title: Characteristics and pitfalls of contrast-enhanced, T1-weighted magnetization transfer images of the brain.
abstract: OBJECTIVE
  This study was undertaken to clarify the difference in signal pattern on contrast material-enhanced T1-weighted magnetic resonance (MR) magnetization transfer (MT) images between enhancing and nonenhancing lesions in various intracranial diseases and to determine the necessity of nonenhanced MT images for evaluating lesional contrast enhancement.
  
  
  METHODS
  MR images of 116 patients who underwent nonenhanced T1-weighted imaging, nonenhanced MT imaging, and contrast-enhanced MT imaging were reviewed. The increase in signal intensity of lesions relative to normal brain was compared between nonenhanced T1-weighted images and contrast-enhanced MT images. Signal intensity of lesions was compared with that of the striate nucleus and white matter on contrast-enhanced MT images. True enhancement was determined by comparison with nonenhanced MT images.
  
  
  RESULTS
  In all, 143 lesions, including 86 enhancing and 57 nonenhancing lesions, were identified among 63 patients. Almost all (99%) of the enhancing lesions were hyperintense to striate nucleus on contrast-enhanced MT images, and most (>87%) showed moderate to marked signal intensity increase from nonenhanced T1-weighted images to contrast-enhanced MT images. Most (>95%) of the nonenhancing lesions showed mild or no increase in relative signal intensity, and most (75%) were iso- or hypointense to striate nucleus on contrast-enhanced MT images. A few nonenhancing lesions (4%-6%), however, showed increase in signal intensity that was indistinguishable from true enhancement without comparison to non-enhanced MT images.
  
  
  CONCLUSIONS
  Nonenhanced MT images should be obtained to assess pathologic enhancement accurately.
authors.affiliation: Department of Radiology, University of Rochester Medical Center, NY, USA.
authors.forename: S
authors.initials: S
authors.lastname: Higano
authors.forename: D A
authors.initials: DA
authors.lastname: Shrier
authors.forename: Y
authors.initials: Y
authors.lastname: Numaguchi
authors.forename: D K
authors.initials: DK
authors.lastname: Shibata
authors.forename: E
authors.initials: E
authors.lastname: Kwok
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology*; D001927:Brain Diseases / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D003951:Diagnostic Errors; D005260:Female; D005682:Gadolinium; D019786:Gadolinium DTPA; D006571:Heterocyclic Compounds; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; C064925:gadodiamide; D005682:Gadolinium; D019786:Gadolinium DTPA