⁶⁸Ga-DOTA-FAPI-04 PET/MR in the Evaluation of Gastric Carcinomas: Comparison with ¹⁸F-FDG PET/CT

Abstract

We sought to evaluate the performance of 68 Ga-DOTA-FAPI-04 ( 68 Ga-FAPI) PET/MR for the diagnosis of primary tumor and metastatic lesions in patients with gastric carcinomas and to compare the results with those of 18 F-FDG PET/CT. Methods: Twenty patients with histologically proven gastric carcinomas were recruited, and each patient underwent both 18 F-FDG PET/CT and 68 Ga-FAPI PET/MR. A visual scoring system was established to compare the detectability of primary tumors and metastases in different organs/regions (the peritoneum, abdominal lymph nodes, supradiaphragmatic lymph nodes, liver, ovary, bone, and other tissues). The original maximum standardized uptake value (SUVmax) and normalized SUVmax (calculated by dividing a lesion's original SUVmax with the mean SUV of the descending aorta) of selected lesions on both 18 F-FDG PET/CT and 68 Ga-FAPI PET/MR were measured.Original/normalized SUVmax-FAPI and SUVmax-FDG were compared for patient-based (including a single lesion with the highest activity uptake in each organ/region) and lesion-based (including all lesions [≤ 5] or the 5 lesions with highest activity [> 5]) analyses, respectively. Results:The 20 recruited patients (median age: 56.0 y; range: 29-70 y) included 9 men and 11 women, 14 patients for initial staging and 6 for recurrence detection. 68 Ga-FAPI PET was superior to 18 F-FDG PET for primary tumor detection (100.00% [14/14] vs 71.43% [10/14], p = 0.034), and the former had higher tracer uptake levels (p < 0.05). 68 Ga-FAPI PET was superior to 18 F-FDG PET in both patient-based and lesion-based evaluation except for the metastatic lesions in supradiaphragmatic lymph nodes and ovaries. Additionally, multiple sequences of MR images were beneficial for the interpretation of hepatic metastases in 3 patients, uterine and rectal metastases in 1 patient, ovarian lesions in 7 patients, and osseous metastases in 2 patients. Conclusion:68 Ga-FAPI PET/MR outperformed 18 F-FDG PET/CT in visualizing the primary and most metastatic lesions of gastric cancer, and might be a promising method with the potential of replacing 18 F-FDG PET/CT.

Fibroblast Activation Protein-α as a Target in the Bench-to-Bedside Diagnosis and Treatment of Tumors: A Narrative Review

“…Recently, 68Ga-FAPI has been clinically adopted, allowing researchers to obtain a variety of tumor images with very high uptake and image contrast, paving the way for new applications in tumor characterization, staging, and treatment. Qin et al (99) evaluated the performance of 68Ga-DOTA-FAPI-04 (68Ga-FAPI) PET/MR in the diagnosis of primary tumors and metastatic lesions in patients with gastric cancer and compared it with 18F-FDG PET/CT. The results show that, due to the high expression of FAP in gastric cancer and its metastatic tissues, 68Ga-FAPI PET/MR is significantly superior to 18F-FDG PET/CT for the diagnosis of primary gastric cancer and its metastatic lesions.…”

Fibroblast-Activated Protein Inhibitor PET/CT: Cancer Diagnosis and Management

“…Overexpression of FAPs in gastric carcinomas has also been demonstrated (41)(42)(43). Quin et al investigated 20 gastric cancer patients and described the superiority of 68 Ga-FAPI04 PET/MR over 18 F-FDG PET/CT in visualizing the primary tumors and most metastatic lesions (44). Pang et al ( 45) evaluated 68 Ga-FAPI04 PET/CT of 20 patients with gastric carcinoma and reported higher detection rates and mean SUV max than 18FDG PET/CT.…”

“…Linz et al (38) Oral cavity squamous cell carcinoma 10 Compared with 18 F-FDG and cervical MRI, 68 Ga-FAPI can reduce patient morbidity, minimizing the number of neck dissections due to false-positive cervical lymph nodes. Qin et al (44) Gastric carcinomas 20 68 Ga-FAPI PET/MR showed better diagnostic performance than 18 F-FDG PET/CT in visualizing the primary and metastatic lesions of gastric cancer. Pang et al (45) Gastric, duodenal, and colorectal cancers 35 68 Ga-FAPI PET/CT showed superior diagnostic performance.…”

“…Quin et al. investigated 20 gastric cancer patients and described the superiority of 68 Ga-FAPI04 PET/MR over 18 F-FDG PET/CT in visualizing the primary tumors and most metastatic lesions ( 44 ). Pang et al.…”

Clinical Significance of Diffusely Increased Uptake of 68Ga-FAPI in Thyroid Gland

“…68 Ga-FAPI is a novel tumor-targeting agent, as fibroblast activation protein is overexpressed in cancer-associated fibroblasts (1)(2)(3). Existing research has shown that FAPI revealed favorable pharmacokinetics and biodistribution in vivo and a clear delineation of primary tumors and their metastases (4)(5)(6)(7). With the increasing use of 68 Ga-FAPI in clinical trials, accurate interpretation of unexpected findings remains a challenge, because the impact of accidental findings on patient management may be significant.…”