Comparison of strain ratio with elastography score system in differentiating malignant from benign thyroid nodules

Clinical Imaging, 05/15/2012

Wang H et al. – Strain ratio is more specific than conventional elastography score system in differentiating malignant from benign thyroid nodules.


  • The local institutional review board approved the study, and all patients provided written informed consent.
  • The authors examined 168 thyroid nodules (52 malignant and 116 benign) with freehand elastography.
  • The elastogram was performed with both the five-degree elastography score system and thyroid tissue-to-nodule strain ratio before core biopsies as standard reference.
  • The area under the curve (AUC) and the best cut-off point were both obtained using receiver-operating characteristic (ROC) curve analysis.
  • The sensitivity, specificity, and accuracy of both techniques were compared with the χ2 test.
  • Furthermore, strain ratio distribution was also compared with histopathological result. P<.05 was considered to indicate significance.


  • The strain ratio distribution of malignant thyroid nodules significantly differed from that of benign nodules (all P<.001).
  • The AUC of strain ratio was higher than that of the elastography score system (0.907 vs. 0.829; P<.05).
  • By applying the best cut-off point of 3.855 for strain ratio and 3.5 for the elastography score system, strain ratio had significantly higher specificity (P<.05) in detecting malignant thyroid nodules.
  • However, there was no significant difference in the sensitivity in distinguishing malignant thyroid nodules from benign ones between strain ratio and the elastography score system (P>.05).

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