Comparison between immediate and delayed imaging after gadolinium chelate injection for detecting enhanced lesions in multiple sclerosis

Magnetic resonance imaging [MRI] is a noninvasive and valuable method in the diagnosis of Multiple Sclerosis [MS]. Compared with other modalities, the sensitivity of MRI for detection of the lesion increases using magnetization transfer [MT] and delayed imaging. Our aim was to compare the two methods in detecting MS lesions. In this double-blind clinical trial, twenty-one patients with the definite diagnosis of MS referred to Poursina Hospital, Rasht were included. Two radiologists evaluated all the images. First, images without contrast were conducted, then 0.1 mmol/kg contrast material [Dotarem, single dose] was injected and after 30 minutes, T1W and MT images were obtained. Seventy-two hours later, T1W images were obtained immediately after injection of 0.2 mmol/kg contrast material [double dose]. The data were analyzed using Fisher's and McNemar tests by SPSS for Windows. Delayed magnetization transfer showed 44 enhanced lesions using MT [69.84%] and 29 lesions using T1 [46.03%]. In addition, the number of enhanced lesions in the delayed method were significantly more than those in the immediate method [p value=0.003]. The use of single dose in combination with MT and delayed images after 20-30 minutes enables us to detect more enhanced lesions