fluoro-D-glucose Positron Emission Tomography Research Articles

Impaired microglial glycolysis promotes inflammatory responses after intracerebral haemorrhage via HK2-dependent mitochondrial dysfunction

IntroductionIntracerebral haemorrhage (ICH) is a devastating disease that leads to severe neurological deficits. Microglia are the first line of defence in the brain and play a crucial role in neurological recovery after ICH, whose activities are primarily driven by glucose metabolism. However, little is known regarding the status of glucose metabolism in microglia and its interactions with inflammatory responses after ICH. ObjectivesThis study investigated microglial glycolysis and its mechanistic effects on microglial inflammation after ICH. MethodsWe explored the status of glucose metabolism in the ipsilateral region and in fluorescence-activated-cell-sorting-isolated (FACS-isolated) microglia via 2-deoxy-[18F]fluoro-D-glucose positron emission tomography (FDG-PET) analyses and gamma emission, respectively. Energy-related targeted metabolomics, along with 13C-glucose isotope tracing, was utilised to analyse glycolytic products in microglia. Mitochondrial membrane potential and mitochondrial reactive oxygen species (MitoROS) accumulation was assessed by flow cytometry. Behavioural, western blotting, gene regulation, and enzymatic activity analyses were conducted with a focus on microglia. ResultsNeurological dysfunction was strongly correlated with decreased FDG-PET signals in the perihaematomal region, where microglial uptake of FDG was reduced. The decreased quantity of glucose-6-phosphate (G-6-P) in microglia was attributed to the downregulation of glucose transporter 1 (GLUT1) and hexokinase 2 (HK2). Enhanced inflammatory responses were driven by HK2 suppression via decreased mitochondrial membrane potential, which could be rescued by MitoROS scavengers. HK inhibitors aggravated neurological injury by suppressing FDG uptake and enhancing microglial inflammation in ICH mice. ConclusionThese findings indicate an unexpected metabolic status in pro-inflammatory microglia after ICH, consisting of glycolysis impairment caused by the downregulation of GLUT1 and HK2. Additionally, HK2 suppression promotes inflammatory responses by disrupting mitochondrial function, providing insight into the mechanisms by which inflammation may be facilitated after ICH and indicating that metabolic enzymes as potential targets for ICH treatment.

Validity and value of metabolic connectivity in mouse models of β-amyloid and tauopathy

Among functional imaging methods, metabolic connectivity (MC) is increasingly used for investigation of regional network changes to examine the pathophysiology of neurodegenerative diseases such as Alzheimer's disease (AD) or movement disorders. Hitherto, MC was mostly used in clinical studies, but only a few studies demonstrated the usefulness of MC in the rodent brain. The goal of the current work was to analyze and validate metabolic regional network alterations in three different mouse models of neurodegenerative diseases (β-amyloid and tau) by use of 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography (FDG-PET) imaging. We compared the results of FDG-µPET MC with conventional VOI-based analysis and behavioral assessment in the Morris water maze (MWM). The impact of awake versus anesthesia conditions on MC read-outs was studied and the robustness of MC data deriving from different scanners was tested. MC proved to be an accurate and robust indicator of functional connectivity loss when sample sizes ≥12 were considered. MC readouts were robust across scanners and in awake/ anesthesia conditions. MC loss was observed throughout all brain regions in tauopathy mice, whereas β-amyloid indicated MC loss mainly in spatial learning areas and subcortical networks. This study established a methodological basis for the utilization of MC in different β-amyloid and tau mouse models. MC has the potential to serve as a read-out of pathological changes within neuronal networks in these models.

18F] FDG uptake in patients with spondyloarthritis: correlation with serum inflammatory biomarker levels

BackgroundWe aimed to evaluate the correlation between 2-deoxy-2-[18F]fluoro-D-glucose (FDG) uptake and disease activity assessed by serum inflammatory biomarker levels in patients with spondyloarthritis (SpA).MethodsA total of 36 SpA patients (24 untreated and 12 treated) were examined using FDG positron emission tomography (PET)/computed tomography and classified into axial SpA (axSpA) and peripheral SpA (pSpA). FDG uptake was evaluated in 23 regions of the body and scored as follows: 0 = less than liver uptake; 1 = more than or equal to liver uptake; and 2 = more than or equal to twice liver uptake. A score of 1 or 2 was considered positive. The number of positive regions and the total score were counted in each patient. The maximum standardized uptake value (SUVmax) was calculated for each region, and maximum SUVmax (MaxSUVmax) was used as a representative value. Correlation of PET findings with serum inflammatory biomarker levels, including C-reactive protein (CRP), erythrocyte sedimentation rate, and matrix metalloproteinase 3 (MMP-3), was analyzed.ResultsAll but two patients had at least one positive lesion. PET indices correlated significantly with most of the serum inflammatory biomarker levels in untreated SpA, but not in treated SpA. Further, MaxSUVmax, number of positive regions, and total score correlated significantly with CRP (all P values < 0.001), and the number of positive regions (P = 0.012) and total score (P = 0.007) correlated significantly with MMP-3 in untreated pSpA. PET indices did not correlate with any serum inflammatory biomarker level in untreated axSpA.ConclusionFDG uptake in untreated pSpA correlated significantly with serum inflammatory biomarker levels.

Cell sorting after tracer injection to elucidate allocation of cellular FDG uptake in different cell types and different microglial activation states

AbstractBackground2‐deoxy‐2‐[18F]fluoro‐d‐glucose positron‐emission‐tomography (FDG‐PET) is widely used to study cerebral glucose metabolism. Radiosorting revealed that the FDG‐PET signal is directly influenced by microglial glucose uptake in mouse models and we found similar associations in patients with neurodegenerative diseases. Now, we questioned the allocation of cellular FDG uptake in the rodent brain.MethodSingle cell [18F]FDG uptake as assessed by magnetic activated cell sorting (MACS) was multiplied with published total cell numbers in the mouse brain, i.e. 71e+6 neurons or 7% (≈ 7.6e+6) microglia cells to estimate the overall uptake per cell fraction. Estimated cellular microglial [18F]FDG uptake as assessed by MACS was cross‐validated with observed %‐FDG‐PET reductions after microglia depletion. Interstitial and vessel [18F]FDG was estimated by interstitial compartment volume and assumed equilibrium of non‐phosphorylated extra‐ and intracellular [14C]Deoxyglucose. Synaptic [18F]FDG uptake was estimated via an enriched synaptosome fraction relative to [18F]FDG uptake of whole‐brain homogenate. A microglia proliferation index of 1.3 was assumed for the whole brain in the Aβ mouse model.ResultMicroglia cells accounted for 8.6% of the overall brain [18F]FDG uptake in wild‐type mice and for 29.9% of the overall brain [18F]FDG uptake in PS2APP mice, confirmed by similar alterations after microglia depletion in PET. Synapses contributed to 13.2‐17.1% of the overall brain [18F]FDG uptake whereas interstitial (5.9‐7.7%) and vessel (2.6‐3.4%) [18F]FDG uptake was of minor magnitude. Neuronal and astrocyte cell bodies accounted for &lt;10% of the overall brain [18F]FDG uptake, but a proportion of 42‐55% was not recovered and likely allocated in lost cell processes, oligodendrocytes and other cell types.ConclusionMicroglial FDG uptake alterations are the source of FDG‐PET changes in models of neurodegenerative diseases. Our data should increase the awareness to consider glia cells as key contributors of FDG uptake and the detailed proportions of these cellular contributions in healthy brains and under disease conditions deserve deeper investigation.

Relationship between [18F]FDG PET/CT and metabolomics in patients with colorectal cancer

IntroductionAdvances in metabolomics have significantly improved cancer detection, diagnosis, treatment, and prognosis.ObjectivesTo investigate the relationship between metabolic tumor volume (MTV) using 2-deoxy-2-[18F]fluoro-D-glucose (FDG) positron emission tomography (PET)/ computed tomography (CT) and metabolomics data in patients with colorectal cancer (CRC).MethodsThe metabolome in tumor tissues was analyzed using capillary electrophoresis time-of-flight mass spectrometry in 33 patients with newly diagnosed CRC who underwent FDG PET/CT before treatment and had tumor tissue post-surgery. Based on the FDG PET data, MTV was calculated and was dichotomized according to the median value, and tumors were divided into low-MTV and high-MTV tumors. Metabolomics data were compared between the low-MTV and high-MTV tumors.ResultsThe levels of most glycolysis-related metabolites were not different between low-MTV and high-MTV tumors. The level of component of the initial part of the tricarboxylic acid (TCA) cycle, citrate, was significantly lower in the high-MTV tumor than in the low-MTV tumor. The TCA intermediate succinate level was significantly higher in the high-MTV tumor than in the low-MTV tumor. In contrast, the TCA intermediate fumarate level was significantly lower in the high-MTV tumor than in the low-MTV tumor. The levels of many amino acids were significantly higher in the high-MTV tumor than in the low-MTV tumor.ConclusionsAlthough preliminary, these results suggest that tumors with high FDG metabolism in CRC may obtain more energy by using a reverse reaction of the TCA cycle and amino-acid metabolism. However, further research is required to clarify this relationship.

Higher SUVmax on FDG-PET is associated with shorter survival in adrenocortical carcinoma

BackgroundAdrenocortical carcinoma (ACC) is an aggressive, rare malignancy. 2-deoxy-2-[18F]-fluoro-d-glucose positron emission tomography (FDG-PET) assesses tumor metabolism and glucose utilization. We hypothesized that higher maximum standard uptake value (SUVmax) is associated with decreased survival. MethodsWe performed a retrospective analysis of patients with ACC. Included patients (n = 26) had an FDG-PET scan available with a documentable SUVmax. Patients were dichotomized into “High” (≥8.4, n = 12) and “Low” (<8.4, n = 14) SUVmax. Univariate analysis and survival analysis were performed to compare groups. ResultsDemographics between groups were equivalent. The high SUVmax cohort demonstrated lower survival (median 479 days or 15.7 months) compared to the low group (median 1490 days or 48.6 months, p = .01). Log-Rank curve confirmed differences in survival (p = .007). ConclusionsHigher SUVmax was associated with significantly worse survival in ACC and may reflect a more aggressive phenotype. FDG-PET may provide clinically useful information to determine prognosis and treatment. Further studies should prospectively evaluate using FDG-PET/CT in ACC.

A Review on the Value of Imaging in Differentiating between Large Vessel Vasculitis and Atherosclerosis

Imaging is becoming increasingly important for the diagnosis of large vessel vasculitis (LVV). Atherosclerosis may be difficult to distinguish from LVV on imaging as both are inflammatory conditions of the arterial wall. Differentiating atherosclerosis from LVV is important to enable optimal diagnosis, risk assessment, and tailored treatment at a patient level. This paper reviews the current evidence of ultrasound (US), 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography (FDG-PET), computed tomography (CT), and magnetic resonance imaging (MRI) to distinguish LVV from atherosclerosis. In this review, we identified a total of eight studies comparing LVV patients to atherosclerosis patients using imaging—four US studies, two FDG-PET studies, and two CT studies. The included studies mostly applied different methodologies and outcome parameters to investigate vessel wall inflammation. This review reports the currently available evidence and provides recommendations on further methodological standardization methods and future directions for research.

Associations Between FDG PET and Expression of VEGF and Microvessel Density in Different Solid Tumors: A Meta-analysis

To date, there are inconsistent data about relationships between 2-deoxy-2 [18F] fluoro-D-glucose positron emission tomography (FDG-PET) and expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD). The aim of the present meta-analysis was to systematize the reported data about associations between maximal standardized uptake value (SUVmax) derived from FDG PET and expression of VEGF and as well as MVD. MEDLINE library, SCOPUS and EMBASE data bases were screened for relationships between SUVmax and VEGF/MVD up to October 2019. Overall, in 18 studies correlations between SUVmax and VEGF and in 13 studies correlations between SUVmax and MVD were reported. The following data were extracted from the literature: authors, year of publication, number of patients, and correlation coefficients. Associations between 18F-FDG PET and VEGF were reported in 18 studies (935 patients). The calculated correlation coefficients between SUVmax and VEGF expression ranged from -0.16 to 0.88. The pooled correlation coefficient was 0.32, (95% confidence interval [CI] = [0.15; 0.48]). Associations between 18F-FDG PET and MVD were investigated in 13 studies (593 patients). The reported correlation coefficients ranged from -0.23 to 0.91. The pooled correlation coefficient was 0.27, (95% CI = [0.00; 0.53]). Analysis of MVD based on CD105 immunohistochemical staining was performed in four studies (117 patients). The pooled correlation coefficient was 0.41 (95% CI = [0.22; 0.59]). In three reports with 233 patients, MVD was estimated by staining with CD31 antibody. The pooled correlation coefficient was 0.01, (95% CI = [-0.44; 0.47]). Finally, in 9 studies (280 patients) MVD was performed on CD34 stained specimens. The pooled correlation coefficient was 0.36, (95% CI = [0.09; 0.63]). SUVmax of FDG PET correlated weakly with expression of VEGF and with MVD. Therefore, FDG PET cannot predict neoangiogenesis in malignant tumors.

Response evaluation of SGLT2 inhibitor therapy in patients with type 2 diabetes mellitus using 18F-FDG PET/MRI

IntroductionInhibitors of sodium-glucose linked transporter-2 (SGLT2i) are enhancing glucose excretion in the proximal renal tubules, and thus are increasingly used to lower blood glucose levels in patients with type 2...

Non-invasive determination of blood input function to compute rate of myocardial glucose uptake from dynamic FDG PET images of rat heart in vivo: comparative study between the inferior vena cava and the left ventricular blood pool with spill over and partial volume corrections

The purpose of this work was to compute blood input function from the inferior vena cava (IVC) with partial volume (PV) corrections and compare to that obtained from the left ventricular blood pool (LVBP) with spill-over (SP) and PV corrections. These were then used to compute and validate rates of myocardial 2-deoxy-2-[18F]fluoro-D-glucose (FDG) uptake (Ki) from dynamic positron emission tomography (PET) images of rat hearts in vivo in comparison to that obtained from invasive arterial blood sampling. Whole body 60 min dynamic FDG PET/CT imaging of n = 8 control Wistar Kyoto (WKY) rats were performed using Albira trimodal PET/CT/SPECT scanner. Image derived blood input function (IDIF) obtained from IVC corrected for PV averaging (IVC-PV) and IDIF from the left ventricular blood pool (LVBP) with SP and PV corrections (LVBP-SP-PV) were computed. Next, computed Ki (indirect comparison) in a 5-parameter (using IVC-PV) and a 15-parameter (using LVBP-SP-PV) 3-compartment models in WKY rat hearts in vivo were compared to that obtained using arterial blood sampling reported in literature in control Spraque Dawley (SD) rats. Using IVC-PV in a three-compartment five-parameter model resulted in a ~46% deviation in the mean computed Ki compared to that obtained with LVBP-SP-PV in a three-compartment 15-parameter model with a ~57% deviation in the mean computed Ki. The mean computed Ki in WKY rat hearts using the above methods, however, did not differ significantly to that obtained from invasive arterial blood sampling in SD rat hearts (p = 0.91 for IVC-PV and p = 0.58 for LVBP-SP-PV). Hence, Ki obtained in WKY rat hearts with input curve from IVC (IVC-PV) in a dynamic FDG PET scan is comparatively more repetitive to that obtained from the LVBP (LVBP-SP-PV). Ki computed using both the methods, however, agree well with each other and that obtained using arterial blood sampling.

Pilot study to enhance FDG-PET imaging of prostate cancers with the metabolic inhibitor ranolazine.

e16551 Background: 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography (FDG-PET) is a widely-used imaging modality for many cancers; however, its utility in prostate cancer is limited. Fatty acid oxidation (FAO) is a primary source of energy for early prostate cancer. We previously demonstrated that FAO inhibition in prostate cancer mouse models resulted in increased glucose metabolism and enhanced tumor FDG uptake, with peak uptake at 24 hours. To validate these preclinical findings, we conducted a pilot study to evaluate whether a partial FAO inhibitor, ranolazine, increases tumor FDG uptake on PET imaging for prostate cancer. Methods: Prostate cancer patients with untreated localized cancer (arm 1) and with metastatic disease on hormonal or other therapy (arm 2) were enrolled and underwent baseline and post-treatment FDG-PET/CT scans (standard dose of 10 mCi FDG). Ranolazine 1000mg PO BID x 2 doses was given within 24-48 hours of the second scan. The primary objective was to evaluate the rate of successful enhancement of FDG uptake on PET imaging, based on one or more of the following criteria: 30% increase in maximum SUV with an absolute change of 2 units; 30% increase in mean SUV with an absolute change of 0.75 units; or 20% increase in mean SUV with an absolute change of 1 unit. Results: Eleven patients (four in arm 1, seven in arm 2) were enrolled. Ranolazine was well tolerated by all participants, with no adverse effects observed. Both increases and decreases in SUV uptake were observed on the post-ranolazine scans. No patient met the predefined criteria for successful enhancement of FDG uptake. There was an incidental finding of thyroid cancer seen in one patient that was discovered on PET imaging. The study was closed early due to the emerging clinical availability of alternative and effective PET imaging modalities such as [11C] choline, [18F] fluciclovine, [68Ga] PSMA, and [18F] sodium fluoride. Conclusions: Given the small sample size, we were not able to make any firm conclusions. In this limited study, ranolazine treatment did not result in enhanced FDG-PET-tumor detection. ClinicalTrials.gov identifier: NCT01992016. Supported by the William Meyn Foundation; NIH/NCI P30CA46934, 5K12CA086913, CA168934; ACS RSG-16-256-01-TBE; Colorado Translational Research Imaging Center Pilot Award; Paul Sandoval Cancer Research Summer Fellowship. Clinical trial information: NCT01992016.

Brentuximab vedotin followed by bendamustine supercharge for refractory or relapsed Hodgkin lymphoma

AbstractWe evaluated the impact on progression-free survival (PFS) of achieving a deep metabolic response at 2-deoxy-2[18F] fluoro-d-glucose positron emission tomography (FDG-PET) in patients with refractory or relapsed (R/R) classic Hodgkin lymphoma (cHL) following a new salvage regimen named Bv+Bs (brentuximab vedotin + bendamustine supercharge), from 2013 to 2017. In this real-life study, 20 consecutive patients (aged <60 years) with R/R cHL after failure of ≥1 salvage treatments received Bv+Bs regimen consisting of 3-days outpatient IV infusions of 1.8 mg/kg of Bv on day 1 of each 3-week cycle combined in sequence to bendamustine on days 2 and 3 of the treatment cycle at a fixed dose of 120 mg/m2 per day, for a total of 4 courses. A robust primary prophylaxis approach, including premedication, antimicrobials, stimulating factors, and cytomegalovirus monitoring, was systematically performed. The 20 patients (all evaluable) underwent 4 courses of Bv+Bs with a median dose intensity of 100% for both Bv and Bs. Ten patients (50%) experienced grade ≥3 treatment-related adverse events, without requiring hospitalization. At post-Bv+Bs reevaluation, 80% of patients had deep metabolic responses with Deauville 5-point scale scores ≤2. Thereafter, 14 patients (70%) received autologous hematopoietic stem cell transplantation (HSCT; peripheral blood stem cells previously harvested in 12 cases), and 4 patients (10%) received allogeneic HSCT. At a median follow-up of 27 months from Bv+Bs regimen initiation, the 2-year PFS of the entire population was 93.7% (95% confidence interval, 62.7% to 99.6%). Our data suggest that Bv+Bs regimen-driven strategy may be a promising salvage option to improve long-term control of high-risk Hodgkin lymphoma.

Evolution of Brain Glucose Metabolic Abnormalities in Children With Epilepsy and SCN1A Gene Variants.

Three children with drug-refractory epilepsy, normal magnetic resonance image (MRI), and a heterozygous SCN1A variant underwent 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography (FDG-PET) scanning between age 6 months and 1 year and then at age 3 years 6 months to 5 years 5 months. Regional FDG uptake values were compared to those measured in age- and gender-matched pseudo-controls. At baseline, the brain glucose metabolic pattern in the SCN1A group was similar to that of the pseudo-controls. At follow-up, robust decreases of normalized FDG uptake was found in bilateral frontal, parietal and temporal cortex, with milder decreases in occipital cortex. Children with epilepsy and an SCN1A variant have a normal pattern of cerebral glucose metabolism at around 1 year of age but develop bilateral cortical glucose hypometabolism by age 4 years, with maximal decreases in frontal, parietal, and temporal cortex. This metabolic pattern may be characteristic of epilepsy associated with SCN1A variants and may serve as a biomarker to monitor disease progression and response to treatments.

Diabetic Foot Infection: The Role of PET/CT Imaging.

Osteomyelitis in the diabetic foot can be difficult to diagnose and has serious consequences. Although 2-deoxy-2-[18F]-fluoro-D-glucose (FDG) positron emission tomography (PET) was traditionally used in oncology, it is emerging as a useful method in inflammatory and infectious entities. In this chapter, original research articles, meta-analyses, and reviews on the performance of FDG PET in diagnosing osteomyelitis in the diabetic foot will be discussed. In addition, PET available data in comparison to different imaging methods, different analysis methods, and impact of other co-existing conditions such as hyperglycemia, and long-term antibiotic treatment on the performance of FDG PET will be reviewed. Studies published in the last two decades showed variable performance of FDG PET in the assessment of diabetic foot infection with a relatively high specificity (67-93%) but a wide range of sensitivity (29-100%). More recent studies showed better sensitivity, probably due to improved imaging technology and analysis methods and use of hybrid imaging with positron emission tomography/ computed tomography (PET/CT). FDG PET/CT has several advantages compared to other anatomical and functional imaging methods, including short acquisition time, high resolution, low radiation dose, and better tolerability. Further research is required to establish its role in the clinical practice.

Inter-subject FDG PET Brain Networks Exhibit Multi-scale Community Structure with Different Normalization Techniques.

Inter-subject networks are used to model correlations between brain regions and are particularly useful for metabolic imaging techniques, like 18F-2-deoxy-2-(18F)fluoro-D-glucose (FDG) positron emission tomography (PET). Since FDG PET typically produces a single image, correlations cannot be calculated over time. Little focus has been placed on the basic properties of inter-subject networks and if they are affected by group size and image normalization. FDG PET images were acquired from rats (n = 18), normalized by whole brain, visual cortex, or cerebellar FDG uptake, and used to construct correlation matrices. Group size effects on network stability were investigated by systematically adding rats and evaluating local network connectivity (node strength and clustering coefficient). Modularity and community structure were also evaluated in the differently normalized networks to assess meso-scale network relationships. Local network properties are stable regardless of normalization region for groups of at least 10. Whole brain-normalized networks are more modular than visual cortex- or cerebellum-normalized network (p < 0.00001); however, community structure is similar at network resolutions where modularity differs most between brain and randomized networks. Hierarchical analysis reveals consistent modules at different scales and clustering of spatially-proximate brain regions. Findings suggest inter-subject FDG PET networks are stable for reasonable group sizes and exhibit multi-scale modularity.

Occipital hypometabolism on [18F]-FDG PET scans in patients with idiopathic REM sleep behavior disorder is less prominent than those of patients with Parkinson’s disease

Objective: Idiopathic REM sleep behavior disorder (iRBD) is a prodromal manifestation of Parkinson’s dis- ease (PD) or dementia with Lewy bodies (DLB). PD, DLB, and iRBD are known to show diffuse occipital hypometabolism on [18F] fluoro-D-glucose (FDG) positron emission tomography (PET) scans. This study compared the degree of hypometabolism between patients with iRBD and PD.

O133 Objective detection of cortical glucose metabolic abnormalities in children with epilepsy surgery: Validation with intracranial EEG

Objective To evaluate the accuracy of objectively identified hypo- and hypermetabolic cortex to detect the lobe(s) of seizure onset in young children with focal epilepsy. Methods Presurgical 2-deoxy-2[18F]fluoro-D-glucose positron emission tomography (FDG-PET) scans of 37 children (mean age: 9.7 years) with drug-resistant focal epilepsy, who underwent 2-stage epilepsy surgery guided by subdural EEG, were compared to pseudo-normal pediatric control PET data ( N = 64; age 1–18 years, mean age: 9.3 years) by statistical parametric mapping (SPM). The control PET data were from non-surgical epileptic children with normal MRI and FDG-PET on expert visual assessment and were also used to create age-specific pediatric PET templates. Accuracy of intracranial seizure onset zone (SOZ) detection by SPM-defined FDG-PET abnormalities was determined on the lobar level. Results At least one cluster of cortical metabolic abnormality was detected by SPM in 36 children. In the whole group, hypometabolic clusters had 75% sensitivity and 64% specificity to detect the SOZ lobe(s). Hypermetabolic clusters had a slighly higher specificity (69%) but low sensitivity (34%). A similar accuracy of SOZ detection was found in young children ( Discussion Objective detection of metabolic abnormalities by PET is difficult in young children due to lack of age-matched healthy controls. The findings validate the use of SPM with an age-matched pediatric pseudo-normal control group. Conclusion SPM with pediatric pseudo-normal control PET data can identify the lobe(s) of seizure onset with around 70% lobar accuracy even in young children. Significance This approach extends the use of FDG-PET for the objective detection of metabolic abnormalities in the seizure onset lobe(s) to young children above 1 year of age.

Diagnostic role and limitations of 2-deoxy-2-(F-18) fluoro- D-Glucose positron emission tomography (FDG-PET) in screening of synchronous cancer of other organs in patients with head and neck cancers

Diagnostic role and limitations of 2-deoxy-2-(F-18) fluoro- D-Glucose positron emission tomography (FDG-PET) in screening of synchronous cancer of other organs in patients with head and neck cancers

Schizencephaly and intractable epilepsy: an FDG-PET study

Background: To assess the role of 2-deoxy-2(18F)-fluoro-D-glucose positron emission tomography (FDG-PET) scans in the comprehensive evaluation and surgical decision-making in patients with schizencephaly. Methods: We evaluated 11 patients (8M) with schizencephaly (mean follow-up: 4.5 years), including detailed clinical, MRI, FDG-PET, EEG, surgical and neuropathology data. Results: Eight patients had unilateral and three had bilateral clefts on MRI. Mean age at seizure onset was 20 months, with seizure being frequent in 10 and rare in one. Multiple seizure types were noted, with complex partial seizures being the most common (n=8) followed by infantile spasms (n=6). FDG-PET showed larger area of involvement than MRI in all the patients which corresponded better with the electrophysiological changes. Five patients (with unilateral disease on MRI) underwent epilepsy surgery (4 hemispherectomy and 1 multilobar resection). Two patients with focal defect on MRI underwent hemispherectomy due to larger area of abnormality revealed by FDG-PET. One patient was excluded from the surgery due to bilateral abnormalities on FDG PET. Six patients (4 with surgery) were seizure-free at last follow-up (average seizure-free duration: 70 months). One patient who underwent hemispherectomy due to apparently unilateral disease on both video-EEG and MRI but having bilateral abnormality on PET continued to have seizures. ACTH treatment had only a brief (1 month to 1 year) or no response in the six infantile spasms patients. Conclusions: FDG-PET typically shows a much larger area of involvement than MRI thus supplementing MRI in defining the full extent of malformation and assessing the functional integrity of the contralateral hemisphere. FDG-PET may prove to be a useful tool to aid in surgical decision-making and predicting surgical outcome, as patients with contralateral abnormality on FDG-PET may have poor surgical outcomes. When the malformation is unilateral with an intact contralateral hemisphere, surgery (usually hemispherectomy) may be curative of the epilepsy.

The role of serial FDG PET for assessing therapeutic response in patients with cardiac sarcoidosis

BackgroundThe purpose of this study was to determine the feasibility of serial quantitative 2-deoxy-2-[18F]fluoro-D-glucose (FDG) positron emission tomography (PET) to monitor the response of cardiac sarcoidosis to treatment. Methods and ResultsA total of 38 PET scan intervals (54 PET scans) were obtained in 16 patients with cardiac sarcoidosis who underwent serial FDG PET during treatment. FDG-avid lesions of the heart were interpreted quantitatively using 4 PET parameters: maximum standardized uptake value (SUVmax), partial volume corrected mean standardized uptake value (SUVmean), partial volume corrected metabolic volume product (MVP), and global metabolic volume product (gMVP). Clinical response to treatment (improved, stable, or progressive disease) was evaluated by clinical symptoms, NYHA class, and EKG in all the patients. SUVmax, SUVmean, MVP, and gMVP had significantly decreased value on repeat PET in patients who were either stable or showed clinical improvement between two serial PET scans, while none of them had significant change on repeat PET in patients who were clinically worse. Correlation analysis between PET findings and clinical assessment revealed that the changes of SUVmax and SUVmean on repeat PET were negatively correlated with patient’s clinical outcome. ConclusionOur results indicated that serial FDG PET is feasible to determine the extent of disease activity and to quantitatively assess the response of cardiac sarcoidosis to therapy.