title: Metastatic lesions of the brain: imaging with magnetization transfer.
abstract: OBJECTIVE
  To study solitary metastatic lesions of the brain with routine spin-echo (SE) and magnetization transfer (MT) magnetic resonance (MR) imaging.
  
  
  METHODS
  In 15 patients with such lesions, the MT ratio (MTR) was calculated in the center and at the periphery of the metastatic lesion, and distally in adjacent white matter, from the periphery of the lesion radially to the most distant cortex. It also was calculated for mirror-image locations in the opposite hemisphere to provide control values.
  
  
  RESULTS
  MTRs were decreased in and immediately around the site of the metastatic focus. MTRs also were lower than control values far distal to the metastatic focus, even when no abnormality was seen on SE MR images obtained before and those obtained after administration of gadopentetate dimeglumine.
  
  
  CONCLUSIONS
  MT enables demonstration of white matter abnormalities in patients with metastatic lesions not seen on SE MR images. These changes can be found in white matter far distal to the lesion and surrounding areas of edema.
authors.affiliation: Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104.
authors.forename: J M
authors.initials: JM
authors.lastname: Boorstein
authors.forename: K T
authors.initials: KT
authors.lastname: Wong
authors.forename: R I
authors.initials: RI
authors.lastname: Grossman
authors.forename: L
authors.initials: L
authors.lastname: Bolinger
authors.forename: J C
authors.initials: JC
authors.lastname: McGowan
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged