Small Cell Carcinoma Prostate: A Case Report with Findings on 18-F FDG PET/CT.

Small-cell carcinoma of the prostate (SCCP) is a rare and very aggressive malignancy with neuroendocrine differentiation. In contrast to conventional prostate adenocarcinoma, SCCP is an aggressive carcinoma and portends to have a poor prognosis. Around 50% of these patients have metastatic disease at the first clinical presentation. We report the findings of 18-F fluorodeoxyglucose positron emission tomography/computed tomography in a case of histologically proven SCCP with an unusual finding of the left internal mammary lymph node.

The Application of 68Ga-Somatostatin Analog and 18F-FDG PET/CT for Bone Metastasis from Neuroendocrine Tumors.

INTRODUCTION: Aims of the study were to assess the differences in the diagnostic efficacy of 68Ga-somatostatin receptor analogs (68Ga-SSAs) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for detecting bone metastases in neuroendocrine neoplasm (NEN) and to analyze the correlation between imaging features and clinical features of BMs. METHODS: We retrospectively analyzed the clinical and imaging data of 213 NEN patients who underwent 68Ga-SSA PET/CT and were finally diagnosed as BMs by pathology or follow-up. Of those, 103 patients underwent 18F-FDG PET/CT within 7 days after 68Ga-SSA PET/CT. RESULT: The BM detection rate of 68Ga-SSA PET/CT was higher than 18F-FDG PET/CT (86.4% vs. 66.0%, p = 0.02) in 103 patients with dual scanning. Meanwhile, the number of positive lesions in 68Ga-SSA PET/CT was significantly more than in 18F-FDG PET/CT (3.37 ± 1.95 vs. 2.23 ± 2.16, t = 4.137, p < 0.001). Most bone metastasis lesions presented as osteogenic change in CT (55.4%, 118/213). Concerning the primary tumor, the most frequent were of pancreatic origin (26.3%, 56/213), followed by rectal origin (22.5%, 48/213), thymic origin in 33 cases (15.5%), pulmonary origin in 29 cases (13.6%), paraganglioma in 20 cases (9.4%). The efficiency of 68Ga-SSA PET/CT to detect BMs was significantly correlated with the primary site (p = 0.02), with thymic carcinoid BMs being the most difficult to detect, and the positive rate was only 60.6% (20/33). However, 18F-FDG PET/CT positive rate was 76.92% (10/13) in thymic carcinoid BMs. In addition, the BMs of 7 patients in this study were detected by 68Ga-SSA PET earlier than CT for 4.57 months (range: 2-10 months). CONCLUSION: 68Ga-SSA PET/CT has higher sensitivity for detecting the BMs of NEN than 18F-FDG and detects the BM earlier than CT. Moreover, 18F-FDG PET/CT should be a complement for diagnosing the BMs of thymic carcinoids.

Diagnostic value of 18F-FDG PET/CT versus diffusion-weighted MRI in detection of residual or recurrent tumors after definitive (chemo) radiotherapy for laryngeal and hypopharyngeal squamous cell carcinoma: A prospective study.

BACKGROUND: Despite advances in treatment, residual or recurrent tumors after definitive (chemo) radiotherapy for laryngeal and hypopharyngeal squamous cell carcinoma (SCC) remain a challenge in clinical management and require accurate and timely detection for optimal salvage therapy. This study aimed to compare the diagnostic value of Fluorine 18 (18F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and diffusion-weighted magnetic resonance imaging (DW-MRI) in detecting residual or recurrent tumors after definitive (chemo) radiotherapy for laryngeal and hypopharyngeal SCC. METHODS: A prospective study was conducted on 30 patients who presented with new symptoms after definitive (chemo) radiotherapy for laryngeal (n = 21) and hypopharyngeal (n = 9) carcinoma. Both 18F-FDG PET/CT and DW-MRI were performed and histopathologic analysis served as the standard of reference. RESULTS: Histopathology showed 20 patients as positive and 10 as negative for tumors. 18F-FDG PET/CT detected all tumors correctly but was falsely positive in one case. DW-MRI detected tumors in 18 out of 20 positive patients and correctly excluded tumors in all negative patients. The sensitivity and specificity of 18F-FDG PET/CT were 100% and 90%, respectively, while the values for DW-MRI were 90% and 100%, respectively. CONCLUSIONS: The study concludes that 18F-FDG PET/CT is slightly superior to DW-MRI in detecting residual or recurrent tumors after definitive (chemo) radiotherapy for laryngeal and hypopharyngeal SCC. The combined use of 18F-FDG PET/CT and DW-MRI can potentially improve specificity in therapy response evaluation.

18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography and 68Ga-prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography Imaging in the Evaluation of Rare Entity Adult Embryonal Rhabdomyosarcoma of Prostate.

A 21-year-old male with embryonal rhabdomyosarcoma of the prostate was referred for 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and 68Ga-prostate-specific membrane antigen (PSMA) PET/CT for initial disease staging. The PET scans revealed hypermetabolic and PSMA expressing lobulated mass involving both lobes of the prostate and weakly metabolic and PSMA expressing few bilateral pararectal and external iliac nodes, multiple bilateral lung nodules scattered over the lung parenchyma and multiple bone marrow lesions in both axial and appendicular skeleton. Magnetic resonance imaging prostate showed gross prostatomegaly with large lobulated T2 hyperintense heterogeneously enhancing mass lesion showing restricted diffusion, involving both lobes of the prostate with extraprostatic spread along anterior, posterior, and left lateral margins with evidence of lymph nodal and osseous metastases. The demonstration of increased uptake of 18F-FDG and 68Ga-PSMA in the primary as well as bilateral pararectal and external iliac nodes, multiple bilateral lung nodules, and multiple bone marrow lesions in both axial and appendicular skeleton indicates a potential role of 18F-FDG PET/CT and 68Ga-PSMA PET/CT in disease staging in this rare aggressive tumor of the prostate.

Rare Case of Primary Leiomyosarcoma of Bone - Findings on 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

Primary leiomyosarcoma of bone (PLB) is a rare tumor, constituting <0.7% of all primary bone malignancies. It is clinically aggressive with heterogeneous presentation and a dismal prognosis. The most common presentation is pain with swelling and pathological fracture at times. Limited literature is available on PLB and only about 150 cases have been reported to date with only a few case reports defining the utility of 18F-fluorodeoxyglucose (18-F FDG) positron emission tomography/computed tomography (PET-CT) in its management. We hereby present a case of primary leiomyosarcoma of the right distal femur and the role of FDG-PET-CT in its management.

Recent advancements in 18F-FDG PET/CT for the diagnosis, staging, and treatment management of HIV-related lymphoma.

Infection with the Human Immunodeficiency Virus (HIV) is one of the most pressing issues facing public health on a worldwide scale. Currently, HIV-related lymphoma is the most common cause of death among people living with HIV, and warrants more attention. The unique challenges associated with HIV-related lymphoma management derive from the underlying HIV infection and its immunosuppressive effects. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has gained significant prominence in the past few years as a valuable diagnostic and therapeutic instrument for the treatment of HIV-related lymphoma. This review will start with an overview of the subtypes, risk factors, and therapeutic choices for individuals with HIV-related lymphoma. We will then briefly discuss the current application of 18F-FDG PET/CT in the medical management of HIV-related lymphoma patients, followed by the initial staging of the disease, the evaluation of therapeutic response, the prediction of prognostic outcomes, the decision-making process for radiotherapy guided by PET findings, and the distinguishing of various diagnoses.

Exploring the latest advances in 18F-FDG PET/CT and cardiac magnetic resonance for imaging for cardiac sarcoidosis diagnosis.

Sarcoidosis is a systemic inflammatory disease that affects multiple organs. Various clinical signs are associated with cardiac sarcoidosis (CS), and the diagnosis process is complicated because any organ could be involved. Despite the critical clinical importance of early and precise diagnosis of CS, there is currently no gold-standard method for CS evaluation. The non-invasive imaging modalities of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and cardiac magnetic resonance (CMR) imaging have demonstrated the potential for identifying various histological characteristics of CS. Recently, the development of hybrid FDG-PET/CMR scanners has enabled the simultaneous acquisition of these attributes. Compared to just one imaging modality, these scanners detect CS and stratify risk more accurately and with higher sensitivity. Analyzing the potential role of concurrent FDG-PET/CMR in enhancing the diagnosis of CS, the present review concentrates on the advantages of this technique in light of recent technological developments.

Preliminary study on the ability of the machine learning models based on 18F-FDG PET/CT to differentiate between mass-forming pancreatic lymphoma and pancreatic carcinoma.

PURPOSE: The objective of this study was to preliminarily assess the ability of metabolic parameters and radiomics derived from 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) to distinguish mass-forming pancreatic lymphoma from pancreatic carcinoma using machine learning. METHODS: A total of 88 lesions from 86 patients diagnosed as mass-forming pancreatic lymphoma or pancreatic carcinoma were included and randomly divided into a training set and a validation set at a 4-to-1 ratio. The segmentation of regions of interest was performed using ITK-SNAP software, PET metabolic parameters and radiomics features were extracted using 3Dslicer and PYTHON. Following the selection of optimal metabolic parameters and radiomics features, Logistic regression (LR), support vector machine (SVM), and random forest (RF) models were constructed for PET metabolic parameters, CT radiomics, PET radiomics, and PET/CT radiomics. Model performance was assessed in terms of area under the curve (AUC), accuracy, sensitivity, and specificity in both the training and validation sets. RESULTS: Strong discriminative ability observed in all models, with AUC values ranging from 0.727 to 0.978. The highest performance exhibited by the combined PET and CT radiomics features. AUC values for PET/CT radiomics models in the training set were LR 0.994, SVM 0.994, RF 0.989. In the validation set, AUC values were LR 0.909, SVM 0.883, RF 0.844. CONCLUSION: Machine learning models utilizing the metabolic parameters and radiomics of 18F-FDG PET/CT show promise in distinguishing between pancreatic carcinoma and mass-forming pancreatic lymphoma. Further validation on a larger cohort is necessary before practical implementation in clinical settings.

Recent Insights Into Native Valve Infective Endocarditis: JACC Focus Seminar 4/4.

This focused review highlights the latest issues in native valve infective endocarditis. Native valve disease moderately increases the risk of developing infective endocarditis. In 2023, new diagnostic criteria were published by the Duke-International Society of Cardiovascular Infectious Diseases group. New pathogens were designated as typical, and findings on computed tomography imaging were included as diagnostic criteria. It is now recognized that a multidisciplinary approach to care is vital, and the role of an "endocarditis team" is highlighted. Recent studies have suggested that a transition from intravenous to oral antibiotics in selected patients may be reasonable, and the role of long-acting antibiotics is discussed. It is also now clear that an aggressive surgical approach can be life-saving in some patients. Finally, results of several recent studies have suggested there is an association between dental and other invasive procedures and an increased risk of developing infective endocarditis. Moreover, data indicate that antibiotic prophylaxis may be effective in some scenarios.

18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) imaging of pediatric neuroblastoma: a multi-omics parameters method to predict MYCN copy number category.

Background: The MYCN copy number category is closely related to the prognosis of neuroblastoma (NB). Therefore, this study aimed to assess the predictive ability of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) radiomic features for MYCN copy number in NB. Methods: A retrospective analysis was performed on 104 pediatric patients with NB that had been confirmed by pathology. To develop the Bio-omics model (B-model), which incorporated clinical and biological aspects, PET/CT radiographic features, PET quantitative parameters, and significant features with multivariable stepwise logistic regression were preserved. Important radiomics features were identified through least absolute shrinkage and selection operator (LASSO) and univariable analysis. On the basis of radiomics features obtained from PET and CT scans, the radiomics model (R-model) was developed. The significant bio-omics and radiomics features were combined to establish a Multi-omics model (M-model). The above 3 models were established to differentiate MYCN wild from MYCN gain and MYCN amplification (MNA). The calibration curve and receiver operating characteristic (ROC) curve analyses were performed to verify the prediction performance. Post hoc analysis was conducted to compare whether the constructed M-model can distinguish MYCN gain from MNA. Results: The M-model showed excellent predictive performance in differentiating MYCN wild from MYCN gain and MNA, which was better than that of the B-model and R-model [area under the curve (AUC) 0.83, 95% confidence interval (CI): 0.74-0.92 vs. 0.81, 95% CI: 0.72-0.90 and 0.79, 95% CI: 0.69-0.89]. The calibration curve showed that the M-model had the highest reliability. Post hoc analysis revealed the great potential of the M-model in differentiating MYCN gain from MNA (AUC 0.95, 95% CI: 0.89-1). Conclusions: The M-model model based on bio-omics and radiomics features is an effective tool to distinguish MYCN copy number category in pediatric patients with NB.

18F-FDG PET/CT assists the diagnosis of primary pancreatic lymphoma: Two case reports and literature review.

Primary pancreatic lymphoma (PPL) is a rare malignancy, which is defined as a mass centered in pancreas with involvement of contiguous lymph nodes and distant spread may exist. Accurate diagnosis of PPL prior to pathological confirmation remains challenging, underscoring the critical significance of preoperative imaging assessments. This case report collected two instances of PPL that underwent initial evaluation via 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) between August 2021 and July 2022. Correspondingly, pertinent literature encompassing 18F-FDG PET/CT data related to PPL was meticulously reviewed. Including our aforementioned pair of cases, a cumulative total of 25 instances of PPL were assembled. The distinctive profile of 18F-FDG PET/CT images of PPL predominantly manifests as hypermetabolic lesions with diminished density. Primarily characterized by singular lesions and comparatively substantial volumetric dimensions, a total of eleven cases revealed contiguous lymph node engagement, with five instances displaying distant dissemination encompassing lymph nodes in multiple locations. Amongst these, ten patients underwent sequential 18F-FDG PET/CT follow-up post-intervention. In comparison to pancreatic carcinoma, PPL lesions exhibited heightened hypermetabolism, augmented volumetric proportions, and distinct patterns of distant metastasis. This study indicates that the pivotal role of 18F-FDG PET/CT in the diagnosis and assessment of therapeutic efficacy in PPL is unequivocal. Combined with the clinical attributes of patients, the integration of 18F-FDG PET/CT augments the differential diagnostic capacity differentiating PPL from pancreatic carcinoma.

Prognostic value of 18F-FDG PET/CT tumor metabolic parameters and Ki-67 in pre-treatment diffuse large B-cell lymphoma.

Background: Diffuse large B-cell lymphoma (DLBCL) is a highly aggressive lymphoma. Rituximab-based conventional chemotherapy still leads to drug resistance or relapse in 30-40% of patients. Therefore, early identification of high-risk patients and accurate assessment of prognosis are very important for clinical decision-making. The aim of this study is to investigate the value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) of tumor metabolic, clinical and biological parameters in the prognostic risk stratification of DLBCL before treatment. Methods: We retrospectively collected clinical data on 63 patients with newly diagnosed DLBCL admitted to Shanxi Bethune Hospital during the period from November 2016 to April 2020 who underwent 18F-FDG PET/CT prior to treatment in a cohort study. Metabolic, clinical, and biological parameters were analyzed by Cox regression. Kaplan-Meier curves of patient survival were compared by the log-rank test. Results: The median follow-up was 21 months. The 2-year progression-free survival (PFS) was 47.62%, and the overall survival (OS) was 53.97%. The subtype, double expression, Ann Abor stage, NCCN-IPI score, Ki-67, maximum standardized uptake value (SUVmax), bulk volume glycolysis (BVG), total lesion glycolysis (TLG), total metabolic tumor volume (TMTV) were the influencing factors for PFS and OS (P<0.050) in univariate analysis. BVG (PFS: HR =6.62, P<0.001; OS: HR =3.53, P=0.029), TLG (PFS: HR =8.56, P<0.001; OS: HR =5.20, P=0.004), TMTV (PFS: HR =12.02, P=0.001; OS: HR =5.05, P=0.033) and Ki-67 were found to be independent prognostic risk stratification parameters affecting PFS and OS by multivariate regression analysis. The 2-year PFS and OS rates for patients with high BVG (≥288.00 cm3), TLG (≥1,854.00 cm3), TMTV (≥103.00 cm3), and Ki-67 (≥85%) were 20% and 28.57%, 9.68% and 22.58%, 20.51%, and 30.77%, and 25% and 33.33%, respectively; and the 2-year PFS and OS rates for patients with low BVG (<288.00 cm3), TLG (<1,854.00 cm3), TMTV (<103.00 cm3), and Ki-67 (<85%) patients were 82.14% and 85.71%, 84.37% and 84.37%, 91.67% and 91.67%, and 61.54% and 66.67%, respectively. Patients with high BVG, TLG, TMTV, and Ki-67 had a worse 2-year PFS as well as OS rate (Ki-67: P=0.0018/P=0.0025; P<0.0001 for the rest of the groups). Conclusions: Our findings suggest that BVG, TLG, TMTV, and Ki-67 are independent prognostic indicators for survival in patients with pre-treatment DLBCL, especially BVG, which is a novel prognostic indicator that has to be validated in future research.

18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in a Rare Case of Epithelioid Hemangioendothelioma - A Diagnostic Challenge.

Our case highlights the 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan findings in a rare case of biopsy-proven epithelioid hemangioendothelioma (EHE) in a 66-year-old woman with multi-organ involvement (lung, liver, and bone) who was subsequently treated with palliative radiation therapy and oral pazopanib. Furthermore, follow-up 18F-FDG PET/CT findings are detailed. EHE is a rare malignant vascular neoplasm (<1% of all vascular tumors) with an epithelioid and histiocytoid appearance arising from the vascular endothelial and preendothelial cells.

A Prospective Comparative Study between 99mTc MIBI Myocardial Perfusion Single-Photon Emission Computed Tomography and Dobutamine Stress Echocardiography to Detect Viable Myocardium in Patients with Coronary Artery Disease.

Introduction: The objective of this study was to compare 99mTc MIBI myocardial perfusion SPECT and Dobutamine Stress Echocardiography (DSE) in detecting viable myocardium in patients with Coronary Artery Disease. Materials and Methods: Total of 50 patients who with CAD and poor LV function were idenitifed on 2D Echo using 16 segment cardiac model. These patients underwent 99mTc MIBI myocardial perfusion SPECT and Dobutamine Stress Echocardiography and the results were compared with the gold standard 18F-FDG PET-CT findings. Results: A Total of 550 dysfunctional segments were identified in datasets of 50 patients on 2D echo. No significant difference was noted between the pairwise positive outcome of viable segment between MIBI SPECT and DSE (p=0.875). MIBI SPECT showed a sensitivity of 86.5% and specificity of 90.0% when compared with 18F-FDG PET-CT which was comparable with DSE having a sensitivity of 87.6% and specificity of 90.7%. Conclusion: 99mTc MIBI SPECT is an effective good alternative for evaluation of viable myocardial segments in patients with dysfunctional myocardium and can be considered especially in elderly or obese patients and patients with lung disease having poor echocardiographic imaging window due to lack of an optimal acoustic window.

Whole-body 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Demonstrating Multiple Rare Extracranial Metastases in a Treated Case of Glioblastoma.

Glioblastoma (GBM) is the most aggressive primary brain tumor in adults that accounts for nearly 20% of all primary malignant brain tumors. While GBM is notable for local recurrence and invasion, extracranial metastases (ECMs) are exceedingly rare, occurring in <2% of patients. However, the report of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) imaging in evaluating ECM is limited, and the importance of whole-body FDG PET/CT imaging in GBM has not been well elucidated. We present here a case of GBM, post excision 12 years before, whole-body 18F-FDG PET/CT showing no recurrence in the brain and ECM to multiple bones, right kidney, and pancreas.

Predictive value of metabolic parameters derived from preoperative 18F-FDG positron emission tomography/computed tomography for brain metastases in patients with surgically resected non-small cell lung cancer.

Background: Brain metastases (BMs) are common complications in patients with non-small cell lung cancer (NSCLC). The purpose of this study was to investigate whether the metabolic parameters derived from preoperative 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) can predict BM development in patients with surgically resected NSCLC. Methods: We retrospectively reviewed 128 consecutive patients with stage I-IIIA NSCLC who underwent 18F-FDG PET/CT before curative surgery at The First Affiliated Hospital of Jinan University between November 2012 and October 2021. By drawing a volume of interest (VOI), the maximum standardized uptake values (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumor as well as the mean SUV (SUVmean) of the liver and arterial blood were measured. The tumor-to-liver SUV ratio (TLR) and tumor-to-blood SUV ratio (TBR) were also calculated. Receiver operating characteristic curve analysis was used to determine the best cut-off values for positron emission tomography (PET) parameters to predict BM-free survival, and Cox proportional hazards regression analysis was used to assess the predictive value of clinical variables and PET parameters. Results: The median follow-up duration for survival patients was 23.4 months, and 15 patients (11.7%) experienced BM as the initial relapse site. The cumulative rates of BM over the course of 1, 2, and 5 years were 4.5%, 10.5%, and 17.5%, respectively. The optimal cut-off values for the prediction of BM-free survival were 7.7, 4.9, and 4.5 for SUVmax, TLR, and TBR, and 5.5 mL and 16.1 for MTV and TLG, respectively. In the Cox proportional hazards model, the risk of BM was significantly associated with TLR [hazard ratio (HR) =10.712; 95% confidence interval (CI): 2.958-38.801; P<0.001] and MTV (HR =3.150; 95% CI: 0.964-10.293; P=0.020) after adjusting for tumor stage, clinicopathological factors, and other PET parameters. Conclusions: Preoperative TLR and MTV of the primary tumor may be helpful in predicting BM development in patients with surgically resected NSCLC. Tumor metabolic parameters may potentially be used to stratify the risk of BM and determine individualized surveillance strategies.

Appearance of aseptic vascular grafts after endovascular aortic repair on [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography.

BACKGROUND: Diagnosis of prosthetic vascular graft infection with [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) allows for early detection of functional changes associated with infection, based on increased glucose utilization by activated macrophages and granulocytes. Aseptic vascular grafts, like all foreign bodies, can stimulate an inflammatory response, which can present as increased activity on 18F-FDG PET/CT. Consequently, distinguishing aseptic inflammation from graft infection, though important, can be difficult. In the case of endovascular aneurysm repair (EVAR), a minimally invasive procedure involving the transfemoral insertion of an endoprosthetic stent graft, the normal postoperative appearance of these grafts on 18F-FDG PET/CT can vary over time, potentially confounding study interpretation. AIM: To investigate the visual, semiquantitative, and temporal characteristics of aseptic vascular grafts in patients status post EVAR. METHODS: In this observational retrospective cohort study, patients with history of EVAR who underwent 18F-FDG PET/CT for indications other than infection were identified retrospectively. All patients were asymptomatic for graft infection - no abdominal pain, fever of unknown origin, sepsis, or leukocytosis - at the time of imaging and for ≥ 2 mo after each PET/CT. Imaging studies such as CT for each patient were also reviewed, and any patients with suspected or confirmed vascular graft infection were excluded. One hundred two scans performed on 43 patients (34 males; 9 females; age = 77 ± 8 years at the time of the final PET/CT) were retrospectively reviewed. All 43 patients had an abdominal aortic (AA) vascular graft, 40 patients had a right iliac (RI) limb graft, and 41 patients had a left iliac (LI) limb graft. Twenty-two patients had 1 PET/CT and 21 patients had from 2 to 9 PET/CTs. Grafts were imaged between 2 mo to 168 mo (about 14 years) post placement. Eight grafts were imaged within 6 mo of placement, including three that were imaged within three months of placement. The mean interval between graft placement and PET/CT for all 102 scans was 51 ± 39 mo. PET/CT data was reconstructed with region-of-interest analysis of proximal, mid and distal portions of the grafts and background ascending aorta. Maximum standardized uptake value (SUVmax) was recorded for each region. SUVmax-to-background uptake ratios (URs) were calculated. Visual assessment was performed using a 2-pattern grading scale: Diffuse (homogeneous uptake less than liver uptake) and focal (one or more areas of focal uptake in any part of the graft). Statistical analysis was performed. RESULTS: In total, there were 306 AA grafts, 285 LI grafts, 282 RI grafts, and 306 ascending aorta background SUVmax measurements. For all 102 scans, mean SUVmax values for AA grafts were 2.8-3.0 along proximal, mid, and distal segments. Mean SUVmax values for LI grafts and RI grafts were 2.7-2.8. Mean SUVmax values for background were 2.5 ± 0.5. Mean URs were 1.1-1.2. Visual analysis of the scans reflected results of quantitative analysis. On visual inspection, 98% revealed diffuse, homogeneous 18F-FDG uptake less than liver. Graft URs and visual pattern categories were significantly associated for AA graft URs (F-ratio = 21.5, P < 0.001), LI graft URs (F-ratio = 20.4, P < 0.001), and RI graft URs (F-ratio = 30.4, P < 0.001). Thus, visual patterns of 18F-FDG uptake corresponded statistically significantly to semiquantitative URs. The age of grafts showing focal patterns was greater than grafts showing diffuse patterns, 87 ± 89 vs 50 ± 37 mo, respectively (P = 0.02). URs were significantly associated with graft age for AA grafts (r = 0.19, P = 0.001). URs were also significantly associated with graft age for LI grafts (r = 0.25, P < 0.0001), and RI grafts (r = 0.31, P < 0.001). Quartiles of similar numbers of graft (n = 25-27) grouped by graft age indicated that URs were significantly higher for 4th quartile vs 2nd quartile URs (F-ratio = 19.5, P < 0.001). When evaluating URs, graft SUVmax values within 10%-20% of the ascending aorta SUVmax is evident in aseptic grafts, except for grafts in the oldest quartiles. In this study, grafts in the oldest quartiles (> 7 years post EVAR) showed SUVmax up to 30% higher than the ascending aorta SUVmax. CONCLUSION: Characteristics of an aseptic vascular stent graft in the aorta and iliac vessels on 18F-FDG PET/CT include graft SUVmax values within 10%-20% of the ascending aorta background SUVmax. The SUVmax of older aseptic grafts can be as much as 30% above background. The visual uptake pattern of diffuse, homogeneous uptake less than liver was seen in 98% of aseptic vascular grafts, making this pattern particularly reassuring for clinicians.

Recurrent Renal Cell Carcinoma Presenting as Port-Site Metastases, Detected on 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography.

The incidence of port-site metastases (PSMs) varies with the tumor type with adenocarcinoma having a high incidence. However, it is rarely seen in urological malignancies and more so in renal cell carcinoma (RCC). We hereby describe one such case of PSM after laparoscopic radical nephrectomy for RCC, which was detected on 18F-fluorodeoxyglucose positron emission tomography-computed tomography.

F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Muscle Uptake in Antiglutamic Acid Decarboxylase Antibody-positive Stiff-person Syndrome.

Antiglutamic acid decarboxylase-65 (anti-GAD65) autoantibodies have been identified in variety of rare neurologic disorders most frequently in stiff-person syndrome (SPS), condition characterized by muscle rigidity and overlying painful spasms, typically affecting axial and limb musculature. In anti-GAD65-related neurologic disorder, malignancy screening is often performed with 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). Here, we present an interesting image of 18FFDG PET/CT whole body showing muscle uptake and FDG brain showing thalamic hypometabolism in SPS.