FAPI PET/CT in the Diagnosis of Abdominal and Pelvic Tumors

Abstract

Positron emission tomography/computed tomography (PET/CT) with 18F-fluorodeoxyglucose (18F-FDG) is currently a standard imaging examination used in clinical practice, and plays an essential role in preoperative systemic evaluation and tumor staging in patients with tumors. However, 18F-FDG PET/CT has certain limitations in imaging of some tumors, like gastric mucus adenocarcinoma, highly differentiated hepatocellular carcinoma, renal cell carcinoma, and peritoneal metastasis. Therefore, to search for new tumor diagnosis methods has always been an important topic in radiographic imaging research. Fibroblast activation protein (FAP) is highly expressed in many epithelial carcinomas, and various isotope-labelled fibroblast activation protein inhibitors (FAPI) show lower uptake in the brain and abdominal tissues than in tumor, thus achieving high image contrast and good tumor delineation. In addition to primary tumors, FAPI PET/CT is better than FDG PET/CT for detecting lymph nodes and metastases. Additionally, the highly selective tumor uptake of FAPI may open up new application areas for the non-invasive characterization, staging of tumors, as well as monitoring tumor treatment efficacy. This review focuses on the recent research progress of FAPI PET/CT in the application to abdominal and pelvic tumors, with the aim of providing new insights for diagnostic strategies for tumor patients, especially those with metastases.

[18F]FAPI-42 PET/CT in differentiated thyroid cancer: diagnostic performance, uptake values, and comparison with 2-[18F]FDG PET/CT

“…Second, histopathological analyses did not allow the detection of all lesions. This is an inherent problem of clinical research because not every lesion can be safely biopsied or surgically removed [ 32 ]. Third, the evaluation for possible false-negative lesions was incomplete because non-invasive imaging was also taken as the reference standard for detecting lesions.…”

[18F]FAPI-42 PET/CT in differentiated thyroid cancer: Diagnostic performance, uptake values and comparison with 2-[18F]FDG PET/CT

“…Second, histopathological analyses did not allow the detection of all lesions. This is an inherent problem of clinical research because not every lesion can be safely biopsied or surgically removed [29]. Third, the evaluation for possible false-negative lesions was incomplete because noninvasive imaging was also taken as the reference standard for detecting lesions.…”

FAPI PET/CT in Diagnostic and Treatment Management of Colorectal Cancer: Review of Current Research Status

“…Compared to FDG PET/CT, FAPI PET/CT has more advantages in detecting primary and metastatic lesions. In addition, targeting FAP imaging may break new ground with its applications, such as non-invasive tumor characterization, tumor staging and tumor treatment effect monitoring [ 7 ]. This article reviews the current research status of FAPI PET/CT in diagnosis and management of colorectal cancer ( Table 1 ).…”