title: Differential diagnosis between metastatic and non-metastatic lymph nodes using DW-MRI: a meta-analysis of diagnostic accuracy studies.
abstract: OBJECTIVE
  The purpose of our meta-analysis was to assess the overall diagnostic value of diffusion-weighted magnetic resonance imaging (DW-MRI) in detecting node metastases and investigate whether the apparent diffusion coefficient (ADC) value could be used to discriminate between metastatic and non-metastatic lymph nodes in patients with primary tumors.
  
  
  METHODS
  The meta-analysis included a total of 1,748 metastatic and 6,547 non-metastatic lymph nodes from 39 studies, including 8 different tumor types with lymph node metastases.
  
  
  RESULTS
  The pooled sensitivity and specificity of DW-MRI were 0.82 (95 % CI 0.76-0.87) and 0.92 (95 % CI 0.88-0.94), respectively. The positive likelihood ratio (PLR), negative likelihood ratio (NLR), and the area under the curve were 9.8 (95 % CI 6.9-14.0), 0.20 (95 % CI 0.15-0.26) and 0.93 (95 % CI 0.91-0.95), respectively. The probability of 42 % can be viewed as the cutoff pretest probability for DW-MRI to diagnosis lymph node metastases; when the more chance of metastatic increased from 42 % that the pretest probability was estimated, it was more suitable to emphasize on "ruling in," on the contrary, and when the more chance of metastatic decreased from 42 %, it was more suitable to emphasize on "ruling out." Furthermore, the mean ADC value of metastatic lymph nodes was significantly lower than that of non-metastatic (P = 0.001).
  
  
  CONCLUSIONS
  DW-MRI is useful for differentiation between metastatic and non-metastatic lymph nodes. However, DW-MRI has a moderate diagnostic value for physician's decision making when PLR and NLR took into consideration, while a superior ability for nodal metastases confirmation, but an inferior ability for ruling out. In the future, large-scale, high-quality trials are necessary to evaluate, respectively, their clinical value in different tumor types with nodal metastases.
authors.affiliation: Department of General Surgery, Chaohu Hospital of Anhui Medical University, No. 64 Chaohu Bei Road, Chaohu, Hefei, 238000, China, zhoumin1119@foxmail.com.
authors.forename: Min
authors.initials: M
authors.lastname: Zhou
authors.forename: Bin
authors.initials: B
authors.lastname: Lu
authors.forename: Gang
authors.initials: G
authors.lastname: Lv
authors.forename: Qin
authors.initials: Q
authors.lastname: Tang
authors.forename: Jibiao
authors.initials: J
authors.lastname: Zhu
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Kaide
authors.initials: K
authors.lastname: Shi
mesh_terms: D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D049451:Nomograms; D016017:Odds Ratio; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed