title: Diagnostic performance of diffusion weighted imaging of malignant and benign pulmonary nodules and masses: comparison with positron emission tomography.
abstract: BACKGROUND
  Diffusion-weighted imaging (DWI) makes it possible to detect malignant tumors based on the diffusion of water molecules. However, it is uncertain whether DWI has advantages over FDG-PET for distinguishing malignant from benign pulmonary nodules and masses.
  
  
  METHODS
  One hundred- forty-three lung cancers, 17 metastatic lung tumors, and 29 benign pulmonary nodules and masses were assessed in this study. DWI and FDG-PET were performed.
  
  
  RESULTS
  The apparent diffusion coefficient (ADC) value (1.27 ± 0.35 ?10-3 mm2/sec) of malignant pulmonary nodules and masses was significantly lower than that (1.66 ± 0.58 ?10-3 mm2/sec) of benign pulmonary nodules and masses. The maximum standardized uptake value (SUV max: 7.47 ± 6.10) of malignant pulmonary nodules and masses were also significantly higher than that (3.89 ± 4.04) of benign nodules and masses. By using optimal cutoff values for ADC (1.44?10-3 mm2/sec) and for SUV max (3.43), which were determined with receiver operating characteristics curves (ROC curves), the sensitivity (80.0%) of DWI was significantly higher than that (70.0%) of FDG-PET. The specificity (65.5%) of DWI was equal to that (65.5%) of FDG-PET. The accuracy (77.8%) of DWI was not significantly higher than that (69.3%) of FDG- PET for pulmonary nodules and masses. As the percentage of bronchioloalveolar carcinoma (BAC) component in adenocarcinoma increased, the sensitivity of FDG-PET decreased. DWI could not help in the diagnosis of mucinous adenocarcinomas as malignant, and FDG-PET could help in the correct diagnosis of 5 out of 6 mucinous adenocarcinomas as malignant.
  
  
  CONCLUSIONS
  DWI has higher potential than PET in assessing pulmonary nodules and masses. Both diagnostic approaches have their specific strengths and weaknesses which are determined by the underlying pathology of pulmonary nodules and masses.
authors: Department of Thoracic Surgery, Kanazawa Medical University, Uchinada, Ishikawa, Japan E-mail : usuda@kanazawa-med.ac.jp.
authors: Katsuo
authors: K
authors: Usuda
authors: Motoyasu
authors: M
authors: Sagawa
authors: Nozomu
authors: N
authors: Motono
authors: Masakatsu
authors: M
authors: Ueno
authors: Makoto
authors: M
authors: Tanaka
authors: Yuichiro
authors: Y
authors: Machida
authors: Sumiko
authors: S
authors: Maeda
authors: Munetaka
authors: M
authors: Matoba
authors: Yasuaki
authors: Y
authors: Kuginuki
authors: Mitsuru
authors: M
authors: Taniguchi
authors: Hisao
authors: H
authors: Tonami
authors: Yoshimichi
authors: Y
authors: Ueda
authors: Tsutomu
authors: T
authors: Sakuma
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000473:pathology; D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000175:diagnosis / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D003074:Solitary Pulmonary Nodule / Q000175:diagnosis* / Q000473:pathology*