The value of magnetization transfer in delineation and differentiation of intracranial lesions

Abstract

Purpose: Determination of the value of magnetization transfer (MT) imaging in the detection of lesions by evaluating the contrast difference between MT and non-MT spin-echo (SE) images of different types of enhancing intra-axial lesions, and the assessment of the applicability of MT effect (MTE) on lesion characterization.Methods: Twenty-seven patients (ages 11 to 72) having 36 lesion consisted of 12 multiple sclerosis plaques, nine metastatic lesions, 12 glial tumours and three abscesses were studied on 1.0T imager with Gd-DTPA enhanced non-MT and MT sequences by application of 1500Hz off-resonance pulse. Signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) obtained with both techniques were compared to assess contrast improvement. MT effect (MTE) was used to evaluate the degree of saturation produced and its variances were analysed for lesion characterization.Results: The difference between MT and non-MT images for CNR was significant for all lesion types (P<0.05). Compared to the non-MTs, there was 60% improvement in CNR on MT images. MTE was not diagnostically significant in lesion characterization due to marked overlapping of MTE values for different lesion types.Conclusions: With the parameters used, MT almost doubles the CNR of enhancing intra-axial lesions, obviating the use of high dose regimens.