title: Discrimination between Metastatic and Nonmetastatic Mesorectal Lymph Nodes in Rectal Cancer Using Intravoxel Incoherent Motion Diffusion-weighted Magnetic Resonance Imaging.
abstract: OBJECTIVE
  The aim of the study was to investigate the diagnostic value of intravoxel incoherent motion diffusion-weighted magnetic resonance imaging (IVIM DWI) for discriminating nonmetastatic from metastatic mesorectal lymph nodes in rectal cancer.
  
  
  METHODS
  IVIM DWI was performed preoperatively on 50 patients with rectal carcinoma. The short-axis diameter, short- to long-axis diameter ratio, and IVIM-based parameter (pure diffusion coefficient [D], pseudo-diffusion coefficient [D*] and perfusion fraction [f]) values were compared between the metastatic and nonmetastatic lymph node groups.
  
  
  RESULTS
  The short-axis diameter; short- to long-axis diameter ratio; and D, D*, and f values for the nonmetastatic lymph node group (n = 28) were 6.446 ± 1.201 mm, 0.815 ± 0.099, 1.071 ± 0.234 × 10(-3) mm(2)/s, 15.443 ± 5.946 mm(2)/s and 0.261 ± 0.128, respectively, and were 9.045 ± 3.185 mm, 0.809 ± 0.099, 0.816 ± 0.121 × 10(-3) mm(2)/s, 11.679 ± 7.521 × 10(-3) mm(2)/s, and 0.190 ± 0.064, respectively, for the metastatic lymph node group (n = 31). The short-axis diameter for the metastatic group was significantly higher than for the nonmetastatic group (P <0.001). The metastatic group exhibited significantly lower D and D* values than the nonmetastatic group (P <0.01). The short- to long-axis diameter ratio and f values did not differ significantly between the two groups. Optimal cutoff values (area under the curve, sensitivity, and specificity) for distinguishing metastatic from nonmetastatic lymph nodes were as follows: short-axis diameter = 5.563 mm (0.783, 74.2%, 82.1%); D = 0.667 × 10(-3) mm(2)/s (0.885, 77.4%, 89.3%); and D* = 0.485 × 10(-3) mm(2)/s (0.727, 80.6%, 67.9%).
  
  
  CONCLUSIONS
  IVIM DWI is useful to differentiate between metastatic and nonmetastatic mesorectal lymph nodes in rectal cancer.
authors: Department of Radiology, The Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Yuelu District, Changsha, 410013, Hunan, China; Department of Diagnostic Radiology, The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China; Hunan Provincial Key Laboratory of Translational Radiation Oncology, Hunan Cancer Hospital, Changsha, Hunan, China.
authors: Xiao-ping
authors: XP
authors: Yu
authors: Department of Diagnostic Radiology, The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.
authors: Lu
authors: L
authors: Wen
authors: Department of Diagnostic Radiology, The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.
authors: Jing
authors: J
authors: Hou
authors: Department of Diagnostic Radiology, The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.
authors: Feng
authors: F
authors: Bi
authors: Department of Diagnostic Radiology, The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.
authors: Pingsheng
authors: P
authors: Hu
authors: Hunan Provincial Key Laboratory of Translational Radiation Oncology, Hunan Cancer Hospital, Changsha, Hunan, China.
authors: Hui
authors: H
authors: Wang
authors: Department of Radiology, The Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Yuelu District, Changsha, 410013, Hunan, China. Electronic address: cjr.wangwei@vip.163.com.
authors: Wei
authors: W
authors: Wang
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009038:Motion; D015588:Observer Variation; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000473:pathology*; D012680:Sensitivity and Specificity
keywords: Intravoxel incoherent motion; diffusion-weighted magnetic resonance imaging; lymph nodes; rectal cancer; sensitivity and specificity