International Journal of Anatomy Radiology and Surgery (Oct 2020)
Role of Magnetisation Transfer Imaging in Evaluation of Tuberculoma and Neurocysticercosis
Abstract
Introduction: Precise imaging differentiation of intracranial tuberculoma and Neurocysticercosis (NCC) is essential for their effective treatment. Conventional Magnetic Resonance Imaging (MRI) is an effective modality in its evaluation. However, certain stages of both the diseases show significant simulation in their imaging features paving need for additional sequences like Magnetisation Transfer Contrast (MTC) for their precise differentiation. Aim: To determine the Magnetisation Transfer Ratio (MTR) and its role in differentiating between intracranial tuberculoma and NCC. Materials and Methods: A hospital based cross-sectional study was done from November 2017 to May 2019 in a tertiary care centre of Southern India, where 55 patients with imaging diagnosis of NCC or tuberculoma were subjected to Magnetisation Transfer (MT) imaging and the MTR ratio was analysed. Consistency and reliability of the measurements were confirmed by obtaining the values repeatedly. For each Region Of Interest (ROI), MTR was calculated using the formula: MTR = (Mo- Mt) x 100/ Mo Where, Mo- the mean signal intensity with saturation pulse off, Mt-the mean signal intensity with saturation pulse on. Mean MT ratios were obtained for each category with standard deviation (SD) from the Mean. The mean distribution of MTR was calculated by Kruskal-wallis test and the significance was ascertained by Mann-whitney test. Results: MT ratio of tuberculoma ascertained by the study was 25.42±0.81 (24.62-26.22). MT ratio of vesicular stage of NCC was 10.31±1.6 (8.71-11.91). MT ratio of colloid vesicular/ granular nodular stage of NCC was 23.38±1.22 (22.18-23.58). T2 invisible tuberculomas were better visualised in MT images. Post hoc tests showed mean difference in the MTR values of the lesions as significant with a p value of 0.03. Conclusion: MTC imaging and MT ratio aids in better detection of ambiguous lesions than the conventional MRI and is an effective noncontrast sequence for better detection of the disease load. Since its application is non-cumbersome, MTC can be effectively used as an addition sequence in the standard protocol. The mean MTR values obtained in the study were very well reproducible and were of statistical significance.
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