Program Information
Evaluation of Two Ultrasound Systems for Shear Wave Elastography Measurements of Small Targets
Z Long*, D Tradup , S Eby , P Song , S Chen , K Glazebrook , N Hangiandreou , Mayo Clinic, Rochester, MN
Presentations
WE-DE-708-6 (Wednesday, August 2, 2017) 10:15 AM - 12:15 PM Room: 708
Purpose: Reliable measurements of the stiffness of small targets, such as tendons and nerves, are desirable in clinical musculoskeletal ultrasound practice. This study aimed to evaluate and compare performance of two ultrasound systems for shear wave elastography function with different target sizes.
Methods: A Supersonic Aixplorer scanner (V8.4) with two linear transducers (SL10-2 and SL15-4) and a GE LE9 XDclear 2.0 scanner with one linear transducer (9L) were studied using the CIRS 049A elasticity QA phantom. 10.4, 6.5 and 4.1 mm-diameter cylinders with reference nominal Young’s moduli of 45 and 8 kPa were scanned at 3 cm depth in a uniform background (25 kPa). Both transaxial and longitudinal views were measured five times for each transducer. All measurements were made in phantom mode. Mean shear wave speed and standard deviations from each target according to the known diameters were computed using an in-house MATLAB program.
Results: For each corresponding target measurement, differences in shear wave speed among transducers ((Max – Min)/Max) ranged from 2.1% to 16.9%. For targets with the same stiffness, linear relationships were found between measured shear wave speeds and target sizes for each transducer (R² ranged from 0.88 to 1). Measured speeds were closer to background material’s reference shear wave speed for smaller target for all transducers. Transaxial measurements were closer to reference values for each transducer compared to longitudinal measurements. SL15-4 transaxial measurements were the closet to reference values for all targets.
Conclusion: Differences in shear wave speed measurements exist not only between different scanners/transducers, but also among measurement views. Transaxial measurements were closer to reference values possibly due to reduced elevational partial volume effect compared with longitudinal measurements. It is very challenging to reliably measure ~4 mm target at 3 cm depth using the evaluated scanners.
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