Centre for Biomedical Engineering, Indian Institute of Technology Delhi, Block II, Room No. 299, New Delhi, 110016, India.
Fortis Memorial Research Institute, Gurgaon, India.
Mol Imaging Biol. 2020 Apr;22(2):384-396. doi: 10.1007/s11307-019-01382-x.
To evaluate the role of amide proton transfer-weighted (APT-w) magnetic resonance imaging (MRI) in differentiating neoplastic and infective mass lesions using different contrast normalizations, region of interest (ROI) selection, and histogram analysis.
Retrospective study included 32 treatment-naive patients having intracranial mass lesions (ICMLs): low-grade glioma (LGG) = 14, high-grade glioma (HGG) = 10, and infective mass lesions = 8. APT-w MRI images were acquired along with conventional MRI images at 3 T. APT-w contrast, corrected for B-field inhomogeneity, was computed and optimized with respect to different types of normalizations. Different ROIs on lesion region were selected followed by ROI analysis and histogram analysis. Statistical analysis was performed using Shapiro-Wilk's test, t tests, ANOVA with Tukey's post hoc test, and receiver operation characteristic (ROC) analysis.
ICMLs showed significantly (p < 0.01) higher APT-w contrast in lesion compared with contralateral side. There was a substantial overlap between mean APT-w contrast of neoplastic and infective mass lesions as well as among different groups of ICMLs irrespective of ROI selection and normalizations. APT-w contrast (using type 4 normalization: normalized with reference signal at negative offset frequency and APT-w contrast in normal-appearing white matter) reduced variability of APT-w contrast across different subjects, and overlap was less compared with other types of normalizations. There was a significant difference (p < 0.05) between neoplastic and infective mass lesions using t test for different histogram parameters of type 4 normalized APT-w contrast. ANOVA with post hoc showed significant difference (p < 0.05) for different histogram parameters of APT-w contrast (Type 4 normalization) between LGG and HGG, LGG, and infective mass lesion. Histogram parameters such as standard deviation, mean of top percentiles, and median provided improved differentiation between neoplastic and infective mass lesions compared with mean APT-w contrast. A greater number of histogram parameters of type 4 normalized APT-w contrast corresponding to active lesion region can significantly differentiate between ICMLs than other types of normalizations and ROIs.
APT-w contrast using type 4 normalization and active lesion region (ROI-2) should be used for studying APT. APT-MRI should be combined with other MRI techniques to further improve the differential diagnosis of ICMLs.
使用不同的对比归一化、感兴趣区（ROI）选择和直方图分析，评估酰胺质子转移加权（APT-w）磁共振成像（MRI）在区分肿瘤和感染性肿块病变中的作用。
回顾性研究纳入了 32 名未经治疗的颅内肿块病变（ICML）患者：低级别胶质瘤（LGG）=14 例，高级别胶质瘤（HGG）=10 例，感染性肿块病变=8 例。在 3T 下采集 APT-w MRI 图像和常规 MRI 图像。计算并优化 APT-w 对比，以校正 B 场不均匀性。在病变区域选择不同的 ROI，然后进行 ROI 分析和直方图分析。使用 Shapiro-Wilk 检验、t 检验、方差分析和 Tukey 事后检验以及接收操作特征（ROC）分析进行统计分析。
ICML 病变的 APT-w 对比明显高于对侧（p<0.01）。肿瘤和感染性肿块病变的平均 APT-w 对比以及不同 ICML 组之间存在很大的重叠，无论 ROI 选择和归一化如何。使用 4 型归一化（用负偏移频率的参考信号和正常白质的 APT-w 对比归一化）时，APT-w 对比减少了不同受试者之间的 APT-w 对比的变异性，与其他类型的归一化相比，重叠较少。使用不同的直方图参数对 4 型归一化 APT-w 对比进行 t 检验，发现肿瘤和感染性肿块病变之间存在显著差异（p<0.05）。方差分析和事后检验显示，LGG 和 HGG、LGG 和感染性肿块病变之间的 APT-w 对比的不同直方图参数（4 型归一化）存在显著差异（p<0.05）。与平均 APT-w 对比相比，标准差、前百分位平均值和中位数等直方图参数可改善肿瘤和感染性肿块病变之间的区分。与其他类型的归一化和 ROI 相比，4 型归一化 APT-w 对比的更多直方图参数对应于活性病变区域，可显著区分 ICML。
应使用 4 型归一化和活性病变区域（ROI-2）的 APT-w 对比来研究 APT。APT-MRI 应与其他 MRI 技术相结合，以进一步提高 ICML 的鉴别诊断。
