Intra-Individual Comparison between 2-D Shear Wave Elastography (GE System) and Virtual Touch Tissue Quantification (Siemens System) in Grading Liver Fibrosis

Ultrasound-based shear wave elastography (SWE) has recently gained substantial attention for non-invasive assessment of liver fibrosis. The purpose of this study was to perform an intra-individual comparison between 2-D shear wave elastography (2-D-SWE with a GE system) and Virtual Touch Tissue Quantification (VTTQ with a Siemens system) to assess whether these can be used interchangeably to grade fibrosis. Ninety-three patients (51 men, 42 women; mean age, 54 y) with liver disease of various etiologies (hepatitis B virus = 47, hepatitis C virus = 22; alcohol = 6, non-alcoholic steatohepatitis = 5, other = 13) were included. Using published system-specific shear wave speed cutoff values, liver fibrosis was classified into clinically non-significant (F0/F1) and significant (≥F2) fibrosis. Results indicated that intra-modality repeatability was excellent for both techniques (GE 2-D-SWE: intra-class correlation coefficient = 0.89 [0.84-0.93]; VTTQ: intra-class correlation coefficient = 0.90 [0.86-0.93]). Intra-modality classification agreement for fibrosis grading was good to excellent (GE 2-D-SWE: κ = 0.65, VTTQ: κ = 0.82). However, inter-modality agreement for fibrosis grading was only fair (κ = 0.31) using published system-specific shear wave speed cutoff values of fibrosis. In conclusion, although both GE 2-D-SWE and Siemens VTTQ exhibit good to excellent intra-modality repeatability, inter-modality agreement is only fair, suggesting that these should not be used interchangeably.

Comparison of Virtual Touch Tissue Quantification and Virtual Touch Tissue Imaging Quantification for diagnosis of solid breast tumors of different sizes

BACKGROUND

Acoustic radiation force impulse imaging (ARFI) with Virtual Touch Tissue Quantification (VTQ) or Virtual Touch Tissue Imaging Quantification (VTIQ) measures shear wave velocity (SWV), which is proportional to tissue stiffness, a diagnostic parameter for malignancy.

OBJECTIVE

To compare the performance of VTQ and VTIQ in diagnosing solid breast tumors.

METHODS

Conventional ultrasound, VTQ and VTIQ were used to examine 246 solid breast tumors from 230 patients. Tumors were grouped according to size: <10 mm, 10-20 mm, >20 mm. Pathological diagnoses were via histological examination of biopsies. ROC curves were used to assess diagnostic performance and optimal cut-off points for VTQ and VTIQ.

RESULTS

For all sizes, SWVVTQ and SWVVTIQ were higher for malignant versus benign tumors (P < 0.05). SWVVTQ and SWVVTIQ were both higher for tumors≥10 mm (P < 0.05). Areas under the ROC curves (diagnostic performance index; 0.860-0.952) did not differ significantly between VTQ and VTIQ. Optimal cut-off values for SWVVTQ and SWVVTIQ were higher for tumors≥10 mm.

CONCLUSION

The diagnostic performance of VTQ and VTIQ was moderate to good for solid breast tumors. Although both methods have higher sensitivities in tumors≥10 mm, their overall diagnostic performance was similar for all sizes.