Sensitivity of enhanced MR in multiple sclerosis: effects of contrast dose and magnetization transfer contrast.
OBJECTIVE
New strategies have been developed to improve the sensitivity of contrast-enhanced MR imaging in quantifying disease activity in patients with multiple sclerosis (MS). The goal of the present study was to evaluate the sensitivity of T1-weighted images after injection of a triple dose of contrast material and application of a magnetization transfer (MT) pulse in the detection of enhancing lesions as compared with the conventional approach.


METHODS
Monthly MR images were obtained in 13 patients with relapsing-remitting MS for a period of 3 months. The MR studies were performed on two separate occasions with single- and triple-dose contrast material. In each session, T1- and T2-weighted spin-echo images with and without the MT pulse were obtained before and after contrast administration. All images were evaluated in a blinded fashion and scored in random order and consensually by two readers. The number of total and new enhancing lesions and active images was counted.


RESULTS
Eighty-six percent more enhancing lesions and 54% more new enhancing lesions were detected with triple-dose as compared with single-dose non-MT sequences, whereas single-dose MT images depicted 33% more enhancing lesions and 18% more new enhancing lesions than the single-dose non-MT images. Twenty-nine percent more lesions were detected on triple-dose non-MT images than on single-dose MT images. The combination of a triple dose of contrast material and MT did not produce any significant change in detection of enhancing lesions as compared with a triple dose of contrast without MT.


CONCLUSIONS
The use of a triple dose of contrast material is the best approach to maximize the sensitivity of enhanced MR imaging.
Bastianello
S
S
Department of Neurological Sciences, University La Sapienza Rome, Italy.
Gasperini
C
C
Paolillo
A
A
Giugni
E
E
Ciccarelli
O
O
Sormani
M P
MP
Horsfield
M A
MA
Rovaris
M
M
Pozzilli
C
C
Filippi
M
M
D000328:Adult; D001921:Brain / Q000473:pathology*; D003287:Contrast Media / Q000008:administration & dosage*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D009103:Multiple Sclerosis / Q000175:diagnosis*; D012680:Sensitivity and Specificity
D003287:Contrast Media