Fluorodeoxyglucose Research Articles

Localized FDG loss in lung cancer lesions

BackgroundAnalysis of [18F]-Fluorodeoxyglucose (FDG) kinetics in cancer has been most often limited to the evaluation of the average uptake over relatively large volumes. Nevertheless, tumor lesions also contain inflammatory infiltrates whose cells are characterized by a significant radioactivity washout due to the hydrolysis of FDG-6P catalyzed by glucose-6P phosphatase. The present study aimed to verify whether voxel-wise compartmental analysis of dynamic imaging can identify tumor regions characterized by tracer washout. The study included 11 patients with lung cancer submitted to PET/CT imaging for staging purposes. Tumour was defined by drawing a volume of interest loosely surrounding the lesion and considering all inside voxels with a standardized uptake value (SUV) > 40% of the maximum. Eight whole-body scans were repeated after 20 min of dynamic imaging centered on the heart. Six parametric maps were generated progressively by computing a Patlak regression line for each voxel. Each analysis considered a different set of frames: starting with all eight frames, then the last seven frames, and so on, down to the last three frames.ResultsDelaying the starting point of the compartmental analysis revealed a progressive increase in the prevalence of voxels with a negative slope. In the most delayed parametric map, these voxels represented 0.5–4.5% (median 2%) of the tumor volume. This effect was independent of tumor size and was predominantly located at the lesion borders.ConclusionsThe voxel-wise parametric maps provided by compartmental analysis identify a measurable volume characterized by radioactivity washout. The spatial localization of this pattern is compatible with the recognized preferential site of inflammatory infiltrates populating the tumor stroma and might improve the power of FDG imaging in monitoring the effectiveness of treatments aimed at empowering the host immune response against cancer.Trial registration: ClinicalTrials. The study was approved by the local ethical committee and it represented a single Institution ancillary trial within the expanded-access program for Nivolumab. NCT02475382. Registered 2015-06-16. URL: https://clinicaltrials.gov/study/NCT02475382?id=NCT02475382.&rank=1

Assessing the Value of 68Ga-FAPI PET/CT in Gastric Mucinous Adenocarcinoma or Signet Ring Cell Carcinoma.

Purpose To investigate the clinical impact and prognostic value of gallium 68 (68Ga)-labeled fibroblast activation protein inhibitor (FAPI) PET/CT in gastric mucinous adenocarcinoma (MAC) and signet ring cell carcinoma (SRCC). Materials and Methods Eighty-six participants with newly diagnosed or recurrent gastric MAC or SRCC were prospectively enrolled from April 2021 to October 2021 and underwent both fluorine 18 (18F) fluorodeoxyglucose (FDG) PET/CT and 68Ga-FAPI PET/CT. The sensitivity, specificity, and accuracy of the two scans in primary and metastatic tumors were evaluated using the McNemar test. Changes of treatment strategies were recorded to compare the treatment management value of the two PET/CT scans. The maximum standardized uptake value (SUVmax) and peritoneal cancer index (PCI) were recorded for survival analysis. Progression-free survival (PFS) was defined as the time interval from the date of PET/CT scans to the date of disease progression. Results Eighty-six participants (median age, 62 years [IQR, 45-78 years]; 49 female) were evaluated. 68Ga-FAPI PET/CT showed higher diagnostic accuracy in detecting involved lymph nodes (87% [212 of 244] vs 71% [173 of 244], P < .001) and peritoneal metastases (96% [70 of 73] vs 55% [40 of 73], P < .001) than 18F-FDG PET/CT. Twenty-six participants (30% [26 of 86]) had treatment changes due to more accurate diagnosis with 68Ga-FAPI PET/CT. Additionally, the 68Ga-FAPI PCI was an independent predictor for PFS (hazard ratio, 6.9; 95% CI: 2.1, 23.1; P = .002). Conclusion 68Ga-FAPI PET/CT had higher accuracy in diagnosis of gastric MAC/SRCC compared with 18F-FDG PET/CT and demonstrated the potential to improve treatment strategies and predict prognosis. Keywords: PET/CT, Mucinous Adenocarcinoma, Signet Ring Cell Carcinoma, Oncology, Abdomen/GI, Molecular Imaging Supplemental material is available for this article. © RSNA, 2024.

Imaging signs of carotid plaque vulnerability predict subclinical neurological events in asymptomatic patients: the carotid artery multi-modality imaging prognostic study

Abstract Background Carotid artery plaques should be considered for invasive treatment if diameter stenoses is ≥60%, in the presence of clinical and/or imaging characteristics associated with an increased risk of ipsilateral stroke, such as intraplaque haemorrhage (IPH) or lipid-rich necrotic core (LRNC). However, little is known about plaque’s characteristics in patients with &amp;lt;60% stenoses. Purpose To evaluate the prevalence and significance of imaging signs of plaque vulnerability in patients with asymptomatic &amp;lt;60% carotid artery stenoses. Methods In the Carotid Artery Multi-modality imaging Prognostic (CAMP) study (granted by Bando Ricerca Salute 2018 - Regione Toscana) we prospectively enrolled 200 patients with asymptomatic, mild/moderate (40-60%) carotid artery stenoses, as assessed at Doppler ultrasound (DUS). All patients were evaluated with multimodality imaging, including computed tomography angiography (CTA), magnetic resonance angiography (MRA) and brain magnetic resonance imaging (MRI), whenever not contraindicated. A subgroup of 75 patients underwent also a 18[F]-fluorodeoxyglucose (FDG) positron emission tomography (PET). A thorough clinical, biochemical, cardiological and neurological evaluation was performed in all patients. Results Imaging signs of plaque vulnerability were frequent (IPH and/or LRNC at MRA were found in 26.3% patients, plaque ulceration at CTA was found in 36.7% of patients). No difference in the prevalence of cardiovascular risk factors was noted in those with and without signs of vulnerability. Subclinical embolic brain infarctions at brain MRI were found in 8.8% of patients at enrollment. These patients had more frequently a LRNC at MRA than patients without subclinical embolic brain infarctions (50% vs 17%, p&amp;lt;0.05), lower estimated glomerular filtration rate (55±8 vs 73±23 mL/min/1.73mq, p&amp;lt;0.001), higher troponin HS values (16±4 vs 12±8 ng/ml, p&amp;lt;0.05). Presence of LRNC at MRA was the only predictor of embolic lesions at MRI (odds ratio 4.86, 95% confidence interval 1.08-21.8, p&amp;lt;0.05). Conclusions Imaging signs of vulnerability are highly prevalent in patients with asymptomatic intermediate carotid artery stenosis. Presence of a LRNC at MRA is associated with subclinical embolic brain infarcts. The use of non-invasive multi-imaging can better characterize carotid plaques, independent of the degree of stenosis, and help identifying a subgroup of patients at higher risk of events.

Progressive Unilateral Proptosis and [18F]FDG-Avid Lesions Connoting Aggressive Disease in Radioiodine-Refractory Differentiated Thyroid Carcinoma

AbstractRadioiodine-refractory differentiated thyroid carcinoma (RAIR-DTC) have poor prognosis as compared with radioiodine concentrating thyroid carcinoma. We present a case of follicular thyroid carcinoma presenting as a disseminated disease initially, underwent thyroid surgery and radioiodine (RAI) therapy. Following RAI, the patient developed a sudden-onset unilateral proptosis, finally diagnosed as orbital metastasis. [18F]-Fluorodeoxyglucose (FDG)-positron emission tomography-computed tomography identified FDG-avid metastatic lesions more numerous than the RAI-avid lesions. The patient was treated with local and systemic targeted therapy, but despite these treatments, he developed progressive disease indicating aggressive nature of the disease consistent with [18F]FDG-avid RAIR-DTC.

Plasma phosphorylated tau181 outperforms [18F] fluorodeoxyglucose positron emission tomography in the identification of early Alzheimer disease.

This study was undertaken to compare the performance of plasma p-tau181 with that of [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in the identification of early biological Alzheimer disease (AD). We included 533 cognitively impaired participants from the Alzheimer's Disease Neuroimaging Initiative. Participants underwent PET scans, biofluid collection, and cognitive tests. Receiver operating characteristic analyses were used to determine the diagnostic accuracy of plasma p-tau181 and [18F]FDG-PET using clinical diagnosis and core AD biomarkers ([18F]florbetapir-PET and cerebrospinal fluid [CSF] p-tau181) as reference standards. Differences in the diagnostic accuracy between plasma p-tau181 and [18F]FDG-PET were determined by bootstrap-based tests. Correlations of [18F]FDG-PET and plasma p-tau181 with CSF p-tau181, amyloid β (Aβ) PET, and cognitive performance were evaluated to compare associations between measurements. We observed that both plasma p-tau181 and [18F]FDG-PET identified individuals with positive AD biomarkers in CSF or on Aβ-PET. In the MCI group, plasma p-tau181 outperformed [18F]FDG-PET in identifying AD measured by CSF (p = 0.0007) and by Aβ-PET (p = 0.001). We also observed that both plasma p-tau181 and [18F]FDG-PET metabolism were associated with core AD biomarkers. However, [18F]FDG-PET uptake was more closely associated with cognitive outcomes (Montreal Cognitive Assessment, Mini-Mental State Examination, Clinical Dementia Rating Sum of Boxes, and logical memory delayed recall, p < 0.001) than plasma p-tau181. Overall, although both plasma p-tau181 and [18F]FDG-PET were associated with core AD biomarkers, plasma p-tau181 outperformed [18F]FDG-PET in identifying individuals with early AD pathophysiology. Taken together, our study suggests that plasma p-tau181 may aid in detecting individuals with underlying early AD.

A single-center case study series assessing the effect of selumetinib use in patients with neurofibromatosis-related plexiform neurofibromas

Abstract Background Neurofibromatosis type 1 (NF1) is a common genetic disorder of phenotypic variability with age-dependent penetrance. This study describes the diagnosis, clinical characterization, management, and outcomes of a large patient cohort with plexiform neurofibroma (PN) treated with selumetinib in a real-world clinical setting. Methods This single-center observational study consecutively enrolled patients with NF1-PN treated with selumetinib from April 2018 to April 2023. Data on clinical features, tumor types and locations, and results from genetic tests were recorded at baseline; details of disease management with selumetinib and surgical intervention and disease evolution including imaging data and evaluations of pain and function were documented. Results Overall, 54 patients with a median age (range) of 16.4 (4.5–58.0) years were enrolled. Most had cutaneous manifestations (88.9%), including cutaneous neurofibromas and PN. Patients underwent [18F]fluorodeoxyglucose (FDG)-PET/CT imaging before treatment to rule out malignant lesions. Initial evaluations included directed MRI, which facilitated future comparisons and allowed for the assessment of PN resectability. Pharmacological treatment with selumetinib (with surgery, without surgery) resulted in the following proportion of patients achieving stable disease (58.8%, 54.3%), partial response (29.4%, 28.6%), and improved pain (58.8%, 37.1%), deformity (17.6%, 20.0%), and functional (17.6%, 20.0%) outcomes, respectively. Conclusions Results from this study demonstrate that NF1-PN can be managed effectively with selumetinib with surgical intervention in some patients. Most patients achieved tumor stability and improved symptom control, and the majority of patients continue under treatment. Effective diagnosis and management were achieved through individualized utility of FDG-PET/CT and MRI imaging and targeted resource allocation.

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.

Low to moderate ethanol exposure reduces astrocyte-induced neuroinflammatory signaling and cognitive decline in presymptomatic APP/PS1 mice

Alcohol use disorder has been associated with the development of neurodegenerative diseases, including Alzheimer’s disease (AD). However, recent studies demonstrate that moderate alcohol consumption may be protective against dementia and cognitive decline. We examined astrocyte function, low-density lipoprotein (LDL) receptor-related protein 1 (LRP1), and the NF-κB p65 and IKK-α/β signaling pathways in modulating neuroinflammation and amyloid beta (Aβ) deposition. We assessed apolipoprotein E (ApoE) in the brain of APP/PS1 mice using IHC and ELISA in response to low to moderate ethanol exposure (MEE). First, to confirm the intracerebral distribution of ApoE, we co-stained with GFAP, a marker for astrocytes that biosynthesize ApoE. We sought to investigate whether the ethanol-induced upregulation of LRP1 could potentially inhibit the activity of IL-1β and TNF-α induced IKK-α/β towards NF-κB p65, resulting in a reduction of pro-inflammatory cytokines. To evaluate the actual Aβ load in the brains of APP/PS1 mice, we performed with a specific antibody Aβ (Thioflavin S) on both air- and ethanol-exposed groups, subsequently analyzing Aβ levels. We also measured glucose uptake using 18F- fluorodeoxyglucose (FDG)-positron emission tomography (PET). Finally, we investigated whether MEE induced cognitive and memory changes using the Y maze, noble object recognition test, and Morris water maze. Our findings demonstrate that MEE reduced astrocytic glial fibrillary acidic protein (GFAP) and ApoE levels in the cortex and hippocampus in presymptomatic APP/PS1 mice. Interestingly, increased LRP1 protein expression was accompanied by dampening the IKK-α/β-NF-κB p65 pathway, resulting in decreased IL-1β and TNF-α levels in male mice. Notably, female mice show reduced levels of anti-inflammatory cytokines IL-4, and IL-10 without altering IL-1β and TNF-α concentrations. In both males and females, Aβ plaques, a hallmark of AD, were reduced in the cortex and hippocampus of APP/PS1 mice exposed to ethanol starting at pre-symptomatic stage. Consistently, MEE increased FDG-PET-based brain activities and normalized cognitive and memory deficits in the APP/PS1 mice. Our findings suggest that MEE may benefit AD pathology via modulating LRP1 expression, potentially reducing neuroinflammation and attenuating Aβ deposition. Our study implies that reduced astrocyte-derived ApoE and LDL cholesterol levels are critical for attenuating AD pathology.

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&lt;0.05), brain and liver (both p&lt;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&lt;0.0001), perhaps due to increased FDG blood pool. FDG uptake in skeletal muscles and brown adipose tissue decreased (both p&lt;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&lt;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&lt;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.

Chemoradiotherapy treatment increases cardiac and aortic [18F]FDG uptake ratios in lung cancer patients

[18F]Fluorodeoxyglucose (FDG) positron emission tomography (PET) is an indispensable non-invasive imaging tool to aid diagnosis, prognostication, and therapeutic monitoring in oncology, but it can also evaluate cardiovascular inflammation1,2. Previously, cardiac metabolic changes using [18F]FDG with chemoradiotherapy have been explored3 but changes in the rest of the cardiovascular system remain undetermined. To investigate the cardiovascular metabolic changes pre- and post-chemoradiotherapy in stage 3b non-small cell lung cancer (NSCLC) patients. A retrospective analysis of 26 patients (43-82 years) with stage 3b NSCLC from the American College of Radiology Imaging Network (ACRIN 6668) trial was performed3. All available pre- and post-treatment imaging were retrieved from the Cancer Imaging Archive (TCIA)4 and regions of interest for the left ventricle and calcified large arteries were contoured on all PET-CT scans using PMOD version 4.0 software. The mean, maximum standard uptake value (SUVmean and SUVmax) and target-to-background ratio (TBR) were quantified on PMOD. At approximately 14 weeks post-chemoradiotherapy, there was a higher SUVmean (mean difference 0.81, p=0.01) and SUVmax (mean difference 2.20, p=0.006) in the left ventricle compared with pretreatment scans. TBR for aorta was higher post-treatment (mean difference 0.06, p=0.005). However, SUVmean for carotid arteries and right brachiocephalic artery was reduced post-chemoradiotherapy (mean difference 0.15, p=0.008 and mean difference 0.28, p=0.03). A reduction in SUVmax was also seen for aortic arch (mean difference 0.58, p=0.03) and right brachiocephalic artery (mean difference 0.42, p=0.03 and mean difference 0.42, p=0.03). Cardiovascular glucose metabolism is selectively increased in the left ventricle and aorta post-chemoradiotherapy. Changes in glucose metabolism of atherosclerotic plaques vary across different vessels throughout the body. Please click on the 'PDF' for the full abstract!

Head to head comparison of 18F-FDG and Al18F-NOTA-FAPI-04 PET/CT imaging used in diagnosis of autoimmune rheumatic diseases.

The aim of this study was to determine the performance of radionuclide-labeled fibroblast activation protein inhibitors (Al18F-NOTA-FAPI-04) PET/CT in patients with autoimmune rheumatic diseases (ARDs) and compare it with fluorine-18 (18F) labeled fluorodeoxyglucose (FDG) imaging. Fifty-eight participants with ARDs were prospectively enrolled from April 2022 to February 2024 and underwent dual-tracer PET/CT imaging. For both 18F-FDG and Al18F-NOTA-FAPI-04 PET/CT, imaging findings were interpreted and compared. The clinical significance was compared between18F-FDG PET/CT and Al18F-NOTA-FAPI-04 PET/CT imaging. 18F-FDG imaging was positive in 53 out of 58 cases (91.4%) while Al18F-NOTA-FAPI-04 imaging was positive in 55 out of 58 cases (94.8%). Overall positive rate of Al18F-NOTA-FAPI-04 imaging was as high as 18F-FDG imaging (P = 0.625). 18F-FDG imaging detected more lesions in lymph node, spleen, and bone marrow. Al18F-NOTA-FAPI-04 imaging detected more lesions in the lung, muscle, and tendon/ligament. There was no statistical difference of composing ratio of grades of clinical significance between two imaging modalities (χ2 = 2.875, P = 0.238). The superior rate of Al18F-NOTA-FAPI-04 PET/CT imaging was higher than 18F-FDG imaging (P = 0.020). In subgroup of adult-onset Still's disease, 18F-FDG imaging showed better performance than Al18F-NOTA-FAPI-04 imaging. In most of the other subgroup of ARDs, Al18F-NOTA-FAPI-04 PET/CT imaging overperformed 18F-FDG imaging. Both 18F-FDG and Al18F-NOTA-FAPI-04 PET/CT imaging have excellent sensitivity in ARDs. The detection capabilities of two tracers varied according to the involving organs of ARDs. In most of ARDs except adult-onset Still's disease, Al18F-NOTA-FAPI-04 PET/CT imaging overperformed 18F-FDG imaging. Key Points • 18F-FDG and Al18F-NOTA-FAPI-04 PET/CT imaging have excellent sensitivity in diagnosing of ARDs. • 18F-FDG PET/CT imaging detected more lesions in lymph node, spleen, and bone marrow. • 18F-NOTA-FAPI-04 PET/CT imaging detected more lesions in the lung, muscle, and tendon/ligament. • 18F-NOTA-FAPI-04 PET/CT imaging overperformed18F-FDG in most subgroups of ARDs.

Early Detection of Residual/Recurrent Lung Malignancies on Post-Radiation FDG PET/CT

Positron Emission Tomography/Computed Tomography (PET/CT) using Fluorodeoxyglucose (FDG) is an important imaging modality for assessing treatment outcomes in patients with pulmonary malignant neoplasms undergoing radiation therapy. However, distinguishing between benign post-radiation changes and residual or recurrent malignancies on PET/CT images is challenging. Leveraging the potential of artificial intelligence (AI), we aimed to develop a hybrid fusion model integrating radiomics and Convolutional Neural Network (CNN) architectures to improve differentiation between benign post-radiation changes and residual or recurrent malignancies on PET/CT images. We retrospectively collected post-radiation PET/CTs with identified labels for benign changes or residual/recurrent malignant lesions from 95 lung cancer patients who received radiation therapy. Firstly, we developed separate radiomics and CNN models using handcrafted and self-learning features, respectively. Then, to build a more reliable model, we fused the probabilities from the two models through an evidential reasoning approach to derive the final prediction probability. Five-folder cross-validation was performed to evaluate the proposed radiomics, CNN, and fusion models. Overall, the hybrid fusion model outperformed the other two models in terms of sensitivity, specificity, accuracy, and the area under the curve (AUC) with values of 0.67, 0.72, 0.69, and 0.72, respectively. Evaluation results on the three AI models we developed suggest that handcrafted features and learned features may provide complementary information for residual or recurrent malignancy identification in PET/CT.

Two Cases of Atypical Sarcoidosis Presenting with AKI: Clinical Significance of Sequential Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET)/CT Images

Two Cases of Atypical Sarcoidosis Presenting with AKI: Clinical Significance of Sequential Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET)/CT Images

Clinical utility of bedside Contrast-Enhanced Ultrasound (CEUS) in the diagnosis of pneumonia in elderly patients: Comparison with clinical, -radiological and ultrasound diagnosis.

to measure the clinical impact of contrast-enhanced ultrasound (CEUS) in the diagnosis of -community-acquired pneumonia (CAP), compared to clinical, radiological and ultrasound diagnosis. 84 patients (47/37 males/females, mean age:78,57±11,7 Y) with clinical suspicion of pneumonia and with ultrasound findings of peripheral lung lesions, were investigated with CEUS for a better characterization. Final diagnosis of 65 cap was obtained with complete disappearance of symptoms and pulmonary nodule(s); 19 neoplasms: 16 patients performed histologically with bronchoscopy; 3 refused (non-invasive diagnosis with basal CT-scan and positron emission tomography (PET) with fluorodeoxyglucose (FDG)). Sensitivity, specificity, overall diagnostic accuracy (ODA) (and corresponding AUROC) of clinical-data (CD), chest X-ray(CXR), Lung-ultrasound(LUS), CEUS were calculated with SPSS 26.0 software. Final diagnosis: 65 CAP, and 19 chest cancers. 9/65 (13%) patients died, of these 7/9 with older age and heart disease as comorbidity. CD: True-Positive (TP):23, True-negative (TN): 17; False-Positive (FP):2; False-negative (FN):42 (sens:35,4% spec:89,5% ODA10%: PPV:92%, NPV:28,8%) (AUROC±SEauc:0,46±0,076); CXR: TP: 36, TN:14; FP:5, FN:29; (sens: 55,4%; spec: 73,7%; ODA: 32%; PPV:87,5%, NPV:32,66%) (AUROC±SEauc:0,645±0,068). US: TP:59; TN: 14; FP:5, FN:6 (sens: 90,8%, spec: 73,7%, ODA: 84,9%, PPV:92,2%, NPV:70%) (AUROC±SEauc:0,9417±0,024); CEUS: TP: 63; TN: 19; FP:0; FN:2 (sens: 96,9%; spec: 100% ODA: 97,5%; PPV: 100%, NPV:90,5%) (AUROC±SEauc:0,98±0,01). Clinical-data and chest X-RAYS are insufficient to obtain a correct diagnosis of CAP in elderly population; US demonstrated a good accuracy to establish CAP, but with a relatively low specificity; in these cases, CEUS is able to give a correct characterization, allowing you to save the need for a chest contrast-enhanced-CT (CECT).

Neurologic Clinical, Electrophysiologic, and Pathologic Characteristics of Primary vs Secondary Neurolymphomatosis.

Neurolymphomatosis (NL) is characterized by lymphomatous infiltration of the peripheral nervous system presenting as the initial manifestation of a lymphoma (primary NL [PNL]) or in relapse of a known lymphoma (secondary NL [SNL]). This report details and compares the neurologic clinicopathologic characteristics of these 2 groups. This retrospective study was performed on patients diagnosed with pathologically confirmed NL in nerve between January 1, 1992, and June 31, 2020. Patient clinical characteristics, neurologic examination, imaging studies, EMG, and nerve biopsy data were collected, analyzed, and compared between PNL and SNL. A total of 58 patients were identified (34 PNL and 24 SNL). Time from neurologic symptom onset to diagnosis was longer in PNL at 18.5 months compared with 5.5 months in SNL (p = 0.01). Neurologic symptoms were similar in both patient groups and included primarily sensory loss (98%), severe pain (76%), and asymmetric weakness (76%). A wide spectrum of EMG-confirmed different neuropathy patterns were observed, but patients with SNL had increased numbers of mononeuropathies (n = 8) compared with PNL (n = 1, p = 0.01). MRI studies detected NL more frequently (86%) compared with fluorodeoxyglucose (FDG)-PET CT imaging studies (60%) (p = 0.007). Nerve biopsies revealed B-cell lymphoma (PNL n = 32, SNL n = 22), followed by T-cell lymphoma (PNL n = 2, SNL n = 2), with increased demyelination in both groups and increased axonal degeneration (p = 0.01) and multifocal myelinated fiber loss (p = 0.04) significant in SNL vs PNL. Identifying SNL resulted in patient treatment modifications but a worse prognosis compared with PNL (p = 0.025). While PNL and SNL are both primarily painful and asymmetric neuropathies with axonal and demyelinating features on EMG and nerve biopsy, SNL presents somewhat differently than PNL with fulminant, asymmetric often mononeuropathies better detected on MRI than FDG-PET/CT. The focal pattern of SNL is likely a result of residual cancer cells that evaded initial chemotherapy, which does not cross the blood-nerve barrier, and these cells can later recur and result in fulminant disease. Although still resulting in a poorer prognosis, identifying SNL is important because this changed treatment and management in every SNL case.

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.

Feasibility of Biology-guided Radiotherapy (BgRT) Targeting Fluorodeoxyglucose (FDG) avid liver metastases

IntroductionBiology-guided radiotherapy (BgRT) is a novel radiation delivery approach utilizing fluorodeoxyglucose (FDG) activity on positron emission tomography (PET) imaging performed in real-time to track and direct RT. Our institution recently acquired the RefleXion X1 BgRT system and sought to assess the feasibility of targeting metastatic sites in various organs, including the liver. However, in order for BgRT to function appropriate, adequate contrast in FDG activity between the tumor and the background tissue, referred to as the normalized SUV (NSUV), is necessary for optimal functioning of BgRT.MethodsWe reviewed the charts of 50 lung adenocarcinoma patients with liver metastases. The following variables were collected: SUVmax and SUVmean for each liver metastasis, SUVmean and SUVmax at 5 and 10 mm radially from the lesion, and NSUV at 5 mm and 10 mm (SUVmax of the liver metastasis divided by SUV mean at 5 mm at 10 mm respectively).Results82 measurable liver metastases were included in the final analysis. The average SUVbackground of liver was 2.26 (95% confidence interval [CI] 2.17–2.35); average SUVmean for liver metastases was 5.31 (95% CI 4.87–5.75), and average SUVmax of liver metastases was 9.19 (95% CI 7.59–10.78). The average SUVmean at 5 mm and 10 mm radially from each lesion were 3.08 (95% CI 3.00-2.16) and 2.60 (95% CI 2.52–2.68), respectively. The mean NSUV at 5 mm and 10 mm were 3.13 (95% CI 2.53–3.73) and 3.69 (95% CI 3.00-4.41) respectively. Furthermore, 90% of lesions had NSUV greater than 1.45 at 5 mm and greater than 1.77 at 10 mm.ConclusionsThis is the first study to comprehensively characterize FDG contrast between the liver tumor and background, referred to as NSUV. Due to the high background SUV normally found in the liver, this work will be valuable for guiding optimization of BgRT for treating liver metastases in the future using the RefleXion® X1 and potentially other similar BgRT platforms.

News on the imaging of large vessel vasculitis

Large vessel vasculitis, including giant cell arteritis (GCA) and Takayasu arteritis (TAK), are autoimmune diseases primarily affecting the aorta and its branches. GCA is the most common primary vasculitis. Inflammatory changes in the vessel walls can cause serious complications such as amaurosis, stroke, and aortic dissection and rupture. Imaging techniques have become an integral part for the diagnosis and monitoring of large vessel vasculitis, allowing for effective disease monitoring. GCA and TAK exhibit similar patterns of vascular distribution. However, the temporal arteries are never involved in TAK, and axillary arteritis occurs more frequently in GCA. In most centers, ultrasound of the temporal and axillary arteries has replaced temporal artery biopsy as the primary diagnostic tool for GCA. In addition to ultrasound, magnetic resonance imaging (MRI), computed tomography (CT), and [18F]-FDG (fluorodeoxyglucose) positron emission tomography-computed tomography (PET) are important, particularly for visualizing the aorta. Moreover, PET-CT is now also capable of assessing the temporal arteries, although it is not yet widely available. In polymyalgia rheumatica (PMR), ultrasound of the shoulder and hip regions is part of the ACR/EULAR classification criteria. MRI allows detailed visualization of additional inflammatory extraarticular manifestations, showing characteristic inflammatory lesions in entheses, tendons, and ligaments. [18F]-FDG-PET-CT also enables the visualization of musculoskeletal inflammation, especially in the shoulder and hip regions, as well as paravertebral areas. Ultrasound can detect subclinical GCA in up to 23% of patients with PMR, which should be treated like GCA. Technological innovations such as new radiotracers and improved MRI imaging could further enhance the diagnosis and monitoring of large vessel vasculitis and PMR, thus playing acrucial role in improving the prognosis through faster initiation of therapy.

An actinomycosis infection resembling peritoneal dissemination of rectal cancer: a case report

BackgroundActinomycosis is a suppurative and granulomatous inflammation commonly caused by Actinomyces israelii. Due to its rarity and the paucity of characteristic clinical features, diagnosis of intra-abdominal actinomycosis is challenging, especially when the patient has a treatment history of abdominal cancer.Case presentationThe patient is a 72-year-old man who has a history of multiple abdominal surgeries for rectal cancer, including low anterior resection for primary rectal cancer, partial hepatic resection for metachronous liver metastasis, and Hartmann surgery for local recurrence. The patient has also undergone parastomal hernia repair using the Sugarbaker method. One year after hernia repair, computed tomography (CT) identified a mass lesion between the abdominal wall and the mesh, suggesting the possibility of peritoneal recurrence of rectal cancer. The accumulation of fluorodeoxyglucose (FDG) was evident via positron emission tomography-CT (PET-CT), while tumor marker levels were within the normal range. On laparotomy, the small intestine, abdominal wall, mesh, colon, and stoma were observed to be associated with the mass lesion, and en bloc resection was carried out. However, postoperative histopathological examination revealed an actinomyces infection without any cancerous cells.ConclusionsThis case highlights the challenges faced by surgeons regarding preoperative diagnosis of actinomycosis, especially when it occurs after the resection of abdominal cancer. Also, this case reminds us of the importance of a histopathological examination for abdominal masses or nodules before starting chemotherapy.