ACUSON Sequoia™ Ultrasound System Virtual Touch Strain Imaging Quick Card
This quick card helps you understand the strain imaging on the ACUSON Sequoia ultrasound system.
ACUSON Sequoia Virtual Touch pSWE Quick Reference Card Sequoia Using point shear wave elastography (pSWE) to measure shear velocity (Vs) in meters per second (m/s) or elasticity (E) in kilopascal (kPa) | Liver Application TIP Either Velocity (m/s) or Elasticity (kPa) can be displayed on the report – customize prior to report generation under: System Configuration > Measurement & Report > Measurement > General > Shear Wave > Measurement Units ................... Step 1 5C1 Step 7 Select compatible transducer* and Abdomen To enter measurement into report: • Abdomen exam preset. Clip Press Image to store image or, • ............. • Step 2 Press right or left Set key. Image Press VT (Virtual Touch) on control VT • panel. ................. Step 8 . ................... Step 3 Unfreeze, repeat steps 5–8 to make • PSWE Freeze pSWE is default application. additional measurements. • Site 1 is default measurement label. Note: During freeze, a cooling timer indicates • remaining seconds until transducer is available If desired, select an alternate label. • for image acquisition. During a short cooling time Select again to close menu. (e.g., 2 seconds), the timer appears and then disappears very quickly. Note: If No Label is selected, measurements will appear next to image but will not be sent to report or added to overall statistics. Step 9 Report Step 4 Select Report on left side of touch • screen. Roll trackball to position ROI • View, delete, store, print or transfer • (region-of-interest). shear wave measurements. Step 5 Liver Site 1 Vs Depth Update 1 0.89 4.45 Press Update on control panel to • 2 0.90 4.45 begin acquisition. 3 0.80 4.45 4 0.89 4.45 5 0.83 4.45 ..... . . . . . . . . . . . . . . . . . . .. 6 0.87 4.45 Step 6 1 Liver Site 1 7 0.88 4.45 8 0.89 4.45 Vs=1.34 m/s 9 0.88 4.45 When acquisition is complete, • E=5.4 kPa 10 0.80 4.45 system automatically freezes, emits Depth=6.01 cm Mean 0.86 m/s Std Dev 0.04 m/s one audible “beep” and displays Median 0.88 m/s IQR 0.06 m/s shear wave measurement and ROI IQR/Median 0.07 depth next to image. Median 0.88 m/s Mean 0.86 m/s Std Dev 0.04 m/s IQR 0.06 m/s IQR/Median 0.07 Overall Statistics Note: Shear Wave Speed and Elasticity values may vary among manufacturers! * pSWE imaging is compatible with 5C1, DAX,4V1: General, Abdomen; 10L4: Abdomen. SIEMENS Healthineers siemens-healthineers.com/ultrasound Abdomen TIB: 1.19 Liver Site 1 TIC:2.97 TIS:1.19 E=3.2 kPa MI:1.39 Vs=1.04 m/s 22fps 98% Virtual Touch pSWE Depth=5.00 cm 20 H Mid 0dB/DR60 PSWE Liver Application 13cm Cooling 0 Liver Site 1: 5 Valid/5 Tota Fig. 1: Optimal Technique Best Practice Techniques Fasting for 4–6 hours In the non-fasting state, the liver can have falsely increased values. Position patient supine or slight (30°) left Optimal positioning to improve intercostal access. lateral decubitus position with right arm raised above head Transducer perpendicular (90°) to skin A transducer angle < 50° to the skin surface, or use of inadequate surface using ample gel amount of gel, can result in artificially low shear wave measurements due to loss of transducer contact. Take measurements in right lobe of liver, Optimal ROI placement to obtain reproducible results and avoid in either segment 8 or 5 (Fig. 1), using cardiac motion. intercostal scanning approach Position ROI between 3–6 cm deep (use The default ROI depth best represents the transducer-specific lens default ROI depth whenever possible focus for that transducer; thus, the best measurements are in this for optimal results) and at least 1–2 cm region. Avoid increased subcapsular reverberation by placing ROI below liver capsule (Fig. 1) perpendicular to and at least 1–2 cm below the liver capsule. Scanning parallel to ribs and in an Rib shadows on either side of the ROI result in poor generation and intercostal space to avoid rib artifacts, propagation of the shear wave from the Acoustic Radiation Force optimize B-mode image (Fig. 1) so liver Impulse (ARFI) push pulse. parenchyma is bright and large vessels, bile ducts and rib shadows are avoided Perform acquisition during suspended Valsalva or deep inspiration can cause an undesired increase in central respiration; patient may resume normal venous pressure which can falsely elevate shear wave measurements. breathing after audible “beep” is heard Instruct patient to breath normally and then to momentarily stop breathing during acquisition. When acquisition is complete, the system freezes and emits one audible “beep”; resume normal breathing. Obtain 10 measurements at same site Multiple measurements to ensure the median value is reliable. Maintain an Interquartile Range (IQR) / Indicates variability of measurements lie within reasonable variability Median Ratio ≤ 0.3 range. It is the recommended quality control measure for adequate technical quality. ACUSON Sequoia and Virtual Touch are trademarks of Siemens Medical Solutions USA, Inc. Siemens Healthineers Headquarters Legal Manufacturer Siemens Healthcare GmbH Siemens Medical Solutions USA, Inc. Henkestr. 127 Ultrasound 91052 Erlangen, Germany 685 East Middlefield Road Phone: +49 9131 84-0 Mountain View, CA 94043, USA siemens-healthineers.com Phone: +1-888-826-9702 siemens.com/ultrasound Published by Siemens Medical Solutions USA, Inc. · Order No. A91US-562-1C-4A00 · HOOD05162002896642 · Printed in Germany · CIT11961 06180.5 © Siemens Medical Solutions USA, Inc., 2018
- ACUSON Sequoia™ Ultrasound System Virtual Touch Strain Imaging Quick Card