title: Ability of diffusion-weighted imaging for the differential diagnosis between chronic expanding hematomas and malignant soft tissue tumors.
abstract: OBJECTIVE
  To evaluate the potential of diffusion-weighted imaging (DWI) in distinguishing chronic expanding hematomas (CEHs) from malignant soft tissue tumors.
  
  
  METHODS
  We performed conventional MRI and DWI of six CEHs and 31 malignant soft tissue tumors from 37 patients seen between May 2000 and November 2006. DWI was obtained with a single-shot echo-planar imaging (EPI) sequence using a 1.5T MR imager. The mean apparent diffusion coefficient (ADC) value was also calculated. We evaluated MRI findings of CEHs and compared ADC value of CEHs with malignant soft tissue tumors.
  
  
  RESULTS
  On conventional MRI, two of six CEHs were difficult to differentiate from malignant soft tissue tumors based on imaging findings. The mean ADC value of CEHs and malignant soft tissue tumors was 1.55+/-0.121x10(-3) mm2/sec and 0.92+/-0.139x10(-3) mm2/sec (mean+/-SD), respectively. The mean ADC value of CEHs was significantly higher than that of malignant soft tissue tumors (P<0.01). There was no overlap in the minimum ADC values among CEHs and malignant soft tissue tumors.
  
  
  CONCLUSIONS
  DWI is useful for differentiating between CEHs and malignant soft tissue tumors.
authors.affiliation: Department of Orthopaedic and Neuro-Musculoskeletal Surgery, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan. okaokay5888@yahoo.co.jp
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Oka
authors.forename: Toshitake
authors.initials: T
authors.lastname: Yakushiji
authors.forename: Hiro
authors.initials: H
authors.lastname: Sato
authors.forename: Shigeta
authors.initials: S
authors.lastname: Yorimitsu
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Hayashida
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mizuta
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006406:Hematoma / Q000175:diagnosis*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012983:Soft Tissue Neoplasms / Q000175:diagnosis*; D055815:Young Adult