Fluorodeoxyglucose F18 Positron Emission Tomography Research Articles

Maximum standardized uptake value-to-tumor size ratio in fluorodeoxyglucose F18 positron emission tomography/computed tomography: a simple prognostic parameter for non-small cell lung cancer.

By correcting the effect of tumor size on metabolic activity, the maximum standardized uptake value-to-tumor size (SUVmax:tumor size) ratio on fluorodeoxyglucose F18 positron emission tomography (18F-FDG PET)/computed tomography (CT) scans can be a prognostic parameter of non-small cell lung cancer (NSCLC). The current study evaluates the prognostic value of SUVmax:tumor size ratio on pretreatment 18F-FDG PET/CT scans in patients with NSCLC. Furthermore, the SUVmax:tumor size ratio is compared with other established PET parameters. This study included 108 patients with NSCLC who underwent pretreatment 18F-FDG PET/CT scans and curative lung surgery. The associations between the SUVmax:tumor size ratio and other conventional PET parameters were investigated. The recurrence-free survival according to the SUVmax:tumor size ratio was also analyzed. In addition, the SUVmax:tumor size ratio was compared according to postoperative pathologic findings. In total, 72 (66.7%) of the 108 participants presented with adenocarcinoma (ADC). Nineteen (17.6%) patients experienced recurrence during a median follow-up period of 32.3 months. The median SUV max:tumor size ratio was 2.37 (1.23 for ADCs and 3.90 for other histologic types). The SUVmax:tumor size ratio was associated with SUVmax and mean SUV, as well as metabolic tumor volume and total lesion glycolysis. Patients with an SUVmax:tumor size ratio higher than the median had a worse recurrence outcome than those with an SUVmax:tumor size ratio lower than the median. Participants with ADC who presented with lymphovascular invasion had a higher SUVmax:tumor size ratio than those without. The presence of lymph node metastasis and advanced histologic grade were associated with a high SUVmax:tumor size ratio in patients with ADC. The SUVmax:tumor size ratio on pretreatment 18F-FDG PET/CT scans was associated with aggressive tumor behavior and poor outcome in NSCLCs, particularly ADC. The SUVmax:tumor size ratio on pretreatment 18F-FDG PET/CT scans has a prognostic value in patients with NSCLCs, especially ADC.

The Role of SPECT/CT and PET/CT Hybrid Imaging in the Management of Ectopic Thyroid Carcinoma-A Systematic Review.

Thyroid ectopy represents a rare disease with an incidence of 0.3-1/100,000. It occurs due to the defective embryological process of the thyroid gland development. The thyroid ectopic tissue may suffer malignant transformation. This review aims to shed light on the roles that I-131 SPECT/CT (radioiodine 131 single-photon emission tomography fused with computed tomography) and F-18 PET/CT (fluorodeoxyglucose F18 positron emission tomography fused with computer tomography) may play in managing patients with ectopic thyroid carcinoma. A total number of 47 articles were identified on the PubMed and Google Scholar databases, and 3 other articles were selected from articles identified in the references cited in the retrieved articles. After refining the selection, the inclusion and exclusion criteria were applied, resulting in 10 articles that were included in the review. The cases of ectopy included in this review were localised as follows: four cases in the thyroglossal duct, two cases in the mediastinum, one case in the oesophagus, one case in the thorax, one case with a pre-tracheal location, and one case with a latero-cervical location. In all the cases, F-18 FDG PET/CT was used as a diagnostic tool. In one case, F-18 FDG PET/CT was combined with I-131 SPECT/CT and MRI (magnetic resonance imaging). In one case, it was combined with 68 Ga-FAPI PET/CT (Ga-68 radiolabelled FAP inhibitor positron emission tomography fused with computer tomography). The maximum SUVs (standardised uptake values) ranged from 5.5 to 25 g/mL. F-18 PET/CT and I-131 SPECT/CT hybrid nuclear imaging is of great value in assessing ectopic thyroid carcinoma. F-18 FDG PET/CT plays an important role in the primary tumour evaluation and distant disease detection. Ga-68 FAPIs are a promising alternative. I-131 SPECT/CT adds important information related to the anatomical characterization of primary and distant iodine-avid lesions.

Abstract PO1-01-03: Pathological response according to early metabolic remission in an interim FDG-PET scan and to tumor infiltrating lymphocytes - A secondary analysis of the phase II trial ABCSG 52/ATHENE investigating atezolizumab in early HER2+ BC

Abstract Background: ABCSG-52/ATHENE investigated a neoadjuvant chemotherapy de-escalation/immunotherapy escalation approach with trastuzumab, pertuzumab, atezolizumab and epirubicin for early-stage HER2-positive breast cancer. The pathological complete response rate (pCR; ypT0/Tis, ypN0) - the primary endpoint of the trial - was 60.3% (95% CI 47.5% - 71.9%), and was higher than the predefined threshold for positivity (≥ 40%). Interestingly, higher pCR rates were observed in PD-L1 immune cell (IC) negative tumors (pCR 69.2%) as compared to PD-L1 IC positive tumors (pCR 55.2%). No new safety concerns were observed. Primary outcome data were reported at the ESMO Breast Cancer Conference 2023. Here, we present the correlation of pathological outcome according to early metabolic response in an interim fluorodeoxyglucose F18 positron emission tomography (FDG-PET) scan, and according to stromal tumor infiltrating lymphocytes (TILs) at baseline. Methods: Patients (pts) with previously untreated, histologically confirmed HER2-positive early breast cancer (EBC; clinical prognostic stage cT1c-4a-d, N0–3, M0) were randomized 1:1 to two 3-weekly cycles of a chemotherapy-free induction phase (Part 1) with trastuzumab and pertuzumab (TP) plus 1200 mg atezolizumab (TP+A), or TP alone. Subsequently, all pts received 4 cycles of TP+A in combination with epirubicin 90 mg/m² (Part 2). Randomization was stratified according to baseline TILs (< 5% vs ≥ 5%), hormone receptor status (positive vs. negative), and prognostic stage (≤ IIA vs. ≥ IIB; AJCC v.8.0). An FDG-PET assessment was performed at baseline and after 2 cycles of study treatment. According to PERCIST, early metabolic responses were classified as metabolic complete response (mCR) and metabolic partial response (mPR) and association with outcome was tested with Fisher’s exact test. TIL assessment in pretreatment biopsy specimen were performed according to the recommendations from the International TILs Working Group. Lymphocytic predominant phenotype was defined as a TIL proportion of ≥ 50%. Correlation of TILs and pCR was modeled with logistic regression. Results: Overall, 58 pts were randomized to TP-A (n=29) or TP (n=29) at 9 sites. In 45 patients, a protocol predefined PERCIST assessment was available. An early mCR was achieved in 14 pts (n=14/45, 31.1%): 5 pts (n=5/21, 23.8%) in the TP group and 9 pts (n=9/24, 37.5%) in the TP-A group. Pts with and without an early mCR achieved a pCR in 92.9% (n=13/14) and 54.8% (n=17/31) of cases (p=0.016), respectively. An early mCR/mPR was achieved in 37 pts (n=37/45, 82.2%). Pts with and without an early mCR/mPR achieved a Residual Cancer Burden (RCB) class 0 or I in 89.2% (n=33/37) and 50.0% (n=4/8) of cases (p=0.024), respectively. The mean stromal TIL proportion was 23.9% in the overall population, with 22.8% in TP group and 25.0% in TP-A group. A lymphocytic predominant phenotype was seen in 10.3% of pts treated in the TP group, and 17.2% of pts treated in the TP-A group. No association between TIL proportion at baseline and pCR could be detected (OR for a 10%-point increase = 1.02, 95% CI 0.78-1.34). A moderate positive correlation between numeric values of TILs and PD-L1 ICs was observed (spearman r=0.57, P< 0.0001). Exploratory correlation analyses of PD-L1 status, TIL proportion and metabolic responses in interim FDG-PET scans will be presented at the meeting. Conclusions: In ABCSG-52, chemotherapy de-escalation with intensified immunotherapy was effective and safe. Early metabolic response assessment was feasible and predicted pathologic response; therefore, incorporation of interim FDG-PET results into de-escalation trials merits further investigation. In contrast to regimens without immune-checkpoint inhibitors, TIL proportion at baseline did not correlate with pathological outcome. Funding: Provision of IMP and financial support by Roche Austria GmbH Citation Format: Gabriel Rinnerthaler, Daniel Egle, Rupert Bartsch, Clemens Schmitt, Andreas Petzer, Marija Balic, Edgar Petru, Ursula Denison, Christian F. Singer, Vesna Bjelic-Radisic, Simon Gampenrieder, Michael Knauer, Karl Sotlar, Christine Brunner, Florian Posch, Dominik Hlauschek, Lidija Sölkner, Zsuzsanna Bago-Horvath, Martin Filipits, Manuela Gili, Michael Gnant, Richard Greil. Pathological response according to early metabolic remission in an interim FDG-PET scan and to tumor infiltrating lymphocytes - A secondary analysis of the phase II trial ABCSG 52/ATHENE investigating atezolizumab in early HER2+ BC [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-01-03.

Renal Cortical Glucose Uptake Is Decreased in Insulin Resistance and Correlates Inversely With Serum Free-fatty Acids.

Studies on human renal metabolism are scanty. Nowadays, functional imaging allows the characterization of renal metabolism in a noninvasive manner. We have recently demonstrated that fluorodeoxyglucose F18 (18F FDG) positron emission tomography can be used to analyze renal glucose uptake (GU) rates, and that the renal cortex is an insulin-sensitive tissue. To confirm that renal GU is decreased in people with obesity and to test whether circulating metabolites are related to renal GU. Eighteen people with obesity and 18 nonobese controls were studied with [18F]FDG positron emission tomography during insulin clamp. Renal scans were obtained ∼60 minutes after [18F]FDG injection. Renal GU was measured using fractional uptake rate and after correcting for residual intratubular [18F]FDG. Circulating metabolites were measured using high-throughput proton nuclear magnetic resonance metabolomics. Cortical GU was higher in healthy nonobese controls compared with people with obesity (4.7 [3.4-5.6] vs 3.1 [2.2-4.3], P = .004, respectively), and it associated positively with the degree of insulin sensitivity (M value) (r = 0.42, P = .01). Moreover, cortical GU was inversely associated with circulating β-OH-butyrate (r = -0.58, P = .009), acetoacetate (r = -0.48, P = .008), citrate (r = -0.44, P = .01), and free fatty acids (r = -0.68, P < .0001), even when accounting for the M value. On the contrary, medullary GU was not associated with any clinical parameters. These data confirm differences in renal cortical GU between people with obesity and healthy nonobese controls. Moreover, the negative correlations between renal cortex GU and free fatty acids, ketone bodies, and citrate are suggestive of substrate competition in the renal cortex.

Elecsys Cerebrospinal Fluid Immunoassays Accurately Detect Alzheimer's Disease Regardless of Concomitant Small Vessel Disease.

Differentiating dementia due to small vessel disease (SVD) from dementia due to Alzheimer's disease (AD) with concomitant SVD is challenging in clinical practice. Accurate and early diagnosis of AD is critical to delivering stratified patient care. We characterized the results of Elecsys® cerebrospinal fluid (CSF) immunoassays (Roche Diagnostics International Ltd) in patients with early AD, diagnosed using core clinical criteria, with varying extent of SVD. Frozen CSF samples (n = 84) were measured using Elecsys β-Amyloid(1-42) (Aβ42), Phospho-Tau (181P) (pTau181), and Total-Tau (tTau) CSF immunoassays, adapted for use on the cobas® e 411 analyzer (Roche Diagnostics International Ltd), and a robust prototype β-Amyloid(1-40) (Aβ40) CSF immunoassay. SVD was assessed by extent of white matter hyperintensities (WMH) using the lesion segmentation tool. Interrelations between WMH, biomarkers, fluorodeoxyglucose F18-positron emission tomography (FDG-PET), and other parameters (including age and Mini-Mental State examinations [MMSE]) were assessed using Spearman's correlation, sensitivity/specificity, and logistic/linear regression analyses. The extent of WMH showed significant correlation with Aβ42/Aβ40 ratio (Rho=-0.250; p = 0.040), tTau (Rho = 0.292; p = 0.016), tTau/Aβ42 ratio (Rho = 0.247; p = 0.042), age (Rho = 0.373; p = 0.002), and MMSE (Rho=-0.410; p = 0.001). Sensitivity/specificity point estimates for Elecsys CSF immunoassays versus FDG-PET positivity for underlying AD pathophysiology were mostly comparable or greater in patients with high versus low WMH. WMH were not a significant predictor and did not interact with CSF biomarker positivity but modified the association between pTau181 and tTau. Elecsys CSF immunoassays detect AD pathophysiology regardless of concomitant SVD and may help to identify patients with early dementia with underlying AD pathophysiology.

Prognostic value of total tumour volume, adding necrosis to metabolic tumour volume, in advanced or metastatic non-small cell lung cancer treated with first-line pembrolizumab.

Metabolic tumour volume (MTV) measured on fluorodeoxyglucose F18 (FDG) positron emission tomography coupled with computed tomography (PET/CT) is a prognostic factor of advanced non-small cell lung cancer (NSCLC) treated by first-line immunotherapy. However, these tumours are often necrotic and the necrosis, which is hypometabolic in PET FDG, is not included in the MTV. The aim of this study was to evaluate the prognostic value of total tumour volume (TTV), adding necrotic tumour volume (NTV) to metabolic tumour volume (MTV). We retrospectively included 65 patients with NSCLC treated with pembrolizumab as monotherapy. All patients had a pretreatment FDG PET/CT. PET/CT measured parameters were MTV, NTV and TTV. Clinical, biological and tumour parameters were also retrieved. Receiver operator characteristics (ROC) analysis was performed and overall survival at 1year was studied using Kaplan-Meier and uni/multivariate Cox analysis. In the ROC analysis, MTV, NTV, TTV, age at diagnosis, polynuclear blood neutrophil, derived neutrophil/leukocyte ratio (dNLR), and haemoglobin had an area under the curve (AUC) significantly higher than 0.5. In Kaplan-Meier analysis, prognosis was worse for patients with high MTV (p = 0.02), high TTV (p = 0.003), high NTV (p = 0.014), low haemoglobin (p < 0.001), older people (p = 0.002), neutrophil polynucleosis (p < 0.001) and dNLR (p = 0.022). All these parameters, except age and neutrophil polynucleosis, were significant prognostic factors in univariate Cox analysis (p < 0.05). In a stepwise multivariate Cox analysis focused on PET parameters, the only significant parameter was TTV (HR = 3.66, p = 0.002) and in a stepwise multivariate Cox analysis exploring all the parameters, a model combining TTV, performance status and brain metastasis was found (p = 0.002). TTV and NTV measured on pretreatment FDG PET/CT are significant prognosis factor for stage III-IV NSCLC treated by pembrolizumab and TTV could have a higher prognostic value than MTV.

Clinical characteristics and outcomes of Langerhans cell histiocytosis at a single institution in Thailand: a 20-year retrospective study.

Langerhans cell histiocytosis (LCH) is a rare disease characterized by the various systems involved and clinical manifestations with a wide range of symptoms. To describe clinical characteristics, imaging, treatment, and outcomes of pediatric LCH at Phramongkutklao Hospital, Bangkok, Thailand. We conducted a 20-year retrospective review of the medical records of patients diagnosed with LCH from birth to 21 years old from January 1, 1997, to December 31, 2016. In all, 14 patients with median age of 2.5 years were studied. Six (43%) patients had single-system (SS) LCH. Five patients (63%) with multisystem (MS) LCH (n = 8. 57%) had risk-organ involvement (RO+). All patients had plain X-ray imaging of their skull with 11 (79%) showing abnormal findings. Tc-99m bone imaging and fluorodeoxyglucose F18 (FDG) positron emission tomography (PET)-computed tomography (CT) demonstrated abnormal findings in 8 (89%) and 4 (29%) patients, respectively. The 5-year event-free survival (EFS) for patients with RO+ MS-LCH was less than that for those without risk-organ involvement (RO-) MS-LCH and SS-LCH (20% vs. 100%, P = 0.005). Hematological dysfunction, hypoalbuminemia, and conjugated hyperbilirubinemia may be worse prognostic factors for RO+ MS-LCH. FDG-PET-CT might have a greater accuracy to detect LCH disease than conventional plain X-ray and Tc-99m bone imaging. RO+ MS-LCH has been encountered with relapse and poor outcomes. Hematopoietic involvement, hypoalbuminemia, and conjugated hyperbilirubinemia may be worse prognostic factors for RO+ MS-LCH.

Partial Inhibition of Mitochondrial Complex I Reduces Tau Pathology and Improves Energy Homeostasis and Synaptic Function in 3xTg-AD Mice.

Background:Accumulation of hyperphosphorylated tau (pTau) protein is associated with synaptic dysfunction in Alzheimer’s disease (AD). We previously demonstrated that neuroprotection in familial mouse models of AD could be achieved by targeting mitochondria complex I (MCI) and activating the adaptive stress response. Efficacy of this strategy on pTau-related pathology remained unknown.Objective:To investigate the effect of specific MCI inhibitor tricyclic pyrone compound CP2 on levels of human pTau, memory function, long term potentiation (LTP), and energy homeostasis in 18-month-old 3xTg-AD mice and explore the potential mechanisms.Methods:CP2 was administered to male and female 3xTg-AD mice from 3.5–18 months of age. Cognitive function was assessed using the Morris water maze. Glucose metabolism was measured in periphery using a glucose tolerance test and in the brain using fluorodeoxyglucose F18 positron-emission tomography (FDG-PET). LTP was evaluated using electrophysiology in the hippocampus. The expression of key proteins associated with neuroprotective mechanisms were assessed by western blotting.Results:Chronic CP2 treatment restored synaptic activity in female 3xTg-AD mice; cognitive function, levels of synaptic proteins, glucose metabolism, and energy homeostasis were improved in male and female 3xTg-AD mice. Significant reduction of human pTau in the brain was associated with increased activity of protein phosphatase of type 2A (PP2A), and reduced activity of cyclin-dependent kinase 5 (CDK5) and glycogen synthase kinase 3β (GSK3β).Conclusion:CP2 treatment protected against synaptic dysfunction and memory impairment in symptomatic 3xTg-AD mice, and reduced levels of human pTau, indicating that targeting mitochondria with small molecule specific MCI inhibitors represents a promising strategy for treating AD.

Genome-Wide Association Study of Brain Alzheimer's Disease-Related Metabolic Decline as Measured by [18F] FDG-PET Imaging.

Hypometabolism detected by fluorodeoxyglucose F18 positron emission tomography ([18F] FDG PET) is an early neuropathologic changes in Alzheimer's disease (AD) and provides important pathologic staging information. This study aimed to discover genetic interactions that regulate longitudinal glucose metabolic decline in AD-related brain regions. A total of 586 non-Hispanic white individuals from the Alzheimer's Disease Neuroimaging Initiative (ADNI) 1/GO/2 cohorts that met all quality control criteria were included in this study. Genome-wide association study of glucose metabolic decline in regions of interest (ROIs) was performed with linear regression under the additive genetic model. We identified two novel variants that had a strong association with longitudinal metabolic decline in different ROI. Rs4819351-A in gene 1-acylglycerol-3-phosphate O-acyltransferase 3 (AGPAT3) demonstrated reduced metabolic decline in right temporal gyrus (p = 3.97×10-8, β= -0.016), while rs13387360-T in gene LOC101928196 demonstrated reduced metabolic decline in left angular gyrus (p = 1.69×10-8, β= -0.027). Our results suggest two genome-wide significant SNPs (rs4819351, rs13387360) in AGPAT3 and LOC101928196 as protective loci that modulate glucose metabolic decline. These two genes should be further investigated as potential therapeutic target for neurodegeneration diseases.

Genome-wide association study identifies RBFOX1 locus influencing brain glucose metabolism.

Fluorodeoxyglucose f18 positron emission tomography (18F-FDG PET) is regarded as the only functional neuroimaging biomarker for degeneration which can be used to increase the certainty of Alzheimer's disease (AD) pathophysiological process in research settings or as an optional clinical tool where available. Although a decline in FDG metabolism was confirmed in some regions known to be associated with AD, there was little known about the genetic association of FDG metabolism in AD cohorts. In this study, we present the first genome-wide association study (GWAS) analysis of brain FDG metabolism. A total of 222 individuals were included from the Alzheimer's Disease Neuroimaging Initiative 1 (ADNI-1) cohort. All subjects were restricted to non-Hispanic Caucasians and met all quality control (QC) criteria. Associations of 18F-FDG with the genetic variants were assessed using PLINK 1.07 under the additive genetic model. Genome-wide associations were visualized using a software program R 3.2.3. One significant SNP rs12444565 in RNA-binding Fox1 (RBFOX1) was found to have a strong association with 18F-FDG (P=6.06×10-8). Rs235141, rs79037, rs12526331 and rs12529764 were identified as four suggestive loci associated with 18F-FDG. Our study results suggest that a genome-wide significant SNP (rs12444565) in the RBFOX1, and four suggestive loci (rs235141, rs79037, rs12526331 and rs12529764) are associated with 18F-FDG.

Fluorodeoxyglucose F18 Positron Emission Tomography Coupled With Computed Tomography in Suspected Acute Renal Allograft Rejection

Management of kidney transplant recipients (KTRs) with suspected acute rejection (AR) ultimately relies on kidney biopsy; however, noninvasive tests predicting nonrejection would help avoid unnecessary biopsy. AR involves recruitment of leukocytes avid for fluorodeoxyglucose F(18) ((18) F-FDG), thus (18) F-FDG positron emission tomography (PET) coupled with computed tomography (CT) may noninvasively distinguish nonrejection from AR. From January 2013 to February 2015, we prospectively performed 32 (18) F-FDG PET/CT scans in 31 adult KTRs with suspected AR who underwent transplant biopsy. Biopsies were categorized into four groups: normal (n = 8), borderline (n = 10), AR (n = 8), or other (n = 6, including 3 with polyoma BK nephropathy). Estimated GFR was comparable in all groups. PET/CT was performed 201 ± 18 minutes after administration of 3.2 ± 0.2 MBq/kg of (18) F-FDG, before any immunosuppression change. Mean standard uptake values (SUVs) of both upper and lower renal poles were measured. Mean SUVs reached 1.5 ± 0.2, 1.6 ± 0.3, 2.9 ± 0.8, and 2.2 ± 1.2 for the normal, borderline, AR, and other groups, respectively. One-way analysis of variance demonstrated a significant difference of mean SUVs among groups. A positive correlation between mean SUV and acute composite Banff score was found, with r(2) = 0.49. The area under the receiver operating characteristic curve was 0.93, with 100% sensitivity and 50% specificity using a mean SUV threshold of 1.6. In conclusion, (18) F-FDG PET/CT may help noninvasively prevent avoidable transplant biopsies in KTRs with suspected AR.

Fluorodeoxyglucose F18 Positron Emission Tomography in Progressive Apraxia of Speech and Primary Progressive Aphasia Variants

To determine patterns of hypometabolism on fluorodeoxyglucose F18 positron emission tomography (FDG-PET) in patients with progressive apraxia of speech (PAS) and primary progressive aphasia (PPA) variants and to use these patterns to further refine current classification. We identified all patients who had FDG-PET and PAS or PPA who were evaluated by an expert speech-language pathologist. Patterns of hypometabolism were independently classified by 2 raters blinded to clinical data. Three speech-language pathologists reclassified all patients into 1 of 7 operationally defined categories of PAS and PPA blinded to FDG-PET data. Tertiary care medical center. Twenty-four patients with PAS or PPA and FDG-PET. Fluorodeoxyglucose F18 PET hypometabolic pattern. Of the 24 patients in the study, 9 had nonfluent speech output; 14, fluent speech; and 1 was unclassifiable. Twenty-one patients showed FDG hypometabolism; the remaining 3 did not. Among the patients showing hypometabolism, 8 had a prerolandic pattern of which 7 had nonfluent speech including progressive nonfluent aphasia (n = 3), PAS (n = 1), and mixed nonfluent aphasia/apraxia of speech (n = 3); the other patient had PPA unclassifiable. The remaining 13 had a postrolandic pattern, all with fluent speech (P < .001), including logopenic progressive aphasia (n = 6), progressive fluent aphasia (n = 6), and semantic dementia (n = 1). Patterns of hypometabolism differed between the nonfluent variants and between the fluent variants, including progressive fluent aphasia. Patterns of FDG-PET hypometabolism support the clinical categorizations of fluency, the distinction of apraxia of speech from progressive nonfluent aphasia, and the designation of a progressive fluent aphasia category.

The Stripe of Primary Lateral Sclerosis

Primary lateral sclerosis (PLS) is a progressive upper motor neuron neurodegenerative condition. The diagnosis is made using clinical history, objective neurological assessment, and exclusion of other neurodegenerative disorders. To evaluate the role of fluorodeoxyglucose F18 positron emission tomography and 3-dimensional stereotactic surface projection in the diagnosis of PLS. Case series. Outpatient neurology clinic. Patients Three cases of probable PLS. Intervention Fluorodeoxyglucose F18 positron emission tomography in 3 patients with PLS. Three patients (2 male and 1 female; mean age, 65 years) were identified with a clinical diagnosis of PLS. Fluorodeoxyglucose F18 positron emission tomography demonstrated varying degrees of primary motor cortex hypometabolism. Fluorodeoxyglucose F18 positron emission tomography and 3-dimensional stereotactic surface projection provide a useful diagnostic method to support a clinical diagnosis of PLS.

S25-02 FDG-PET and structural MRI in subjective memory impairment

Early recognition of Alzheimer's Disease (AD) is a prerequisite for future strategies against the rapidly increasing prevalence of dementia. Mild cognitive impairment (MCI) has been identified as a clinical pre-dementia syndrome in the course of AD. Epidemiological studies suggest that MCI is preceded by subjective memory impairment (SMI) with still intact cognitive functioning. Studies on biological indicators of AD in SMI, however, are still rare. We compared glucose metabolism using fluorodeoxyglucose F18-positron emission tomography (FDG-PET) and grey matter structure using magnetic resonance imaging (MRI) of 29 SMI subjects and 52 non-complaining volunteers. We found reduced glucose metabolism in the posterior cingulate gyrus/precuneus and in the left parietal lobe and reduced grey matter in bilateral medial temporal lobe areas in SMI. These patterns of hypometabolism and grey matter reduction resemble those of early AD and those that predict cognitive decline in MCI. Our data provides biological support from two independent neuroimaging modalities for SMI as the initial clinical manifestation of AD prior to MCI.

P071 Assessment of Response Using Fluorodeoxyglucose F18 Positron Emission Tomography and Computed Tomography to Evaluate Patients With Head and Neck Cancer After Definitive Radiation Therapy: Preliminary Results

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Perceived Loss of Memory Ability and Cerebral Metabolic Decline in Persons With the Apolipoprotein E-IV Genetic Risk for Alzheimer Disease

Concerns about age-related memory loss are greater in persons who have the apolipoprotein E-IV (APOE4) genetic risk for Alzheimer disease, but the correlation between the degree of concerns and future cerebral metabolic decline is unknown. To investigate whether the degree of self-perceived memory loss is associated with regional cerebral metabolic decline. Longitudinal study. Aging and Memory Research Center, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles. Thirty right-handed, cognitively intact, middle-aged and older adults (age range, 50-82 years) with age-associated memory complaints, 14 of whom were carriers of the apolipoprotein E-IV allele, were recruited for longitudinal study. At baseline, we administered a standardized neuropsychological battery and assessed self-appraisal of memory functioning using the Memory Functioning Questionnaire, which yields 4 factor scores indicating frequency of forgetting, seriousness of forgetting, retrospective functioning, and mnemonics use. Regional cerebral glucose metabolism was determined using fluorodeoxyglucose F18-positron emission tomography at baseline and after 2 years. At baseline, APOE4 carriers and noncarriers did not differ significantly on objective memory measures or on Memory Functioning Questionnaire factor scores. However, the factor score for frequency of forgetting significantly correlated with global cerebral metabolic decline in all subjects regardless of APOE4 genetic risk (P = .01). By contrast, the factor score for mnemonics use significantly correlated with metabolic decline in the temporal regions in APOE4 carriers but not in noncarriers (P = .03). The degree of perceived memory loss correlates with subsequent global cerebral metabolic decline for APOE4 carriers and noncarriers; hence, memory complaints may reflect underlying cerebral metabolic changes. Compensatory strategies, as reflected by more frequent mnemonics use in APOE4 carriers, may reflect underlying metabolic changes in the brain regions associated with prodromal Alzheimer disease. Self-reported mnemonics use may be helpful in identifying persons for clinical monitoring.

Interaction of Colony-Stimulating Factors and Fluorodeoxyglucose F18 Positron Emission Tomography

OBJECTIVE:To evaluate reports of altered diagnostic images with fluorodeoxyglucose F18 (FDG) positron emission tomography (PET) after treatment with colony-stimulating factors (CSFs).DATA SOURCES:Literature was identified by a MEDLINE search (1966–December 2001). Key search terms included granulocyte colony-stimulating factor, granulocyte—macrophage colony-stimulating factor, macrophage colony-stimulating factor, fluorodeoxyglucose, and emission-computed tomography. English language literature was reviewed.DATA SYNTHESIS:Reports have suggested altered FDG PET images following CSF treatment. Studies that assessed the effect of CSF administration on FDG PET imaging of the bone and bone marrow were reviewed.CONCLUSIONS:Administration of CSFs may interfere with accurate FDG PET imaging. Separating FDG PET imaging from CSF therapy by ≥5 days may diminish this interference.

Interaction of colony-stimulating factors and fluorodeoxyglucose f(18) positron emission tomography.

To evaluate reports of altered diagnostic images with fluorodeoxyglucose F(18) (FDG) positron emission tomography (PET) after treatment with colony-stimulating factors (CSFs). Literature was identified by a MEDLINE search (1966-December 2001). Key search terms included granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, macrophage colony-stimulating factor, fluorodeoxyglucose, and emission-computed tomography. English language literature was reviewed. Reports have suggested altered FDG PET images following CSF treatment. Studies that assessed the effect of CSF administration on FDG PET imaging of the bone and bone marrow were reviewed. Administration of CSFs may interfere with accurate FDG PET imaging. Separating FDG PET imaging from CSF therapy by >/=5 days may diminish this interference.