Value of [18F]AlF-NOTA-FAPI-04 PET/CT for differential diagnosis of malignant and various inflammatory lung lesions: comparison with [18F]FDG PET/CT.

OBJECTIVE: Uptake of the imaging tracers [18F]AlF-NOTA-FAPI-04 and [18F]FDG varies in some inflammatory lesions, which may result in false-positive findings for malignancy on PET/CT. Our aim was to compare the [18F]AlF-NOTA-FAPI-04 and [18F]FDG PET/CT imaging features of malignant and various inflammatory lung lesions and to analyze their value for differential diagnosis. METHODS: We retrospectively analyzed [18F]AlF-NOTA-FAPI-04 PET/CT scans from 67 cancer patients taken between December 2020 and January 2022, as well as the scans of 32 patients who also underwent [18F]FDG PET/CT imaging. The maximum and mean standardized uptake values (SUVmax and SUVmean, respectively) and lesion-to-background ratio (LBR) were calculated. The predictive capabilities of semiquantitative PET/CT parameters were analyzed by receiver operating characteristic curve analysis. RESULTS: A total of 70 inflammatory and 37 malignant lung lesions were evaluated by [18F]AlF­NOTA­FAPI­04 PET/CT, and 33 inflammatory and 26 malignant lung lesions also were evaluated by [18F]FDG PET/CT. Inflammatory lesions exhibited lower [18F]AlF-NOTA-FAPI-04 and [18F]FDG uptake compared to malignant lesions, with statistically significant differences in SUVmax, SUVmean, and LBR (all p < 0.001). [18F]AlF-NOTA-FAPI-04 uptake also varied among different types of inflammatory lesions (SUVmax, p = 0.005; SUVmean, p = 0.008; LBR, p < 0.001), with the highest uptake observed in bronchiectasis with infection, followed by postobstructive pneumonia, and the lowest in pneumonia. [18F]FDG uptake was higher in postobstructive pneumonia than in pneumonia (SUVmax, p = 0.009; SUVmean, p = 0.016; LBR, p = 0.004). CONCLUSION: [18F]AlF-NOTA-FAPI-04/[18F]FDG PET/CT showed significantly lower uptake in inflammatory lesions than malignancies as well as variation in different types of inflammatory lesions, and thus, may be valuable for distinguishing malignant and various inflammatory findings. CLINICAL RELEVANCE STATEMENT: Our study confirmed that the uptake of [18F]AlF-NOTA-FAPI-04/[18F]FDG PET/CT in inflammatory and malignant lung lesions is different, which is beneficial to distinguish inflammatory and malignant lung lesions in clinic. KEY POINTS: • Malignant and different inflammatory lung lesions showed varying degrees of uptake of [18F]AlF-NOTA-FAPI-04 and [18F]FDG. • Inflammatory lung lesions showed significantly less uptake than malignancies, and uptake varied among different types of inflammatory lesions. • Both types of PET/CT could differentiate malignant and various inflammatory lung findings.

18F-FAPI-04 PET/CT parameters predict PD-L1 expression in esophageal squamous cell carcinoma.

Purpose: This prospective study examined whether metabolism parameters obtained using the tracer 18F-AlFNOTA-fibroblast activation protein inhibitor (FAPI)-04 (denoted as 18F-FAPI-04) in positron emission tomography/computed tomography (PET/CT) can predict programmed death ligand-1 (PD-L1) expression in patients with locally advanced esophageal squamous cell carcinoma (LA-ESCC). Patients and methods: The 24 enrolled LA-ESCC patients underwent an 18F-FAPI-04 PET/CT scan. The maximum, mean, peak and standard deviation standard uptake values (SUVmax, SUVmean, SUVpeak and SUVsd), metabolic tumor volume (MTV), and total lesion FAP (TLF) expression of the primary tumor were collected. Additionally, we evaluated PD-L1 expression on cancer cells by immunohistochemistry and immunofluorescence methods. Patients were divided into negative and positive expressions according to the expression of PD-L1 (CPS < 10 and CPS ≥ 10), and the variables were compared between the two groups. Results: The SUVmax, SUVmean, SUVpeak and SUVsd were significantly higher in patients with positive expression than in negative expression (all p < 0.05). Receiver operating characteristic curve analysis identified SUVmean (area under the curve [AUC] = 0.882, p = 0.004), SUVsd (AUC = 0.874, p = 0.005), SUVpeak (AUC = 0.840, p = 0.010) and SUVmax (AUC = 0.765, p = 0.045) as significant predictors of the PD-L1 positive expression, with cutoff values of 9.67, 1.90, 9.67 and 13.71, respectively. On univariate logistic regression analysis, SUVmean (p = 0.045), SUVsd (p = 0.024), and SUVpeak (p = 0.031) were significantly correlated with the PD-L1 positive expression. On multivariable logistic regression analysis, SUVsd (p = 0.035) was an optimum predictor factor for PD-L1 positive expression. Conclusion: 18F-FAPI-04 PET/CT parameters, including SUVmean, SUVpeak, and SUVsd, correlated with PD-L1 expression in patients with LA-ESCC, and thus SUVsd was an optimum predictor for PD-L1 positive expression, which could help to explore the existence of immune checkpoints and select ESCC candidates for immunotherapy.

FAPI Compared with FDG PET/CT for Diagnosis of Primary and Metastatic Lung Cancer.

Background The radiotracer fluorine 18 (18F)-labeled fibroblast activation protein inhibitor (FAPI) has shown promise for visualizing several types of cancer, but the accuracy of 18F-FAPI compared with 18F-fluorodeoxyglucose (FDG) for the detection of lung cancer remains uncertain. Purpose To evaluate the effectiveness of 18F-FAPI-based PET/CT imaging for the diagnosis of primary and metastatic lung cancer lesions as compared with 18F-FDG PET/CT. Materials and Methods In this secondary analysis of a prospective trial, consecutively recruited patients from a single center with pathologically confirmed lung cancer were prospectively enrolled from December 2020 to April 2022 and underwent paired 18F-FAPI and 18F-FDG PET/CT examinations at intervals of more than 20 hours and within 7 days of each other. Histopathologic and clinical follow-up results were used as reference standards for final diagnoses. 18F-FAPI and 18F-FDG uptake were compared using the McNemar test or paired Student t test. Diagnostic accuracy was compared between the two techniques by using the McNemar χ2 test. Results Sixty-eight participants (median age, 63 years [IQR, 58-68 years; range, 42-79 years]; 46 male [68%]) were evaluated. Compared with the mean tumor-to-background ratio (TBR) for FDG uptake, TBR for FAPI uptake was lower in primary lung tumors (25.3 ± 14.0 [SD] vs 32.1 ± 21.1; P < .001) but higher in metastatic lymph nodes (7.5 ± 6.6 vs 5.9 ± 8.6; P < .001) and bone metastases (8.6 ± 5.4 vs 4.3 ± 2.3; P < .001). For diagnostic accuracy in a total of 548 lesions in 68 participants, compared with 18F-FDG PET/CT, 18F-FAPI PET/CT demonstrated a higher sensitivity (99% [392 of 397 lesions] vs 87% [346 of 397]; P < .001), specificity (93% [141 of 151 lesions] vs 79% [120 of 151]; P = .004), accuracy (97% [533 of 548 lesions] vs 85% [466 of 548]; P < .001), and negative predictive value (97% [141 of 146 lesions] vs 70% [120 of 171 lesions]; P < .001), but there was no evidence of a difference for positive predictive value (98% [392 of 402 lesions] vs 92% [346 of 377 lesions]; P = .57). Conclusion 18F-FAPI PET/CT may be superior to 18F-FDG PET/CT for detecting lung cancer. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Zukotynski and Gerbaudo in this issue.

Clinical value of 18F-FDG PET/CT to predict MYCN gene, chromosome 1p36 and 11q status in pediatric neuroblastoma and ganglioneuroblastoma.

Objective: To explore the value of 18F-2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET)/computed tomography(CT) in MYCN gene and chromosome 1p36 and 11 statuses in newly diagnosed pediatric NB(neuroblastoma) and GNB(ganglioneuroblastoma). Methods: We retrospectively analyzed newly diagnosed patients with 48 NB and 12 with GNB in our hospital. The data obtained from the clinical medical records included age, sex, pathologic type, and laboratory parameters such as lactate dehydrogenase (LDH), neuron-specific enolase (NSE) and the status of MYCN gene and chromosome 1p36 and 11q. The bone conditions were also obtained in the examination of bone marrow biopsy. Primary tumors were manually segmented to measure the maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), tumor volume(MTV) and total lesion glycolysis(TLG) and the maximal length of the lesion in the axial image(LEGmax). Results: The differences in bone marrow involvement and lymph node metastases in patients with chromosome 11q deletions were statistically significant (all p < 0.05). Chromosome 11q deletion was an independent factor affecting bone marrow involvement (OR=17.796, p=0.011). The levels of NSE, LDH, LEGmax and SUVmax, SUVmean, MTV, TLG all predicted MYCN gene amplification (all p < 0.05). The levels of LDH, LEGmax and MTV, TLG all predicted deletions in chromosomes 1p36 (all p < 0.05), while NSE, SUVmax and SUVmean did not (all p > 005). Conclusion: The LDH levels, LEGmax, MTV and TLG can effectively predict the status of the MYCN oncogene and chromosome 1p36 in pediatric neuroblastoma and ganglioneuroblastoma. Those patients with chromosome 11q deletions are more likely to develop bone marrow involvement and lymph node metastases, showing a worse progression-free survival.

Response Prediction Using 18F-FAPI-04 PET/CT in Patients with Esophageal Squamous Cell Carcinoma Treated with Concurrent Chemoradiotherapy.

This prospective study examined whether imaging results obtained using the tracer 18F-AlF-NOTA-fibroblast activation protein inhibitor (FAPI)-04 (denoted as 18F-FAPI-04) in PET/CT can predict the short-term outcome in patients with locally advanced esophageal squamous cell carcinoma (LA-ESCC) treated with concurrent chemoradiotherapy (CCRT). Methods: The 18 enrolled LA-ESCC patients underwent 18F-FAPI-04 PET/CT scanning before CCRT. The SUVmax, SUVmean, SUVpeak, metabolic tumor volume, and total lesion fibroblast activation protein expression of the primary tumor were recorded. Additionally, the SUVmax of the primary tumor and SUVmean of normal tissue (muscle and blood) were measured, and their ratios were denoted as target-to-background ratios (TBRmuscle and TBRblood). Patients were classified as responders or nonresponders according to RECIST (version 1.1), and variables were compared between the 2 groups. Results: The TBRblood, TBRmuscle, and SUVmean were significantly higher in nonresponders than in responders (all P < 0.05). Receiver-operating-characteristic curve analysis identified TBRblood (area under the curve [AUC], 0.883; P = 0.008), TBRmuscle (AUC, 0.896; P = 0.006) and SUVmean (AUC, 0.870; P = 0.010) as significant predictors of the response to CCRT, with cutoffs of 10.68, 10.95, and 6.88, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were also determined for TBRblood (100.0%, 72.7%, 66.7%, 88.9%, and 77.8%, respectively), TBRmuscle (100.0%, 72.7%, 66.7%, 88.9%, and 77.8%, respectively), and SUVmean (85.7%, 81.8%, 75.0%, 90.0%, and 83.3%, respectively). On univariate logistic regression analysis, TBRblood (P = 0.026), TBRmuscle (P = 0.036), SUVmean (P = 0.045), and tumor site (P = 0.032) were significantly correlated with the short-term outcome. On multivariable logistic regression analysis, TBRblood (P = 0.046) was an independent prognostic factor for short-term outcome. Conclusion: A higher baseline TBRblood on 18F-FAPI-04 PET/CT scans was associated with a poor response to CCRT in LA-ESCC patients, and thus, TBRblood may be useful for screening LA-ESCC patients before CCRT treatment.

Comparing the diagnostic value of 18F-FDG PET/CT scan and bone marrow biopsy in newly diagnosed pediatric neuroblastoma and ganglioneuroblastoma.

Objective: This study aims to compare the diagnostic value of 18F-fluorodeoxyglucose (18-FDG) positron emission tomography (PET)/computed tomography (CT) (18F-FDG PET/CT) scan and bone marrow biopsy (BMB) for evaluating bone marrow infiltration (BMI) in newly diagnosed pediatric neuroblastoma (NB) and ganglioneuroblastoma (GNB). Methods: We retrospectively reviewed 51 patients with newly diagnosed NB and GNB between June 1, 2019 and May 31, 2022. Each patient had undergone 18F-FDG PET/CT and BMB within 1 week and received no treatment. Clinical data were collected and statistically analyzed, including age, sex, pathologic type, and laboratory parameters. 18F-FDG PET/CT and BMB revealed the result of bone lesions. Results: A concordance analysis showed that, in this study population, 18F-FDG PET/CT and BMB were in moderate agreement (Cohen's Kappa = 0.444; p = 0.001), with an absolute agreement consistency of 72.5% (37 of 51). The analysis of the receiver operating characteristic (ROC) curve determined that the areas under the ROC curve (AUCs) of SUVBM and SUV/HE-SUVmax were 0.971 (95% CI: 0.911-1.000; p < 0.001) and 0.917 (95% CI: 0.715-1.000; p < 0.001) to predict bone-bone marrow involvement (BMI), respectively. Conclusion: 18F-FDG PET/CT detects BMI with good diagnostic accuracy and can reduce unnecessary invasive inspections in newly diagnosed pediatric NB and GNB, especially patterns C and D. The analysis of the semi-quantitative uptake of 18F-FDG, including SUVBM and SUVBM/HE-SUVmax, enables an effective differentiation between patterns A and B.

Case report: Imaging findings of true thymic hyperplasia at 18F-FDG PET/CT in an infant.

True thymic hyperplasia (TTH) in children is rare and difficult to distinguish from other thymic tumors such as thymoma and thymic carcinoma. A 3-year-old girl underwent an 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) scan (18F-FDG PET/CT) and a chest CT scan to evaluate an anterior mediastinal mass. 18F-FDG PET/CT revealed a mediastinal mass showing heterogeneously increased FDG uptake with a maximum standardized uptake value (SUVmax) of 7.1. Eventually, postoperative pathological diagnosis demonstrated TTH. So far, there are no reports of 18F-FDG PET/CT imaging of this disease.

The value of 18F-FDG PET/CT in patient with neurofibromatosis type 1: A case report and literature review.

RATIONALE: Neurofibromatosis type one (NF1) is characterized by cutaneous and nervous lesions, and the tendency to form plexiform neurofibromas (PNFs). PNFs may undergo malignant transformation into a malignant peripheral nerve sheath tumors (MPNSTs). MPNSTs often carry an significant morbidity and mortality. PATIENT CONCERNS: A 17-year-old man with gradually increased multiple subcutaneous soft lesions. He also presented with numerous lentigines and multiple café-au-lait macules on his body. DIAGNOSES: These were collagen neurofibroma, which were definitively diagnosed by pathology. NF1 was eventually diagnosed. INTERVENTIONS: These lesions were abnormal uptake of radiotracer, when he underwent positron emission tomography (PET) with fluorine-18-fluorodeoxyglucose (FDG) scanning. Standard uptake value (SUV) and other parameters can help to distinguish benign and malignant lesions in patient with NF1. He was underwent serials F-FDG PET/CT examinations to followed up, in order to monitor these lesions malignant transformation. OUTCOMES: So far, these subcutaneous soft lesions were not malignant transformation. LESSONS: F-FDG PET/CT is being increasingly used as an imaging modality to discover the systemic lesions and to discriminate between benign and malignant plexiform neurofibromas.

Serial renography for evaluation of the impact of capecitabine therapy on renal function: A case report.

RATIONALE: Cancer can cause renal dysfunction and disease either directly or indirectly, through adverse effects of therapies, including chemotherapy and radiation. The assessment of renal function in cancer patients is necessary in clinical practice. PATIENT CONCERNS: A 31-year-old woman had proctoscopy performed in our hospital for a principal complaint of bloody stool for 6 months and worsening 1 month prior to presentation. DIAGNOSES: Following proctoscopy, she was diagnosed with a signet-ring cell carcinoma of the rectum. Hartman surgery was performed. Metastasis of the carcinoma to regional lymph nodes around the rectum was verified by postoperative pathology. INTERVENTIONS: The patient was treated with capecitabine, and renal function was monitored over the course of treatment by renography before, during, and after chemotherapy. OUTCOMES: We found that capecitabine caused a reversible decline of renal function. However, the value of blood urea nitrogen (BUN) and serum creatinine (Cr) remained within the normal range during chemotherapy. The patient's chemotherapy regimen was altered after her oncologists concluded that she was developing nephrotoxicity from capecitabine. She was treated with tegafur, gimeracil and oteracil potassium capsules. This patient was followed over the next 6 months, and no abnormal renal function re-occurred. LESSONS: Our experience with capecitabine shows that dosing adjustments can be warranted for chemotherapy in cancer patients, requiring monitoring of renal function. Renography may provide an early warning to protect the renal function of tumor patients when they receive chemotherapy.