TY - JOUR T1 - <sup>68</sup>Ga-DOTA-FAPI-04 PET/MR in the evaluation of gastric carcinomas: comparison with <sup>18</sup>F-FDG PET/CT JF - Journal of Nuclear Medicine JO - J Nucl Med DO - 10.2967/jnumed.120.258467 SP - jnumed.120.258467 AU - Chunxia Qin AU - Fuqiang Shao AU - Yongkang Gai AU - Qingyao Liu AU - Weiwei Ruan AU - Fang Liu AU - Fan Hu AU - Xiaoli Lan Y1 - 2021/04/01 UR - http://jnm.snmjournals.org/content/early/2021/04/15/jnumed.120.258467.abstract N2 - We sought to evaluate the performance of 68Ga-DOTA-FAPI-04 (68Ga-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 18F-FDG PET/CT. Methods: Twenty patients with histologically proven gastric carcinomas were recruited, and each patient underwent both 18F-FDG PET/CT and 68Ga-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 18F-FDG PET/CT and 68Ga-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 [&gt; 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. 68Ga-FAPI PET was superior to 18F-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 &lt; 0.05). 68Ga-FAPI PET was superior to 18F-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: 68Ga-FAPI PET/MR outperformed 18F-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 18F-FDG PET/CT. ER -