Combination of high-resolution susceptibility-weighted imaging and the apparent diffusion coefficient: added value to brain tumour imaging and clinical feasibility of non-contrast MRI at 3 T.

The purpose of this study was to determine the benefit of high-resolution susceptibility-weighted imaging and the apparent diffusion coefficient for brain tumour imaging, and to assess the clinical feasibility of using a non-contrast MR protocol at 3 T. 73 patients with intra-axial tumours were enrolled into the study. Two experienced neuroradiologists reviewed three MRI sessions: (i) a non-contrast protocol including high-resolution susceptibility-weighted images and apparent diffusion coefficient; (ii) a contrast protocol including MR perfusion images; and (iii) combined contrast and non-contrast protocols. The two observers categorised tumours as glial or non-glial tumours, and then subcategorised the gliomas into low-grade or high-grade tumours. For semi-quantitative analysis, a scoring system based on the degree of intra-tumoral susceptibility signals and the visual apparent diffusion coefficient was used. The two observers diagnosed accurate tumour pathology in 52 (71%) of 73 tumours in the first review, 55 (75%) of 73 tumours in the second review and 61 (84%) of 73 tumours in the third review. The addition of the non-contrast protocol to the contrast protocol significantly differentiated glioblastoma multiforme and metastatic tumours, which was not possible with the contrast protocol alone. The sensitivity, specificity, positive predictive value and negative predictive value for glioma grading with the non-contrast protocol were 83.2%, 100%, 100% and 79.3%, respectively. The addition of both high-resolution susceptibility-weighted imaging and the apparent diffusion coefficient improved the diagnostic performance of the contrast MR protocol for brain tumour imaging and could be feasible in selected patients who cannot tolerate a contrast agent.