F-deoxyglucose Research Articles

Cardiac metabolic changes on 18 F-positron emission tomography after thoracic radiotherapy predict for overall survival in esophageal cancer patients.

Heart doses have been shown to be predictive of cardiac toxicity and overall survival (OS) for esophageal cancer patients. There is potential for functional imaging to provide valuable cardiac information. The purpose of this study was to evaluate the cardiac metabolic dose-response using 18 F-deoxyglucose (FDG)-PET and to assess whether standard uptake value (SUV) changes in the heart were predictive of OS. Fifty-one patients with esophageal cancer treated with radiation who underwent pre- and post-treatment FDG-PET scans were retrospectively evaluated. Pre- and post-treatment PET-scans were rigidly registered to the planning CT for each patient. Pre-treatment to post-treatment absolute mean SUV (SUVmean) changes in the heart were calculated to assess dose-response. A dose-response curve was generated by binning each voxel in the heart into 10Gy dose-bins and analyzing the SUVmean changes in each dose-bin. Multivariate cox proportional hazard models were used to assess whether pre-to-post treatment cardiac SUVmean changes predicted for OS. The cardiac dose-response curve demonstrated a trend of increasing cardiac SUV changes as a function of dose with an average increase of 0.044 SUV for every 10Gy dose bin. In multivariate analysis, disease stage and SUVmean change in the heart were predictive (p<0.05) for OS. Changes in pre- to post-treatment cardiac SUV were predictive of OS with patients having a higher pre- to post-treatment cardiac SUV change surviving longer.

Characterization of Atypical Pheochromocytomas with Correlative MRI and Planar/Hybrid Radionuclide Imaging: A Preliminary Study

Pheochromocytomas may show atypical imaging findings leading to diagnostic pitfalls. We correlated the results of magnetic resonance imaging (MRI) with those of radionuclide studies in patients with pheochromocytomas. T2-weighted (-w), T1-w chemical-shift and T1-w dynamic contrast enhanced (DCE) MRI sequences were evaluated to assess tumor structure. 131Iodine metaiodobenzylguanidine (MIBG) scintigraphy, 18fluoro (F) deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) or FDG PET/MRI were evaluated for direct comparison. Of a total of 80 adrenal lesions in 73 patients, 20 in 18 patients were pheochromocytomas. More than half (55%) of the pheochromocytomas (n = 11) had the typical increased signal intensity on T2-w and T1-w DCE, while the remaining (n = 9) lesions showed atypical findings; of these nine latter atypical lesions, seven (35%) were cystic (two totally, three predominantly and two partially) and two (10%) were hemorrhagic on MRI. In these atypical lesions, MIBG scintigraphy (n = 5), FDG PET/CT (n = 6) or FDG PET/MRI (n = 2) showed inhomogeneous tracer uptake in the residual viable tissue providing tumor characterization; however, one predominantly cystic pheochromocytoma showed false negative MIBG scan. Our preliminary results show that cystic degeneration may be frequent in pheochromocytoma being so marked that only a thin rim of viable cells may residue to disclose the true nature of the tumor. MRI findings together with those of correlative planar/hybrid radionuclide images are helpful to characterize these atypical pheochromocytomas. In particular, tumor accumulation of MIBG and/or FDG is able to classify these lesions as not simple cysts; in detail, the presence of partial MIBG uptake allows the diagnosis of pheochromocytomas, while the presence of partial FDG uptake generically reflects the presence of viable solid tissue of such cystic tumors.

A novel role of the corticotrophin-releasing hormone regulating peptide, teneurin C-terminal associated peptide 1, on glucose uptake into the brain.

Teneurin C-terminal associated peptide (TCAP) is an ancient paracrine signalling agent that evolved via lateral gene transfer from prokaryotes into an early metazoan ancestor. Although it bears structural similarity to corticotrophin-releasing hormone (CRH), it inhibits the in vivo actions of CRH. The TCAPs are highly expressed in neurones, where they induce rapid cytoskeletal rearrangement and are neuroprotective. Because these processes are highly energy-dependent, this suggests that TCAP has the potential to regulate glucose uptake because glucose is the primary energy substrate in brain, and neurones require a steady supply to meet the high metabolic demands of neuronal communication. Therefore, the objective of the present study was to assess the effect of TCAP-mediated glucose uptake in the brain and in neuronal cell models. TCAP-mediated 18 F-deoxyglucose (FDG) uptake into brain tissue was assessed in male wild-type Wistar rats by functional positron emission tomography. TCAP-1 increased FDG uptake by over 40% into cortical regions of the brain, demonstrating that TCAP-1 can significantly enhance glucose supply. Importantly, a single nanomolar injection of TCAP-1 increased brain glucose after 3days and decreased blood glucose after 1week. This is corroborated by a decreased serum concentration of insulin and an increased serum concentration of glucagon. In immortalised hypothalamic neurones, TCAP-1 increased ATP production and enhanced glucose uptake by increasing glucose transporter recruitment to the plasma membrane likely via AKT and mitogen-activated protein kinase/ERK phosphorylation events. Taken together, these data demonstrate that TCAP-1 increases glucose metabolism in neurones, and may represent a peptide signalling agent that regulated glucose uptake before insulin and related peptides.

Biodistribution and radiation dosimetry in healthy volunteers of a novel tumour-specific probe for PET/CT imaging: BAY 85-8050

Novel tracers for the diagnosis of malignant disease with PET and PET/CT are being developed as the most commonly used (18)F deoxyglucose (FDG) tracer shows certain limitations. Employing radioactively labelled glutamate derivatives for specific imaging of the truncated citrate cycle potentially allows more specific tumour imaging. Radiation dosimetry of the novel tracer BAY 85-8050, a glutamate derivative, was calculated and the effective dose (ED) was compared with that of FDG. Five healthy volunteers were included in the study. Attenuation-corrected whole-body PET/CT scans were performed from 0 to 90 min, at 120 and at 240 min after injection of 305.0 ± 17.6 MBq of BAY 85-8050. Organs with moderate to high uptake at any of the imaging time points were used as source organs. Total activity in each organ at each time point was measured. Time-activity curves (TAC) were determined for the whole body and all source organs. The resulting TACs were fitted to exponential equations and accumulated activities were determined. OLINDA/EXM software was used to calculate individual organ doses and the whole-body ED from the acquired data. Uptake of the tracer was highest in the kidneys due to renal excretion of the tracer, followed by the pancreas, heart wall and osteogenic cells. The mean organ doses were: kidneys 38.4 ± 11.2 μSv/MBq, pancreas 23.2 ± 3.8 μSv/MBq, heart wall 17.4 ± 4.1 μSv/MBq, and osteogenic cells 13.6 ± 3.5 μSv/MBq. The calculated ED was 8.9 ± 1.5 μSv/MBq. Based on the distribution and dose estimates, the calculated radiation dose of BAY 85-8050 is 2.67 ± 0.45 mSv at a patient dose of 300 MBq, which compares favourably with the radiation dose of FDG (5.7 mSv).

Comparison of lesion detection and quantitation of tracer uptake between PET from a simultaneously acquiring whole-body PET/MR hybrid scanner and PET from PET/CT

PET/MR hybrid scanners have recently been introduced, but not yet validated. The aim of this study was to compare the PET components of a PET/CT hybrid system and of a simultaneous whole-body PET/MR hybrid system with regard to reproducibility of lesion detection and quantitation of tracer uptake. A total of 46 patients underwent a whole-body PET/CT scan 1h after injection and an average of 88min later a second scan using a hybrid PET/MR system. The radioactive tracers used were (18)F-deoxyglucose (FDG), (18)F-ethylcholine (FEC) and (68)Ga-DOTATATE (Ga-DOTATATE). The PET images from PET/CT (PET(CT)) and from PET/MR (PET(MR)) were analysed for tracer-positive lesions. Regional tracer uptake in these foci was quantified using volumes of interest, and maximal and average standardized uptake values (SUV(max) and SUV(avg), respectively) were calculated. Of the 46 patients, 43 were eligible for comparison and statistical analysis. All lesions except one identified by PET(CT) were identified by PET(MR) (99.2%). In 38 patients (88.4%), the same number of foci were identified by PET(CT) and by PET(MR). In four patients, more lesions were identified by PET(MR) than by PET(CT), in one patient PET(CT) revealed an additional focus compared to PET(MR). The mean SUV(max) and SUV(avg) of all lesions determined by PET(MR) were by 21% and 11% lower, respectively, than the values determined by PET(CT) (p < 0.05), and a strong correlation between these variables was identified (Spearman rho 0.835; p < 0.01). PET/MR showed equivalent performance in terms of qualitative lesion detection to PET/CT. The differences demonstrated in quantitation of tracer uptake between PET(CT) and PET(MR) were minor, but statistically significant. Nevertheless, a more detailed study of the quantitative accuracy of PET(MR) and the factors governing it is needed to ultimately assess its accuracy in measuring tissue tracer concentrations.

Compliance with PET acquisition protocols for therapeutic monitoring of erlotinib therapy in an international trial for patients with non-small cell lung cancer

The Response Evaluation Criteria in Solid Tumors (RECIST) are widely used but have recognized limitations. Molecular imaging assessments, including changes in (18)F-deoxyglucose (FDG) or (18)F-deoxythymidine (FLT) uptake by positron emission tomography (PET), may provide earlier, more robust evaluation of treatment efficacy. A prospective trial evaluated on-treatment changes in FDG and FLT PET imaging among patients with relapsed or recurrent non-small cell lung cancer treated with erlotinib to assess the relationship between PET-evaluated response and clinical outcomes. We describe an audit of compliance with the study imaging charter, to establish the feasibility of achieving methodological consistency in a multicentre setting. Patients underwent PET scans at baseline and approximately day 14 and day 56 of treatment (n = 73, 66 and 51 studies, and n = 73, 63 and 50 studies for FDG PET and FLT PET, respectively). Blood glucose levels were within the target range for all FDG PET scans. Charter-specified uptake times were achieved in 86% (63/73) and 89% (65/73) of baseline FDG and FLT scans, respectively. On-treatment scans were less consistent: 72% (84/117) and 68% (77/113), respectively, achieved the target of ±5min of baseline uptake time. However, 96% (112/117) and 94% (106/113) of FDG and FLT PET studies, respectively, were within ±15min. Bland-Altman analysis of intra-individual hepatic average standardized uptake value (SUV(ave)), to assess reproducibility, showed only a small difference in physiological uptake (-0.006 ± 0.224 in 118 follow-up FDG scans and 0.09 ± 0.81 in 111 follow-up FLT scans). It is possible to achieve high reproducibility of scan acquisition methodology, provided that strict imaging compliance guidelines are mandated in the study protocol.

18F-deoxyglucose PET: useful in the management of patients with stem cell transplantation for lymphoma?

Evaluation of: Lambert JR, Bomanji JB, Peggs KS et al. Prognostic role of PET scanning before and after reduced-intensity allogeneic stem cell transplantation for lymphoma. Blood 115(14), 2763–2768 (2010).18F-deoxyglucose (FDG) positron emission tomography (PET) and more recently FDG PET/computed tomography (CT) has become an important tool in the management of patients with Hodgkin and non-Hodgkin lymphoma. It adds metabolic and functional information to conventional anatomical imaging, mainly assessed by CT. Especially for the detection of early response to treatment and prognostic considerations, this type of information seems better suited than anatomical information. Consequently, the ability of FDG PET to predict the outcome in patients with stem cell transplantation (SCT) for lymphoma has been tested in several studies. Results in patients with autologous SCT have been promising, and pretransplant FDG PET is likely to become routine in this group of patients. The evaluated study investigates, for the first time, the predictive value of pretransplant FDG PET in allogeneic SCT, as well as the utility of FDG PET for the follow-up of these patients. All 80 patients included in the prospective study had reduced-intensity conditioning. In contrast to FDG PET before autologous SCT, there was no correlation at all between pretransplant FDG PET results and the outcome after allogeneic SCT. This reflects the fact that other or additional reasons, especially the graft-versus-leukemia effect, are substantial for the outcome of allogeneic SCT in comparison with autologous SCT. Follow-up with FDG PET after reduced-intensity allogeneic SCT was significantly more sensitive than CT to detect disease progression or relapse, and was useful in guiding treatment in the situation of disease relapse.

The Correlation between FDG PET/CT Imaging and Molecule Makers in Non-Small Cell Lung Cancer.

PET is a sensitive and special method of determining malignant degree of the lung cancer. This study investigates the correlation between (18)F-deoxyglucose (FDG) uptake and various biological markers in clinical stage I non-small cell lung cancer (NSCLC). The non-small cell lung cancer specimens of 23 patients were examined by flow cytometry and immunohistochemistry, the relationship between the max standard uptake value (SUV) of FDG and the expression of the biological markers p53, Ki-67, proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), glucose transporter-1 (GLUT-1), S-phase fraction (SPF) were studied. The max SUV was correlated with the expression of p53 (P <0.05), Ki-67 (P <0.05), PCNA (P <0.05), VEGF (P <0.05) and SPF (P <0.05) in stage I NSCLC. Glut-1 expression showed significant correlation with FDG uptake (P =0.001), however the max SUV showed no correlation with tumor pathology. Our study indicates that (18)F-FDG uptake in NSCLC correlates well with the expression of p53, Ki-67, PCNA, VEGF, GLUT-1, SPF.

Targeting of VX2 Rabbit Liver Tumor by Selective Delivery of 3-Bromopyruvate: A Biodistribution and Survival Study

The aim of this study was to determine the biodistribution and tumor targeting ability of (14)C-labeled 3-bromopyruvate ([(14)C]3-BrPA) after i.a. and i.v. delivery in the VX2 rabbit model. In addition, we evaluated the effects of [(14)C]3-BrPA on tumor and healthy tissue glucose metabolism by determining (18)F-deoxyglucose (FDG) uptake. Last, we determined the survival benefit of i.a. administered 3-BrPA. In total, 60 rabbits with VX2 liver tumor received either 1.75 mM [(14)C]3-BrPA i.a., 1.75 mM [(14)C]3-BrPA i.v., 20 mM [(14)C]3-BrPA i.v., or 25 ml of phosphate-buffered saline (PBS). All rabbits (with the exception of the 20 mM i.v. group) received FDG 1 h before sacrifice. Next, we compared survival of animals treated with i.a. administered 1.75 mM [(14)C]3-BrPA in 25 ml of PBS (n = 22) with controls (n = 10). After i.a. infusion, tumor uptake of [(14)C]3-BrPA was 1.8 +/- 0.2% percentage of injected dose per gram of tissue (%ID/g), whereas other tissues showed minimal uptake. After i.v. infusion (1.75 mM), tumor uptake of [(14)C]3-BrPA was 0.03 +/- 0.01% ID/g. After i.a. administration of [(14)C]3-BrPA, tumor uptake of FDG was 26 times lower than in controls. After i.v. administration of [(14)C]3-BrPA, there was no significant difference in tumor FDG uptake. Survival analysis showed that rabbits treated with 1.75 mM 3-BrPA survived longer (55 days) than controls (18.6 days). Intra-arterially delivered 3-BrPA has a favorable biodistribution profile, combining a high tumor uptake resulting in blockage of FDG uptake with no effects on healthy tissue. The local control of the liver tumor by 3-BrPA resulted in a significant survival benefit.

Stability of 18F-Deoxyglucose Uptake Locations Within Tumor During Radiotherapy for NSCLC: A Prospective Study

Because individual tumors are heterogeneous, including for (18)F-deoxyglucose (FDG) uptake and, most likely, for radioresistance, selective boosting of high FDG uptake zones within the tumor has been suggested. To do this, it is critical to know whether the location of these high FDG uptake patterns within the tumor remain stable during radiotherapy (RT). Twenty-three patients with Stage I-III non-small-cell lung cancer underwent repeated FDG positron emission tomography computed tomography scans before radical RT (Day 0) and at Days 7 and 14 of RT. On all scans, the high and low FDG uptake regions were autodelineated using several standardized uptake value thresholds, varying from 34% to 80% of the maximal standardized uptake value. The volumes and overlap fractions of these delineations were calculated to demonstrate the stability of the high FDG uptake regions during RT. The mean overlap fraction of the 34% uptake zones at Day 0 with Days 7 and 14 was 82.8% +/- 8.1% and 84.3% +/- 7.6%, respectively. The mean overlap fraction of the high uptake zones (60%) was 72.3% +/- 15.0% and 71.3% +/- 19.7% at Day 0 with Days 7 and 14, respectively. The volumes of the thresholds varied markedly (e.g., at Day 0, the volume of the 60% zone was 16.8 +/- 20.3 cm(3)). In contrast, although the location of the high FDG uptake patterns within the tumor during RT remained stable, the delineated volumes varied markedly. The location of the low and high FDG uptake areas within the tumor remained stable during RT. This knowledge may enable selective boosting of high FDG uptake areas within the tumor.

Effects of disease duration on the clinical features and brain glucose metabolism in patients with mixed type multiple system atrophy

To study the effect of disease duration on the clinical, neuropsychological and [(18)F]-deoxyglucose (FDG) PET findings in patients with mixed type multiple system atrophy (MSA), this study included 16 controls and 37 mixed-type MSA patients with a shorter than a 3-year history of cerebellar or parkinsonian symptoms. We classified the patients into three groups according to the duration of parkinsonian or cerebellar symptoms (Group I = <or=1 year; II = 13-24 months; III = 25-36 months). We performed UPDRS, international cooperative ataxia rating scale (ICARS), and a neuropsychological test battery. We compared the FDG PET findings of each group of patients with controls. Group I patients frequently had memory and frontal executive dysfunction. They showed hypometabolism in the frontal cortex, anterior cerebellar hemisphere and vermis. They had parkinsonian motor deficits, but no basal ganglia hypometabolism. Group II and III patients frequently had multiple domain cognitive impairments, and showed hypometabolism in the frontal and parieto-temporal cortices. Hypometabolism of the bilateral caudate and the left posterolateral putamen was observed in Group II, and whole striatum in Group III. In summary, the cortical hypometabolism begins in the frontal cortex and spreads to the parieto-temporal cortex in MSA. This spreading pattern coincides with the progressive cognitive decline. Early caudate hypometabolism may also contribute to the cognitive impairment. Parkinsonian motor deficits precede putaminal hypometabolism that begins in its posterolateral part. Cerebellar hypometabolism occurs early in the clinical courses and seems to be a relevant metabolic descriptor of cerebellar deficits.

PET scanning and patient reported dysphagia before and after chemotherapy (CT) for prediction of pathological response after CT and chemoradiotherapy (CRT) in patients with locally advanced esophageal cancer (EC): A multicenter phase ll trial of the Swiss

4587 Background: Only responding patients (pts) ultimately benefit from preoperative therapy for locally advanced EC. To predict response quality after CRT and detect non-responders earlier, we evaluated changes from baseline in FDG uptake by PET scans and patient reported dysphagia after two cycles of CT. Methods: Pts with resectable, locally advanced squamous cell carcinoma or adenocarcinoma of the esophagus were treated with 2 cycles of CT with docetaxel/cisplatin (DC) q3w followed by CRT (DC weekly x5 with concomitant 45 Gy RT) and surgery. PET imaging using [F]-deoxyglucose (FDG) uptake and subjective dysphagia assessment using a quality of life module specific to EC (EORTC QLQ-OES24) were performed at baseline and after the 2nd cycle of CT. 40% decrease of FDG uptake was prospectively hypothesized to be an early predictor for a pathological complete remission (tumor regression grade 1, TRG) and subtotal regression (TRG 2) after the CRT. The predictive value of improvement in dysphagia was tested by analysis of covariance with baseline dysphagia as covariate. Results: Out of included 66 pts, 56 completed preoperative therapy and surgery. Dysphagia scores (range 0–100) were available in 51 pts, mean changes were 14 (n=13), 12 (n=16) and 12 (n=22) for pts with TRG 1, 2 or &gt;2, respectively, lacking any significance. 44 pts had two PET scans (5: centers not participating, 3: no FDG-uptake at baseline, 4: second scan too late or not done). Mean FDG-decrease was 49% (n=7), 44% (n=17), 15% (n=20) for pts with TRG 1, 2 or &gt;2, respectively. Less than 40% reduction in FDG uptake predicted non-response (TRG&gt;2) with sensitivity 70%, specificity 50%, negative predictive value 70% and positive predictive value 50%. FDG- uptake reduction indicated reduced risk of TRG&gt;2 in a logistic regression model (p&lt;0.01, 95%-CI 2–273). Conclusions: Decreased FDG uptake in sequential PET scans strongly correlates with tumor response, but is not accurate enough to early identify non- responders. Early improvement of dysphagia after 2 cycles CT did not predict TRG after CRT. No significant financial relationships to disclose.

Specific accumulation of 18F-deoxyglucose in three-dimensional long-term cultures of human and rodent brain tissue

Organotypic slice cultures (OSC) of human brain specimens represent an intriguing experimental model for translational studies addressing, e.g., stem cell transplantation in neurodegenerative diseases or targeting invasion by malignant glioma ex vivo. However, long-term viability and phenomena of structural reorganization of human OSC remain to be further characterized. Here, we report the use of (18)F-deoxyglucose (FDG) for evaluating the viability of brain slice preparations obtained either from postnatal rats or human hippocampal specimens. Anatomically well preserved human hippocampi obtained from epilepsy surgery and rat hippocampus slice cultures obtained from six day old Wistar rats were dissected into horizontal slices. The slices were incubated with FDG in phosphate buffered saline up to 1 h, either with or without supplementation of glucose at a concentration of 2.5 mg/ml. Radioactivity within the medium or slice cultures was measured using a gamma-counter. In addition, distribution of radioactivity was autoradiographically visualized and quantified as counts per mm(2). In rat hippocampal slices, FDG accumulated with 1 300 000 +/- 68 000 counts/mm(2), whereas the incorporation of the radioactive label in human slices was in the order of 1 500 000 +/- 370 000 counts/mm(2). The elevation of glucose concentration within the medium led to a significant three-fold decrease of FDG accumulation in rat slices and to a 2.4-fold decrease in human specimens. FDG accumulated in organotypic brain cultures of human or rodent origin. FDG is thus suited to investigate the viability of OSC. Furthermore, these preparations open new ways to study the factors governing cerebral FDG uptake in brain tissue ex vivo.

The Influence of CA 125 and CEA Levels on the Results of 18F-Deoxyglucose Positron Emission Tomography in Suspected Recurrence of Epithelial Ovarian Cancer

The follow-up of epithelial ovarian cancer (OCA) consists of clinical investigation, sonography, and tumor markers (TMs), especially CA 125. If tumor recurrence is suspected, other imaging modalities including positron emission tomography (PET) with (18)F-deoxyglucose (FDG) are often used. While there is still no consensus about the method of choice and the timing of its application, this study aims to find a TM threshold at which a PET would be appropriate. A total of 90 PET studies and the associated CA 125 values (normal value < 35 U/ml) were available in 71 patients during the follow-up after primary therapy for OCA. In 48 studies a CEA value (normal value < 3 ng/ml) was also available. The results of PET imaging were related to the level of TM increase. In 23/90 studies the PET scan was normal. These patients had a median CA 125 of 13.3 U/ml (range 4.2-168 U/ml). In 67/90 studies the PET indicated a potential recurrence of OCA and the median CA 125 was 166.7 U/ml (range 13.3-4,060 U/ml). The TM levels were significantly different (p < 0.001, U-test). With one exception, there were no normal PET scans above CA 125 levels of 30 U/ml; between 20 and 30 U/ml PET was positive in 4/7 studies. In suspected recurrence of OCA, if imaging modalities are to be used, an FDG PET may be considered. Since the costs of this investigation are high, it should be restricted to clinical situations where it is likely to be most effective. In this study a PET indication is worthwhile at CA 125 levels of approximately 30 U/ml.

18F-Deoxyglucose PET for the staging of oesophageal cancer

Evaluation of the influence of histopathologic sub-types and grading of primaries of oesophageal cancer, relative to their size and location, on the uptake of (18)F-deoxyglucose (FDG) as measured by positron emission tomography (PET). 50 consecutive patients were evaluated. There were four drop-outs due to previous surgical and/or chemotherapeutical treatments and thus in 46 patients (28 squamous cell carcinomas and 18 adenocarcinomas) a pretherapeutic PET evaluation of the primary including a standard uptake value (SUV) was obtained. In 42 cases data on tumour grading were available also. Squamous cell carcinomas (SCC) were in 7/13/8 cases located in the proximal, medial and distal part of the oesophagus, respectively the grading was Gx in 3, G 2 in 12, G2-3 in 7, and G3 in 6 cases. The SUV(max) showed a mean of 6.5+/-2.8 (range 1.7-13.5). Adenocarcinomas (ACA) were located in the medial oesophagus in two cases and otherwise in its distal parts. Grading was Gx in one, G2 in 4, G2-3 in 3, G3 in 3, G3-4 in 3, and G4 in one case. The mean SUV(max) was 5.2+/-3.2 (range 1-13.6) and this was not significantly different from the SCC. Concerning the tumour grading there was a slight, statistically not relevant trend towards higher SUV(max) in more dedifferentiated cancer. SCC and ACA of the oesophagus show no relevant differences in the FDG-uptake. While there was a significant variability of tumour uptake in the overall study group, a correlation of SUV and tumour grading was not found.

Correlational patterns of cerebral glucose metabolism in never-medicated schizophrenics.

We studied 18 never-mediated schizophrenic patients and 22 normal control subjects with 18F-deoxyglucose (FDG) positron emission tomography. Patients and controls performed the continuous performance test during FDG uptake. Cortical and subcortical structures comprising two circuits selected on the basis of several theoretical models of schizophrenia were examined. The correlation of glucose metabolic rate (GMR) for each structure in each circuit with connected structures was calculated and tested for two-tailed significance. Schizophrenics showed significantly different patterns of intercorrelations for both circuits. The largest difference was in the correlation of GMR in the anterior thalamus with the frontal cortex, a key element in the thalamo-cortical-striatal circuit suggested to be abnormal in some models of schizophrenia. Correlations of the frontal lobe with other regions were also more positive in normal controls than schizophrenics; controls had three correlational paths from the frontal cortex (to temporal cortex, ventral anterior thalamus, and dorsal medial thalamus) with significantly more positive correlations than schizophrenics perhaps consistent with other findings of frontal cortical dysfunction in schizophrenia. Normal controls also had both more significant positive and more significant negative correlations between the occipital cortex and other brain areas than schizophrenics. Correlations between homologous areas in the right and left hemispheres were prominent in both groups.