title: Strain elastography of abnormal axillary nodes in breast cancer patients does not improve diagnostic accuracy compared with conventional ultrasound alone.
abstract: OBJECTIVE
  The purpose of this study was to determine the diagnostic value of strain elastography (SE) alone and in combination with gray-scale ultrasound in the diagnosis of benign versus metastatic disease for abnormal axillary lymph nodes in breast cancer patients.
  
  
  METHODS
  Patients with breast cancer and axillary lymph nodes suspicious for metastatic disease on conventional ultrasound who underwent SE of the suspicious node before ultrasound-guided fine-needle aspiration biopsy (FNAB) were included in this study. On conventional ultrasound, the long- and short-axis diameters, long-axis-to-short-axis ratio, cortical echogenicity, thickness, and evenness were documented. The nodal vascularity was assessed on power Doppler imaging. Elastograms were evaluated for the percentage of black (hard) areas in the lymph node, and the SE-ultrasound size ratio was calculated. Two readers assessed the images independently and then in consensus in cases of disagreement. ROC AUCs were calculated for conventional ultrasound, SE, and both methods combined. Interreader reliability was assessed using kappa statistics.
  
  
  RESULTS
  A total of 101 patients with 104 nodes were examined; 35 nodes were benign, and 69 had metastases. SE alone showed a significantly lower AUC (62%) than did conventional ultrasound (92%) (p<0.001). There was no difference between the AUC of conventional ultrasound and the AUC of the combination of conventional ultrasound and SE (93%) (p=0.16). Interreader reliability was moderate for all variables (κ≥0.60) except the SE-ultrasound size ratio (κ=0.35).
  
  
  CONCLUSIONS
  Added SE does not improve the diagnostic ability of conventional ultrasound when evaluating abnormal axillary lymph nodes.
authors.affiliation: 1 Department of Diagnostic Radiology, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Unit 1459, Houston, TX 77030.
authors.forename: Young Mi
authors.initials: YM
authors.lastname: Park
authors.forename: Bruno D
authors.initials: BD
authors.lastname: Fornage
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Benveniste
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Fox
authors.forename: Roland L
authors.initials: RL
authors.lastname: Bassett
authors.forename: Wei Tse
authors.initials: WT
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016217:Ultrasonography, Mammary / Q000379:methods*
keywords: axilla; breast cancer; elastography; lymph node; metastasis; sonography; ultrasound