Positron Emission Tomography/computed Tomography Research Articles

Retrospective study on clinical value and optimal use of [18F] FDG PET/CT for inflammation of unknown origin in Japanese patients.

Despite advancements in medical technology, the challenges of diagnosing fever of unknown origin (FUO) and inflammation of unknown origin (IUO) persist. Positron emission tomography/computed tomography (PET/CT) has been used to assess these conditions; however, it is unclear which patients most benefit from this approach. This study aimed to assess the clinical value and optimal use of fluorine-18-labelled-fluorodeoxyglucose (18F-FDG)-PET/CT in patients with FUO/IUO. We reviewed FDG-PET/CT scans conducted at our department between January 2014 and December 2020 to further assess FUO/IUO. FUO was defined as a fever lasting over three weeks without a diagnosis based on conventional assessment. IUO was defined as prolonged inflammation with a body temperature below 38.3 ℃ and without a diagnosis after conventional diagnostic procedures. The efficacy of FDG-PET/CT was determined based on the diagnostic outcomes achieved by integrating imaging findings with histopathological or microbiological evidence, clinical criteria, or follow-up assessments. We conducted crude and age-sex adjusted logistic regression for potential risk factors to determine the degree of burden on demographic and clinical characteristics. Forty-five patients with FUO/IUO underwent FDG-PET/CT, and final diagnoses were made in 32 patients (71.1%). The percentages of diagnostic categories were 53.3%, 8.9%, and 6.7% for non-infectious inflammatory diseases, malignancy, and infection, respectively. In multivariable logistic regression analysis, IUO was the only independent predictor of the efficacy of FDG-PET/CT in the final diagnosis (odds ratio, 67.02; 95% confidence interval, 4.02-1119). Our results indicate that IUO was associated with a higher diagnostic yield compared to those with FUO.

Correlation between glucose metabolism and body mass index in tumor lesions of patients with lung cancer.

Lung cancer, along with various other cancers, is characterized by increased glucose metabolism. The maximum standardized uptake value (SUVmax), derived from positron emission tomography-computed tomography (PET-CT), serves as an indicator of glucose metabolic activity in tumor lesions. This study aimed to evaluate the correlation between body mass index (BMI) and SUVmax in individuals with lung cancer. This study included 41 patients with lung cancer, who were divided into two groups: Group 1 (n = 21), with a BMI greater than 22.4, and Group 2 (n = 20), with a BMI less than 22.4. All participants underwent 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) imaging. The SUVmax was calculated by manually delineating the regions of interest. A t-test was performed to assess whether the differences in SUVmax between the two groups were statistically significant. The mean SUVmax for Group 1 was 11.20 ± 5.45, while for Group 2 it was 10.65 ± 5.96. Although the mean SUVmax was higher in Group 1 compared to Group 2, the difference between the groups was not statistically significant (P = 0.757). The findings indicate a non-significant difference in glucose metabolism in lung cancer lesions between patients with different BMI levels. These results offer valuable insights into the metabolic characteristics of lung cancer and contribute to a deeper understanding of its pathophysiology.

Pericardial Tamponade Two Years after Central Venous Catheter Implantation in a Patient with Breast Cancer: A Case Report

We report a rare and diagnostically challenging case of pericardial tamponade in a breast cancer patient, treated two years earlier. Echocardiogram and an enhanced computed tomography (CT) scan revealed a large mass in the right pericardium with indistinct borders. A positron emission tomography-computed tomography (PET-CT) scan showed no uptake of fluorine-18 fluorodeoxyglucose (18F-GDP) by the mass. Cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement confirmed no signal enhancement within the mass and a clear border, decisively ruling out malignancy. This case highlights the importance of late gadolinium enhancement in this diagnostically challenging case and explores the pericardial tamponade development mechanism.

A 18F-FDG PET/CT-based deep learning-radiomics-clinical model for prediction of cervical lymph node metastasis in esophageal squamous cell carcinoma.

To develop an artificial intelligence (AI)-based model using Radiomics, deep learning (DL) features extracted from 18F-fluorodeoxyglucose (18F-FDG) Positron emission tomography/Computed Tomography (PET/CT) images of tumor and cervical lymph node with clinical feature for predicting cervical lymph node metastasis (CLNM) in patients with esophageal squamous cell carcinoma (ESCC). The study included 300 ESCC patients from the First Affiliated Hospital of Zhengzhou University who were divided into a training cohort and an internal testing cohort with an 8:2 ratio. Another 111 patients from Shanghai Chest Hospital were included as the external cohort. For each sample, we extracted 428 PET/CT-based Radiomics features from the gross tumor volume (GTV) and cervical lymph node (CLN) delineated layer by layer and 256 PET/CT-based DL features from the maximum cross-section of GTV and CLN images We input these features into seven different machine learning algorithms and ultimately selected logistic regression (LR) as the model classifier. Subsequently, we evaluated seven models (Clinical, Radiomics, Radiomics-Clinical, DL-Clinical, DL-Radiomics, DL-Radiomics-Clinical) using Radiomics features, DL features and clinical feature. The DL-Radiomics-Clinical (DRC) model demonstrated higher AUC of 0.955 and 0.916 compared to the other six models in both internal and external testing cohorts respectively. The DRC model achieved the highest accuracy among the seven models in both the internal and external test sets, with scores of 0.951 and 0.892, respectively. Through the combination of Radiomics features and DL features from PET/CT imaging and clinical feature, we developed a predictive model exhibiting exceptional classification capabilities. This model can be considered as a non-invasive method for predication of CLNM in patients with ESCC. It might facilitate decision-making regarding to the extend of lymph node dissection, and to select candidates for postoperative adjuvant therapy.

A Rare Case of Osteoblastoma of the Sacrum

Osteoblastoma (OB) is a rare bone tumor. It is classified as benign and represents about 1% of all bone neoplasms. While it typically occurs in the axial skeleton, sacral involvement is extremely rare. Despite its non-malignant nature, OB can be locally aggressive and may lead to considerable morbidity if not addressed in a timely manner. This report discusses a unique case of sacral, focusing on the clinical, radiological, and surgical features.A 14-year-old male patient reported experiencing increasing pain in his left lower limb and lumbosacral region for two years. A magnetic resonance imaging (MRI) of the lumbosacral area identified a mass measuring 50x43 mm on the left side of the sacrum in T2-weighted images. Further evaluation with a positron emission tomography/computerized tomography (PET/CT) scan indicated a destructive bone lesion in the left sacrum, measuring 43x40 mm, with a soft tissue component and increased fluorodeoxyglucose (FDG) uptake (standardized uptake value maximum: 11). The patient underwent surgical excision by a neurosurgery team, and histopathological analysis confirmed the diagnosis of OB.Although OB is a benign tumor, its location can cause significant symptoms, particularly in rare areas like the sacrum. Diagnostic imaging modalities such as MRI and PET/CT are crucial for identifying the tumor and planning surgical intervention. The elevated FDG uptake observed on PET/CT indicated a metabolically active lesion, reinforcing the need for surgical treatment.Sacral OB is an exceptionally rare entity. This case underscores the need to include OB in the differential diagnosis of sacral lesions and illustrates the value of imaging in facilitating accurate diagnosis and management. Surgical resection remains the cornerstone of treatment, offering good clinical outcomes.

Expert consensus on workflow of PET/CT with long axial field-of-view.

Positron emission tomography/computed tomography (PET/CT) imaging has been widely used in clinical practice. Long axial field-of-view (LAFOV) systems have enhanced clinical practice by leveraging their technological advantages and have emerged as the new state-of-the-art PET imaging modalities. A consensus was conducted to explore expert views in this emerging field to comprehensively elucidate the proposed workflow in LAFOV PET/CT examinations and highlight the potential challenges inherent in the workflow. A multidisciplinary task group formed by 28 experts from six countries over the world discussed and approved the consensus based on the published guidelines, peer-reviewed articles of LAFOV PET/CT, and the collective experience from clinical practice. This consensus focuses on the workflow that allows for a broader range of imaging protocols of LAFOV PET/CT, catering to diverse patient needs and in line with precision medicine principles. This consensus describes the workflows and imaging protocols of LAFOV PET/CT for various imaging scenarios including routine static imaging, dynamic imaging, low-activity imaging, fast imaging, prolonged imaging, delayed imaging, and dual-tracer imaging. In addition, imaging reconstruction and reviewing specific to LAFOV PET/CT imaging, as well as the main challenges facing installation and application of LAFOV PET/CT scanner were also summarized. This consensus summarized the various imaging workflow, imaging protocol, and challenges of LAFOV PET/CT imaging, aiming to enhance the clinical and research applications of these scanners.

An Atypical Case of Pancreatic Cancer with Mesenchymal Differentiation in a Patient with Primary Lung Adenocarcinoma: Insights into Tumor Biology and Novel Therapeutic Pathways

Background: Pancreatic cancer is among the malignancies with the poorest prognosis, largely due to its aggressive nature and resistance to conventional therapies. Case Summary: This report describes the case of a 69-year-old male patient with stage IV primary lung adenocarcinoma presenting with high levels of programmed death-ligand 1 (PD-L1). Simultaneously, abdominal computed tomography (CT) showed a dilated pancreatic duct at the level of the pancreatic head and a hypodense lesion in the uncinate process involving the superior mesenteric artery. Fine-needle aspiration (FNA) of the pancreatic lesions was negative. After three cycles of chemoimmunotherapy, positron emission tomography–computed tomography (PET-CT) showed complete remission of the lung nodules, lymphadenopathy, and pleural thickening, as well as a decrease in the size of the pancreatic lesion. After another six months, a PET-CT scan showed a focal increased uptake in the pancreatic mass in the same location, indicating disease progression. A core biopsy of the pancreatic tumor showed atypical spindle cell morphology with positive staining for vimentin, characteristic of mesenchymal differentiation with no apparent epithelial features. Comprehensive molecular profiling through Caris Molecular Intelligence® revealed four genes with actionable mutations in the pancreatic tissue, including KRAS (p.G12D) and TP53 (p.R175H). These molecular findings suggested the diagnoses of sarcomatoid carcinoma and conventional pancreatic ductal adenocarcinoma with epithelial–mesenchymal transition. Primary mesenchymal tumors and neuroendocrine neoplasms were excluded because immunohistochemistry was negative for anaplastic lymphoma kinase (ALK), smooth muscle actin (SMA), desmin, CD34, signal transducer and activator of transcription 6 (STAT6), S100, HMB45, CD117, discovered on GIST-1 (DOG1), CD56, progesterone, and synaptophysin. However, despite multiple rounds of systemic chemotherapy, immunotherapy, and radiation, his pancreatic disease rapidly deteriorated and metastasized to the liver and bone. Conclusions: Despite multiple lines of treatment, the patient’s condition worsened and he succumbed to his pancreatic malignancy. This study highlights the clinical characteristics, diagnosis, and treatment of rare pancreatic cancer, emphasizing the importance of molecular testing and histopathological biomarkers in personalizing treatment. It also provides insights into promising therapeutic approaches for similar cases with an unusual presentation.

2-[18F]F-p-aminobenzoic acid specifically detects infective endocarditis in positron emission tomography.

To the present day infective endocarditis (IE) represents a life-threatening disease with high mortality rate especially when caused by Staphylococcus aureus (S. aureus), the most common causative pathogen in this disease. Diagnosis of IE is based on clinical manifestations, pathogen detection by blood cultures and echocardiographic or other imaging findings. However, none of the methods used is capable of detecting the causative bacterial cells on the endothelium directly. Modern molecular imaging such as positron emission tomography/computed tomography (PET/CT) is playing an increasingly important role in unclear IE cases. This study focused on 2-[18F]F-p-aminobenzoic acid (2-[18F]F-PABA), a bacteria specific tracer for the diagnosis of IE using PET imaging for direct pathogen detection. In vitro assays were performed to analyze 2-[18F]F-PABA uptake by S. aureus. For proof-of-concept in vivo trials an endocarditis mouse model was used to diagnose IE by PET/Magnetic resonance (MR) imaging. A subcutaneous abscess mouse model was supplemented to create larger bacterial vegetations for PET imaging. 2-[18F]F-PABA in vitro uptake by S. aureus was confirmed. Only living bacteria were able to accumulate the tracer while the extent of uptake varied between different S. aureus strains. In the in vivo proof-of-concept, IE was visualized in mice using 2-[18F]F-PABA-PET/MR imaging. Subsequently, 2-[18F]F-PABA specifically located S. aureus vegetations in the subcutaneous abscess model. This study highlights the great potential of 2-[18F]F-PABA imaging for the direct detection of IE. Future studies might further investigate the clinical potential of this molecular imaging approach, finally aiming at a clinical implementation.

Evaluation of a Novel MET-Targeting Camelid-Derived Antibody in Head and Neck Cancer.

In head and neck squamous cell carcinoma (HNSCC), the mesenchymal epithelial transition (MET) receptor drives cancer growth, proliferation, and metastasis. MET is known to be overexpressed in HNSCC and, therefore, is an appealing therapeutic target. In this study, we evaluated MET expression in patients with HNSCC and investigated the potential imaging application of a novel MET-binding single-domain camelid antibody using positron emission tomography/computed tomography (PET/CT) in a preclinical MET-expressing HNSCC model. Multiplex immunostaining for MET protein performed on a tissue microarray from 203 patients with HNSCC found 86% of patients to have MET expression, with 14% having high expression and 53% having low MET expression. Using The Cancer Genome Atlas (TCGA) database, high MET RNA expression was associated with worse progression-free survival and overall survival in patients with HPV-negative HSNCC. Utilizing flow cytometry and immunofluorescence, our novel camelid antibody fused to a human IgG Fc chain (1E7-Fc) showed high binding affinity and specificity to high MET-expressing Detroit 562 cells but not to low MET-expressing HNSCC cells. The efficacy and biodistribution of [89Zr]Zr-1E7-Fc as a PET imaging agent was then investigated in a MET-expressing head and neck xenograft model. [89Zr]Zr-1E7-Fc rapidly localized and showed high tumor uptake in Detroit 562 xenografts (8.4% ID/g at 72 h postinjection), with rapid clearance from the circulatory system (2.7 tumor-to-blood radioactivity ratio at 72 h postinjection). Our preclinical data suggest that the camelid antibody 1E7-Fc could be a potential theranostic agent for HNSCC. Further investigations are warranted to confirm these findings in patients and to evaluate 1E7-Fc as an imaging agent and platform to deliver radionuclide or drug therapy to MET-driven cancers.

Highlights of the 2024 ASCO Annual Meeting: radiotherapy of head and neck cancer

At the 2024 Annual Meeting of the American Society of Clinical Oncology (ASCO), several important studies on radiotherapy for head and neck squamous cell carcinoma (HNSCC) were presented. There were two Chinese phaseIII trials on treatment escalation for locally advanced nasopharyngeal carcinoma: adjuvant immune checkpoint inhibition with camrelizumab after induction chemotherapy and cisplatin-based chemoradiotherapy (RCT) in the DIPPER trial reached the primary endpoint of improved event-free survival (EFS) but did not improve overall survival (OS). Simultaneous and adjuvant administration of the angiogenesis inhibitor endostar in addition to cisplatin-based RCT for locally advanced nasopharyngeal carcinoma led to asignificant improvement in progression-free survival (PFS) and OS. Another major focus was on treatment optimization and deintensification for oropharyngeal cancer (OPC): using intensity-modulated proton therapy (IMPT), aphaseIII trial demonstrated noninferiority in definitive RCT for OPC compared to photon-based intensity-modulated radiotherapy (IMRT). In adjuvant treatment of human papillomavirus-positive (HPV+) OPC, the long-term results of the E3311 phaseII study confirmed that individually deintensified radiotherapy is feasible. Lee etal. showed with the results of aphaseII study that HPV+ OPC might be treatable with chemoradiotherapy to atotal dose of only 30 Gy if no hypoxia is detected in the 18F‑fluoromisonidazole positron-emission tomography-computed tomography (F-MISO-PET) scan. Both the deintensified treatment of HPV+ OPC as well as additive immune checkpoint and angiogenesis inhibition in chemoradiotherapy of nasopharyngeal carcinoma require further studies before they can be recommended in clinical practice.

Assessing Changes in Vascular Inflammation and Urate Deposition in the Vasculature of Gout Patients After Administration of Pegloticase Using Positron Emission Tomography and Dual-Energy Computed Tomography—A Pilot Study

We assessed changes in vascular inflammation and monosodium urate (MSU)-coded deposits after administration of Pegloticase in the vasculature of tophaceous gout patients using 18F-fluorodeoxyglucose (18F-FDG) Positron emission tomography/computed tomography (PET/CT) and dual-energy CT (DECT). Ten patients with tophaceous gout, intolerant or refractory to urate-lowering therapy (ULT), were treated with Pegloticase every two weeks for six months. 18F-FDG PET/CT and DECT were performed at baseline and after Pegloticase therapy to detect vessel wall inflammation (Standard uptake value, SUVmean, and SUVmax) and vascular MSU-coded deposition (MSU volume). Data were summarized using means and standard deviations. Baseline and follow-up values were compared for each variable using mixed-effect models. Significant decreases in SUVmean (p = 0.0003) and SUVmax (p = 0.009) were found with a trend towards a decrease in vessel wall MSU volume after treatment. There was a significant decrease in serum urate, correlating with reduction in SUVmean (R2 = 0.65), with a trend towards a decrease in CRP and blood pressure in all patients. Despite the small sample size, we were able to demonstrate a decrease in vessel wall inflammation and a trend towards a decrease in MSU volume by intensively lowering serum urate. These findings suggest that MSU-coded deposits and hyperuricemia may play a role in vascular wall inflammation. It remains to be seen whether this correlates with a decrease in adverse cardiovascular outcomes.

Significance of increased 18F-FDG uptake in determining pathological status in post-chemotherapy lymphoma cases involving head-neck region on PET-CT

BackgroundCurrently, all follow-up cases of lymphoma showing fluorodeoxyglucose (FDG) avid uptake on positron emission tomography/computed tomography (PET-CT) in head-neck region undergo biopsy for tissue confirmation of diagnosis. There are no consensus or practice guidelines in literature pertaining, whether to biopsy all such FDG avid lesions post-chemotherapy. Hence, this study was conducted to determine the significance of PET-CT (SUVmax 5.0 or above) in determining remission or pathological status in these patients. MethodsA retrospective cohort analysis conducted between July 2019 and May 2023 at our institute of 40 follow-up cases of lymphoma post-chemotherapy (Group A) showing FDG Uptake with SUVmax 5.0 or above on PET-CT in Waldeyer's Ring (WR) or neck, and 40 non- lymphoma cases (Group B) showing FDG Uptake with similar SUVmax in WR or neck. All cases in group A underwent tonsillectomy and results of histopathology were correlated with PET-CT findings. All cases in group B underwent thorough clinical correlation with respect to PET-CT findings. A Receiver Operating Characteristic (ROC) curve for SUVmax was plotted to statistically analyse this data. ResultsStatistical analysis of our observations by plotting a ROC curve for SUVmax revealed a sensitivity of 90% with 10% specificity and an insignificant p-value of 0.733. ConclusionWe propose that unnecessary biopsy in all cases with FDG avid uptake must not be encouraged unless accompanied by a suspicious holistic clinical picture of asymmetry, significant lymph node involvement with FDG avid uptake and counterpart finding on CT. A tissue confirmation in all such cases may result in unnecessary risk and increase the cost of therapy.

Tubarial salivary glands show a low relative contribution to functional salivary gland tissue mass.

In 2021, the tubarial salivary glands (TSGs) were newly identified on prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) as macroscopic glands in the nasopharyngeal wall. However, the relative contribution of the TSGs to the total salivary gland function, and consequently on the development of xerostomia after external beam radiotherapy (EBRT) or PSMA-targeted radionuclide therapy (RNT) is not known. Therefore, we aimed to determine the presence of the TSGs and to quantify uptake in the TSGs on PSMA PET. Qualitative and quantitative analyses were performed on 68Ga-PSMA-11 PET/CT scans of 100 patients with prostate cancer. The mean and maximum standardized uptake value (SUVmean and SUVmax) in the TSGs were measured and compared to the parotid, submandibular and sublingual salivary glands (PSGs, SMSGs and SLSGs, respectively). Furthermore, proportional function of the TSGs was compared to the PSGs, SMSGs and SLSGs based on the total organ PSMA (TO-PSMA). The TSGs were visible on 95% of the 68Ga-PSMA-11 PET/CT scans. The normalized median SUVmean and SUVmax was significantly higher for the PSGs (p < 0.001) and SMSGs (p < 0.001) compared to the TSGs, but not for the SLSGs (p = 0.242 and p = 0.300, respectively). The normalized median TO-PSMA was significantly higher for the PSGs (p < 0.001) and SMSGs (p < 0.001), and significant lower for the SLSGs (p < 0.001) compared the TSGs. The SUVmean, SUVmax and TO-PSMA of the TSGs were most comparable to the SLSGs. However, the measured PSMA uptake may be disproportional towards the saliva production. Therefore, future studies should focus on the relation between PSMA uptake and salivary function before and after PSMA therapy.

[89Zr]Zr-girentuximab PET-CT imaging to diagnose, characterize, and differentiate clear-cell renal cell carcinoma

In the phase 3 ZIRCON trial, [89Zr]Zr-girentuximab positron emission tomography-computed tomography (PET-CT) detected the presence of clear-cell renal cell carcinoma (ccRCC) with a sensitivity of 86% and a specificity of 87% in patients with an indeterminate renal mass undergoing nephrectomy.1 This imaging technique could be a promising tool that could revolutionize the management of small renal masses (SRMs) and ccRCC.

Value of 18F-FDG PET/CT in the Diagnosis and Grading of Incidental Colorectal Adenomas

PurposeColorectal adenomas (CRAs) are at a higher risk of progressing to colorectal cancer (CRC) as their histological grade increases. Herein, this study investigated the relationship between the maximum standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) and the histological grades of CRAs and constructed the optimal regression model for distinguishing between different histological grades. MethodsThis study retrospectively analyzed the data of 153 patients with CRAs who had colorectal 18F-FDG uptake incidentally found on PET/CT. The patients were categorized into low-grade intraepithelial neoplasia (LGIN) and high-grade intraepithelial neoplasia (HGIN) groups based on their histological grade. After the analysis of the relationship between SUVmax measured on preoperative 18F-FDG PET/CT scans and histological grades, receiver-operating characteristic (ROC) curves were analyzed to determine the optimal cut-off values for distinguishing between the two groups. Common clinical and pathological factors were included and subjected to univariate and multivariate logistic regression analyses to identify independent risk factors. A diagnostic model integrating SUVmax and several risk factors was developed with the multivariate logistic regression analysis. ResultsSUVmax was significantly different between the two groups (P < 0.001) and increased with an elevation in the malignancy degree. The area under the ROC curve (AUC) for identifying LGIN and HGIN was 0.796, and the AUC of the combination model was 0.822. Furthermore, SUVmax was an independent risk factor for distinguishing between different histological grades in pairwise comparisons. ConclusionThe regression model involving SUVmax on 18F-FDG PET/CT can distinguish between histological grades of CRAs, which therefore can be used as a noninvasive tool for the accurate diagnosis of CRAs and assist in developing patient-specific treatment strategies before surgery.

PSMA PET/CT Accuracy in Diagnosing Prostate Cancer Nodes Metastases.

This study aimed to evaluate the diagnostic accuracy of prostate-specific membrane antigen (PSMA)-directed positron emission tomography/computed tomography (PET/CT) in pelvic nodal staging, using postoperative histopathology data as the reference standard. From January 2020 to June 2024, 78 patients with clinically significant prostate cancer (PCa) (ISUP Grade Group 2) underwent radical prostatectomy plus extended pelvic lymph node dissection (ePLND): 60 (77%) vs. 18 (23%) men had an intermediate vs. high risk PCa. All the patients underwent PSMA PET/TC before surgery for clinical staging and nodes focal uptake (standardized uptake value "SUVmax) was evaluated to rule out the presence of metastases. PSMA PET/CT was suspicious for nodes metastases in 16/78 (20.5%) men (median SUVmax 26.2), conversely, histology demonstrated nodes metastases in 18/78 (23.1%). PSMA PET/CT was negative for nodal involvement in all Grade Group 2 (GG2) PCa, positive in 4/4 (100%) GG3 PCa, and in 10/14 (71.4%) GG5 PCa. In detail, PSMA PET/CT was false negative in 2/4 PCa, characterized by GG5 plus ductal adenocarcinoma. Overall, PSMA PET/CT sensitivity, specificity, positive and negative predictive value, and diagnostic accuracy in diagnosing nodal metastases were equal to 87.5, 96.8, 87.5 96.7, and 92.3%, respectively. PSMA PET/CT demonstrated an overall diagnostic accuracy of 92.3% in nodal staging (100% in GG2 PCa), which decreased to 63.6% in GG5 PCa. In high-risk patients or in case of ductal adenocarcinoma, a negative PSMA PET/CT does not rule out the need for ePLND.

Patent foramen ovale and stroke: a possible association with deep vein thrombosis

Patent foramen ovale (PFO) is a congenital heart abnormality consisting of the persistence of a tunnel between the right and left atrium; it is associated with a higher prevalence of strokes. A 52-year-old man was admitted to the emergency room for confusion and deep vein thrombosis with signs of pulmonary embolism; he started treatment with fondaparinux. After admission, there was an ischemic stroke. Blood tests, thrombogenic screening, and infectious diseases showed no alterations. Holter-electrocardiogram, echocardiography, and positron emission tomography-computed tomography were negative except for the presence of PFO. Apixaban and cardioaspirin were started. The surgical treatment was planned, but despite the therapy, there was a new ischemic stroke, so the treatment with mechanical thrombectomy was attempted but failed. The patient was continuing therapy until a new cerebral ischemic episode caused his death; the etiopathogenesis of brain events appears to be associated with the presence of PFO; association with deep venous thrombosis is described in the literature.

18F-FDG PET/CT in the diagnosis of infective endocarditis

Abstract Background Increased uptake of 18F-fluorodeoxyglucose (FDG) by positron-emission tomography/computed tomography (PET/CT) is one of the diagnostic criteria for prosthetic valve endocarditis (PVE). However, there is limited data on the diagnostic value of FDG PET/CT in diagnosing native valve endocarditis (NVE) and semi-quantitative parameters of FDG uptake. Purpose The objective of this retrospective study was to evaluate the accuracy of FDG PET/CT and additional value of semi-quantitative measures of FDG uptake in the detection of NVE and PVE. Methods All patients who had undergone FDG PET/CT due to suspected infective endocarditis (IE) at a single tertiary referral center between 2010 and 2020 were identified. Additional patients who underwent FDG PET/CT for detecting an infection focus were included as controls. Clinical reports were evaluated and images were analyzed for maximal standardized uptake value (SUVmax) and target to background ratio (TBR = SUVmax normalized to mean blood pool SUV) around valves. The scan was defined positive based on either clinical reading or previously proposed cut-off values for SUVmax and TBR (&amp;gt;4.2 and &amp;gt;2.1, respectively). The final diagnosis of IE was defined based on all available information in electronic medical records. Results The study cohort included 16 patients with suspected NVE (median age 58 years, 88% male), 24 patients with suspected PVE (median age 72 years, 92% male) and 37 patients who underwent FDG PET/CT for detecting an infectious focus (8 with a prosthetic valve). The final diagnosis was definite IE in 25 (14 PVE), possible IE in 7 (6 PVE), and no IE in 45 (12 with a prosthetic valve). Overall, clinical reading of FDG PET/CT identified 17 (sensitivity 68%) of definite IE with a specificity of 91% and accuracy of 83%. Compared with NVE, the sensitivity of FDG PET/CT was higher in the detection of PVE (46% vs. 86%) whereas specificity was lower (97% vs. 75%) resulting in small difference in accuracy (84% vs. 81%). In PVE, SUVmax had higher sensitivity (93%) than clinical reading, resulting in the same accuracy (81%) despite lower specificity (67%). A combination of either positive clinical reading or positive SUVmax identified all patients with PVE (sensitivity 100%). In NVE, TBR had higher sensitivity (64%) than clinical reading, but accuracy (66%) and specificity (67%) were significantly lower. Conclusions FDG PET/CT shows high sensitivity in the detection of PVE and high specificity in the detection of NVE in a real-world clinical cohort. Semi-quantitative parameters of FDG uptake can improve sensitivity of detecting PVE maintaining diagnostic accuracy. However, in NVE semi-quantitative parameters were associated with a prominent reduction in specificity.

Evaluation of aortic inflammation in marfan syndrome patients with 18-fluorodeoxyglucose positron emission and computed tomography

Abstract Background The role of inflammation in Marfan Syndrome (MS) has been well studied in current research. These studies have investigated the role of serum Interleukin 6 (IL-6), Transforming Growth Factor-b (TGF-b) and Macrophage Colony Stimulating Factor (MCSF) as biomarkers of disease severity and progression. Surgical repair is the recommended treatment of aortic aneurysms when aortic diameter reaches the indication threshold. It has been observed however that dissection may occur even before this threshold is reached. 18-fluorodeoxyglucose (18 F-FDG) positron emission tomography / computed tomography (PET/CT) is the gold standard imaging modality to noninvasively assess vascular inflammation. Purpose Our aim was to investigate whether MS patients have increased aortic wall inflammation as assessed by 18F-FDG PET/CT, and the relationship between aortic wall inflammation with serum levels of IL-6, TGF-b and MCSF. Methods The study population consisted of fifteen MS patients and seventeen sex and age matched controls. In all subjects, serum levels of circulating IL-6, TGF-b and MCSF were measured. In PET/CT, the arterial target-to-background ratio (TBR) was calculated for aortic root (AR), ascending aorta(As), aortic arch (AA) and descending aorta (DA). Also, all patients were assessed with transthoracic echocardiography where the diameters of AR, As, AA, and DA were estimated at baseline and were reexamined at the end of the follow up period. Results TBR for MS vs. controls was 2.17±0.75 vs 2.01±0.36, p=0.75 at AR; 2.15±0.67 vs 1.84±0.35, p=0.040 at As; 2.16±0.64 vs 1.70±0.25, p=0.03 at AA and 1.97±0.52 vs 1.83±0.42, p=0.23 at DA respectively. Additionally, Marfan patients had increased levels of serum biomarkers. However, this difference was statistically significant (SS) only for IL-6 serum levels; 2.17±0.46 vs 1.08±0.12 p=0.011 and IL-6 was SS associated with AR TBR (rho=0.572, p=0.033), As TBR (rho=0.604, p=0.022) and DA TBR (rho=0.714, p=0.004). Two of our patients were operated due to severe dilatation of the aortic root and the surgical specimens showed aortic wall inflammation of moderate severity along with fibrosis. Conclusion MS patients have increased of aortic wall inflammation as assessed by 18F-FDG PET/CT, a finding that highlights the role of inflammation in the pathway of disturbed TGF signaling. Further research is needed to determine its prognostic role and value in identifying patients with an indication for early intervention.

First in-human study of 64Cu-DOTATATE positron emission tomography/computed tomography(PET/CT) in infective endocarditis: a prospective head-to-head comparison with 18-FDG PET/CT

Abstract Background Infective endocarditis (IE) is a severe and potentially fatal condition, which can be challenging to diagnose. Positron emission tomography/computed tomography (PET/CT) with [18F]fluorodeoxyglucose ([18F]FDG) is proposed as a diagnostic tool in the ESC endocarditis guidelines, but holds limitations. Purpose To compare the tracer uptake between [64Cu]Cu-DOTATATE and [18F]FDG in patients with IE, and to examine sensitivity and specificity in patients with prosthetic valve endocarditis (PVE) or native valve endocarditis (NVE). Methods The CuDOS-study was a prospective study including 20 cases with IE (10 with PVE and 10 with NVE) and 20 controls. [64Cu]Cu-DOTATATE and [18F]FDG PET/CT were performed in all participants. Scans were read blinded to clinical data. Tracer uptakes were measured as maximum standardized uptake values (SUVmax) in each heart valve. A visual interpretation of the presence or absence of IE was recorded for [64Cu]Cu-DOTATATE and [18F]FDG, respectively. Results The median age of the cases and controls was 68 years [IQR 53-71] and 61 years [IQR 56-67], respectively. In cases and controls, 85% and 70% were men, respectively. [64Cu]Cu-DOTATATE uptake (median SUVmax [IQR]) in patients with IE was higher than in controls (2.38 [1.87-2.90] vs. 1.43 [1.30-1.56], p&amp;lt;0.001), although this difference was mainly driven by PVE-cases (2.99 [2.22-3.75] vs. 1.43 [1.30-1.56 (controls), p&amp;lt;0.001) and to a lesser extent the NVE-cases (1.78 [1.22-2.33] vs. 1.43 [1.30-1.56 (controls), p=0.079), Figure 1. The sensitivity of [64Cu]Cu-DOTATATE and [18F]FDG PET/CT in 20 cases and the 20 controls were comparable, and the specificity was 90% and 75%, respectively. The analysis of PVE versus the 20 controls showed equal sensitivity (80%) for [64Cu]Cu-DOTATATE and [18F]FDG PET/CT and a specificity of 90% and 75%, respectively. The difference in the specificity between [64Cu]Cu-DOTATATE and [18F]FDG was 15% [IQR -5.9-36%], p=0.38. Conclusion [64Cu]Cu-DOTATATE PET/CT showed relevant uptake in the infected valve in patients with infective endocarditis. [64Cu]Cu-DOTATATE had a numerically higher specificity than [18F]FDG in prosthetic valve endocarditis, although the difference was not statistically significant. Both tracers were limited in the detection of native valve endocarditis.Figure 1 [64Cu]Cu-DOTATATE and [18F]FDG