title: Diagnostic utility of magnetic resonance imaging in malignant melanoma.
abstract: BACKGROUND
  Dermatologists sometimes have difficulty in making the diagnosis of a melanocytic tumor.
  
  
  OBJECTIVE
  Our purpose was to establish a noninvasive method for the diagnosis of malignant melanoma. We investigated the diagnostic usefulness of magnetic resonance imaging (MRI) in 23 lesions of primary malignant melanoma, metastatic malignant melanoma, and benign pigmented skin tumors.
  
  
  METHODS
  The morphologic characteristics and the signal intensity of the tumors were analyzed to differentiate malignant and benign pigmented skin tumors by means of the tumor-to-fat contrast ratio of the signal intensity.
  
  
  RESULTS
  The morphologic characteristics of the tumors obtained by MRI were not an absolute criterion for diagnosis of malignant melanoma, but the signal intensity of the tumor assessed by the tumor-to-fat contrast ratio on T2-weighted images clearly differentiated between primary malignant melanoma and benign pigmented skin tumors.
  
  
  CONCLUSIONS
  These findings indicated that MRI is useful for noninvasive diagnosis of malignant melanoma.
authors.affiliation: Department of Internal Medicine, Saga Medical School, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: H
authors.initials: H
authors.lastname: Kohda
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D007642:Keratosis / Q000175:diagnosis; D008279:Magnetic Resonance Imaging; D008545:Melanoma / Q000175:diagnosis* / Q000556:secondary; D009508:Nevus, Pigmented / Q000175:diagnosis; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000556:secondary