title: Three subsequent single doses of gadolinium chelate for brain MR imaging in multiple sclerosis.
abstract: OBJECTIVE
  A triple-dose (TD) of gadolinium chelate is highly sensitive approach for detecting lesion activity in multiple sclerosis (MS). However, individual TD injections do not provide data on the severity of the pathologic process in a population of lesions, and its clinical use is limited by the cost-benefit considerations. Our aim was to determine whether the use of three subsequent single doses (SD) of a gadolinium chelate in brain MR imaging is useful in detecting MS lesions with different patterns of enhancement.
  
  
  METHODS
  In 10 patients, T1-weighted spin-echo images were acquired before and after three intravenous administrations of 0.1 mmol/kg of gadodiamide.
  
  
  RESULTS
  In all patients, SD images showed six enhancing lesions; double-dose (DD) images, 13; and TD images, 22. Differences between SD and TD and between DD and TD were significant (P <.018). Six lesions (27%) enhanced with all the three doses; seven (32%), with both DD and TD; and nine (41%), with only TD. Proportions of patients with at least one enhancing lesion were, for SD, four of 10; DD, seven of 10; and TD, nine of 10. In defining active disease in these nine patients, we needed only 19 SDs versus the 30 SDs that would have been needed if individual TD injections were used.
  
  
  CONCLUSIONS
  With three subsequent SD injections, the number of enhancing lesions progressively increases. This approach allows the distinction of three levels of enhancement, and it reduces the amount of contrast agent needed to distinguish patients with active MS from those with nonactive MS.
authors.affiliation: Department of Diagnostic Imaging, Istituto Policlinico San Donato, San Donato Milanese, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Sardanelli
authors.forename: Andrea
authors.initials: A
authors.lastname: Iozzelli
authors.forename: Caterina
authors.initials: C
authors.lastname: Losacco
authors.forename: Alessandra
authors.initials: A
authors.lastname: Murialdo
authors.forename: Massimo
authors.initials: M
authors.lastname: Filippi
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology; D003287:Contrast Media / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020528:Multiple Sclerosis, Chronic Progressive / Q000175:diagnosis*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis*; D015588:Observer Variation; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA