Ga-FAPI-46 PET/CT in the evaluation of gliomas: comparison withF-FDG PET/CT and contrast-enhanced MRI.

in Theranostics by Dan Ruan, Jianping Sun, Chengkun Han, Jiayu Cai, Lingyu Yu, Liang Zhao, Yizhen Pang, Changjing Zuo, Long Sun, Zhanxiang Wang, Guowei Tan, Xiaobo Qu, Haojun Chen

TLDR

  • The study compared Ga-FAPI-46 PET/CT, FDG PET/CT, and CE-MRI for glioma imaging and found that Ga-FAPI-46 PET/CT may be a useful adjunct to FDG PET/CT for visualizing and classifying gliomas.

Abstract

This study comparedGa-FAPI-46 PET/CT,F-fluorodeoxyglucose (FDG) PET/CT, and contrast-enhanced MRI (CE-MRI) for glioma imaging, classification, and recurrence detection and explored PET parameters and molecular pathological profiles.Between June 2020 and June 2024, we prospectively enrolled patients with space-occupying lesions in the brain or previously treated gliomas. All patients underwent sequential CE-MRI,Ga-FAPI-46, andF-FDG PET/CT. Diagnostic accuracy was assessed based on a reference standard, and PET parameters were analysed for correlations with WHO grading and molecular characteristics.Forty-eight patients (median age, 51 years; 32 men) with 40 confirmed gliomas were enrolled. For primary tumour diagnosis, the sensitivity ofGa-FAPI-46 PET/CT was equivalent to CE-MRI (95% vs. 100%,= 0.99) andF-FDG PET/CT (95% vs. 77%,= 0.13).Ga-FAPI-46 uptake was higher in grade IV than in grade I-II gliomas (5.03 vs. 1.14,= 0.02).Ga-FAPI-46 PET/CT showed significantly higher maximum standardized uptake value and tumour-to-background ratio (TBR) in recurrent tumours than in treatment-related changes and demonstrated favourable sensitivity and specificity for detecting recurrent gliomas, though not significantly superior toF-FDG PET/CT (sensitivity: 100% vs. 85%,= 0.48; specificity: 100% vs. 80%,= 0.99) and CE-MRI (sensitivity: 100% vs. 100%,= NA; specificity: 100% vs. 40%,= 0.25). Glial fibrillary acidic protein-mutant gliomas exhibited higherGa-FAPI-46 uptake than wild-type gliomas.Ga-FAPI-46 PET/CT outperformedF-FDG and CE-MRI in diagnosing glioma recurrence, although the results were not statistically significant. For primary glioma diagnosis,Ga-FAPI-46 PET/CT, despite having a better TBR, did not surpassF-FDG PET/CT and CE-MRI in terms of sensitivity and specificity. However,Ga-FAPI-46 PET/CT is superior toF-FDG for visualizing and classifying gliomas.

Overview

  • The study compared Ga-FAPI-46 PET/CT, F-fluorodeoxyglucose (FDG) PET/CT, and contrast-enhanced MRI (CE-MRI) for glioma imaging, classification, and recurrence detection.
  • The study enrolled patients with space-occupying lesions in the brain or previously treated gliomas and assessed diagnostic accuracy based on a reference standard.
  • The primary objective was to explore PET parameters and molecular pathological profiles, with a focus on Ga-FAPI-46 uptake and its correlation with WHO grading and molecular characteristics.

Comparative Analysis & Findings

  • The study found that Ga-FAPI-46 PET/CT had a sensitivity of 95% for primary tumour diagnosis, equivalent to CE-MRI (100% sensitivity), but lower than FDG PET/CT (95% sensitivity, p = 0.13).
  • Ga-FAPI-46 uptake was higher in grade IV gliomas than in grade I-II gliomas (p = 0.02), and higher maximum standardized uptake value and tumour-to-background ratio (TBR) were observed in recurrent tumours.
  • While Ga-FAPI-46 PET/CT showed good sensitivity and specificity for detecting recurrent gliomas, it did not demonstrate a statistically significant advantage over FDG PET/CT (sensitivity: 85%) or CE-MRI (sensitivity: 100%).

Implications and Future Directions

  • The study suggests that Ga-FAPI-46 PET/CT may be a useful adjunct to FDG PET/CT for visualizing and classifying gliomas, particularly in cases where FDG PET/CT is inconclusive.
  • Further studies are needed to fully evaluate the potential of Ga-FAPI-46 PET/CT for glioma diagnosis and recurrence detection, as well as its potential applications in molecular pathological profiling.
  • The study highlights the importance of combining multiple imaging modalities and biomarkers to improve diagnostic accuracy and personalization of treatment for glioma patients.
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