Comparison of 18 F-FDG and 68 Ga-FAPI PET/CT in a Rare Renal Leiomyoma.

ABSTRACT: Renal leiomyoma is a rare benign mesenchymal tumor of the kidney, which mainly originates from the renal capsule or pelvis. We described 18 F-FDG and 68 Ga-FAPI PET/CT findings in a case of renal leiomyoma. The PET/CT findings showed that the left renal leiomyoma demonstrated intensively increased 68 Ga-FAPI uptake, whereas only inhomogeneously slightly increased 18 F-FDG uptake. This case illustrates that 68 Ga-FAPI PET/CT may be an effective tool for detecting renal leiomyoma.

68Ga-DOTA-Exendin-4 PET/CT Demonstrated a Higher Detection Efficacy for Double-Primary Insulinomas Than MRI: A Case Report.

ABSTRACT: We presented a 20-year-old woman with gradually increasing lethargy and multiple episodes of dizziness for 5 months. The laboratory examination revealed decreasing level of blood glucose and elevated levels of fasting plasma insulin and C-peptide. The MRI identified a focal nodule in the tail of the pancreas. 68Ga-DOTA-exendin-4 PET/CT revealed 2 intense focal tracer uptakes in the tail of the pancreas, one of which corresponded to the lesion revealed on MRI. The immunohistochemical results of resected samples confirmed the diagnosis of double-primary insulinomas. 68Ga-DOTA-exendin-4 PET/CT demonstrated excellent localization and characterization for double-primary insulinomas in the tail of the pancreas.

Prospective Comparison of 68Ga-FAPI versus 18F-FDG PET/CT for Tumor Staging in Biliary Tract Cancers.

Background Gallium 68-labeled fibroblast-activation protein inhibitor (68Ga-FAPI), an imaging agent for detecting tumors, represents a promising alternative to fluorine 18 fluorodeoxyglucose (18F-FDG). Purpose To compare the potential efficacy of 68Ga-FAPI PET/CT with that of 18F-FDG PET/CT for detecting primary tumor and nodal and distant metastases in biliary tract cancer (BTC) and to explore the impact (tumor staging) of 68Ga-FAPI compared with 18F-FDG on clinical management of BTC. Materials and Methods This single-center prospective clinical study was performed at the Affiliated Hospital of Southwest Medical University between June 2020 and June 2021. Participants with BTC underwent both 68Ga-FAPI and 18F-FDG PET/CT. Histopathologic examination, morphologic imaging, and/or follow-up imaging served as the reference standard. The maximum standardized uptake value (SUVmax) of the primary tumor and nodal and distant metastases between 18F-FDG and 68Ga-FAPI PET/CT were compared using the paired-sample t test. Results Eighteen participants with primary or recurrent BTC were evaluated (mean age, 61 years ± 10 [SD]). The sensitivity of 68Ga-FAPI PET/CT was higher than that of 18F-FDG PET/CT for detecting primary tumors (16 of 16 [100%] vs 13 of 16 [81%]), nodal metastases (41 of 42 [98%] vs 35 of 42 [83%]), and distant metastases (99 of 99 [100%] vs 78 of 99 [79%]). 68Ga-FAPI PET/CT resulted in new oncologic findings in 10 of 18 participants and upgraded tumor staging or restaging in five of 18 participants compared with 18F-FDG PET/CT. 68Ga-FAPI PET/CT demonstrated higher sensitivity than 18F-FDG PET/CT in inflammatory processes secondary to tumor-related obstruction (seven of eight [88%] vs one of eight [13%]). 68Ga-FAPI showed lower average SUVmax in inflammatory processes than in oncologic lesions (4.9 ± 2.6 vs 10.0 ± 4.6, respectively; P = .003). Conclusion Gallium 68-labeled fibroblast-activation protein inhibitor PET/CT for tumor staging showed potential for more accurate staging of biliary tract cancer, thereby improving treatment decision making. Clinical trial registration no. ChiCTR2100044131 © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Choyke in this issue.

The potential utility of [68 Ga]Ga-DOTA-FAPI-04 as a novel broad-spectrum oncological and non-oncological imaging agent-comparison with [18F]FDG.

PURPOSE: This study aimed to compare the detection performance of [68 Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT in the patients with various oncological and non-oncological lesions. METHODS: A total of 123 patients underwent contemporaneous [68 Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT were included in this prospective study. The maximum standard uptake value (SUVmax) was measured to compare oncological and non-oncological lesion uptake. The sensitivity, specificity, predictive values, and accuracy of [18F]FDG and [68 Ga]Ga-DOTA-FAPI-04 PET/CT for detecting primary, metastatic, and non-oncological lesions were calculated and compared to evaluate the detection efficacy. RESULTS: The study subjects consisted of 123 patients (69 men and 54 women; mean age 56.11 ± 11.94 years). Among the 102 patients with either newly diagnosed (82 patients) or previously treated solid tumor (20 patients), a total of 88 solid primary malignant tumors in 84/102 patients were detected. Two patients had two primary tumors each and 1 patient had three primary tumors. Among them, 58/102 and 43/102 patients had nodal (376 lesions) and distant metastases (406 lesions), respectively. Eight patients had hematological neoplasm. No malignant oncological diseases were detected in the remaining 13 patients. A total of 145 non-oncological lesions and benign tumors in 52/123 patients were detected incidentally. [68 Ga]Ga-DOTA-FAPI-04 PET/CT demonstrated a significantly higher uptake and detection rate for the primary (SUVmax 10.98 ± 5.83 vs. 8.36 ± 6.43, p < 0.001; sensitivity 97.67 vs. 84.89%; and accuracy 96.59 vs. 82.95%, X2 = 0.538, p = 0.021), nodal (SUVmax 10.50 ± 5.98 vs. 8.20 ± 6.29, p = 0.011; sensitivity 97.59 vs. 84.72%; and accuracy 97.34 vs. 84.31%, X2 = 2.067, p < 0.001), and distant metastatic lesions (SUVmax 9.64 ± 6.45 vs. 6.74 ± 4.83; p < 0.001; sensitivity 98.01 vs. 65.59%; and accuracy 97.04 vs. 65.51%, X2 = 4.897, p < 0.001) of solid tumor than did [18F]FDG PET/CT. [68 Ga]Ga-DOTA-FAPI-04 PET/CT demonstrated a lower activity (SUVmax: 6.84 ± 4.67 vs. 13.09 ± 7.29, p < 0.001) and detection rate (sensitivity 50.65 vs. 96.75%, and accuracy 51.28 vs. 95.51%, X2 = 5.166, p < 0.001) for multiple myeloma and lymphoma compared to [18F]FDG PET/CT. [68 Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT PET/CT demonstrated a comparative activity (SUVmax 6.40 ± 3.95 vs. 5.74 ± 15.78, p = 0.729) and detection efficacy (sensitivity 86.52 vs. 72.34%, and accuracy 84.83 vs. 72.41%, X2 = 9.460, p = 0.007) for non-oncological lesion and benign tumor detection. CONCLUSIONS: Except for myeloma and lymphoma, [68 Ga]Ga-DOTA-FAPI-04 PET/CT showed a superior detection efficacy for detecting various primary and metastatic lesions than [18F]FDG PET/CT. A comparative detection utility for non-oncological lesion was obtained with both tracers. [68 Ga]Ga-DOTA-FAPI-04 could be used as a broad-spectrum tumor and inflammatory imaging agent in the clinical especially for various solid tumors and non-oncological lesions.

68Ga-FAPI PET/CT Detected Non-FDG-Avid Gastric Stromal Tumor.

ABSTRACT: We presented a case of 67-year-old man with epigastric discomfort and anorexia for more than 2 months. No abnormal 18F-FDG uptake was found throughout the gastrointestinal tract on 18F-FDG PET/CT. The patient was enrolled in the 68Ga-FAPI PET/CT clinical trial, and a 68Ga-FAPI PET/CT was performed to help detect primary lesion. This examination demonstrated a nodular thickening of the gastric wall with an increased 68Ga-FAPI uptake in the greater curvature of the stomach. Finally, the pathological result confirmed the diagnosis of gastric stromal tumor. This case highlights that 68Ga-FAPI PET/CT might outperform 18F-FDG PET/CT in helping identify gastrointestinal stromal tumors.

T2 Values for Diagnosing Acute-on-Chronic Liver Failure in Hepatitis B Patients.

OBJECTIVES: The aim of this study was to investigate the value of hepatic T2 imaging for the evaluation of chronic hepatitis-B-related acute-on-chronic liver failure (HBV-ACLF). METHODS: Three groups of patients underwent liver MRI utilising m-GRASE sequence (multi-echo gradient and spin echo): HBV-ACLF patients (n = 28), chronic hepatitis B patients (n = 11), and healthy control patients (n = 14). A T2 image was produced using post-processing software, and the mean T2 (relaxation time) value was calculated. Blood biochemical indices for the HBV-ACLF and Chronic Hepatitis B were obtained within 2 days pre- or post-MR scanning. The patients' T2 values, and the correlation between their biochemical indices and T2 values were analysed. A receiver operating characteristic curve was employed to evaluate the efficiency of utilising T2 values in the diagnosis of HBV-ACLF. RESULTS: There were significant variations in the T2 values (χ2 = 19.074, P < 0.001) among the 3 groups. The AUC of T2 values for diagnosing HBV-ACLF was 0.86 (P < 0.001), with a cut-off value of 57.73 ms. A moderately positive correlation was observed between the T2 value and the international normalised ratio, prothrombin time, and hyaluronic acid values (rs = 0.65, P < 0.001; rs = 0.67, P < 0.001; rs = 0.39, P = 0.025). A moderately negative correlation was observed between the T2 value and the prothrombin activity, albumin, and prealbumin values (rs = -0.67, P < 0.001; rs = -0.48, P = 0.004; rs = -0.37, P = 0.030). CONCLUSION: T2 values could accurately reflect liver function state, as they correlated well with certain biochemical indices, illustrating good diagnostic efficiency for diagnosing HBV-ACLF.

Pulmonary Actinomycosis Imitating Lung Cancer on (18)F-FDG PET/CT: A Case Report and Literature Review.

Here we report a case of 41-year-old man with a soft tissue density mass at right upper lung and palpable abscesses at right upper backside and right wrist. (18)F-fluorodeoxyglucose positron emission tomography/computed tomography demonstrated a 7.8 × 5.0 cm mass with soft-tissue density in the upper lobe of the right lung with high metabolic activity. The infiltrative mass extended to adjacent chest wall soft tissue. Final diagnosis of pulmonary actinomycosis with multiple abscesses was made. The patient responded well to antibiotics treatment.