title: Sensitivity of immediate and delayed gadolinium-enhanced MRI after injection of 0.5 M and 1.0 M gadolinium chelates for detecting multiple sclerosis lesions.
abstract: OBJECTIVE
  The purpose of our study was to compare the efficacy of cranial MR images obtained immediately after, 5 minutes after, and 10 minutes after the injection of 0.5-mol/L (Magnevist) and 1.0-mol/L (Gadovist) gadolinium chelates in the detection of active multiple sclerosis (MS) lesions.
  
  
  METHODS
  Thirty patients with MS were examined with MRI first with 0.5-mol/L and then, after 24-48 hours, with 1.0-mol/L gadolinium chelates. T1-weighted spin-echo images with magnetization transfer were obtained immediately, 5 minutes, and 10 minutes after the injection of the contrast material. Three radiologists evaluated the gadolinium-enhanced T1-weighted images on a remote MR console (Advantage Windows) in six separate sessions and counted the number of enhancing lesions in consensus.
  
  
  RESULTS
  Significantly fewer enhancing lesions were seen on MR images immediately after the injection of 0.5- and 1.0-mol/L gadolinium chelates (n = 18 and n = 36, respectively; p < 0.05) than at 5 minutes (n = 32 and n = 54; p < 0.05) and 10 minutes (n = 34 and n =55; p < 0.05) after the injection (p < 0.05). Likewise, significantly fewer patients with at least one enhancing lesion after the injection of 0.5- and 1.0-mol/L gadolinium chelates (n = 10 and n = 16; p < 0.05) were found immediately after injection than were found 5 minutes (n = 18 and n = 24; p < 0.05) and 10 minutes (n = 18 and n = 24; p < 0.05) after injection (p < 0.01).
  
  
  CONCLUSIONS
  The use of 1.0-mol/L gadolinium chelate enables us to detect an increased number of enhancing lesions and patients with active disease. A delay of 5 minutes after the injection of the gadolinium chelate might be sufficient to detect active lesions in patients with MS.
authors.affiliation: Department of Radiology, Sisli Etfal Hospital, Etfal Sok, Istanbul 80220, Turkey. enderuysaltr@yahoo.com
authors.forename: Ender
authors.initials: E
authors.lastname: Uysal
authors.forename: Sukru Mehmet
authors.initials: SM
authors.lastname: Erturk
authors.forename: Hakan
authors.initials: H
authors.lastname: Yildirim
authors.forename: Feray
authors.initials: F
authors.lastname: Seleker
authors.forename: Muzaffer
authors.initials: M
authors.lastname: Basak
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D002614:Chelating Agents / Q000008:administration & dosage; D003287:Contrast Media / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005682:Gadolinium / Q000008:administration & dosage*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007269:Injections, Intra-Arterial; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009103:Multiple Sclerosis / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D002614:Chelating Agents; D003287:Contrast Media; D005682:Gadolinium