title: Role of diffusion-weighted imaging in the differential diagnosis of benign and malignant lesions of the chest-mediastinum.
abstract: OBJECTIVE
  We retrospectively evaluated the role of diffusion-weighted imaging (DWI) with fat and background signal suppression in the differential diagnosis of benign and malignant lesions of the chest-mediastinum by calculating the mean apparent diffusion coefficient (ADC) values.
  
  
  METHODS
  Thirty-four patients with lung nodules/mediastinal masses underwent magnetic resonance (MR) imaging of the chest with conventional and DWI sequences. All patients had been previously studied with computed tomography (CT). After magnetic resonance (MR) imaging the patients underwent transthoracic CT-guided biopsy or mediastinoscopy. After the histopathological diagnosis had been obtained, the lesions were retrospectively divided into five groups: adenocarcinomas (n=16), squamous cell carcinomas (n=12), chronic pneumonias (n=2), malignant mediastinal tumours (n=2) and typical carcinoids (n=2). We compared ADC values in the different lesion groups using the Mann-Whitney U test.
  
  
  RESULTS
  There were statistically significant differences (p<0.05) between ADC values of benign and malignant lesions. Using an ADC value of 1.25×10⁻³ mm²/s as a threshold, we were able to differentiate malignant from benign lesions with 91% diagnostic accuracy, 90% sensitivity, 100% specificity, 100% positive predictive value and 57% negative predictive value.
  
  
  CONCLUSIONS
  Short-tau inversion-recovery echo-planar imaging (STIR-EPI) sequences applied to the chest-mediastinum provided potentially useful images for the differential diagnosis of benign and malignant lesions.
authors.affiliation: SCDU Radiologia, Università del Piemonte Orientale A. Avogadro, C.so Mazzini 18, 28100, Novara, Italy. salento4u@yahoo.it
authors.forename: F
authors.initials: F
authors.lastname: Tondo
authors.forename: A
authors.initials: A
authors.lastname: Saponaro
authors.forename: A
authors.initials: A
authors.lastname: Stecco
authors.forename: M
authors.initials: M
authors.lastname: Lombardi
authors.forename: C
authors.initials: C
authors.lastname: Casadio
authors.forename: A
authors.initials: A
authors.lastname: Carriero
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis; D000368:Aged; D001706:Biopsy; D002276:Carcinoid Tumor / Q000175:diagnosis; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008479:Mediastinal Neoplasms / Q000175:diagnosis*; D008875:Middle Aged; D011014:Pneumonia / Q000175:diagnosis; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed