Fibroblast activation protein inhibitor (FAPI)–PET is a novel imaging modality that targets FAP. The purpose of this study was to conduct a meta-analysis and synthesize the available data about the sensitivity and specificity of FAPI–PET in assessing cardiac fibroblast activation and predicting left ventricular function in patients with cardiovascular disease (CVD). We searched the PubMed, Web of Science, and Embase databases from the time the databases were created until December 19, 2025. The diagnostic performance of FAPI–PET was meta-analyzed with Python (version 3.12). Data management and numerical computations were carried out with pandas and NumPy; meta-analytic calculations and statistical tests were implemented using SciPy; and all figures (forest plots, subgroup analyses, Deeks’funnel plot, SROC curve, and leave-one-out sensitivity analyses) were produced using Matplotlib. There were 13 studies involving 256 patients, including 166 males with CVD. The age of the patients ranged from 23.0 to 76.1 years. The CVD patient-level pooled sensitivity, specificity and area under the curve (AUC) of FAPI–PET in evaluating cardiac fibroblast activation were 0.91, 0.75 and 0.9358, respectively. The pooled sensitivity and specificity of FAPI–PET in evaluating cardiac fibroblast activation in CAD patients were 0.96 and 0.82, respectively; those in non-CAD patients were 0.89 and 0.58, respectively. Multiple semiquantitative FAPI–PET uptake metrics were significantly correlated with LVEF. Among them, FAP volume (Pearson) demonstrated the best random effects pooled correlation estimate (-0.73), with substantial heterogeneity (I2 = 0

A 66-year-old man with a history of prostate adenocarcinoma treated with radiotherapy and endocrine therapy underwent 18 F-FDG and 68 Ga-PSMA PET/CT. Both scans showed marked radiotracer uptake, raising suspicion for disease recurrence. However, subsequent transurethral resection of the prostate was performed for treatment with concurrent pathologic biopsy, confirmed only chronic inflammation accompanied by focal necrosis and calcification, emphasizing the false-positive risk of these modalities in nonmalignant conditions.

Diffuse gastric metastasis of esophageal squamous cell carcinoma (SCC) manifested as linitis plastica is extremely rare. A 49-year-old man complained of postprandial vomiting and epigastric colicky pain, and biopsy indicated mucosal inflammation. 18F-FDG PET/CT revealed diffuse wall thickening of mid-to-lower esophagus and diffuse gastric wall thickening accompanied by mediastinal lymph node, perigastric, and peripancreatic lesions with intense FDG accumulation. Malignancy of mid-to-lower esophagus and linitis plastica accompanied by lymph node, perigastric, and peripancreatic metastases was suspected. Biopsies of multiple sites of esophagus and stomach confirmed SCC. 18F-FDG PET/CT is instrumental for evaluating rare metastasis of esophageal SCC and guiding biopsy.

A 66-year-old man with a history of prostate adenocarcinoma treated with radiotherapy and endocrine therapy underwent 18F-FDG and 68Ga-PSMA PET/CT. Both scans showed marked radiotracer uptake, raising suspicion for disease recurrence. However, subsequent transurethral resection of the prostate was performed for treatment with concurrent pathologic biopsy, confirmed only chronic inflammation accompanied by focal necrosis and calcification, emphasizing the false-positive risk of these modalities in nonmalignant conditions.

Parkinson's disease (PD) and atypical parkinsonian syndrome (APS) are both highly disabling neurodegenerative disorders. While they show significant overlap in clinical features, the therapies and prognoses are distinct. The differential diagnosis between PD and APS is challenging and critical for patient management. This study aimed to evaluate the diagnostic accuracy of dopamine transporter (DAT) radionuclide imaging in the differential diagnosis of PD and APS.

BACKGROUND:CD155, an emerging immune checkpoint, contributes to tumor immune evasion and progression, but its roles in metabolic reprogramming and tumor-associated macrophages (TAMs) polarization in lung adenocarcinoma (LUAD) remain uncharacterized. This study combines molecular biology, metabolic imaging, and clinical data to elucidate CD155's dual role in driving LUAD progression through glycolytic rewiring and immunosuppressive TAMs polarization. METHODS:Through immunohistochemistry (IHC) and 18F-FDG PET/CT imaging, we analyzed CD155 expression and its association with glycolysis in 80 LUAD patients. Functional assays and molecular studies revealed CD155-mediated regulation of tumor glycolysis and macrophage polarization via YAP/TEAD1-GLUT1 signaling. Xenograft models validated the in vivo findings, with 18F-FDG micro-PET imaging performing noninvasive metabolic profiling. RESULTS:CD155 was significantly overexpressed in LUAD tissues and positively correlated with advanced TNM stage, lymph node metastasis and elevated 18F-FDG uptake. Mechanistically, CD155 interacts with YAP, reducing YAP phosphorylation at Ser127 to promote its nuclear translocation and TEAD1 activation, thereby upregulating GLUT1 transcription. This signaling axis enhanced glycolysis, thereby fueling LUAD proliferation and migration. Notably, CD155-induced lactate production and extracellular acidification drove macrophage polarization toward the immunosuppressive M2 phenotype. In vivo, CD155 silencing suppressed tumor glucose metabolism and growth, whereas overexpression accelerated tumor progression, both dynamically monitored through 18F-FDG PET visualization. CONCLUSIONS:We identify a novel CD155/YAP/TEAD1/GLUT1 axis that reprograms LUAD metabolism and facilitates immunosuppressive tumor microenvironment formation. CD155 functions as a metabolic-immune hub in LUAD, and its targeting could simultaneously suppress tumor growth and restore antitumor immunity, offering dual therapeutic advantages. Clinically, 18F-FDG PET/CT represents a noninvasive biomarker for CD155-driven metabolic aggression, potentially guiding precision immunotherapy.

RATIONALE AND OBJECTIVES:Gastrointestinal cancers pose a major public health challenge due to very aggressive malignancy, the quick and widespread metastases, relapse frequently in lymph node and omentum, and poor prognosis. [68Ga]Ga-FAPI-04 PET is widely used to diagnose gastrointestinal tumors. This study aimed to conduct a head-to-head comparison of the [68Ga]Ga-FAPI-04 and [18F]-FDG imaging methods for diagnosing primary gastrointestinal tumors and metastases. METHODS:The PubMed, Embase, Web of Science, and Cochrane Library databases were systematically searched up to 16 April 2024. The included studies involved head-to-head comparisons to evaluate [68Ga]Ga-FAPI-04 and [18F]FDG PET in gastrointestinal cancers. QUADAS-2 was used to assess the quality of the included articles. RESULTS:The study included 16 studies. Nine studies were performed on gastric cancer, four on colorectal cancer, and the remaining three studies of various gastrointestinal tumors, including gastric, duodenal, appendiceal and colorectal cancers. The total number of patients was 597, including 384 males. In gastric cancer, [68Ga]Ga-FAPI-04 PET demonstrated superior sensitivity for the primary tumors (0.98 vs. 0.74) and lymph node metastases (0.90 vs. 0.45) than [18F]FDG. In gastric cancer, [68Ga]Ga-FAPI-04 PET demonstrated superior specificity for the primary tumors (0.93 vs. 0.48) and lymph node metastases (0.93 vs. 0.83) than [18F]FDG. [68Ga]Ga-FAPI-04 PET had a sensitivity of 0.99 (95% CI 0.19-1.00) for gastric signet-ring-cell carcinoma (GSRCC), and [18F]FDG PET had a sensitivity of 0.46 for GSRCC. There was a significant difference in mean difference (MD) of SUVmax (MD 5.75 [95% CI 1.42-10.08]) for GSRCC between [68Ga]Ga-FAPI-04 and [18F]FDG. In colorectal cancer, [68Ga]Ga-FAPI-04 PET was more sensitive for primary tumors (1.00 vs. 0.97). In gastrointestinal cancers, [68Ga]Ga-FAPI-04 PET showed superior pooled sensitivity compared with [18F]FDG for primary tumors (0.99 [95% CI 0.95-1.00] vs. 0.82 [95% CI 0.67-0.91]), metastatic lymph nodes (0.95 [95% CI 0.81-0.99] vs. 0.56 [95% CI 0.43-0.69]), distant metastases (0.93 vs. 0.63), and peritoneal metastases (0.99 vs. 0.51). In gastrointestinal cancers, [68Ga]Ga-FAPI-04 PET showed superior pooled specificity compared with [18F]FDG for primary tumors (0.90 vs. 0.74), and metastatic lymph nodes (0.89 vs. 0.84). Furthermore, [68Ga]Ga-FAPI-04 had a superior SUVmax and TBR compared with [18F]FDG for primary gastrointestinal tumors and metastases. CONCLUSION:[68Ga]Ga-FAPI-04 PET demonstrated superior sensitivity and specificity in primary gastrointestinal cancers and metastases in comparison with [18F]FDG. The results demonstrated that [68Ga]Ga-FAPI-04 PET was a more suitable modality than [18F]FDG PET for the diagnosis of SRCC.

ABSTRACT:Uterine carcinosarcoma is a rare type of endometrial carcinoma with poor prognosis. A bone metastasis to the skull base is extremely scarce in uterine carcinosarcoma. A 54-year-old woman with uterine carcinosarcoma complained of right ear otorrhea and otalgia. 18 F-FDG PET/CT presented an increased FDG uptake at the right middle ear involving the mastoid process and external acoustic meatus. Primary carcinoma of the middle ear was considered according to clinical symptoms and PET manifestation. However, the skull base metastasis from uterine carcinosarcoma was pathologically confirmed. The rare metastasis from uterine carcinosarcoma should be differentiated from primary carcinoma of the middle ear.

Positron emission tomography/magnetic resonance imaging (PET/MRI) combines the advantages of both imaging modalities. PET/MRI demonstrates superior performance in the evaluation of the therapeutic impact, staging, diagnosis, and treatment planning of malignancies because of its lower radiation dose, higher contrast for soft tissues, and multiparametric functional imaging. 18 F-fluorodeoxyglucose PET/MRI has demonstrated considerable potential in the assessment of pelvic malignancies. This review briefly describes the evolution of PET/MRI imaging technology and compares the application of PET/MRI in five common pelvic tumors, including endometrial cancer, cervical cancer, ovarian cancer, prostate cancer, and bladder cancer, with that of PET/computed tomography. Additionally, radiotracers other than 18 F-fluorodeoxyglucose have been introduced for use in pelvic tumors. The development and application of these new tracers further enhance the clinical application of PET/MRI in precision medicine for pelvic malignant cancers. Overall, this review revealed the unique contribution of PET/MRI as a promising diagnostic instrument in the management of pelvic tumors, demonstrating its important position in future clinical practice.

FAP-2286, which is a novel cyclic peptide that targets fibroblast activation protein (FAP), demonstrates enhanced plasma stability and improved receptor selectivity compared with small-molecule FAP inhibitors (FAPIs). Although [18 F]FAP-2286 exhibits benefits due to the favorable characteristics of fluorine-18-labeled tracers, its diagnostic performance in lung cancer remains to be fully elucidated. This study aimed to compare the diagnostic efficacy of [18 F]FAP-2286 PET/CT with that of [18 F]FDG PET/CT in lung cancer patients. Thirty patients with suspected lung cancer (18 men and 12 women; median age: 64 years [IQR: 35–81]) underwent both [18 F]FAP-2286 and [18 F]FDG PET/CT for initial staging (n = 27) or the detection of recurrence (n = 3). Diagnostic performance was assessed using histopathology and clinical follow-up as reference standards. The quantitative analysis included the maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR). Compared with [18 F]FDG, [18 F]FAP-2286 PET/CT significantly increased the TBR in primary tumors (11.60 ± 6.02 vs. 5.80 ± 3.08; P < 0.001), whereas the SUVmax was not significantly different (15.20 ± 8.25 vs. 13.81 ± 7.73; P = 0.524). Although [18 F]FAP-2286 PET/CT demonstrated a lower detection rate for metastatic lymph nodes (67.46

A 66-year-old man presented with both small-cell lung cancer and prostate adenocarcinoma. Staging PET with 18 F-FDG PET/CT revealed increased uptake in the right pulmonary hilum, mediastinum, fifth cervical vertebra, and fifth lumbar vertebra. In contrast, subsequent 68 Ga-PSMA PET/CT revealed intense uptake only in the prostate and vertebrae, which demonstrated that the bone lesions had metastasized from prostate cancer.

Accurately predicting the malignant risk of ground-glass nodules (GGOs) is crucial for precise treatment planning. This study aims to utilize convolutional neural networks based on dual-time-point 18F-FDG PET/CT to predict the malignant risk of GGOs. Retrospectively analyzing 311 patients with 397 GGOs, this study identified 118 low-risk GGOs and 279 high-risk GGOs through pathology and follow-up according to the new WHO classification. The dataset was randomly divided into a training set comprising 239 patients (318 lesions) and a testing set comprising 72 patients (79 lesions), we employed a self-configuring 3D nnU-net convolutional neural network with majority voting method to segment GGOs and predict malignant risk of GGOs. Three independent segmentation prediction models were developed based on thin-section lung CT, early-phase 18F-FDG PET/CT, and dual-time-point 18F-FDG PET/CT, respectively. Simultaneously, the results of the dual-time-point 18F-FDG PET/CT model on the testing set were compared with the diagnostic of nuclear medicine physicians. The dual-time-point 18F-FDG PET/CT model achieving a Dice coefficient of 0.84 ± 0.02 for GGOs segmentation and demonstrating high accuracy (84.81

Currently, immunotherapy is being widely used for treating cancers. However, the significant heterogeneity in patient responses is a major challenge for its successful application. CD8-positive T cells (CD8+ T cells) play a critical role in immunotherapy. Both their infiltration and functional status in tumors contribute to treatment outcomes. Therefore, accurate monitoring of CD8+ T cells, a potential biomarker, may improve therapeutic strategy. Positron emission tomography (PET) is an optimal option which can provide molecular imaging with enhanced specificity. This review summarizes the mechanism of action of CD8+ T cells in immunotherapy, and highlights the recent advancements in PET-based tracers that can visualize CD8+ T cells and discusses their clinical applications to elucidate their potential role in cancer immunotherapy.

Abstract Gallbladder’s adenocarcinoma with enteroblastic differentiation (GAED) is extremely rare. A 43-year-old woman complained of pain in the right upper abdomen, and enhanced CT showed a cystic and solid mixed mass in the hepatic hilar region. Adenocarcinoma with enteroblastic differentiation was pathologically identified. 18F-FDG PET/CT revealed a lesion in the gallbladder neck with increased FDG uptake, accompanied by a cystic and solid mixed mass in the hepatic hilar region with liver and lymph node metastases. Gallbladder biopsy was also carried out, and GAED was confirmed. 18F-FDG PET/CT may assist in the evaluation of GAED and guide biopsy.

Abstract A 44-year-old woman presented with extensive skin patches and pruritus persisting for 3 years. Histopathological examination of the skin from the right abdomen confirmed mycosis fungoides–type cutaneous T-cell lymphoma. Staging PET with 18F-FDG PET/CT) showed increased uptake in the skin on the right abdomen and left hip. Subsequently 18F-FAPI-42 PET/CT revealed additional foci of abnormal uptake on the skin of the chest and back.

Diffuse involvement of pancreatic neuroendocrine tumor (PNET) is a rare presentation. Here, we report a case of suspected autoimmune pancreatitis with F-18-FDG and F-18-FAPI-42 PET/CT showing increased tracer uptake in the entire pancreas, which was eventually confirmed by biopsy pathologic analysis as diffuse PNET. F-18-AlF-NOTA-octreotide PET/CT imaging showed heterogeneous tracer uptake in the entire pancreas.

PET/CT is the preferred device for lung cancer and lymph node metastasis diagnosis, and mining effective features from PET/CT images to identify lung lymph node metastasis has important research significance and application value. Multi-phase PET/CT has temporal properties that can better represent changes in lesions’ structural and metabolic properties. Early-phase PET images can show a wide range of lesion areas. Delayed-phase PET images can show the high uptake properties of 18F-FDG in malignant tumor cells. Thus, multi-phase PET represents the variability of benign/malignant lesions better in the temporal dimension. This paper first proposes a metabolic enhancement method for lung lymph nodes and their microenvironment, a lymph node metastasis recognition network (LNMER-Net). The network has three branches: multi-modal early-phase feature fusion channel, multi-modal delayed-phase feature fusion channel, and single-modal metabolic decay channel. To enhance the feature of the lymph node region, a multi-receptive field-based feature extraction and feature space optimization (MRFO) method is proposed to extract lymph node features by multi-scale convolution operations and embed them in the multi-modal fusion channel. To exploit the information on the metabolic changes of the lesion in the early-phase and delayed-phase, differential results of the multi-phase PET images are fed into the single-modal metabolic decay channel to enhance the microenvironmental features. To verify its effectiveness, a multi-phase PET/CT dataset from China Medical University is used. The proposed method achieves 84.5

A 44-year-old woman presented with extensive skin patches and pruritus persisting for 3 years. Histopathological examination of the skin from the right abdomen confirmed mycosis fungoides-type cutaneous T-cell lymphoma. Staging PET with F-18-FDG PET/CT) showed increased uptake in the skin on the right abdomen and left hip. Subsequently F-18-FAPI-42 PET/CT revealed additional foci of abnormal uptake on the skin of the chest and back.