Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, India.
Department of Neurology, National Institute of Mental Health and Neurosciences, India.
Neuroradiol J. 2021 Oct;34(5):440-448. doi: 10.1177/19714009211002766. Epub 2021 Apr 7.
Tuberculomas can occasionally masquerade as high-grade gliomas (HGG). Evidence from magnetisation transfer (MT) imaging suggests that there is lower protein content in the tuberculoma microenvironment. Building on the principles of chemical exchange saturation transfer and MT, amide proton transfer (APT) imaging generates tissue contrast as a function of the mobile amide protons in tissue's native peptides and intracellular proteins. This study aimed to further the understanding of tuberculomas using APT and to compare it with HGG.
Twenty-two patients ( = 8 tuberculoma; = 14 HGG) were included in the study. APT was a 3D turbo spin-echo Dixon sequence with inbuilt B correction. A two-second, 2 μT saturation pulse alternating over transmit channels was applied at ±3.5 ppm around water resonance. The APT-weighted image (APTw) was computed as the MT ratio asymmetry (MTR) at 3.5 ppm. Mean MTR values in regions of interest (areas = 9 mm; positioned in component with homogeneous enhancement/least apparent diffusion coefficient) were used for the analysis.
MTR values of tuberculomas ( = 14; 8 cases) ranged from 1.34% to 3.11% ( = 2.32 ± 0.50). HGG ( = 17;14 cases) showed MTR ranging from 2.40% to 5.70% ( = 4.32 ± 0.84). The inter-group difference in MTR was statistically significant ( < 0.001). APTw images in tuberculomas were notable for high MTR values in the perilesional oedematous-appearing parenchyma (compared to contralateral white matter; < 0.001).
Tuberculomas demonstrate lower MTR ratios compared to HGG, reflective of a relative paucity of mobile amide protons in the ambient microenvironment. Elevated MTR values in perilesional parenchyma in tuberculomas are a unique observation that may be a clue to the inflammatory milieu.
结核瘤偶尔可能表现为高级别胶质瘤（HGG）。磁共振磁化转移（MT）成像的证据表明，结核瘤微环境中的蛋白含量较低。基于化学交换饱和转移和 MT 的原理，酰胺质子转移（APT）成像生成的组织对比度是组织天然肽和细胞内蛋白质中可移动酰胺质子的函数。本研究旨在进一步了解结核瘤，并将其与 HGG 进行比较。
共纳入 22 例患者（8 例结核瘤；14 例 HGG）。APT 是一种 3D 涡轮自旋回波 Dixon 序列，具有内置 B 校正。在水共振处±3.5ppm 左右，应用 2 秒、2μT 饱和脉冲，在发射通道之间交替。APT 加权图像（APTw）是通过在 3.5ppm 处计算 MT 比不对称（MTR）来获得。感兴趣区域（ROI；位置在具有均匀增强/最小表观扩散系数的成分中）的平均 MTR 值用于分析。
结核瘤（8 例）的 MTR 值范围为 1.34%至 3.11%（平均值为 2.32±0.50）。HGG（14 例）的 MTR 值范围为 2.40%至 5.70%（平均值为 4.32±0.84）。两组间的 MTR 差异具有统计学意义（ < 0.001）。结核瘤的 APTw 图像显示，病变周围水肿样实质中的 MTR 值较高（与对侧白质相比； < 0.001）。
与 HGG 相比，结核瘤的 MTR 比值较低，反映了周围微环境中可移动酰胺质子相对较少。结核瘤病变周围实质中 MTR 值升高是一个独特的观察结果，可能是炎症环境的一个线索。
