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A comparative study of strain and shear-wave elastography in an elasticity phantom
Jonathan F Carlsen1, Malene R Pedersen, Caroline Ewertsen
11 Department of Radiology, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, 2100 Copenhagen, Denmark.
AJR. American Journal of Roentgenology
|February 26, 2015
Summary
This study found that strain elastography methods, specifically strain ratio, were more accurate than shear-wave elastography for assessing target stiffness in phantoms. Both methods were impacted by target size, and shear-wave elastography accuracy was affected by depth.
Area of Science:
- Medical Imaging
- Diagnostic Ultrasound
- Biophysics
Background:
- Elastography is a non-invasive ultrasound technique used to assess tissue stiffness.
- Strain elastography and shear-wave elastography are two primary methods with varying diagnostic accuracy.
- Understanding factors influencing elastography performance is crucial for clinical application.
Purpose of the Study:
- To evaluate the diagnostic accuracy of strain elastography (strain ratio, strain histogram) and shear-wave elastography (shear-wave velocity) in a phantom model.
- To investigate the impact of target diameter on elastographic assessments.
- To determine the effect of target depth on shear-wave elastography measurements.
Main Methods:
- Utilized a phantom with targets of varying stiffnesses (8-80 kPa) and diameters (2.5-16.7 mm).
- Performed 600 evaluations using shear-wave elastography, strain ratio, and strain histogram analysis with a linear-array transducer.
- Assessed the effect of depth (3.5 vs. 6 cm) on shear-wave elastography using a curved-array transducer.
- Employed mixed model analysis to evaluate the influence of target diameter and depth.
Main Results:
- Strain ratio and strain histogram analysis demonstrated higher diagnostic accuracy (AUC) than shear-wave velocity when differentiating between distinct stiffness levels.
- All three elastography methods were significantly affected by target diameter (p=0.001).
- Target depth influenced shear-wave velocity measurements (p=0.001), while strain elastography methods were not significantly affected by depth in this study.
Conclusions:
- Diagnostic performance for differentiating target stiffness varies between strain and shear-wave elastography techniques.
- Target diameter is a critical factor influencing the accuracy of all evaluated elastography methods.
- Shear-wave elastography accuracy is demonstrably affected by target depth, necessitating careful consideration in clinical settings.
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