title: Gadofosveset-enhanced MRI for the assessment of rectal cancer lymph nodes: predictive criteria.
abstract: OBJECTIVE
  To confirm the use of the nodal signal intensity (SI) and the 'chemical shift' artefact as diagnostic criteria for detecting nodal metastases from rectal cancer on gadofosveset contrast-enhanced MRI.
  
  
  METHODS
  Thirty-three patients underwent a non-enhanced and gadofosveset-enhanced 3D-T1W GRE-MRI at 1.5T. For each lymph node, the SI of the middle part of the node (mSI) and white rim of the chemical shift artefact encircling the node (wSI) were measured on the non-enhanced and gadofosveset-enhanced images. Second, the aspect of the chemical shift artefact encircling the nodes was scored using a 4-point scale. Results were compared with histology on a node-by-node basis.
  
  
  RESULTS
  289 nodes (55 N+) were analysed. On gadofosveset-MRI, mSI and wSI were significantly higher for the benign than for the metastatic lymph nodes (p < 0.001). Areas under the ROC curve (AUC) for identification of metastases were 0.74 (mSI) and 0.73 (wSI). The chemical shift criterion rendered an AUC of 0.85. The combination of mSI and the chemical shift criterion resulted in an AUC of 0.88 and the rendered an AUC of 0.86-0.92 when subjectively (visually) assessed by two independent readers.
  
  
  CONCLUSIONS
  Benign lymph nodes show significant contrast enhancement after gadofosveset injection, while metastatic nodes do not. The uptake of gadofosveset in the nodes also affects the chemical shift artefact encircling the nodes. Combined assessment of these two features on gadofosveset-enhanced MRI provides a high diagnostic performance for diagnosing metastatic lymph nodes in patients with rectal cancer.
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P.O. Box 5800, 6202, AZ, Maastricht, The Netherlands.
authors.forename: Doenja M J
authors.initials: DM
authors.lastname: Lambregts
authors.forename: Luc A
authors.initials: LA
authors.lastname: Heijnen
authors.forename: Monique
authors.initials: M
authors.lastname: Maas
authors.forename: Iris J G
authors.initials: IJ
authors.lastname: Rutten
authors.forename: Milou H
authors.initials: MH
authors.lastname: Martens
authors.forename: Walter H
authors.initials: WH
authors.lastname: Backes
authors.forename: Robert G
authors.initials: RG
authors.lastname: Riedl
authors.forename: Frans C H
authors.initials: FC
authors.lastname: Bakers
authors.forename: Vincent C
authors.initials: VC
authors.lastname: Cappendijk
authors.forename: Geerard L
authors.initials: GL
authors.lastname: Beets
authors.forename: Regina G H
authors.initials: RG
authors.lastname: Beets-Tan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D012372:ROC Curve; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D005682:Gadolinium; C109932:gadofosveset trisodium