the image. To enter a measurement into the report, you would select a measurement label and then press the right or left “Set” key. Multiple shear wave measurements can be made anywhere within the region of interest on a single acquisition. You would select “Report” on the left side of the touch screen to view, store, print, or transfer shear wave measurements. Page 8: If the shear wave measurement exceeds the current maximum measurement setting, the measured results display HIGH for the shear wave measurement value. If the measurement is lower than the current minimum measurement setting, the measured results display LOW. The measured results will display an invalid “X” value if the shear wave was not detected within the region of interest or if a measurement was performed outside of the region of interest. Page 9: Use best practice techniques when performing 2D shear wave elastography for reliable and repeatable results. Optimize the scan direction by positioning the patient to obtain as much of a perpendicular plane to skin surface as possible. Use ample gel so that the transducer surface is in continuous contact with the skin surface. Apply the appropriate amount of scanning pressure, using minimal compression for optimal results. Excessive pressure with the transducer may artificially elevate shear wave values and result in unreliable shear wave measurements. Page 10: Position a compatible transducer perpendicular to the skin surface over the area of interest and optimize the B-mode image. When 2D shear wave elastography is activated, the B-mode image and elastogram display in a Live Dual format. Reposition and resize the region of interest over the area of interest as needed. The image can be zoomed before or after it is frozen. Using minimal scanning pressure perform the acquisition. When the acquisition is complete, the transparency of the 2D Shear Wave image can be changed to better assess the underlying B-mode image. If needed, adjust the minimum or maximum velocity setting. Check the quality map for reliable measurement areas and the displacement map to identify potential artifacts. Activate and position the measurement region of interest within the 2D Shear Wave region of interest and resize as needed. Multiple measurements can be performed within the 2D Shear Wave region of interest and will be duplicated on the B-mode image when the Shadow measurement tool is activated. Shear wave measurements can be performed or viewed in the “Velocity” or “Elasticity’, “Quality”, or Displacement maps. Page 11: It is important to understand what happens when the ultrasound beam encounters a “pure” cyst when performing shear wave elastography. Shear waves cannot travel in clear, non-viscous liquid. In this fluid-filled “pure” cyst, shear waves are not induced; therefore, the shear wave velocity or elasticity is undetectable, and a blank signal with no color is displayed. The “Quality” map shows us that the shear waves within the cyst are of low quality, they are not detectable or non-determinant. The “Displacement” map reveals the characteristic “bull’s-eye” appearance of a cyst. Each 2D shear wave elastography display map contributes information for the diagnosis. Page 12: The “Displacement” map should be used in conjunction with the other maps to help identify potential artifacts, especially in very stiff lesions. For example, the blue cancer appearance, is the result of a very stiff breast lesion that attenuates the Acoustic Radiation Force Imaging, or ARFI beam, resulting in a lower shear wave velocity and soft appearance or ‘blue’ cancer. The displacement map in this example would indicate an artificially low velocity in a very hard lesion. The quality map shows, in red and yellow, that the lesion has low-quality shear wave signals that are not reliable estimates of true stiffness. Page 13: Breast lesions can span an unusually wide range of elastic values. Strain imaging provides information about the relative stiffness differences of all the tissue represented in the region of interest; whereas, in 2D shear wave elastography, the image is composed of many thousands of discrete shear wave measurement samples, thus stiffness heterogeneity is well visualized. These discrete shear wave measurement samples also contribute to 2D shear wave elastography’s high spatial resolution for greater confidence in measurement placement and accuracy. In this example, the strain image on the left displays an area of stiffness. The known breast clip and area of calcification displayed on the B-mode image are difficult to visualize on the elastogram. The shear wave image in the middle shows an area of moderately high shear wave velocities in green, a small area of high velocities in red, where the breast clip is located, and a second, even smaller area, of high shear wave velocity, where a small calcification is located. The “Quality” map on the right is mostly green with a small area of red; therefore, if the measurement region of interest is placed in the green area of the “Quality” map, we can feel confident about its accuracy in measuring tissue. The “Quality” map adds information that is helpful in interpreting shear wave images. Page 14: Thyroid lesions can be heterogeneous. Research has shown that elastography is an additional tool for thyroid lesion differentiation and may provide measurement and fine needle aspiration guidance to the “hot spots”. In this example, the “hot spot”, or stiffest area, is visualized in red on the “Velocity” map. The “Quality” map displays green in this area; therefore, we can feel confident about measurement accuracy. The “Displacement” map shows low displacement in this area, which indicates that it is an area of relatively higher stiffness. PEPconnect ID: 17515 Embed Code: https://pep.siemens-info.com/stream/efac48be-807d-4648-b093-2f59b8af074f Folder name: 008-sequoia-va25-2d-swe-sm-parts; File names: sequoia-va25-2d-swe-small-parts-v1.story, sequoia-va25-2d-swe-sm-parts-v1.vtt, sequoia-va25-2d-swe-sm-parts-v1.mp4 ? Additional Information No Audio accompanies this slide. You can find the following quick reference cards in the Resources section: ACUSON Sequoia ultrasound system VA25 SW release Virtual Touch Strain Imaging ACUSON Sequoia ultrasound system VA25 SW release Virtual Touch pSWE ACUSON Sequoia ultrasound system VA25 SW release Virtual Touch 2D SWE – Liver ACUSON Sequoia ultrasound system VA25 SW release Virtual Touch 2D SWE – Small Parts Additional Informatoin ? Course Review No Audio accompanies this slide. Congratulations. You have completed the ACUSON Sequoia Ultrasound System Virtual Touch Elastography | VA25 Software Online Training course. Select the numbered buttons below to review the material. 1 1 1 3 3 3 2 2 2 4 4 4 Explain Virtual Touch technologies Compare 2D SWE in the liver and small parts applications Describe pSWE in liver applications Demonstrate strain imaging controls and techniques Course Review No audio Compare 2D SWE in the Liver and Small Parts Applications Measurement range adjustment Min Max Velocity Elasticity Shear wave values are lower in soft tissue and higher in less soft tissue Always refer to the color bar to interpret utilized maps Display modes: Velocity or Elasticity Quality map determines the accuracy of the shear wave measurement Displacement map indicates the relative stiffness of the tissue Describe pSWE in Liver Applications Whenever possible, use the default ROI depth to ensure placement within the lens focus area for the utilized transducer Optimize acquisition technique using the following: Avoid large vessels, bile ducts and rib shadows Position the ROI deep to subcapsular reverberation Image parallel to the skin surface Use normal breathing with suspension during aquisition Obtain 10 measurements Monitor the Interquartile Range to Median ratio to maintain a value less than or equal to 0.3 Demonstrate Strain Imaging Controls and Techniques Strain imaging is a quantitative method to map relative tissue stiffness Color overlays indicate tissue stiffness relative to the surrounding tissue Strain Controls: Anatomy can be viewed in “Live Dual” or as a single image Creation of an optimal strain image Quality Factor score greater than 50 Calculate a Strain Ratio < 1 indicates tissue softer than the surrounding area > 1 indicates tissue harder than the surrounding area Utilize the Shadow Measurement to ensure quantification of the same area on both the B-mode and Elastogram Adjust the Frequency, Color, and Map Index on the real-time or frozen image Explain Virtual Touch Technologies Elastography is a method to measure the stiffness of tissue Tissue stiffness varies by the type and surrounding structures Color assignments (i.e., white / gray; red / blue) indicate tissue stiffness differences Acoustic Radiation Force Imaging (ARFI) Uses a controlled ‘push pulse’ to deform tissue Creates the shear wave Disclaimer Please note that the learning material is for training purposes only. For the proper use of the software or hardware, please always use the Operator Manual or Instructions for Use (hereinafter collectively “Operator Manual”) issued by Siemens Healthineers. This material is to be used as training material only and shall by no means substitute the Operator Manual. Any material used in this training will not be updated on a regular basis and does not necessarily reflect the latest version of the software and hardware available at the time of the training. The Operator Manual shall be used as your main reference, in particular for relevant safety information like warnings and cautions. Please note: Some functions shown in this material are optional and might not be part of your system. Certain products, product related claims or functionalities (hereinafter collectively “Functionality”) may not (yet) be commercially available in your country. Due to regulatory requirements, the future availability of said Functionalities in any specific country is not guaranteed. Please contact your local Siemens Healthineers sales representative for the most current information. The reproduction, transmission or distribution of this training or its contents is not permitted without express written authority. Offenders will be liable for damages. All names and data of patients, parameters and configuration dependent designations are fictional and examples only. ACUSON Sequoia and Virtual Touch Technologies are trademarks of Siemens Medical Solutions USA, Inc. All rights, including rights created by patent grant or registration of a utility model or design, are reserved. © Siemens Healthcare GmbH 2021 Siemens Healthineers Headquarters\Siemens Healthcare GmbH\Henkestr. 127\ 91052 Erlangen, Germany\Telephone: +49 9131 84-0\siemens-healthineers.com ? Disclaimer Exit To access your Certificate of Completion, select the Launch button drop down on the course overview page. You can also access the certificate from your PEPconnect transcript. ? You have completed the ACUSON Sequoia Ultrasound System Virtual Touch Elastography | VA25 Software Online Training Completion No audio Navigation Help Select the icon above to open the table of contents. Click Next to continue. Next Welcome Slide The timeline displays the slide progression. Slide the orange bar backwards to rewind the timeline. Click Next to continue. Next Timeline The video timeline displays a progression. Slide the white video bar backwards to rewind the timeline. Select the CC icon on the video to display closed captioning (subtitles). Click Next to continue. Next Video Timeline Select the to close the help navigation. Exit Help Navigation add subtitles Question Bank 1 HOOD05162003212823 | Effective Date: 10-Aug-2021 ACUSON Sequoia system Virtual Touch Strain Imaging ACUSON Sequoia system Virtual Touch pSWE ACUSON Sequoia system Virtual Touch 2D SWE - Liver ACUSON Sequoia system Virtual Touch 2D SWE - Small Parts 2D shear wave elastography (2D SWE) The display of shear wave speed within a user adjustable ROI as a color overlay on the 2D-mode image. 2D-mode imaging (i.e., brightness mode, grayscale, B-mode) Ultrasound display of the amplitude of echoes returning from the body. The higher the amplitude, the brighter the display. Acoustic radiation force impulse imaging (ARFI) This technology uses a track, push pulse, detect sequence to create a qualitative elastogram of soft tissue. Elasticity Ability of a structure to return to its original shape after compression. Elasticity box Adjustable area used to obtain data to create the elastogram. Elastogram The image demonstrating the conversion of tissue strain. Elastography An imaging method to map the elastic properties of tissue (i.e., stiff vs. soft) to provide information on changes due to disease. Hooke’s law Small changes in a tissue mass due to compression are directly proportional to the size changes due to that compression. Interquartile range (IQR) The distance between the 75th percentile and the 25th percentile for all measurements with an assigned label. IQR/Median Ratio Unitless method to find the variability between measurements. Mean The mid-point of a group of measurements. Median The average of a group of measurements. Point shear wave elastography (pSWE) ARFI generation of shear wave within a fixed ROI that gives an average velocity measurement in m/s or kPa. Region of interest (ROI) Defined area showing sample area for obtaining shear wave data. The user selects ROI depth and location but cannot change the size. Shear wave Wave produced perpendicular to the transmit pulse. Standard Deviation (Std Dev) Calculation for all measurements associated with the assigned label to determine the extent from the average. Stiffness Tissue deformation in response to force (i.e., compression, acoustic radiation force). Young’s modulus (elasticity modulus; E) Mathematical description of tissue elasticity when using axial compression. 1.1 Welcome 1.2 VT Technology 1.3 Strain Imaging 1.4 Features 1.5 Soft Keys 1.6 pSWE | Liver 1.7 pSWE | Liver 1.8 Important 1.9 2D SWE | Liver 1.10 2D SWE | Liver 1.11 2D SWE | Small Parts 1.12 Additional Information 1.13 Course Review 1.14 Disclaimer 1.15 Completion

  • Thyroid
  • liver
  • pSWE
  • point shear wave elastography
  • elastography
  • elasto
  • 2D SWE
  • 2D shear wave elastography
  • shear wave
  • shear wave elastography
  • ultrasound
  • ACUSON
  • Sequoia
  • ACUSON Sequoia
  • strain
  • abdomen
  • ARFI
  • small parts
  • breast
  • blue cancer
  • cancer
  • stiff
  • soft
  • hard
  • VA25