title: Comparison of muscle-to-nodule and parenchyma-to-nodule strain ratios in the differentiation of benign and malignant thyroid nodules: which one should we use?
abstract: OBJECTIVE
  The aim of this study is to investigate the diagnostic accuracy of muscle-to-nodule strain ratio (MNSR) in the differentiation of benign and malignant thyroid nodules and to see if there was a difference between MNSR and parenchyma-to-nodule strain ratios (PNSR) in diagnosis.
  
  
  METHODS
  A total of 106 consecutive patients (88 women and 18 men; age range 19-79 years) with thyroid nodules were prospectively examined using ultrasound and sonoelastography before the fine-needle aspiration biopsy. The mean MNSR and PNSR were calculated for each nodule and the elasticity score was determined according to four-point scoring system.
  
  
  RESULTS
  According to the four-point scoring system, 44 of the 83 benign nodules had a score of one or two while 22 of the 23 malignant nodules had a score of three or four (p<0.001). Using ROC analysis, the best cutoff point for MNSR 1.85 and for PNSR 3.14 was calculated. The sensitivity and specificity for the MNSR were 95.6%, 92.8%, respectively; for the PNSR were 95.6%, 93.4%, respectively, when the best cutoff points were used (p<0.001). The κ value for the PNSR and MNSR methods was 0.87, which indicated an almost perfect agreement (p<0.001).
  
  
  CONCLUSIONS
  Sonoelastography has a high diagnostic accuracy in the differentiation of benign and malignant thyroid nodules. There was no significant difference between MNSR and PNSR in the differentiation of benign and malignant thyroid nodules. Therefore, we think that MNSR could safely be used in situations where PNSR could not be used.
authors.affiliation: Department of Radiology, Samsun Education and Research Hospital, Samsun, Turkey. Electronic address: raydin1984@hotmail.com.
authors.forename: Ramazan
authors.initials: R
authors.lastname: Aydin
authors.affiliation: Department of Radiology, Ondokuz Mayis University, Faculty of Medicine, Samsun, Turkey. Electronic address: muzafel@yahoo.com.tr.
authors.forename: Muzaffer
authors.initials: M
authors.lastname: Elmali
authors.affiliation: Department of Radiology, Ondokuz Mayis University, Faculty of Medicine, Samsun, Turkey. Electronic address: veyselp@hotmail.com.
authors.forename: Ahmet Veysel
authors.initials: AV
authors.lastname: Polat
authors.affiliation: Department of Radiology, Ondokuz Mayis University, Faculty of Medicine, Samsun, Turkey. Electronic address: danacim55@yahoo.com.
authors.forename: Murat
authors.initials: M
authors.lastname: Danaci
authors.affiliation: Department of Pathology, Ondokuz Mayis University, Faculty of Medicine, Samsun, Turkey. Electronic address: ilkserakpolat@yahoo.com.
authors.forename: Ilkser
authors.initials: I
authors.lastname: Akpolat
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D003937:Diagnosis, Differential; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009334:Neck Muscles / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016606:Thyroid Nodule / Q000175:diagnosis* / Q000503:physiopathology*; D055815:Young Adult
keywords: Color Doppler ultrasound; Sonoelastography; Strain ratio; Thyroid nodule; Ultrasound