Fluorodeoxyglucose Uptake Research Articles

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.

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.

Positron emission tomography neuroimaging of [18F]fluorodeoxyglucose uptake and related behavior in the Pink1-/- rat model of Parkinson disease.

Parkinson disease (PD) is a neurodegenerative condition affecting multiple sensorimotor and cognitive systems. The Pink1-/- rat model exhibits vocal, cognitive, and limb use deficits seen in idiopathic PD. We sought to measure glucose metabolism in brain regions in Pink1-/- and wild type (WT) rats, and to associate these to measures of ultrasonic vocalization, cognition, and limb use behavior. Pink1-/- (n = 12) and WT (n = 14) rats were imaged by [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in a repeated measures design at approximately 10 months of age and 6 weeks later. Relative regional glucose metabolism was indexed by whole brain normalized FDG uptake, which was calculated for 18 regions identified a priori for comparison. Behavioral measures included tests of communication via ultrasonic vocalization, cognition with 5-Choice Serial Reaction Time Test (5-CSRTT), and limb use with Cylinder Test and Challenge Beam. Relative glucose metabolism was significantly different in Pink1-/- rats in prelimbic area, striatum, nucleus ambiguus, globus pallidus, and posterior parietal association cortex compared to WT controls. For behavioral measures, Pink1-/- rats demonstrated quieter vocalizations with a restricted frequency range, and they showed increased number of foot-faults and hindlimb steps (shuffling) in limb motor tests. Significant behavior vs. brain correlations included associations of ultrasonic vocalization parameters with glucose metabolism indices in locus coeruleus and substantia nigra. FDG PET reveals abnormalities in relative regional brain glucose metabolism in Pink1-/- rats in brain regions that are important to cognition, vocalization, and limb motor control that are also impacted by Parkinson disease. This method may be useful for mechanistic studies of behavioral deficits and therapeutic interventions in translational studies in the Pink1-/- PD model.

Comparing total-body metabolic PET imaging signatures of lung cancer cachexia to other wasting conditions

Cancer cachexia (CC) is a debilitating wasting condition. While anorexia and muscle wasting are features of cachexia, CC is a distinct and poorly understood metabolic syndrome1. We harnessed preclinical models of lung cancer to study how glucose uptake changes during CC and performed comparative analyses with anorexia and muscle wasting. Lung K-rasG12D/+;Lkb1-/-(KL) mice suffering CC were imaged using [18F]fluorodeoxyglucose (FDG) PET at 15-19% weight loss alongside K-ras wild-type (WT) non-tumour bearing controls. Mice were injected with 12-18MBq of FDG, imaging 80-100 minutes post injection with the Mediso nanoScan® PET/MRI 1T. In non-tumour bearing male animals, we modelled anorexia, muscle wasting, and circulation of cachexia factor GDF15 as follows, respectively: fasted overnight for 20 hr, treated with dexamethasone 21-phosphate (dexa) (2mg/kg, i.p. daily, 21 days) and single injection of recombinant human GDF15 hormone (0.1 mg/kg s.c.). FDG ex vivo biodistribution showed increased uptake in myocardium (p<0.05), brain and liver (both p<0.01) of KL cachexic animals with no significant change in FDG blood pool. Like cachexic KL animals, FDG uptake in fasted animals increased in brain (p<0.0001), perhaps due to increased FDG blood pool. FDG uptake in skeletal muscles and brown adipose tissue decreased (both p<0.05) in fasted state suggesting lower muscle activity and decreased thermogenesis respectively. Dexa-induced muscle atrophy also resulted in decreased FDG uptake in gastrocnemius/soleus muscles (SUVmean 0.63 vehicle vs. 0.45 dexa, p<0.05) but no changes in skeletal muscle FDG uptake were noted in cachexic animals. In contrast to KL animals, GDF15 injection resulted in decreased FDG uptake in myocardium (p<0.05). Overall, the cachexic FDG signature showed differences to other wasting conditions in this mouse model, suggesting different underlying mechanisms. Total-body PET can reveal diverse metabolic wasting states. We aim to elucidate mechanisms of metabolic changes in cachexia to allow metabolic subtyping and personalised treatment options. Please click on the 'PDF' for the full abstract!

Heparin does not improve myocardial glucose metabolism suppression in [18 F]FDG PET/CT in patients with low β-hydroxybutyrate level

BackgroundInadequate myocardial glucose metabolism suppression (GMS) can hamper interpretation of cardiac [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET/CT). Use of β-hydroxybutyrate (BHB) measurement before [18F]FDG injection has been proposed for predicting adequate GMS. However, limited information is available on BHB measurement in guiding preparations for [18F]FDG-PET/CT. The purpose of this study was to evaluate if point-of-care measured BHB is useful in guiding heparin premedication for cardiac [18F]FDG-PET/CT.Results155 patients (82 male) had followed a high-fat, low-carbohydrate diet and fasted for at least twelve hours. For the first 63 patients, BHB was measured, but it was not used to guide premedication. For the subsequent 92 patients, heparin 50 IU/kg was injected intravenously 15–20 min before [18F]FDG injection if the BHB level was low (< 0.35 mmol/l). Cardiac [18F]FDG uptake pattern was evaluated visually and [18F]FDG uptake in the myocardium and blood pool were measured. Median BHB level was 0.4 (range 0.1–5.8) mmol/l. Eighty-eight patients (57%) reached a BHB level higher than 0.35 mmol/l. 112 patients (72%) had adequate GMS. In the high BHB group, 74 patients (84%) had adequate GMS, whereas of those with low BHB, only 38 (57%) had adequate GMS (p < 0.001). In the low BHB group, the prevalence of inadequate GMS was comparable in patients with and without heparin (44% vs. 42%, p = 0.875).ConclusionsWhile high BHB predicts adequate GMS, unfractionated heparin does not improve GMS in patients with low BHB.

Imaging Features Differentiating Between Cardiac Sarcomas and Hematologic Neoplasms.

The aim of the study is to assess the efficacy of computed tomography (CT) and positron emission tomography (PET)/CT findings in differentiating between cardiac sarcoma and cardiac hematologic neoplasms, which are rare but potentially lethal primary cardiac malignancies. We searched the electronic medical record for pathology-proven cases from 2012 to 2023, finding 69 patients (46 sarcomas, 23 cardiac hematologic neoplasms). Imaging features including tumor size, atrioventricular (AV) groove involvement, right coronary artery (RCA) encasement by 180°, pericardial effusion, lymphadenopathy, and metabolic activity on fluorodeoxyglucose PET were reviewed by a radiology fellow. Statistical analysis was performed using Fisher exact test and Wilcoxon test. Cardiac sarcoma patients were younger (median age 49 years) compared to patients with cardiac hematologic malignancies (66 years, P = 0.006). While tumor size and chamber involvement were similar between the 2 categories, hematologic malignancies exhibited a notable predilection for AV groove involvement (70% vs 43%, P = 0.04) and RCA encasement (52% vs 26%, P = 0.02). Pulmonary metastases were more frequent in sarcoma cases (33% vs 4%, P = 0.006). There was no significant difference in fluorodeoxyglucose uptake. Lymphadenopathy was similar between the 2 disease groups. A decision tree constructed using AV groove involvement and patient age achieved 75% accuracy in predicting the diagnosis of the mass. Overall, there is a substantial overlap in imaging features of cardiac sarcomas and hematologic malignancies involving the heart. Involvement of the AV groove and RCA encasement can allow a radiologist to favor hematologic malignancy. Ultimately, biopsy is required to establish a diagnosis.

Cardiovascular Disease, Brain Glucose Metabolism, and Neurocognitive Decline in People With Human Immunodeficiency Virus.

Cardiovascular disease (CVD) and neuroinflammation are thought to exacerbate neurocognitive dysfunction in treated people with human immunodeficiency virus (PWH). Here, we longitudinally measured brain glucose metabolism as a measure of neuronal integrity in treated PWH using [18F]Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in correlation with atherosclerotic cardiovascular disease (ASCVD) scores, cerebrospinal fluid (CSF) neuroinflammatory markers, neurocognitive outcomes, and other clinical and laboratory variables (CLVs). Well-controlled PWH (n = 36) underwent baseline and follow-up FDG PET/CT obtained 3.5 years apart on average. Longitudinal changes in whole brain and regional relative FDG uptake, brain volumes, CLVs, CSF cytokines, and neuropsychological measures were measured. A variable selection model identified baseline variables related to future brain metabolic changes while multivariable models explored neuropsychological implications of brain metabolism and volumetrics. High ASCVD scores predicted future decreased thalamic uptake (slope = -0.0068, P = .027) and decreasing thalamic uptake correlated with worsening cognition (slope = 15.80, P = .020). Despite longitudinal greater than expected gray matter loss, whole brain FDG uptake did not change over the follow-up period. Most CSF cytokines decreased longitudinally but were not predictive of FDG changes. We found that high ASCVD scores in a group of treated PWH were related to thalamic hypometabolism, which in turn correlated with neurocognitive decline. Our findings support the contribution of CVD to neurocognitive dysfunction. More proactive CVD management may have a role in mitigating progression of cognitive impairment. Lack of change in global brain glucose metabolism despite documented accelerated gray matter volume loss over the same period suggests that FDG PET might underestimate neuronal injury in PWH compared to structural magnetic resonance imaging.

Cancer and hidradenitis suppurativa

Patients with hidradenitis suppurativa (HS) have an increased risk of developing cancer. This includes not only hematologic malignancies and solid tumors but also cutaneous squamous cell carcinoma (SCC) originating within the HS lesions. The development of SCC is most commonly associated with Caucasian men who smoke and have severe gluteal or perianal lesions of more than 25 years. Other factors that have occasionally been associated with HS-related SCC include treatment with a tumor necrosis factor-alpha inhibitor (such as infliximab and adalimumab), genodermatoses (such as keratitis-ichthyosis-deafness syndrome and Dowling-Degos disease), and paraneoplastic syndromes (such as hypercalcemia, hypercalcemia-leukocytosis, and paraneoplastic neuropathy). The tumor may demonstrate the presence of human papillomavirus; even after treatment, patients have a poor prognosis because cancer metastasis, recurrence, or both commonly occur. The potential role of human papillomavirus vaccination for cancer prevention and early treatment of SCC with targeted therapy (with an epidermal growth factor inhibitor such as cetuximab) and/or checkpoint inhibitor immunotherapy (such as cemiplimab and pembrolizumab) remains to be determined. Rarely, HS lesions have mimicked cutaneous metastases in patients with visceral malignancy by demonstrating an increased uptake of fluorine-18 fluorodeoxyglucose on positron emission tomography and/or computed tomography scans. Primary cancers (such as cutaneous SCC and mucinous adenocarcinoma) and breast cancer skin metastases can masquerade as HS lesions. When a lesion is located at a current or earlier site of HS that is new or rapidly growing and/or does not respond to HS-directed therapy, prompt evaluation to establish or exclude the diagnosis of cancer should be considered.

Risk Stratification in Cardiac Sarcoidosis With Cardiac Positron Emission Tomography: A Systematic Review and Meta-Analysis

BackgroundAlthough positron emission tomography (PET) imaging is well established for its diagnostic role in cardiac sarcoidosis, less is known about the prognostic value of PET and its use in risk stratification for major adverse cardiac events (MACE). ObjectivesThe goal of this study was to perform a systematic review and meta-analysis looking at the prognostic value of PET imaging in patients with cardiac sarcoidosis. MethodsStudy investigators systematically searched EMBASE (Excerpta Medica dataBASE), MEDLINE, PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, CINAHL (Cumulative Index to Nursing and Allied Health Literature), ClinicalTrials.gov, and the European Union Clinical Trial Registry for cardiac sarcoidosis and PET imaging. The primary outcome of interest was MACE. ResultsThe search revealed 3,010 records, of which 55 studies were included. This represented 5,250 patients. Factors associated with MACE included the following: the combination of abnormal fluorodeoxyglucose (FDG) uptake and perfusion defect, which had an OR of 2.86 (95% CI: 1.74-4.71; P < 0.0001); abnormal perfusion or FDG uptake, which had an OR of 2.69 (95% CI: 1.67-4.33); abnormal FDG uptake, which had an OR of 2.61 (95% CI: 1.51-4.50); focal abnormal right ventricular uptake, which had an OR of 6.27 (95% CI: 3.19-12.32; P < 0.00001); and a lack of response to immunosuppression on serial PET, which had an OR of 8.43 (95% CI: 3.25-21.85; P < 0.0001). A QUIPS (Quality in Prognostic Studies) tool analysis found a low to moderate risk of bias, particularly given the small sample sizes in the individual studies. ConclusionsMultiple cardiac PET parameters provide risk stratification value in cardiac sarcoidosis. Focal right ventricular uptake and a lack of response to immunosuppressive therapy on serial PET imaging were particularly predictive of MACE.

The diagnostic value of prostate-specific membrane antigen PET-CT in differentiating medication-related osteonecrosis of the jaw and metastasis to the jawbone.

Medication-related osteonecrosis of the jaw (MRONJ) and jaw metastasis might share similar clinical and radiographic characteristics, with both demonstrating F-18 fluorodeoxyglucose (FDG) uptake on PET-CT. Prostate-specific membrane antigen (PSMA) PET-CT is used to demonstrate prostate cancer dissemination. Unlike FDG PET-CT, PSMA PET-CT is more specific to cancer than to inflammation. Therefore, we hypothesized that it might be a useful tool to differentiate between MRONJ and jaw metastasis. All files of prostate cancer patients diagnosed with MRONJ and with available PSMA PET-CT studies were retrieved. A similar number of solid cancer patients with MRONJ and with available FDG PET-CT studies served as a second study group. All studies were reviewed by 2 blinded co-investigators (L.D. and M.F.). Seventeen patients who underwent PSMA PET-CT (24 studies) and 15 patients who underwent FDG PET-CT (29 studies) met the inclusion criteria. All patients with FDG PET-CT studies showed pathological uptake at the site of MRONJ in at least one of their studies versus only 23.5% of patients in the PSMA PET-CT group (P < .001). FDG PET-CT studies showed pathological uptake in 89.6% of the studies compared with only 20.8% in the PSMA PET-CT group (P < .001). The mean standardized uptake value (SUVmax) and the mean uptake volume in the FDG PET-CT group were significantly higher compared with the PSMA PET-CT group (P < .001 and P < .005, respectively). The interclass correlation coefficient for all parameters was higher than 0.95. PSMA PET-CT is useful to differentiate between MRONJ and jaw metastasis.

Characterization of idiopathic chronic diarrhea and associated intestinal inflammation and preliminary observations of effects of vagal nerve stimulation in a non-human primate.

Diarrhea is commonly associated with irritable bowel syndrome, inflammatory bowel disease, microscopic colitis, and other gastrointestinal dysfunctions. Spontaneously occurring idiopathic chronic diarrhea is frequent in rhesus macaques, but has not been used as a model for the investigation of diarrhea or its treatment. We characterized this condition and present preliminary data demonstrating that left vagal nerve stimulation provides relief. Stool consistency scores were followed for up to 12 years. Inflammation was assessed by plasma C-reactive protein, [18F]fluorodeoxyglucose (FDG) uptake, measured by positron emission tomography (PET), multiplex T cell localization, endoscopy and histology. The vagus was stimulated for 9 weeks in conscious macaques, using fully implanted electrodes, under wireless control. Macaques exhibited recurrent periods of diarrhea for up to 12 years, and signs of inflammation: elevated plasma C-reactive protein, increased bowel FDG uptake and increased mucosal T helper1 T-cells. The colon and distal ileum were endoscopically normal, and histology revealed mild colonic inflammation. Application of vagal nerve stimulation to conscious macaques (10 Hz, 30 s every 3 h; 24 h a day for 9 weeks) significantly reduced severity of diarrhea and also reduced inflammation, as measured by FDG uptake and C-reactive protein. These macaques exhibit spontaneously occurring diarrhea with intestinal inflammation that can be reduced by VNS. The data demonstrate the utility of this naturally occurring primate model to study the physiology and treatments for chronic diarrhea and the neural control circuits influencing diarrhea and inflammation that are not accessible in human subjects.

Cardiac sarcoidosis treated with nonsteroidal immunosuppressive therapy

BackgroundNonsteroidal immunosuppressive therapy is a potential therapeutic strategy for cardiac sarcoidosis. However, it is not recommended as an established treatment option. This study aimed to demonstrate the clinical outcomes of patients with cardiac sarcoidosis using nonsteroidal immunosuppressants through the ILLUstration of the Management and PrognosIs of JapaNese PATiEnts with Cardiac Sarcoidosis multicenter retrospective registry. MethodsFrom a cohort of 512 patients, 426 who received corticosteroid therapy and 26 who received other immunosuppressive therapy were included for analysis. Clinical outcomes included all-cause death, fatal ventricular arrhythmic events (FVAE), and worsening heart failure with hospitalization. ResultsNonsteroidal immunosuppressants were used for retained fluorodeoxyglucose uptake in the heart (n = 14), corticosteroid side effects (n = 7), ventricular arrhythmia (n = 4), complete atrioventricular block (n = 2), worsened extracardiac sarcoidosis (n = 2), and other reasons (n = 2). They comprised of methotrexate (n = 20), cyclosporine (n = 2), cyclophosphamide (n = 2), and azathioprine (n = 3). After the addition of a nonsteroidal immunosuppressant, corticosteroids were reduced in 14 of 26 patients (5 [5–17] mg), although no patient discontinued corticosteroids. Of the 14 patients, decreased fluorodeoxyglucose uptake was observed in seven at follow-up. Clinical outcomes were observed in 11 patients (42.3 %). Detected events included all-cause death in five patients (19.2 %), FVAE in four (15.4 %), and worsening heart failure with hospitalization in five (19.2 %), with some overlap. ConclusionsNonsteroidal immunosuppressive therapy may be a possible treatment option for patients who are not stabilized with corticosteroids alone or develop corticosteroid side effects.

Multiple foci of Rosai–Dorfman disease in colon: a case report

BackgroundRosai–Dorfman disease (RDD) is an uncommon proliferative histiocytic disorder involving lymph nodes and various organs. Forty-three percent of RDD cases originate from extranodal sites; however, RDD rarely arises from the colon.Case presentationA 75-year-old man was admitted to our hospital because of intra-abdominal masses that were incidentally detected during surveillance by computed tomography (CT) after treatment for lung cancer. Enhanced CT showed two mass lesions located in the cecum to the appendix (diameter, 40 mm) and around the sigmoid colon (diameter, 24 mm). Positron emission tomography (PET)-CT revealed an apparent uptake of fluorodeoxyglucose. Intraluminal endoscopy did not reveal definite mucosal abnormalities. These findings suggest the presence of malignant neoplasms including gastrointestinal stromal tumors, lung cancer metastasis, and malignant lymphoma. Exploratory laparoscopy and/or tumor excision were planned to obtain a definitive diagnosis. Based on laparoscopic findings, ileocecal resection and sigmoidectomy were simultaneously performed to excise the tumors. Postoperative histopathological examination revealed multiple RDD originating from the mesocolon side of the cecum and the sigmoid colon. The patient did not receive any adjuvant therapy. No recurrence was observed one year after surgery.ConclusionRDD originating from the colon is extremely rare. Tumor extirpation or organ resection is sometimes required to obtain a definitive diagnosis of RDD, and minimally invasive surgery is helpful.

Diagnostic ability of [18F]FDG PET/CT for distinguishing benign from malignant spleen lesions.

[18F]Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is a non-invasive imaging modality used in the differential diagnosis of splenic lesions, although ideal parameters and thresholds remain unclear. The present study evaluated the ability of [18F]FDG PET/CT, including its visual and quantitative parameters, to differentiate between benign and malignant splenic lesions. Patients who underwent [18F]FDG PET/CT following the detection of splenic lesions on contrast-enhanced CT were retrospectively analysed. Visual parameters assessed on [18F]FDG PET/CT included whole spleen uptake intensity, lesion multiplicity, and lesion uptake, and quantitative parameters included maximum standardised uptake value (SUVmax), lesion-to-background ratio (LBR), metabolic tumour volume (MTV), total lesion glycolysis (TLG), and lesion size. Parameters differentiating between benign and malignant lesions were evaluated by Pearson's chi-square test, Mann-Whitney U-test, and receiver operating characteristics (ROC) curve analysis. Splenic lesion uptake (p = 0.001) was the only visual parameter significantly distinguishing between benign and malignant lesions. ROC curve analysis demonstrated that SUVmax had the largest area under the ROC, 0.91 (p < 0.001), with an optimal cut-off > 5.3 having a sensitivity of 90.3% and a specificity of 80.6%. Subgroup analysis of malignant lesions showed that SUVmax (p = 0.013), LBR (p = 0.012), and TLG (p = 0.034) were significantly higher in splenic lymphomas than in splenic metastases. Of the [18F]FDG PET/CT parameters investigated, SUVmax had the highest accuracy in diagnosing malignant splenic lesions and was significantly higher in splenic lymphomas than in splenic metastases. Visual determination of [18F]FDG uptake by splenic lesions may be an easily evaluated parameter. SUVmax and visual grade of [18F]FDG PET/CT help to differentiate spleen lesions. [18F]FDG PET/CT is useful for discriminating between benign and malignant spleen lesions. Many splenic lesions are difficult to diagnose on anatomical imaging, with histopathologic analyses are required. SUVmax of PET/CT provided the diagnostic ability to differentiate between benign and malignant splenic lesions. More than normal spleen uptake can be a convenient parameter to diagnose malignant spleen lesions.

SEC61 translocon gamma subunit is correlated with glycolytic activity, epithelial mesenchymal transition and the immune suppressive phenotype of lung adenocarcinoma.

Lung adenocarcinoma (LUAD) remains a predominant cause of cancer-related mortality globally, underscoring the urgency for targeted therapeutic strategies. The specific role and impact of the SEC61 translocon gamma subunit (SEC61G) in LUAD progression and metastasis remain largely unexplored. In this study, we use a multifaceted approach, combining bioinformatics analysis with experimental validation, to elucidate the pivotal role of SEC61G and its associated molecular mechanisms in LUAD. Our integrated analyses reveal a significant positive correlation between SEC61G expression and the glycolytic activity of LUAD, as evidenced by increased fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET)/CT scans. Further investigations show the potential influence of SEC61G on metabolic reprogramming, which contributes to the immunosuppressive tumor microenvironment (TME). Remarkably, we identify a negative association between SEC61G expression levels and the infiltration of critical immune cell populations within the TME, along with correlations with immune checkpoint gene expression and tumor heterogeneity scores in LUAD. Functional studies demonstrate that SEC61G knockdown markedly inhibits the migration of A549 and H2030 LUAD cells. This inhibitory effect is accompanied by a significant downregulation of key regulators of tumor progression, including hypoxia-inducible factor-1 alpha (HIF-1α), lactate dehydrogenase A, and genes involved in the epithelial-mesenchymal transition pathway. In conclusion, our comprehensive analyses position SEC61G as a potential prognostic biomarker intricately linked to glycolytic metabolism, the EMT pathway, and the establishment of an immune-suppressive phenotype in LUAD. These findings underscore the potential of SEC61G as a therapeutic target and predictive marker for immunotherapeutic responses in LUAD patients.

Comparative Uptake Patterns of Radioactive Iodine and [18F]-Fluorodeoxyglucose (FDG) in Metastatic Differentiated Thyroid Cancers.

Background: Metastatic differentiated thyroid cancer (DTC) represents a molecularly heterogeneous group of cancers with varying radioactive iodine (RAI) and [18F]-fluorodeoxyglucose (FDG) uptake patterns potentially correlated with the degree of de-differentiation through the so-called "flip-flop" phenomenon. However, it is unknown if RAI and FDG uptake patterns correlate with molecular status or metastatic site. Materials and Methods: A retrospective analysis of metastatic DTC patients (n = 46) with radioactive 131-iodine whole body scan (WBS) and FDG-PET imaging between 2008 and 2022 was performed. The inclusion criteria included accessible FDG-PET and WBS studies within 1 year of each other. Studies were interpreted by two blinded radiologists for iodine or FDG uptake in extrathyroidal sites including lungs, lymph nodes, and bone. Cases were stratified by BRAF V600E mutation status, histology, and a combination of tumor genotype and histology. The data were analyzed by McNemar's Chi-square test. Results: Lung metastasis FDG uptake was significantly more common than iodine uptake (WBS: 52%, FDG: 84%, p = 0.04), but no significant differences were found for lymph or bone metastases. Lung metastasis FDG uptake was significantly more prevalent in the papillary pattern sub-cohort (WBS: 37%, FDG: 89%, p = 0.02) than the follicular pattern sub-cohort (WBS: 75%, FDG: 75%, p = 1.00). Similarly, BRAF V600E+ tumors with lung metastases also demonstrated a preponderance of FDG uptake (WBS: 29%, FDG: 93%, p = 0.02) than BRAF V600E- tumors (WBS: 83%, FDG: 83%, p = 1.00) with lung metastases. Papillary histology featured higher FDG uptake in lung metastasis (WBS: 39%, FDG: 89%, p = 0.03) compared with follicular histology (WBS: 69%, FDG: 77%, p = 1.00). Patients with papillary pattern disease, BRAF V600E+ mutation, or papillary histology had reduced agreement between both modalities in uptake at all metastatic sites compared with those with follicular pattern disease, BRAF V600E- mutation, or follicular histology. Low agreement in lymph node uptake was observed in all patients irrespective of molecular status or histology. Conclusions: The pattern of FDG-PET and radioiodine uptake is dependent on molecular status and metastatic site, with those with papillary histology or BRAF V600E+ mutation featuring increased FDG uptake in distant metastasis. Further study with an expanded cohort may identify which patients may benefit from specific imaging modalities to recognize and surveil metastases.

Neurolymphomatosis secondary to primary central nervous system lymphoma: illustrative case.

Neurolymphomatosis (NL) is a rare disease defined as an invasion of lymphoma into peripheral nerves, nerve roots, or nerve plexuses, including the cranial nerves. No clear treatment protocols have yet been defined for this pathology. A woman in her 40s had a primary central nervous system lymphoma diagnosed from an intracranial tumor biopsy and underwent chemotherapy and radiation therapy. After she complained of pain in the trunk and extremities, magnetic resonance imaging and [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) performed 25 months after initial diagnosis revealed multiple lesions in the nerve ganglia, plexuses, and peripheral nerves from the cervical to the sacral spinal cord. Cerebrospinal fluid cytology revealed atypical lymphocytes and lymphoma dissemination in the spinal cavity. Based on these findings, NL was diagnosed. An intrathecal antineoplastic regimen temporarily reduced abnormal uptake of FDG, but the lesion recurred. After additional high-dose methotrexate therapy, FDG accumulation in the previously identified lesions disappeared. However, peripheral neuropathic pain and paraplegia remained. The patient died 9 months after the initial diagnosis of NL. The authors reported a case of NL following primary central nervous system lymphoma. In this case, FDG-PET proved useful for diagnosis, and high-dose methotrexate therapy was temporarily effective. https://thejns.org/doi/suppl/10.3171/CASE24107.

Controlled Delivery of Rosuvastatin or Rapamycin through Electrospun Bismuth Nanoparticle-Infused Perivascular Wraps Promotes Arteriovenous Fistula Maturation.

In the context of arteriovenous fistula (AVF) failure, local delivery enables the release of higher concentrations of drugs that can suppress neointimal hyperplasia (NIH) while reducing systemic adverse effects. However, the radiolucency of polymeric delivery systems hinders long-term in vivo surveillance of safety and efficacy. We hypothesize that using a radiopaque perivascular wrap to deliver anti-NIH drugs could enhance AVF maturation. Through electrospinning, we fabricated multifunctional perivascular polycaprolactone (PCL) wraps loaded with bismuth nanoparticles (BiNPs) for enhanced radiologic visibility and drugs that can attenuate NIH─rosuvastatin (Rosu) and rapamycin (Rapa). The following groups were tested on the AVFs of a total of 24 Sprague-Dawley rats with induced chronic kidney disease: control (i.e., without wrap), PCL-Bi (i.e., wrap with BiNPs), PCL-Bi-Rosu, and PCL-Bi-Rapa. We found that BiNPs significantly improved the wraps' radiopacity without affecting biocompatibility. The drug release profiles of Rosu (hydrophilic drug) and Rapa (hydrophobic drug) differed significantly. Rosu demonstrated a burst release followed by gradual tapering over 8 weeks, while Rapa demonstrated a gradual release similar to that of the hydrophobic BiNPs. In vivo investigations revealed that both drug-loaded wraps can reduce vascular stenosis on ultrasonography and histomorphometry, as well as reduce [18F]Fluorodeoxyglucose uptake on positron emission tomography. Immunohistochemical studies revealed that PCL-Bi-Rosu primarily attenuated endothelial dysfunction and hypoxia in the neointimal layer, while PCL-Bi-Rapa modulated hypoxia, inflammation, and cellular proliferation across the whole outflow vein. In summary, the controlled delivery of drugs with different properties and mechanisms of action against NIH through a multifunctional, radiopaque perivascular wrap can improve imaging and histologic parameters of AVF maturation.

Increased [18F]FDG uptake of radiation-induced giant cells: a single-cell study in lung cancer models

Positron emission tomography (PET), a cornerstone in cancer diagnosis and treatment monitoring, relies on the enhanced uptake of fluorodeoxyglucose ([18F]FDG) by cancer cells to highlight tumors and other malignancies. While instrumental in the clinical setting, the accuracy of [18F]FDG-PET is susceptible to metabolic changes introduced by radiation therapy. Specifically, radiation induces the formation of giant cells, whose metabolic characteristics and [18F]FDG uptake patterns are not fully understood. Through a novel single-cell gamma counting methodology, we characterized the [18F]FDG uptake of giant A549 and H1299 lung cancer cells that were induced by radiation, and found it to be considerably higher than that of their non-giant counterparts. This observation was further validated in tumor-bearing mice, which similarly demonstrated increased [18F]FDG uptake in radiation-induced giant cells. These findings underscore the metabolic implications of radiation-induced giant cells, as their enhanced [18F]FDG uptake could potentially obfuscate the interpretation of [18F]FDG-PET scans in patients who have recently undergone radiation therapy.

68Ga]FAPI PET for Imaging and Treatment Monitoring in a Preclinical Model of Pulmonary Fibrosis: Comparison to [18F]FDG PET and CT.

This study aimed to evaluate the feasibility of using [68Ga]-fibroblast-activating protein inhibitor (FAPI) positron emission tomography (PET) imaging for diagnosing pulmonary fibrosis in a mouse model. We also examined its value in monitoring treatment response and compared it with traditional [18F]-fluorodeoxyglucose (FDG) PET and computed tomography (CT) imaging. A model of idiopathic pulmonary fibrosis was established using intratracheal injection of bleomycin (BLM, 2 mg/kg) into C57BL/6 male mice. For the treatment of IPF, a daily oral dose of 400 mg/kg/day of pirfenidone was administered from 9 to 28 days after the establishment of the model. Disease progression and treatment efficacy were assessed at different stages of the disease every week for four weeks using CT, [18F]FDG PET, and [68Ga]FAPI PET (baseline imaging performed at week 0). Mice were sacrificed and lung tissues were harvested for hematoxylin-eosin staining, picrosirius red staining, and immunohistochemical staining for glucose transporter 1 (GLUT1) and FAP. Expression levels of GLUT1 and FAP in pathological sections were quantified. Correlations between imaging parameters and pathological quantitative values were analyzed. CT, [18F]FDG PET and [68Ga]FAPI PET revealed anatomical and functional changes in the lung that reflected progression of pulmonary fibrosis. In untreated mice with pulmonary fibrosis, lung uptake of [18F]FDG peaked on day 14, while [68Ga]FAPI uptake and mean lung density peaked on day 21. In mice treated with pirfenidone, mean lung density and lung uptake of both PET tracers decreased. Mean lung density, [18F]FDG uptake, and [68Ga]FAPI uptake correlated well with quantitative values of picrosirius red staining, GLUT1 expression, and FAP expression, respectively. Conclusions: Although traditional CT and [18F]FDG PET reflect anatomical and metabolic status in fibrotic lung, [68Ga]FAPI PET provides a means of evaluating fibrosis progression and monitoring treatment response.