title: Contrast medium enhanced susceptibility imaging signal mechanism; should we use contrast medium?
abstract: BACKGROUND
  Intracranial lesions exhibit clear contrast enhancement in T1-weighted imaging, but the mechanism whereby contrast-enhanced susceptibility-weighted imaging (CE-SWI) generates signals remains unclear. Contrast enhancement patterns cannot be reliably predicted.
  
  
  OBJECTIVE
  To explore the mechanism of CE-SWI contrast enhancement.
  
  
  METHODS
  Fifty-five patients were retrospectively enrolled. All of the imaging employed a clinical 3T magnetic resonance imaging (MRI) system fitted with a 32-channel head coil. Minimum-intensity projection reformatted images were evaluated. Intracranial lesions and brain parenchymal intensities were explored using SWI and CE-SWI. signal intensity rates were calculated by dividing the lesional intensity by the white matter intensity, after which the SWI and CE-SWI signal intensity rate were compared. Two observers independently performed intralesional susceptibility signal analysis.
  
  
  RESULTS
  After contrast medium administration, malignant and extra-axial tumors exhibited obvious contrast enhancement on CE-SWI (P < 0.001 and P = 0.013, respectively). The signal intensity of white matter was significantly reduced. The signal intensity rates rose significantly in the benign, malignant, and extra-axial groups (P < 0.001). Between-radiologist agreement in terms of intralesional susceptibility signal assessment was strong (kappa = 0.8, P < 0.001).
  
  
  CONCLUSIONS
  Contrast media can either reduce or increase SWI signal intensities. The dual contrast feature of CE-SWI can be useful when exploring intracranial disorders.
authors.affiliation: Department of Radiology, Ali Osman Sönmez Oncology Hospital, Bursa, Turkey oaydinuludag@gmail.com.
authors.forename: Ömer
authors.initials: Ö
authors.lastname: Aydın
authors.affiliation: Department of Radiology, Düzce School of Medicine, Düzce, Turkey.
authors.forename: Ramazan
authors.initials: R
authors.lastname: Büyükkaya
authors.affiliation: Department of Radiology, Uludağ University School of Medicine, Bursa, Turkey.
authors.forename: Bahattin
authors.initials: B
authors.lastname: Hakyemez
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000150:complications / Q000000981:diagnostic imaging*; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000150:complications / Q000000981:diagnostic imaging*; D009942:Organometallic Compounds; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine
keywords: Contrast medium; angiogenesis; blood brain barrier; susceptibility weighted imaging; tumor