title: Differentiation of Metastatic and Non-Metastatic Mesenteric Lymph Nodes by Strain Elastography in Surgical Specimens.
abstract: OBJECTIVE
  To investigate if strain elastography could differentiate between metastatic and non-metastatic mesenteric lymph nodes ex-vivo.
  
  
  METHODS
  90 mesenteric lymph nodes were examined shortly after resection from 25 patients including 17 patients with colorectal cancer and 8 patients with Crohn's disease. Ultrasound-based strain elastography was performed with a linear probe. Tissue hardness in lymph nodes was assessed using visual scales and measuring the strain ratio. B-mode characteristics were also recorded. Pathological diagnosis with grading of fibrosis served as the reference standard.
  
  
  RESULTS
  20 lymph nodes were metastatic and 70 lymph nodes were non-metastatic. The strain ratios of metastatic and non-metastatic lymph nodes were significantly different (1.83 vs. 1.42, p = 0.021). The VAS scale (0 - 100) for tissue hardness gave higher mean values for metastatic than non-metastatic nodes, but the difference was not significant (65.5 vs. 55.0, p = 0.055). There was no difference between lymph nodes in Crohn's and non-metastatic cancer specimens. The metastatic lymph nodes were significantly more fibrotic than the non-metastatic lymph nodes by the ordinal fibrosis score (0 - 3). In an ROC analysis, quantitative strain imaging was not superior to the measurement of the short-axis diameter of lymph nodes in differentiating metastatic from non-metastatic mesenteric lymph nodes ex-vivo.
  
  
  CONCLUSIONS
  Strain elastography is correlated to fibrosis in lymph nodes and a significant difference was observed on a group level using the strain ratio. Due to measurement overlap, individual mesenteric lymph nodes could not be identified accurately as metastatic or not in this ex-vivo model by strain imaging alone.
authors.affiliation: National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway.
authors.forename: R F
authors.initials: RF
authors.lastname: Havre
authors.affiliation: Department of Pathology, Haukeland University Hospital, Bergen, Norway.
authors.forename: S M
authors.initials: SM
authors.lastname: Leh
authors.affiliation: Department of Medicine, Haukeland University Hospital, National Centre for Ultrasound in Gastroenterology, Bergen, Norway.
authors.forename: O H
authors.initials: OH
authors.lastname: Gilja
authors.affiliation: Department of Medicine, Haukeland University Hospital, National Centre for Ultrasound in Gastroenterology, Bergen, Norway.
authors.forename: S
authors.initials: S
authors.lastname: Ødegaard
authors.affiliation: Department of Clinical Medicine, University of Bergen, Norway.
authors.forename: J E R
authors.initials: JE
authors.lastname: Waage
authors.affiliation: Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: G
authors.initials: G
authors.lastname: Baatrup
authors.affiliation: Department of Pathology, Haukeland University Hospital, Bergen, Norway.
authors.forename: L B
authors.initials: LB
authors.lastname: Nesje
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D003424:Crohn Disease / Q000000981:diagnostic imaging / Q000473:pathology; D003937:Diagnosis, Differential; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D005355:Fibrosis; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008643:Mesentery / Q000000981:diagnostic imaging; D008875:Middle Aged; D009367:Neoplasm Staging; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013223:Statistics as Topic