title: Quantitative shear wave elastography as a prognostic implication of papillary thyroid carcinoma (PTC): elasticity index can predict extrathyroidal extension (ETE).
abstract: OBJECTIVE
  To investigate whether the quantitative elasticity index of shear wave elastography (SWE) can predict extrathyroidal extension (ETE) of papillary thyroid carcinoma (PTC) preoperatively.
  
  
  METHODS
  A total of 208 patients with pathology confirmed PTC whom underwent SWE during preoperative staging US between April 2011 to June 2012 were included.SWE indices of E mean, E max, E min of the index malignancy, the ratios between E mean of the lesion and parenchyma (E ratio-P), and muscle (E ratio-M), and grayscale US findings, including ETE, multifocality, bilaterality, and central and lateral lymph node (LN) metastasis were evaluated. The correlations of SWE indices and grayscale US findings with pathologic prognostic factors of PTC were analyzed by Chi square or Fisher's exact test, and multivariate regression analysis.
  
  
  RESULTS
  ETE was associated with E mean, E max, E min, and E ratio-M (P = 0.005, 0.009, 0.016 and <0.001, respectively), multifocality was associated with E mean, E max, and E min (P = 0.028, 0.007, and 0.004, respectively), and central LN metastasis was associated with E ratio-M (P = 0.03). On multivariate analysis, E mean and E min were independent factors for predicting ETE (P = 0.032, 0.049, respectively).
  
  
  CONCLUSIONS
  Quantitative elasticity index of SWE could predict pathologic ETE, and SWE could be a complimentary method to grayscale US for preoperative prediction of prognostic factors of PTC.
authors: Department of Radiology, Yonsei University College of Medicine, Gangnam Severance Hospital, Seoul, South Korea.
authors: Yun Joo
authors: YJ
authors: Park
authors: Jeong-Ah
authors: JA
authors: Kim
authors: Eun Ju
authors: EJ
authors: Son
authors: Ji Hyun
authors: JH
authors: Youk
authors: Cheong Soo
authors: CS
authors: Park
mesh_terms: D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D002291:Carcinoma, Papillary; D016009:Chi-Square Distribution; D016001:Confidence Intervals; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness / Q000000981:diagnostic imaging; D009367:Neoplasm Staging; D016017:Odds Ratio; D011379:Prognosis; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy; D055815:Young Adult