The influence of precompression on elasticity of thyroid nodules estimated by ultrasound shear wave elastography
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To investigate the influence of variations in resting pressure (precompression) on thyroid ultrasound supersonic shear wave elastography (SWE).
Thirty-five normal thyroid glands (Norm), 55 benign hyperplastic nodules (BHN), and 17 papillary thyroid cancers (PTC) in 96 subjects underwent thyroid SWE. Four precompression levels were applied manually by the operator, ranging from A (baseline, 0 % strain) to D (high, 22–30 % strain). SWE results at each precompression level were compared using ANOVA tests with P < 0.05 indicating significance.
SWE indices were highest in PTC, followed by BHN and Norm at each precompression level (P < 0.05). All tissue types showed successive increases in SWE results as precompression increased, although the rate was higher for PTC than BHN and Norm (Ps < 0.05). SWE values (kPa) of Norm, BHN, and PTC at baseline precompression (A) were 10.3 ± 3.3, 17.7 ± 7.6, and 22.2 ± 11.9 compared with 21.1 ± 4.2, 42.3 ± 16.0, and 97.6 ± 46.8 at high precompression (D). SWE index differences between precompression levels A and D were 10.8 kPa for Norm, 24.6 kPa for BHN, and 75.4 kPa for PTC.
PTCs show greater SWE stiffening than BHN as precompression rises. Precompression effects on thyroid nodules are not negligible and may account for wide discrepancies in published SWE discriminatory performance results for thyroid malignancy.
• Increases in resting pressure (precompression) applied by the operator increases thyroid stiffness.
• Papillary cancers show greater increases in stiffness (strain hardening) than benign nodules.
• Precompression may affect the diagnostic performance of shearwave elastography for thyroid malignancy.
KeywordsElastography Ultrasound Thyroid nodules Precompression Shear wave imaging
Shear wave elastography
Papillary thyroid carcinoma
Benign hyperplastic nodule
Normal thyroid tissue
Regions of interest
The scientific guarantor of this publication is Kunwar Bhatia. The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article. This study has received funding by Research Grants Council of the Hong Kong Special Administrative Region, China (grant Chinese University of Hong Kong; project no. 460412). No complex statistical methods were necessary for this paper. Institutional Review Board approval was obtained. Written informed consent was obtained from all subjects (patients) in this study. Approval from the institutional animal care committee was not required because animal subject was not used in this research. Study subjects or cohorts have not been previously reported. Methodology: prospective, diagnostic or prognostic study, multicenter study / performed at one institution.
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