Amide Proton Transfer Imaging for Differentiating Gliomas and Meningiomas and Assessing Tumor Infiltration

Summary

This study evaluates Amide Proton Transfer (APT) imaging combined with conventional magnetic resonance imaging (MRI) to differentiate meningiomas from low- and high-grade gliomas and assess imaging features related to tumor infiltration, demonstrating its potential to improve preoperative classification and provide imaging-based information that may inform surgical planning.

Abstract

Differentiating gliomas from meningiomas and assessing imaging features related to glioma infiltration remain challenging with conventional magnetic resonance imaging (MRI). Amide Proton Transfer (APT) imaging, a chemical exchange saturation transfer technique, can detect changes in tissue protein content and pH, offering potential functional insights into brain tumors. This retrospective study evaluated APT imaging combined with conventional MRI in 105 patients with pathologically confirmed brain tumors (55 meningiomas, 20 low-grade gliomas [LGGs], and 30 high-grade gliomas [HGGs]). APT-derived mean signal intensity (APT_mean) and the ratios of APT abnormal area to T2 hyperintense area (RAPT/T2) and to contrast-enhancing area (RAPT/E) were measured and compared among groups. APTmean was significantly higher in HGGs (median 4.60%) than in LGGs (2.95%) and meningiomas (2.70%, P < 0.001). RAPT/T2 and RAPT/E were also markedly elevated in HGGs. For distinguishing HGGs from meningiomas, APTmean achieved excellent diagnostic performance (area under the curve [AUC] = 0.969), compared with RAPT/E (0.836) and RAPT/T2 (0.800). For differentiating LGGs from meningiomas, RAPT/E (AUC = 0.781) and RAPT/T2 (AUC = 0.734) showed good performance, whereas APT_mean did not differ significantly. For glioma grading (HGG vs. LGG), APTmean yielded an AUC of 0.916, superior to contrast enhancement degree (0.823). These findings indicate that APT imaging effectively distinguishes meningiomas from gliomas of different grades and provides valuable imaging-based information for inferring the extent of tumor infiltration. The combination of APTmean and spatial extent ratios provides a practical imaging tool for improving preoperative diagnosis and supporting surgical planning, particularly in challenging atypical cases.

Introduction

Intracranial tumors are among the most common disorders of the nervous system. Their incidence is increasing globally, posing a serious threat to human health¹. Based on histopathological origin, intracranial tumors can be classified into two major categories: primary and secondary (metastatic). Among primary intracranial tumors, meningioma and glioma represent the two most prevalent types with distinctly different origins and biological behaviors². Glioma, originating from glial cells, is the most common malignant intracranial tumor, characterized by infiltrative growth, ill-defined borders, a high tendency for recurren....

Protocol

This study protocol adhered to the ethical principles outlined in the Declaration of Helsinki and was approved by the Shenzhen Bao'an District Songgang People's Hospital ethics review board (Approval number: IRB-YJ-2025-045). Given its retrospective design, the study involved only the analysis of archived clinical and imaging data. All patient-identifiable information was strictly anonymized.

Research design and subjects

This study is a retrospective diagnostic analysis. We retrospectively collected clinical and imaging data from brain tumor patients admitted to the Neurosurgical Oncology D....

Results

Baseline and clinical characteristics

Significant differences were observed among the three patient groups in terms of age, Karnofsky Performance Status (KPS) score, initial presenting symptoms, and WHO grade (P < 0.001). Patients in the HGG group were older, had lower KPS scores, and more frequently presented with focal neurological deficits as their initial symptom. In contrast, patients in the LGG group predominantly presented with seizures as their initial symptom. No s.......

Discussion

Accurately distinguishing between gliomas and meningiomas preoperatively and precisely delineating presumed tumor infiltration boundaries on imaging constitute core challenges in neuro-oncology, directly impacting treatment strategies and patients' ultimate prognosis. This study, based on APT, an emerging molecular magnetic resonance technique, systematically evaluated its application value in differentiating gliomas of various grades from meningiomas. Furthermore, by introducing the spatial extent ratio parameter, w.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
3.0T MR Scanner	GE Healthcare	Discovery 750W	Used for all conventional and APT imaging sequences.
Contrast Agent (Gadopentetate Dimeglumine)	Bayer Healthcare	Magnevist	Standard dose of 0.1 mmol/kg body weight, administered intravenously at 2 mL/s.
Head Coil	GE Healthcare	Standard 8-channel	Receive-only head coil for signal acquisition.
Image Analysis Software	MicroDicom Ltd.	MicroDicom Viewer (version 3.0)	Used for ROI delineation and parameter measurement by neuroradiologists.
Post-processing Software	GE Healthcare	FuncTool (built-in)	Automatically generates APT-weighted images and MTRasym maps on the scanner.
Statistical Analysis Software	IBM Corp.	SPSS (version 25.0)	Used for all statistical analyses, including ROC curves and group comparisons.