Distinguishing Benign and Malignant Findings on [⁶⁸ Ga]-FAPI PET/CT Based on Quantitative SUV Measurements

Area of Science:

• Nuclear medicine
• Oncology
• Radiochemistry

Background:

• Fibroblast activation protein (FAP) is overexpressed by cancer-associated fibroblasts.
• Activated fibroblasts are also involved in benign conditions like wound healing and chronic inflammation.
• Differentiating benign from malignant processes using FAP imaging requires further investigation.

Purpose of the Study:

• To investigate differences in FAPI uptake between malignant lesions and benign conditions.
• To evaluate the diagnostic performance of semiquantitative PET/CT parameters for differentiating benign and malignant findings.

Main Methods:

• Retrospective analysis of 155 patients who underwent [68Ga]-FAPI-04/02-PET/CT.
• Measurement of SUVmax, SUVmean, and lesion-to-background ratios (LBR) for FAPI uptake.
• Receiver operating characteristic (ROC) curve analysis to assess predictive capabilities.

Main Results:

• Benign lesions showed significantly lower FAPI uptake (mean SUVmax 4.2) compared to malignant lesions (mean SUVmax 10.6).
• ROC analysis established a SUVmax cutoff value of 5.5 for differentiating benign and malignant lesions.
• The SUVmax cutoff demonstrated a sensitivity of 78.8% and specificity of 85.1%.

Conclusions:

• FAPI uptake patterns differ between benign and malignant processes.
• FAPI PET/CT imaging can potentially differentiate malignant from benign findings.
• FAPI imaging holds promise for improved diagnostic accuracy in various conditions.