MRI evolution of new MS lesions enhancing after different doses of gadolinium.
OBJECTIVE
To investigate the evolution of multiple sclerosis (MS) lesions enhancing after single dose (SD) or triple dose (TD) of gadolinium-DTPA (Gd).


METHODS
For 3 months, 30 relapsing-remitting MS patients underwent 2 monthly MRI sessions, consisting of Gd-enhanced T1-weighted scans, after SD (i.e., 0.1 mmol/kg) in one session and TD (i.e., 0.3 mmol/kg) in the other. New enhancing lesions on month 1 and month 2 follow-up scans were studied and for them any persistence of enhancement was evaluated on the scans obtained the next month.


RESULTS
In all, 151 lesions enhancing after both SD and TD and 91 lesions enhancing only after TD entered the analysis. After 1 month, for the 151 lesions enhancing after both SD and TD, 73 (48%) were not enhancing, 50 (33%) were still enhancing after both SD and TD and 28 (19%) were enhancing only after TD. For the 91 lesions enhancing only after TD, 61 (67%; P<0.005) were not enhancing, 16 (18%; P<0.01) were still enhancing only after TD and 14 (15%; P=NS) showed enhancement after both SD and TD.


CONCLUSIONS
Enhancing lesions in patients with MS are heterogeneous. Those enhancing only after TD of Gd are characterized by a milder and shorter opening of the blood-brain barrier.
Rovaris
M
M
Neuroimaging Research Unit, IRCCS Ospedale San Raffaele, University of Milan, Italy.
Mastronardo
G
G
Gasperini
C
C
Prandini
F
F
Yousry
T A
TA
Filippi
M
M
D001812:Blood-Brain Barrier / Q000502:physiology; D001921:Brain / Q000473:pathology; D003287:Contrast Media / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000503:physiopathology
D003287:Contrast Media; D019786:Gadolinium DTPA