Differentiation of Meningiomas and Gliomas by Amide Proton Transfer Imaging: A Preliminary Study of Brain Tumour Infiltration

BACKGROUND: Gliomas are more malignant and invasive than meningiomas. OBJECTIVE: To distinguish meningiomas from low-grade/high-grade gliomas (LGGs/HGGs) using amide proton transfer imaging (APT) combined with conventional magnetic resonance imaging (MRI) and to explore the application of APT in evaluating brain tumour invasiveness. MATERIALS AND METHODS: The imaging data of 50 brain tumors confirmed by pathology in patients who underwent APT scanning in our centre were retrospectively analysed. Of these tumors, 25 were meningiomas, 10 were LGGs, and 15 were HGGs. The extent of the tumour-induced range was measured on APT images, T2-weighted imaging (T2WI), and MRI enhancement; additionally, and the degree of enhancement was graded. Ratios (R(APT/T2) and R(APT/E)) were obtained by dividing the range of changes observed by APT by the range of changes observed via T2WI and MR enhancement, respectively, and APT(mean) values were measured. The Mann–Whitney U test was used to compare the above measured values with the pathological results obtained for gliomas and meningiomas, the Kruskal-Wallis test was used to compare LGGs, HGGs and meningiomas, and Dunn’s test was used for pairwise comparisons. In addition, receiver operating characteristic (ROC) curves were drawn. RESULTS: The Mann–Whitney U test showed that APT(mean) (p=0.005), R(APT/T2) (p<0.001), and R(APT/E) (p<0.001) values were statistically significant in the identification of meningioma and glioma. The Kruskal-Wallis test showed that the parameters APT(mean), R(APT/T2), R(APT/E) and the degree of enhancement are statistically significant. Dunn’s test revealed that R(APT/T2) (p=0.004) and R(APT/E) (p=0.008) could be used for the identification of LGGs and meningiomas. APT(mean) (p<0.001), R(APT/T2) (p<0.001), and R(APT/E) (p<0.001) could be used for the identification of HGGs and meningiomas. APT(mean) (p<0.001) was statistically significant in the comparison of LGGs and HGGs. ROC curves showed that R(APT/T2) (area under the curve (AUC)=0.947) and R(APT/E) (AUC=0.919) could be used to distinguish gliomas from meningiomas. CONCLUSION: APT can be used for the differential diagnosis of meningioma and glioma, but APT(mean) values can only be used for the differential diagnosis of HGGs and meningiomas or HGGs and LGGs. Gliomas exhibit more obvious changes than meningiomas in APT images of brain tissue; this outcome may be caused by brain infiltration.