68Ga-FAP-2286 PET of Solid Tumors: Biodistribution, Dosimetry, and Comparison with 18F-FDG.

Fibroblast activation protein (FAP), expressed in the tumor microenvironment of a variety of cancers, has become a target of novel PET tracers. The purpose of this report is to evaluate the imaging characteristics of 68Ga-FAP-2286, present the first-to our knowledge-dosimetry analysis to date, and compare the agent with 18F-FDG and FAPI compounds. Methods: Patients were administered 219 ± 43 MBq of 68Ga-FAP-2286 and scanned after 60 min. Uptake was measured in up to 5 lesions per patient and within the kidneys, spleen, liver, and mediastinum (blood pool). Absorbed doses were evaluated using MIM Encore and OLINDA/EXM version 1.1 using the International Commission on Radiological Protection publication 103 tissue weighting factor. Results: Forty-six patients were imaged with 68Ga-FAP-2286 PET. The highest average uptake was seen in sarcoma, cholangiocarcinoma, and colon cancer. The lowest uptake was found in lung cancer and testicular cancer. The average SUVmax was significantly higher on 68Ga-FAP-2286 PET than on 18F-FDG PET in cholangiocarcinoma (18.2 ± 6.4 vs. 9.1 ± 5.0, P = 0.007), breast cancer (11.1 ± 6.8 vs. 4.1 ± 2.2, P < 0.001), colon cancer (13.8 ± 2.2 vs. 7.6 ± 1.7, P = 0.001), hepatocellular carcinoma (9.3 ± 3.5 vs. 4.7 ± 1.3, P = 0.01), head and neck cancer (11.3 ± 3.5 vs. 7.6 ± 5.5, P = 0.04), and pancreatic adenocarcinoma (7.4 ± 1.8 vs. 3.7 ± 1.0, P = 0.01). The total-body effective dose was estimated at 1.16E-02 mSv/MBq, with the greatest absorbed organ dose in the urinary bladder wall (9.98E-02 mGy/MBq). Conclusion: 68Ga-FAP-2286 biodistribution, dosimetry, and tumor uptake were similar to those of previously reported FAPI compounds. Additionally,68Ga-FAP-2286 PET had consistently higher uptake than 18F-FDG PET. These results are especially promising in the setting of small-volume disease and differentiating tumor from inflammatory uptake.

Heterogeneous Uptake of 68 Ga-DOTATATE and 18 F-FDG in Initial Diagnosed Neuroendocrine Tumors Patients : Which Patients Are Suitable for Dual-Tracer PET Imaging?

PURPOSE: This study was designed to assess the uptake heterogeneity in neuroendocrine tumor (NET) patients at initial diagnosis with dual-tracer PET imaging and the staging changes and prognostic value it brings to explore the indication of the use of dual-tracer PET. METHODS: Fifty-one newly diagnosed patients with pathologically confirmed NET who underwent 18 F-FDG and 68 Ga-DOTATATE PET imaging between January 2020 and September 2022 were enrolled. Dual-tracer uptake patterns were classified into 3 groups: A. 68 Ga-DOTATATE positive and 18 F-FDG negative, B. 68 Ga-DOTATATE positive and 18 F-FDG positive, and C. 68 Ga-DOTATATE negative and 18 F-FDG positive. Descriptive statistics were used to evaluate the heterogeneity of dual-tracer uptake patterns among different grading (G) groups, between primary and metastatic lesions, and staging changes. Moreover, dual-tracer uptake patterns, grade, age, sex, and stage were compared with progression-free survival (PFS) by Cox regression. RESULTS: In the different G groups, none of the patients with dual-tracer uptake pattern A had grade 3 histology, but 57% of patients with grade 1 disease had FDG avidity (25% of them resulting in dual-tracer uptake pattern C). Patients with no metastasis were well differentiated, but one of them presented with dual-tracer uptake pattern C. Different uptake patterns were also observed between primary and metastatic lesions, particularly 44% of patients with dual-tracer uptake pattern A of primary with FDG avidity of metastases. Moreover, 9 (17.6%) had new lesions detected by additional 18 F-FDG PET imaging, and 3 of them (5.9%) had clinical stage changed accordingly. The Cox regression test showed that the dual-tracer uptake patterns were significantly correlated with PFS by univariate and multivariate analyses ( P = 0.026 and 0.039, respectively), whereas the grade and stage did not correlate with survival (all P >0.05). CONCLUSION: The current study has proven the uptake heterogeneity of the NET at initial diagnosis and demonstrated the staging and prognostic value of dual-tracer PET imaging. Our preliminary results have confirmed the importance of dual-tracer imaging modalities and concluded that dual-tracer PET imaging could be considered as prognostic tool for all patients with an initial diagnosis of NET.

Overview of F18-FDG uptake patterns in retroperitoneal pathologies: imaging findings, pitfalls, and artifacts.

INTRODUCTION: Retroperitoneum can be the origin of a wide variety of pathologic conditions and potential space for disease spread to other compartments of the abdomen and pelvis. Computed tomography (CT) and magnetic resonance imaging (MRI) are often the initial imaging modalities to evaluate the retroperitoneal pathologies, however given the intrinsic limitations, F18-FDG PET/CT provides additional valuable metabolic information which can change the patient management and clinical outcomes. We highlight the features of retroperitoneal pathologies on F18-FDG PET/CT and the commonly encountered imaging artifacts and pitfalls. The aim of this review is to characterize primary and secondary retroperitoneal pathologies based on their metabolic features, and correlate PET findings with anatomic imaging. CONCLUSION: Retroperitoneal pathologies can be complex, ranging from oncologic to a spectrum of non-oncologic disorders. While crosse-sectional imaging (CT and MRI) are often the initial imaging modalities to localize and characterize pathologies, metabolic information provided by F18-FDG PET/CT can change the management and clinical outcome in many cases.

Drinking Large Volume of Hot Water May Cause Increased 18 F-FDG Uptake in Esophagus.

ABSTRACT: We present 2 cases of diffuse FDG accumulation in the esophagus due to drinking hot water before an 18 F-FDG PET/CT scan. Drinking large volume of hot water immediately before the FDG PET/CT study may lead to challenges in the interpretation of the hypermetabolic esophagus.

Preclinical study and first-in-human imaging of [18F]FAP-2286, and comparison with 2-[18F]FDG PET/CT in various cancer patients.

PURPOSE: Fibroblast-activated protein (FAP) is highly expressed in cancer-associated fibroblasts (CAFs) of many solid cancers, but low or absent in normal tissues. Our study aimed to develop a novel FAP-specific tracer, namely [18F]FAP-2286, and evaluated its performance in comparison with well-established agents such as [18F]FAPI-42 and [68Ga]Ga-FAP-2286 in preclinical research, as well as 2-[18F]FDG in pilot clinical study. METHODS: [18F]FAP-2286 was manually synthesized in accordance with Good Manufacturing Practice (GMP). Subsequent investigations encompassed cell uptake, competitive binding affinity, internalization and efflux assays using HT-1080hFAP cell lines. PET imaging and biodistribution studies were conducted in HEK-293ThFAP, A549hFAP, HT-1080hFAP tumor-bearing mice as well as HEK-293T, A549 and HT-1080 control groups. Furthermore, clinical evaluation of [18F]FAP-2286 was performed in fifteen patients with various cancers compared to 2-[18F]FDG PET. RESULTS: The radiolabeling yield of [18F]FAP-2286 was 30.53 ± 5.20%, with a radiochemical purity exceeding 97%. In cell assays, [18F]FAP-2286 showed specific uptake, high internalization fraction and low cellular efflux. Rapid tumor uptake and satisfactory tumor retention was observed on micro-PET imaging and cancer patients. Meanwhile, the clinical research demonstrated that [18F]FAP-2286 may represent an alternative for low glucose-metabolism malignant tumors PET imaging such as gastric cancers. CONCLUSION: [18F]FAP-2286 showed superior imaging quality including rapid and high target uptake and satisfactory retention in both tumor-bearing mice and cancer patients. It may emerge as a promising candidate for early or delayed phase imaging and 2-[18F]FDG non-avid cancers PET scan.

First-in-human assessment of the novel LAT1 targeting PET probe 18F-FIMP.

In the first-in-human PET study, we evaluated the biodistribution and tumor accumulation of the novel PET probe, (S)-2-amino-3-[3-(2-18F-fluoroethoxy)-4-iodophenyl]-2-methylpropanoic acid (18F-FIMP), which targets the tumor-related L-type amino acid transporter 1 (LAT1), and compared it with L-[methyl-11C]methionine (11C-MET) and 2-Deoxy-2-18F-fluoro-D-glucose (18F-FDG). 18F-FIMP biodistribution was revealed by whole-body and brain scans in 13 healthy controls. Tumor accumulation of 18F-FIMP was evaluated in 7 patients with a brain tumor, and compared with those of 11C-MET and 18F-FDG. None of the subjects had significant problems due to probe administration, such as adverse effects or abnormal vital signs. 18F-FIMP was rapidly excreted from the kidneys to the urinary bladder. There was no characteristic physiological accumulation in healthy controls. 18F-FIMP PET resulted in extremely clear images in patients with suspected glioblastoma compared with 11C-MET and 18F-FDG. 18F-FIMP could be a useful novel PET probe for LAT1-positive tumor imaging including glioblastoma.

Source-to-Target Automatic Rotating Estimation (STARE) - A publicly-available, blood-free quantification approach for PET tracers with irreversible kinetics: Theoretical framework and validation for [18F]FDG.

INTRODUCTION: Full quantification of positron emission tomography (PET) data requires an input function. This generally means arterial blood sampling, which is invasive, labor-intensive and burdensome. There is no current, standardized method to fully quantify PET radiotracers with irreversible kinetics in the absence of blood data. Here, we present Source-to-Target Automatic Rotating Estimation (STARE), a novel, data-driven approach to quantify the net influx rate (Ki) of irreversible PET radiotracers, that requires only individual-level PET data and no blood data. We validate STARE with human [18F]FDG PET scans and assess its performance using simulations. METHODS: STARE builds upon a source-to-target tissue model, where the tracer time activity curves (TACs) in multiple "target" regions are expressed at once as a function of a "source" region, based on the two-tissue irreversible compartment model, and separates target region Ki from source Ki by fitting the source-to-target model across all target regions simultaneously. To ensure identifiability, data-driven, subject-specific anchoring is used in the STARE minimization, which takes advantage of the PET signal in a vasculature cluster in the field of view (FOV) that is automatically extracted and partial volume-corrected. To avoid the need for any a priori determination of a single source region, each of the considered regions acts in turn as the source, and a final Ki is estimated in each region by averaging the estimates obtained in each source rotation. RESULTS: In a large dataset of human [18F]FDG scans (N = 69), STARE Ki estimates were correlated with corresponding arterial blood-based Ki estimates (r = 0.80), with an overall regression slope of 0.88, and were precisely estimated, as assessed by comparing STARE Ki estimates across several runs of the algorithm (coefficient of variation across runs=6.74 ± 2.48%). In simulations, STARE Ki estimates were largely robust to factors that influence the individualized anchoring used within its algorithm. CONCLUSION: Through simulations and application to [18F]FDG PET data, feasibility is demonstrated for STARE blood-free, data-driven quantification of Ki. Future work will include applying STARE to PET data obtained with a portable PET camera and to other irreversible radiotracers.

The CT and PET/CT findings in primary pulmonary lymphoepithelioma-like carcinoma with pathological correlation: a study of 215 cases.

AIM: To investigate the computed tomography (CT) and integrated positron-emission tomography (PET)/CT findings of primary pulmonary lymphoepithelioma-like carcinoma (PLELC). MATERIALS AND METHODS: The imaging and histopathological data of 215 patients with PLELC confirmed at histopathology were analysed retrospectively. All patients underwent CT, and 70 underwent PET/CT. None of the cohort had nasopharyngeal lymphoepithelioma-like carcinoma. RESULTS: The PLELC was demonstrated as a solitary nodule/mass in 188 cases (188/215, 87%), multiple nodules/masses in 12 cases (12/215, 6%), lobar or segmental consolidation in 15 cases (15/215, 7%). The tumour showed a well-defined margin in 171 cases (171/215, 80%), lobular sign in 177 cases (177/215, 82%), and spicule sign in 91 cases (91/215, 42%). Most of the cases showed homogeneous density in unenhanced CT (128/215, 60%), and vascular shadows inside the tumour in the arterial stage were found in 105 cases (105/158, 66%). Involvement of the bronchus was found in 154 cases (154/215, 72%). Hilar or mediastinal lymph nodes were enlarged in 160 patients (160/215, 74%). Seventy cases demonstrated avid 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) uptake on PET/CT. The range of maximum standardised uptake values (SUVmax) was 2.1-28.5 (14 ± 5.93). Microscopic pathological classification of 124 resected specimens included 87 cases of the Regaud type and 37 cases of the Schmincke type. Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) was positive in all 215 cases. CONCLUSION: PLELC should be suspected when a large, lobulate, well-defined lung tumour with homogeneous density, vascular encasement, and high 18F-FDG uptake is found. Moreover, EBERs are helpful in patients with suspected PLELC.

Evolution of 18F-FDG PET/CT Findings in Patients After COVID-19: An Initial Investigation.

The aim of this study was to assess the temporal evolution of pulmonary 18F-FDG uptake in patients with coronavirus disease 2019 (COVID-19) and post-COVID-19 lung disease (PCLD). Methods: Using our hospital's clinical electronic records, we retrospectively identified 23 acute COVID-19, 18 PCLD, and 9 completely recovered 18F-FDG PET/CT patients during the 2 peaks of the U.K. pandemic. Pulmonary 18F-FDG uptake was measured as a lung target-to-background ratio (TBRlung = SUVmax/SUVmin) and compared with temporal stage. Results: In acute COVID-19, less than 3 wk after infection, TBRlung was strongly correlated with time after infection (rs = 0.81, P < 0.001) and was significantly higher in the late stage than in the early stage (P = 0.001). In PCLD, TBRlung was lower in patients treated with high-dose steroids (P = 0.003) and in asymptomatic patients (P < 0.001). Conclusion: Pulmonary 18F-FDG uptake in COVID-19 increases with time after infection. In PCLD, pulmonary 18F-FDG uptake rises despite viral clearance, suggesting ongoing inflammation. There was lower pulmonary 18F-FDG uptake in PCLD patients treated with steroids.

Association Between Time Since Administration of Pegylated G-CSF (Pegfilgrastim) and Bone Marrow Uptake on FDG PET/CT: Determination of a Minimum Interval.

BACKGROUND. Pegfilgrastim administration after chemotherapy increases bone marrow and spleen FDG uptake. Consensus is lacking regarding the optimal interval between pegfilgrastim administration and FDG PET/CT. OBJECTIVE. The purpose of this study was to assess the association between bone marrow and spleen uptake and the interval between pegfilgrastim administration and FDG PET/CT. METHODS. This retrospective study included 70 oncology patients (mean age, 64 ± 12 [SD] years; 48 men, 22 women) receiving chemotherapy who underwent FDG PET/CT (study scan) within 35 days after pegfilgrastim administration and who underwent additional FDG PET/CT at least 4 months before pegfilgrastim initiation or at least 3 months after last pegfilgrastim administration (reference scan). A nuclear medicine physician recorded the SUVmean for normal osseous structures and spleen and assessed bone marrow uptake using a 4-point visual scale (1, no abnormal uptake; 2, clinically insignificant uptake; 3, clinically significant uptake possibly interfering with interpretation; 4, clinically significant uptake expected to interfere with interpretation). RESULTS. Percentage change in SUVmean between reference and study scans significantly increased (p < .05) as the interval increased for five sites (i.e., for patients with interval of 7-13 vs 29-35 days, mean percentage change was 32.3% ± 18.2% vs 11.5% ± 17.3% for cervical vertebra, 42.2% ± 18.3% vs 21.3% ± 14.2% for thoracic vertebra, 47.2% ± 19.8% vs 19.1% ± 13.9% for lumbar vertebra, 51.1% ± 25.8% vs 12.7% ± 11.3% for pelvis, and 53.0% ± 25.6% vs 4.4% ± 14.1% for lower extremity); percentage change was not associated with the interval for upper extremity or spleen (p > .05). Visual uptake scores of 4, 3, 2, and 1 were observed in days 7-21, 12-22, 12-28, and 14-35, respectively. Percentage of patients with a score of 3 or 4 was 94.4% for days 7-13, 58.1% for days 14-21, 6.7% for days 22-28, and 0% for days 29-35. A total of 71.4% of patients had a score of 3 or 4 on day 7-21, whereas 4.8% had a score of 3 and 0% had a score of 4 on days 22-35. CONCLUSION. A visual uptake score of 3 or 4 was consistently observed throughout an approximately 3-week interval following pegfilgrastim administration, without any such case beyond 22 days. CLINICAL IMPACT. We recommend a preferred interval of at least 3 weeks after pegfilgrastim administration before PET/CT.

Effect of metformin on 18F-fluorodeoxyglucose uptake and positron emission tomographic imaging.

Metformin is widely used to treat diabetes, but induces changes in glucose uptake in both normal organs and tumors. Here, we review the effects of metformin on the uptake of 18F-fludeoxyglucose (18F-FDG) in tissues and tumors, and its influence on 18F-FDG positron emission tomographic imaging (18F-FDG PET), as well as the mechanisms involved. This is an important issue, because metformin has diverse effects on tissue uptake of 18F-FDG, and this can affect the quality and interpretation of PET images. Metformin increases glucose uptake in the gastrointestinal tract, cerebral white matter, and the kidney, while regions of the cerebrum associated with memory show decreased glucose uptake, and the myocardium shows no change. Hepatocellular carcinoma and breast cancer show increased glucose uptake after metformin administration, while thyroid cancer shows decreased uptake, and colon and pancreatic cancers show no change. A high-energy diet increases 18F-FDG uptake, but this effect is blocked by metformin. Withdrawal of metformin 48 h before PET image acquisition is widely recommended. However, based on our review of the literature, we propose that the differentiation of metformin discontinuation could be reasonable. But future clinical trials are still needed to support our viewpoint.

18 F-fluorodeoxy-glucose positron emission tomography pattern and prognostic predictors in patients with anti-GABAB receptor encephalitis.

AIMS: To identify the metabolic pattern and prognostic predictors in anti-gamma-aminobutyric-acid B (GABAB) receptor encephalitis using 18 F-fluorodeoxy-glucose positron emission tomography (18 F-FDG-PET). METHODS: Twenty-one patients diagnosed anti-GABAB receptor encephalitis who underwent 18 F-FDG-PET at first hospitalization were retrospectively reviewed. 18 F-FDG-PET images were analyzed in comparison with controls. Further group comparisons of 18 F-FDG-PET data were carried out between prognostic subgroups. RESULTS: 18 F-FDG-PET was abnormal in 81% patients with anti-GABAB receptor encephalitis and was more sensitive than MRI (81% vs. 42.9%, p = 0.025). Alter limbic lobe glucose metabolism (mostly hypermetabolism) was observed in 14 patients (66.7%), of whom 10 (10/14, 71.4%) demonstrated hypermetabolism in the medial temporal lobe (MTL). Group analysis also confirmed MTL hypermetabolism in association with relative frontal and parietal hypometabolism was a general metabolic pattern. After a median follow-up of 33 months, the group comparisons revealed that patients with poor outcome demonstrated increased metabolism in the MTL compared to those with good outcome. CONCLUSION: 18 F-FDG-PET may be more sensitive than MRI in the early diagnosis of anti-GABAB receptor encephalitis. MTL hypermetabolism was associated with relative frontal or parietal hypometabolism and may serve as a prognostic biomarker in anti-GABAB receptor encephalitis.

Diagnostic yield of CT-guided lung biopsies: how can we limit negative sampling?

OBJECTIVES: To investigate whether lesion imaging features may condition the outcome of CT-guided lung biopsy (CTLB) and to develop a scoring system of biopsy outcome prediction. METHODS: This is a single center retrospective study on 319 CTLBs that were performed in 319 patients (167 males/152 females, mean age 68 ± 12.2). Uni- and multivariate analysis were performed aiming to assess the imaging features that are likely to be correlated to a negative biopsy outcome and patients were stratified in groups accordingly. RESULTS: Technical success was 100%. 78% of the biopsies (250/319) led to a concrete histology report (218 malignant/32 benign). The remaining lesions led to concrete histology at a second attempt that occurred on a later time. Multivariate analysis revealed increased risk of inconclusive result for nodules with low fludeoxyglucose uptake [odds ration (OR) = 2.64, 95% confidence interval (CI) 1.4-4.97; p = 0.003], for nodules with diameter smaller than 18 mm (OR = 2.03, 95% CI 1.14-3.62; p = 0.017) and for nodules that are located in one of the lung bases (OR = 1.96, 95% CI 1.06-3.62; p = 0.033). Three different groups of patients were identified accordingly with low (<30%), medium (30-50%) and high (>50%) probability of obtaining an inconclusive biopsy sample. CONCLUSION: This study confirms that percutaneous CT-guided biopsy in nodules that are either small in diameter or present low positron emission tomography-fludeoxyglucose uptake or are in one of the lung bases may lead to inconclusive histology. This information should be factored when planning percutaneous biopsies of such nodules in terms of patient informed consent and biopsy strategy. ADVANCES IN KNOWLEDGE: Inconclusive histology after lung biopsy may be subject to factors irrelevant to technical success. Lung biopsy histology outcomes may be predicted and avoided after adequate planning.

Noninvasive estimation of human radiation dosimetry of 18F-FDG by whole-body small animal PET imaging in rats.

PURPOSE: Small animal PET provides the biodistribution of administrated radiotracer in vivo and have a potential to contribute on dosimetry study. The aim of this study is to investigate the effect of region-of-interest (ROI)-delineation in whole-body rat PET image toward non-invasive estimation of human dosimetry of 18F-FDG. METHOD: After administration of 18F-FDG (averaged 11.7 MBq), 3.5-h PET and 20-min CT scans were sequentially performed for three rats by Clairvivo PET/CT system. Seven source organs, and the remainder of the body, were studied to extrapolate %ID(t) and estimate time-integrated activity coefficients [kBq-h/MBq] in human. The mean absorbed dose in each target organ and the effective dose were estimated by MIRD method. Effects of ROI-definitions on both extrapolated %ID(t) in human and estimated doses were also investigated by using (i) small ROIs of high uptake region and (ii) whole organ ROIs. RESULTS: Averaged effective doses of 18F-FDG in human by using high-uptake and whole-organ ROIs were 27.8 ± 6.54 and 19.3 ± 2.72 µSv/MBq, respectively. CONCLUSION: The use of small animal PET scanner, which allows repeatedly PET scans, have a potential to contribute on the reduction of the number of experimental animals. However, the ways of ROI drawing influences on the estimated effective dose and safe-side ROI definition may be preferred.

The role of 18F-FDG PET/CT in diagnosis and treatment evaluation for ocular adnexal mucosa-associated lymphoid tissue lymphoma.

OBJECTIVE: The purpose of this study is to evaluate the value of fluorine-18-fludeoxyglucose positron emission tomography (18F-FDG PET)/CT in the diagnosis and treatment evaluation of ocular adnexal mucosa-associated lymphoid tissue (MALT) lymphoma. METHODS: 70 patients with OAML who received radiotherapy were recruited in our study. All the patients had the 18F-FDG PET/CT examination before the treatment. We retrospectively reviewed the medical records, pathological reports, laboratory results, and imaging features of all patients. The associations between 18F-FDG PET/CT parameters and Epstein-Barr virus antibodies, treatment response, MRI data, and Ki-67 expression were investigated. RESULTS: The PET/CT scan indicated that 80% (56/70) of the patients showed orbital FDG avidity. The median level of maximum standardized uptake value (SUVmax) of the lesions was 4.65 ± 3.00 (range:1.2-13.5). 92.0% (46/50) of the mass-forming lesions showed 18F-FDG avidity, while only 50.0% (10/20) of the non-massive lesions had 18F-FDG avidity (χ2 = 13.23, p=0.01). The SUVmax in orbit, conjunctiva, and lacrimal gland lymphoma were 5.6, 2.9, and 3.7, respectively. A significant difference was identified of SUVmax among the three locations' lymphoma using one-way ANOVA analysis (F = 5.039, p = 0.01). After completion of radiotherapy, the complete remission rate was achieved in 30.8% (4/13) of the patients without 18F-FDG avidity, and 70.4% (38/54) in cases with 18F-FDG avidity (χ2 = 5.43, p = 0.02). The correlation between high Ki-67 score and 18F-FDG avidity was confirmed (χ2 = 3.916, p = 0.048); however, no significant correlation was found between the SUVmax and Ki-67 score of the lesions (p = 0.971). Three patients (3/70, 4.3%) were upregulated the stage via PET/CT. CONCLUSION: 18F-FDG PET/CT had some potential values in the diagnosis and assessment of treatment response in patients with OAML. ADVANCES IN KNOWLEDGE: The value of 18F-FDG PET/CT for patients with OAML.

Spinal cord injury chronically depresses glucose uptake in the rodent model.

The pathophysiology following spinal cord injury (SCI) progresses from its lesion epicenter resulting in cellular and systemic changes acutely, sub-acutely and chronically. The symptoms of the SCI depend upon the severity of the injury and its location in the spinal cord. However, there is lack of studies that have longitudinally assessed acute through chronic in vivo changes following SCI. In this combinatorial study we fill this gap by evaluating acute to chronic effects of moderate SCI in rats. We have used fluorodeoxyglucose (FDG) imaging with positron emission tomography (PET) as a marker to assess glucose metabolism, motor function, and immunohistochemistry to examine changes following moderate SCI. Our results demonstrate decreased FDG uptake at the injury site chronically at days 28 and 90 post injury compared to baseline. This alteration in glucose uptake was not restricted to the lesion site, showing depressed FDG uptake in non-injured areas (cervical spinal cord and cerebellum). The alteration in glucose uptake was correlated with reductions in neuronal cell viability and increases in glial cell activation at 90 days at the lesion site, as well as chronic impairments in motor function. These data demonstrate the chronic effects of SCI on glucose metabolism both within the lesion and distally within the spinal cord and brain.

Pulmonary cavitations with increased 18F-FDG uptake revealing a thoracic endometriosis: A case report.

RATIONALE: Thoracic endometriosis is a rare disorder that can involve airways, pleura and lung parenchyma. It is the most frequent form of extra-abdominopelvic endometriosis. Multiple lung cavitations are a rare feature of thoracic endometriosis. PATIENT CONCERNS: A 46-year-old woman was referred to our hospital after incidental finding of multiple pulmonary cavitations with surrounding areas of ground glass opacity on a thoraco-abdominal computed tomography-scan performed for abdominal pain. Retrospectively, the patient also reported mild hemoptysis occurring 4 months ago. DIAGNOSES: Positron emission tomography-computed tomography scan revealed moderate and homogeneous [18F] fluoro-2-deoxy-D-glucose (18F-FDG) uptake in pulmonary cavitations (maximum standardized uptake value 5.7). The diagnosis of thoracic endometriosis was confirmed by histological examination of surgical resection of a left lower lobe cavitation. INTERVENTIONS AND OUTCOME: Gonadotropin-releasing hormone analogues associated with add-back therapy was started. Four months after initiating pharmacological treatment, the chest computed tomography-scan showed a dramatic decrease in lung cavitations size. LESSONS: Thoracic endometriosis is a rare disorder requiring a multidisciplinary management including gynaecologist, pulmonologist, radiologist, nuclear physician, pathologist and thoracic surgeon for early diagnosis and treatment. Our case report highlights that an increased 18F-FDG uptake can be found in thoracic endometriosis syndrome presenting as multiple lung cavitations.

Predictive value of metabolic activity detected by pre-operative 18F FDG PET/CT in ampullary adenocarcinoma.

ABSTRACT: In ampullary adenocarcinoma cases, the clinical effects of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) have not yet been well-studied, unlike other prognostic factors that have been reported till date. This study aimed to investigate the clinical impact of maximum standardized uptake value (SUVmax) in predicting the prognosis of ampullary adenocarcinoma.Thirty-eight patients who underwent pre-operative 18F-FDG PET/CT and curative-intent resection of ampullary adenocarcinoma at Pusan National University Hospital (Pusan, South Korea) between 2008 and 2017 were retrospectively analyzed in this study. We evaluated the clinicopathologic outcomes according to the SUVmax using univariate and multivariate Cox proportional hazard regression analyses and receiver operating characteristic analysis to arrive at a cutoff value.Lymph node metastasis was detected in 9 patients, and 15 patients experienced a recurrence during the follow-up period. Among 38 patients, 33 showed an increased FDG uptake by the main tumor. SUVmax of 4.55 was selected as a significant independent predictive factor for patient survival along with poor tumor differentiation and high neutrophil-to-lymphocyte ratio in multivariate analysis (P = .016, hazard ratio = 5.040). Patients with SUVmax under 4.55 exhibited significantly longer overall survival than the rest (<4.55 vs ≥4.55), and the 5-year overall survival was 82.8% versus 57.4% (P = .049).SUVmax of 4.55 on 18F-FDG PET/CT could be a predictive factor for tumor biology and long-term survival in patients with ampullary adenocarcinoma. Nevertheless, considering the cost aspect and its limited prognostic effect, this study seems to require more patient and multicenter studies.

Total lesion glycolysis as a predictor of clinical T3-4a laryngeal cancer with laryngectomy or nonlaryngectomy.

ABSTRACT: The purpose of the present study is to investigate whether the 18F-fluorodeoxyglucose (18F-FDG) uptake parameter is related to survival outcomes for patients with clinical T3-T4a laryngeal cancer with various definitive treatments including total laryngectomy (TL). Parameters of 18F-FDG uptake in the primary tumors of 46 cases which were assessed by positron emission tomography with computed tomography were enrolled in the present observation study. Monovariate or multivariate survival analyses were performed with log-rank test or Cox regression model, with the hazard ratio (HR) and 95% confidence interval (CI), respectively. Cutoff values of the 18F-FDG uptake parameters were determined by the lowest P-value for monovariate overall survival. In the monovariate analysis, both metabolic tumor volume ≥13.1 and total lesion glycolysis (TLG) ≥46.5 were significantly associated with shorter overall survival, and TLG ≥46.5 was also related to a reduction in distant metastasis-free survival. In the multivariate analysis adjusting for clinical T classification (cT4/cT3) and treatment group (TL/non-TL), TLG (≥46.5/<46.5) was associated with both poorer overall (HR: 3.16, 95% CI: 1.10-9.49) and distant metastasis-free (HR: 8.91, 95% CI: 1.93-62.6) survival. In conclusion, TLG is a predictor for survival in laryngeal cancer.