title: Diagnostic value of "absent" pattern in contrast-enhanced ultrasound for the differentiation of thyroid nodules.
abstract: OBJECTIVE
  Our study sought to investigate the unique diagnostic value of "absent" pattern in contrast-enhanced ultrasound (CEUS) for the differentiation of solid thyroid nodules, also, to analyze corresponding characteristics of B-scan ultrasound (US) and real-time elastography (RTE).
  
  
  METHODS
  A total of 96 patients enrolled in our study underwent conventional US, RTE and CEUS before fine needle aspiration (FNA) or surgery. Thyroid nodules with the same "absent" pattern of contrast-enhancement were evaluated on the basis of different ultrasound features in B-scan US and RTE. Then accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for the diagnosis of thyroid cancer were investigated respectively.
  
  
  RESULTS
  Among the five B-scan US features, nodular border obscurity was most predictive of malignancy (accuracy 84.4%, sensitivity 75.0%, specificity 84.8%, p < 0.05). Nevertheless, none of other ultrasound features including RTE was significantly different between benign and malignant thyroid nodules (p > 0.05). Besides, both echohomogeneity and RTE had a high sensitivity of 100%.
  
  
  CONCLUSIONS
  Combined with medical history, our study allows to identify a specific role for "absent" pattern of CEUS in the differentiation of thyroid nodules with suspicious ultrasound features in conventional B-scan US and RTE.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wu
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle / Q000379:methods*; D003287:Contrast Media / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016606:Thyroid Nodule / Q000175:diagnosis* / Q000473:pathology; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: B-scan US; Thyroid nodules; contrast-enhanced ultrasound; fine-needle aspiration; real-time elastography