title: Diagnostic value of diffusion-weighted magnetic resonance imaging: differentiation of benign and malignant lymph nodes in different regions of the body.
abstract: BACKGROUND
  To evaluate the value of diffusion-weighted magnetic resonance imaging compared with conventional magnetic resonance imaging (C-MRI) for the differentiation of benign from malignant lymph nodes in different regions of the body.
  
  
  METHODS
  A total of 31 patients ranging in age from 18 to 75 years (mean age: 53 years) were included in this study. The patients were examined using a 1.5-T magnetic resonance imaging system with coils chosen according to lymph node locations. Diffusion-weighted images were obtained using the single-shot echo planar sequence and had b values of 50, 500, and 1000 s/mm(2.) The apparent diffusion coefficient (ADC) values were measured from ADC maps. The correlation between the pathological diagnoses and mean ADC values in the benign and malignant lymph node groups were compared using the Mann-Whitney U-test with Bonferroni correction. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance of the method.
  
  
  RESULTS
  The mean ADC value for benign lymph nodes was 0.97×10(-3) mm(2)/s (range: 0.6-1.2×10(-3) mm(2)/s), and the mean ADC value for malignant lymph nodes was 0.76×10(-3) mm(2)/s (range: 0.3-1.2×10(-3) mm(2)/s) (P<.001). In ROC analysis, the cut-off ADC value for malignant versus benign lymph node differentiation was 0.8×10(-3) mm(2)/s. Using an ADC value of 0.8×10(-3) mm(2)/s, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the method for differentiating between benign and malignant lymph nodes were 76.4%, 85.7%, 86.6%, 75%, and 80.6%, respectively. The sensitivity, specificity, PPV, NPV, and accuracy of C-MRI were 88.2%, 78.5%, 83.3, 84.6%, and 83.8%, respectively. The sensitivity, specificity, PPV, NPV, and accuracy of C-MRI findings suspicious for malignancy combined with the ADC values were 76.4%, 64.2%, 100%, 81.8%, and 91.6%, respectively.
  
  
  CONCLUSIONS
  C-MRI alone remained superior to diffusion-weighted imaging (DWI) and combination C-MRI and DWI for differentiating malignant from benign lymph nodes; however, DWI and ADC calculation may play a role in lymph node characterization.
authors.affiliation: Dr. A. Y. Ankara Oncology Education and Research Hospital, Department of Radiology. Electronic address: turgutseber@hotmail.com.
authors.forename: Turgut
authors.initials: T
authors.lastname: Seber
authors.affiliation: Dr. A. Y. Ankara Oncology Education and Research Hospital, Department of Radiology. Electronic address: caglaremr41@gmail.com.
authors.forename: Emrah
authors.initials: E
authors.lastname: Caglar
authors.affiliation: Dr. A. Y. Ankara Oncology Education and Research Hospital, Department of Radiology. Electronic address: tuylar@gmail.com.
authors.forename: Tuğba
authors.initials: T
authors.lastname: Uylar
authors.affiliation: Dr. A. Y. Ankara Oncology Education and Research Hospital, Department of General Surgery. Electronic address: niyazikaraman@hotmail.com.
authors.forename: Niyazi
authors.initials: N
authors.lastname: Karaman
authors.affiliation: Dr. A. Y. Ankara Oncology Education and Research Hospital, Department of Radiology. Electronic address: elifaktasmd@gmail.com.
authors.forename: Elif
authors.initials: E
authors.lastname: Aktas
authors.affiliation: Dr. A. Y. Ankara Oncology Education and Research Hospital, Department of Radiology. Electronic address: bilginaribas@hotmail.com.
authors.forename: Bilgin Kadri
authors.initials: BK
authors.lastname: Aribas
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008198:Lymph Nodes / Q000473:pathology*; D008206:Lymphatic Diseases / Q000175:diagnosis*; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Diffusion-weighted MRI; Lymph nodes; Malignant