Brain FDG-PET Research Articles

Neurocognitive Profile and 18 F-Fluorodeoxyglucose Positron Emission Tomography Brain Imaging Correlation in Children with Electrical Status Epilepticus during Sleep.

Objective Electrical status epilepticus in sleep (ESES) is defined by near-continuous epileptiform discharges during sleep along with cognitive, behavioral, and/or imaging abnormalities. We studied the neurocognitive profile and their correlation with 18 F fluorodeoxyglucose positron emission tomography (FDG PET) brain abnormalities in children with ESES. Methods Fourteen children with ESES with normal magnetic resonance imaging (MRI) from March to December 2019 were included. The intelligence quotient (IQ) and child behavior checklist (CBCL) scores were estimated using validated scales, and FDG PET brain was done at the same point of time to look for cerebral metabolic defects which was compared with a control group. Results Fourteen patients with a mean age of 8.2 ± 2.7 years were analyzed. The average duration of epilepsy was 6 ± 2.8 years. The mean IQ was 72.4 ± 18.2 and mean CBCL score was 37.3 ± 11.8. There was negative correlation between IQ and CBCL ( r = -0.55, p < 0.001). The duration of epilepsy also showed negative correlation with IQ ( r = -4.75, p < 0.001). FDG PET scan showed predominant thalamic hypometabolism in 12 of 14 patients (85.7%) on visual analysis with multiple other hypometabolic cortical and subcortical regions in the brain. The quantitative analysis showed significant difference in metabolism of basal ganglion when compared with control group. The total number of hypometabolic regions seen in the brain showed moderate positive correlation with CBCL score but no significant correlation with the IQ of cases. Conclusion This study demonstrates functional impairment of cerebral cortical, basal ganglia, and thalamic hypometabolism in a cohort of ESES patients with normal structural MRI brain study. There was a moderate correlation of extent and pattern of cerebral hypometabolism with the neuropsychological status of the child and duration of epilepsy.

Psychological stress is associated with arterial inflammation in people living with treated HIV infection

Stress and depression are increasingly recognized as cerebrovascular risk factors, including among high stress populations such as people living with HIV infection (PLWH). Stress may contribute to stroke risk through activation of neural inflammatory pathways. In this cross-sectional study, we examined the relationships between stress, systemic and arterial inflammation, and metabolic activity in stress-related brain regions on 18F-fluorodeoxyglucose (FDG)-PET in PLWH. Participants were recruited from a parent trial evaluating the impact of alirocumab on radiologic markers of cardiovascular risk in people with treated HIV infection. We administered a stress battery to assess different forms of psychological stress, specifying the Perceived Stress Scale as the primary stress measure, and quantified plasma markers of inflammation and immune activation. Participants underwent FDG-PET of the brain, neck, and chest. Age- and sex-matched control participants without HIV infection were selected for brain FDG-PET comparisons. Among PLWH, we used nonparametric pairwise correlations, partial correlations, and linear regression to investigate the association between stress and 1) systemic inflammation; 2) atherosclerotic inflammation on FDG-PET; and metabolic activity in 3) brain regions in which glucose metabolism differed significantly by HIV serostatus; and 4) in a priori defined stress-responsive regions of interest (ROI) and stress-related neural network activity (i.e., ratio of amygdala to ventromedial prefrontal cortex or temporal lobe activity). We studied 37 PLWH (mean age 60 years, 97% men) and 29 control participants without HIV (mean age 62 years, 97% men). Among PLWH, stress was significantly correlated with systemic inflammation (r = 0.33, p = 0.041) and arterial inflammation in the carotid (r = 0.41, p = 0.023) independent of age, race/ethnicity, traditional vascular risk factors and health-related behaviors. In voxel-wise analyses, metabolic activity in a cluster corresponding to the anterior medial temporal lobes, including the bilateral amygdalae, was significantly lower in PLWH compared with controls. However, we did not find a significant positive relationship between stress and this cluster of decreased metabolic activity in PLWH, a priori defined stress-responsive ROI, or stress-related neural network activity. In conclusion, psychological stress was associated with systemic and carotid arterial inflammation in this group of PLWH with treated infection. These data provide preliminary evidence for a link between psychological stress, inflammation, and atherosclerosis as potential drivers of excess cerebrovascular risk among PLWH.

Brain FDG-PET findings in chimeric antigen receptor T-cell therapy neurotoxicity for diffuse large B-cell lymphoma.

Chimeric antigen receptor (CAR) T-cell therapy is potentially associated with treatment-related toxicities mainly consisting of cytokine release syndrome (CRS) and immune-effector cell-associated neurotoxicity syndrome (ICANS). We evaluated brain metabolic correlates of CRS with and without ICANS in diffuse large B-cell lymphoma patients treated with CAR-T. Twenty-one refractory DLCBLs underwent whole-body and brain [18 F]-fluorodeoxyglucose (FDG) PET before and 30days after treatment with CAR-T. Five patients did not develop inflammatory-related side effects, 11 patients developed CRS, while in 5 patients CRS evolved in ICANS. Baseline and post-CAR-T brain FDG-PET were compared with a local controls dataset to identify hypometabolic patterns both at single-patient and group levels (p<.05 after correction for family-wise error [FWE). Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were computed on baseline FDG-PET and compared between patients' subgroups (t-test). ICANS showed an extended and bilateral hypometabolic pattern mainly involving the orbitofrontal cortex, frontal dorsolateral cortex, and anterior cingulate (p<.003 FWE-corrected). CRS without ICANS showed significant hypometabolism in less extended clusters mainly involving bilateral medial and lateral temporal lobes, posterior parietal lobes, anterior cingulate, and cerebellum (p<.002 FWE-corrected). When compared, ICANS showed a more prominent hypometabolism in the orbitofrontal and frontal dorsolateral cortex in both hemispheres than CRS (p<.002 FWE-corrected). Mean baseline MTV and TLG were significantly higher in ICANS than CRS (p<.02). Patients with ICANS are characterized by a frontolateral hypometabolic signature coherently with the hypothesis of ICANS as a predominant frontal syndrome and with the more prominent susceptibility of frontal lobes to cytokine-induced inflammation.

Teaching Neuro Images : Brain MRI and FDG-PET in malformations of cortical development and hippocampal hypoplasia

A 16-year-old intellectually normal woman, with a history of febrile seizures, presented with focal seizures. MRI showed several regions of polymicrogyria/pachygyria, cortical heterotopia, and left hippocampal hypoplasia, associated with (interictal) FDG-PET hypometabolism ([figure][1]). Other

CSF-based liquid biopsy pointing to a diagnosis of diffuse glioma in a patient with supposed neurodegenerative disorder.

The differential diagnosis of brain diseases becomes challenging in cases where imaging is not sufficiently informative, and surgical biopsy is impossible or unacceptable to the patient. An elderly patient with progressive short-term memory loss and cognitive impairment presented with a normal brain CT scan, a brain FDG-PET that indicated symmetrical deterioration of the white matter in the frontal lobes, and inconclusive results of a molecular marker analysis of suspected dementia in cerebrospinal fluid (CSF). Brain MRI suggested the diagnosis of lower grade glioma. The patient refused surgical biopsy. In order to investigate whether somatic mutations associated with gliomas existed, we performed a "liquid biopsy" by the targeted sequencing of cell-free DNA (cfDNA) from his CSF. Deep sequencing of the cfDNA from CSF revealed somatic mutations characteristically found in gliomas, including mutations of the TP53 (Arg282Trp), BRAF (Val600Glu), and IDH1 (Arg132His) genes. The patient is currently treated with temozolomide, and his clinical and MRI findings suggest the stabilization of his disease. Neurological patients may benefit from liquid biopsy diagnostic work-up as it can reveal therapeutically targetable mutations.

CAR t-cell therapy in BOlogNa-NEUrotoxicity TReatment and Assessment in Lymphoma (CARBON-NEUTRAL): proposed protocol and results from an Italian study.

To investigate neurotoxicity clinical and instrumental features, incidence, risk factors, and early and long-term prognosis in lymphoma patients who received CAR T-cell therapy. In this prospective study, consecutive refractory B-cell non-Hodgkin lymphoma patients who received CAR T-cell therapy were included. Patients were comprehensively evaluated (neurological examination, EEG, brain MRI, and neuropsychological test) before and after (two and twelve months) CAR T-cells. From the day of CAR T-cells infusion, patients underwent daily neurological examinations to monitor the development of neurotoxicity. Forty-six patients were included in the study. The median age was 56.5years, and 13 (28%) were females. Seventeen patients (37%) developed neurotoxicity, characterized by encephalopathy frequently associated with language disturbances (65%) and frontal lobe dysfunction (65%). EEG and brain FDG-PET findings also supported a predominant frontal lobe involvement. The median time at onset and duration were five and eight days, respectively. Baseline EEG abnormalities predicted ICANS development in the multivariable analysis (OR 4.771; CI 1.081-21.048; p = 0.039). Notably, CRS was invariably present before or concomitant with neurotoxicity, and all patients who exhibited severe CRS (grade ≥ 3) developed neurotoxicity. Serum inflammatory markers were significantly higher in patients who developed neurotoxicity. A complete neurological resolution following corticosteroids and anti-cytokines monoclonal antibodies was reached in all patients treated, except for one patient developing a fatal fulminant cerebral edema. All surviving patients completed the 1-year follow-up, and no long-term neurotoxicity was observed. In the first prospective Italian real-life study, we presented novel clinical and investigative insights into ICANS diagnosis, predictive factors, and prognosis.

Neuroimaging revealed long-lasting glucose metabolism changes to morphine withdrawal in rats pretreated with the cannabinoid agonist CP-55,940 during periadolescence

This study evaluates the long-term effects of a six and 14-week morphine withdrawal in rats pretreated with a cannabinoid agonist (CP-55,940, CP) during periadolescence. Wistar rats (33 males; 32 females) were treated with CP or its vehicle (VH) from postnatal day (PND) 28-38. At PND100, rats performed morphine self-administration (MSA, 15d/12h/session). Eight groups were defined according to pretreatment (CP), treatment (morphine), and sex. Three [18F]FDG-PET brain images were acquired: after MSA, and after six and 14 weeks of withdrawal. PET data were analyzed with SPM12. Endocannabinoid (EC) markers were evaluated in frozen brain tissue at endpoint. Females showed a higher mean number of self-injections than males. A main Sex effect on global brain metabolism was found. FDG uptake in males was discrete, whereas females showed greater brain metabolism changes mainly in areas of the limbic system after morphine treatment. Moreover, the morphine-induced metabolic pattern in females was exacerbated when CP was previously present. In addition, the CP-Saline male group showed reduced CB1R, MAGL expression, and NAPE/FAAH ratio compared to the control group, and morphine was able to reverse CB1R and MAGL expression almost to control levels. In conclusion, females showed greater and longer-lasting metabolic changes after morphine withdrawal than males, indicating a higher vulnerability and a different sensitivity to morphine in subjects pre-exposed to CP. In contrast, males primarily showed changes in EC markers. Together, our results suggest that CP pre-exposure contributes to the modulation of brain metabolism and EC systems in a sex-dependent manner.

Attenuation Correction Using Template PET Registration for Brain PET: A Proof-of-Concept Study.

NeuroLF is a dedicated brain PET system with an octagonal prism shape housed in a scanner head that can be positioned around a patient's head. Because it does not have MR or CT capabilities, attenuation correction based on an estimation of the attenuation map is a crucial feature. In this article, we demonstrate this method on [18F]FDG PET brain scans performed with a low-resolution proof of concept prototype of NeuroLF called BPET. We perform an affine registration of a template PET scan to the uncorrected emission image, and then apply the resulting transform to the corresponding template attenuation map. Using a whole-body PET/CT system as reference, we quantitively show that this method yields comparable image quality (0.893 average correlation to reference scan) to using the reference µ-map as obtained from the CT scan of the imaged patient (0.908 average correlation). We conclude from this initial study that attenuation correction using template registration instead of a patient CT delivers similar results and is an option for patients undergoing brain PET.

A Prospective Study of Methotrexate in Combination with Ibrutinib and Temozolomide (MIT) in Newly Diagnosed Primary CNS Lymphoma

Background: Primary central nervous system lymphoma (PCNSL) is a rare non-Hodgkin lymphoma ,High-dose methotrexate (HD-MTX) systemic chemotherapy is considered as the first-line standard therapy for PCNSL, but the ORR of HD-MTX-based chemotherapy was 60%~70%.The activation of the B-cell receptor pathway has been identified as a key mechanism of PCNSL and BTK inhibitor is a promising agent. Here we aimed to investigate the safety and efficacy of induction treatment, high-dose methotrexate in combination with ibrutinib and temozolomide (MIT) in newly diagnosed PCNSL. Methods: This open-label， single-arm, multi-center phase II prospective study(NCT04514393) was designed to enroll 33 patients , and 25 patients have response (approx 75%), the MIT treatment would be considered effective. Eligible patients were ≥18 and ≤75 years of age with adequate organ function, with at least one measurable lesion. The MIT induction treatment included six cycles of high-dose methotrexate (HD-MTX, 3.5 g/m2, every three weeks), ibrutinib (560 mg/d, after HD-MTX clearance), and temozolomide (150 mg/m2 d1-d5, every three weeks). After the completion of the six cycles of MIT induction treatment, ASCT consolidation (only for patients < 65 yr) and daily ibrutinib (560 mg/d) were administered up to two years, or until disease progression, intolerable toxicity, or death. Treatment response was evaluated by brain MRI and FDG-PET and/or cerebrospinal fluid (CSF) examination every two cycles of the induction MIT treatment. The primary endpoint was the overall response rate (ORR) of the 6 cycles of MIT induction treatment for PCNSL evaluated by investigator. The safety of the treatment were also investigated. Baseline and sequential CSF/plasma samples were collected and underwent targeted next-generation sequencing (NGS). Results: Between July 2021 and July 2022, thirty-one newly diagnosed PCNSL patients with no prior therapy were enrolled and 28 patients accepted at least 2 cycles of MIT treatment. The median age of the patients was 53 yr (range: 27-75) and15/28 (53.6%) were male. By data cutoff, 12/28 (42.9%) patients had completed six cycles of treatment, 9/28 had completed 4 cycles of treatment, and 7/28 had completed 2 cycles of treatment. The ORR was 92.9% (26/28), and CR rate was 67.9% (19/28). Among 12 patients had completed 6 cycles of treatment, 11/12 (91.7%) patients achieved CR, 1 patient achived PR. Among 9 patients had completed 4 cycles of treatment, 4 (44.4%) achived CR, 3/9 (33.3%) achived PR. Among 7 patients had completed 2 cycles of treatment, 4 (57.1%) patients achieved CR and 3 (42.8%) pateints achived PR. The mutation profiles of dynamic CFS and plasma ctDNA were collected and analyzed. The most commonly mutated genes in CSF were PIM1, MYD88, BTG2, CD79B, IRF4, and ETS1. The Cerebrospinal fluid protein (CSF-TP) and CSF cfDNA concentration (ng/ml), ctDNA MAF, and ctDNA concentration (hGe/ml), MAF,and hGe/ml were positively correlated. We compared gene profiles of patients in response and no response. KMT2D gene mutations were more commonly detected in patients with progression disease compared to patients responding to treatment (P=0.03). Interestingly, detectable baseline plasma ctDNA and post-treatment CSF ctDNA were significant associated with progression disease (P=0.03, P=0.004, respectively). This clinical trial is still on going. Conclusions: The MIT induction treatment could achieve higher responses compared with HD-MTX-based chemotherapy in newly diagnosed PCNSL patients and the adverse events are manageable.

Preliminary Results of Penpulimab Combined with RMA (rituximab, methotrexate, and cytarabine) for Newly Diagnosed Primary Central Nervous System Lymphoma

Background: Primary central nervous system lymphoma (PCNSL) has been classified as large B-cell lymphomas (LBCL) of immune-privileged sites according to the 5th edition of the World Health Organization (WHO) Classification. The efficacy of high-dose methotrexate as a first-line treatment was suboptimal with a short effective remission time and low response rate. The recent discovery of the frequent copy number alterations in 9p24.1/PD-L1/PD-L2 and increased expression of PD-L1 in PCNSL provide the rationale to evaluate the efficacy of PD-1antibody in PCNSL. Methods: NCT05347641 is an ongoing Phase II, single-center, single-arm, open-label study, aimed to enrolled an estimated 23 newly diagnosed PCNSL patients. Enrolled patients first received the Pen-RMA induction treatment, including rituximab 375 mg/m2, d0; methotrexate 3.5g/m2, d1; cytarabine 1‒2g/m2, q12h, d2-3; penpulimab (an anti-PD1 antibody of IgG1 isotype) 200 mg, d5; 21d/cycle, for six cycles. Patients aged 60 years or younger, with complete response (CR)/unconfirmed complete response (CRu)/partial response (PR) after six cycles of induction treatment then underwent autologous stem cell transplantation (ASCT) before maintenance treatment. The maintenance regimen was administered based on patient response to ASCT, or to induction therapy for patients aged 60 years or older. Patients who achieved CR after ASCT or induction therapy then received 8 cycles of penpulimab as maintenance therapy, and those with PR after ASCT or induction therapy received whole brain radiotherapy (WBRT) combined with 8 cycles of penpulimab as maintenance. Treatment response was evaluated by brain MRI and FDG-PET and/or cerebrospinal fluid (CSF) examination every three cycles of the induction treatment. The primary endpoint of this study was two-year progression-free survival rate. Baseline tissue samples and sequential CSF or plasma samples were collected for targeted next-generation sequencing (NGS) at Nanjing Geneseeq Technology Inc. Results: Between April, 2022 and July, 2022, eleven newly diagnosed PCNSL patients has been enrolled. Treatment response was evaluable in eight patients. At the interim assessment point (after 3 cycles), six patients have achieved CR, with an overall response rate of 75.0%. Of these, three have completed 6 cycles of treatment and all achieved CR at the final assessment (Figure A). Adverse events of grade 3 or 4 occurred in five patients, including three neutropenia (27.3%), one thrombocytopenia (9.1%), and one renal dysfunction (9.1%). In the baseline samples, PIM1, MYD88L265P, and CD79B were the most common mutations, with a more comprehensive genomic landscape revealed by CSF than by blood (Figure B). All nine NGS-tested patients were classifier into the non-GCB subtype by the COO classification and the MCD subtype by the LymphGen classifier. CSF-based ctDNA monitoring was performed in two patients after 6 cycles of treatment. P01 had confirmed CR with ctDNA clearance in CSF. P07, was assessed as CR after 6 cycles, but the CSF ctDNA remained positive. This patient is currently receiving maintenance treatment and is being closely monitored for potential disease relapse. Interestingly, P02 and P04, who were PD and SD at interim evaluation, respectively, had markedly more mutations detected in their baseline plasma samples, indicating a poor prognosis (Figure A). Conclusion: The induction treatment of Pen-RMA has shown excellent responses in newly diagnosed PCNSL patients with mild hematologic toxicity. Our preliminary results also suggested that CSF-based ctDNA could facilitate diagnosis when tissue was inaccessible and show higher sensitivity than imageology in assessing the depth of remission. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

131 USE OF FDG-PET BRAIN IMAGING IN THE DIAGNOSIS AND MANAGEMENT OF DEMENTIA IN A UNIVERSITY HOSPITAL

Abstract Background Neuroimaging is an increasingly important tool dementia work-up. Subtype diagnosis helps predict the course of the disease, aiding prognostication and management. Amyloid-beta peptide is intrinsic to the pathogenesis of Alzheimer’s disease (AD), forming characteristic neuritic plaques which can be imaged in vivo on positron emission tomography (PET) scans. NICE recommendations advise use of PET imaging if dementia sub-type diagnosis is unclear and AD is suspected. We sought to establish the referral patterns for FDG-PET brain scans for patients aged 60 and over in a university hospital and to establish whether this imaging modality contributed to a change in diagnosis or treatment. Methods Requests for FDG-PET CT brain from 2019 – 2022 were retrospectively reviewed. Information was obtained from clinical notes and patient information software. Patient demographics, indication for scan, source of referral and whether imaging results led to a change in diagnosis or treatment was recorded. Results A total of 32 patients were reviewed, with a mean age of 65 years (13 females; 41%). We further analysed the 25 who were aged over 60; this subgroup had a mean age of 70 (9 females; 36%). All 25 patients were appropriately referred to assess for dementia subtype. A revision in diagnosis based on PET imaging was made in 17 (68%) cases. In 9 (30%) cases, results prompted change in dementia-specific pharmacological treatment, including donepezil and memantine. A further 6 (24%) had pharmacological treatment for non-cognitive symptoms of dementia adjusted, such as anti-depressants or anti-psychotics. The majority of referrals had come from neurologists (n = 15; 60%) rather than geriatricians (n = 10; 40%). The final diagnosis was AD in 12 cases (48%) and fronto-temporal dementia in 3 cases (12%). Conclusion PET scans are a useful functional imaging modality which can help to differentiate dementia subtypes and influence management.

18F]FDG brain PET findings in CLIPPERS at diagnosis and therapeutic follow-up.

18F]FDG brain PET findings in CLIPPERS at diagnosis and therapeutic follow-up.

Associations of digital neuro-signatures with molecular and neuroimaging measures of brain resilience: The altoida large cohort study.

Mixed results in the predictive ability of traditional biomarkers to determine cognitive functioning and changes in older adults have led to misdiagnosis and inappropriate treatment plans to address mild cognitive impairment and dementia among older adults. To address this critical gap, the primary goal of the current study is to investigate whether a digital neuro signature (DNS-br) biomarker predicted global cognitive functioning and change over time relative among cognitively impaired and cognitive healthy older adults. The secondary goal is to compare the effect size of the DNS-br biomarker on global cognitive functioning compared to traditional imaging and genomic biomarkers. The tertiary goal is to investigate which demographic and clinical factors predicted DNS-br in cognitively impaired and cognitively healthy older adults. We conducted two experiments (Study A and Study B) to assess DNS for brain resilience (DNS-br) against the established FDG-PET brain imaging signature for brain resilience, based on a 10 min digital cognitive assessment tool. Study A was a semi-naturalistic observational study that included 29 participants, age 65+, with mild to moderate mild cognitive impairment and AD diagnosis. Study B was also a semi-naturalistic observational multicenter study which included 496 participants (213 mild cognitive impairment (MCI) and 283 cognitively healthy controls (HC), a total of 525 participants-cognitively healthy (n = 283) or diagnosed with MCI (n = 213) or AD (n = 29). DNS-br total score and majority of the 11 DNS-br neurocognitive subdomain scores were significantly associated with FDG-PET resilience signature, PIB ratio, cerebral gray matter and white matter volume after adjusting for multiple testing. DNS-br total score predicts cognitive impairment for the 80+ individuals in the Altoida large cohort study. We identified a significant interaction between the DNS-br total score and time, indicating that participants with higher DNS-br total score or FDG-PET in the resilience signature would show less cognitive decline over time. Our findings highlight that a digital biomarker predicted cognitive functioning and change, which established biomarkers are unable to reliably do. Our findings also offer possible etiologies of MCI and AD, where education did not protect against cognitive decline.

Acetyl-dl-leucine in cerebellar ataxia ([18F]-FDG-PET study): how does a cerebellar disorder influence cortical sensorimotor networks?

ObjectiveThe aim of the study was to deepen our insights into central compensatory processes of brain networks in patients with cerebellar ataxia (CA) before and with treatment with acetyl-dl-leucine (AL) by means of resting-state [18F]-FDG-PET brain imaging.MethodsRetrospective analyses of [18F]-FDG-PET data in 22 patients with CA (with vestibular and ocular motor disturbances) of different etiologies who were scanned before (PET A) and on AL treatment (PET B). Group subtraction analyses, e.g., for responders and non-responders, comparisons with healthy controls and correlation analyses of regional cerebral glucose metabolism (rCGM) with symptom duration, ataxia (SARA) and quality of life (QoL) scores were calculated.ResultsPrior to treatment rCGM was consistently downregulated at the cerebellar level and increased in multisensory cortical areas, e.g., somatosensory, primary and secondary visual (including V5, precuneus), secondary vestibular (temporal gyrus, anterior insula), and premotor/supplementary motor areas. With AL (PET B vs. A) cerebellar hypometabolism was deepened and sensorimotor hypermetabolism increased only in responders with clinical benefit, but not for the non-responders and the whole CA group. A positive correlation of ataxia improvement with rCGM was found in visual and vestibular cortices, a negative correlation in cerebellar and brainstem areas. QoL showed a positive correlation with rCGM in the cerebellum and symptom duration in premotor and somatosensory areas.ConclusionsCentral compensatory processes in CA mainly involve multisensory visual, vestibular, and somatosensory networks as well as premotor/primary motor areas at the cortical level. The enhanced divergence of cortical sensorimotor up- and cerebellar downregulation with AL in responders could reflect amplification of inhibitory cerebellar mechanisms.

Prodromal characteristics of dementia with Lewy bodies: baseline results of the MEMENTO memory clinics nationwide cohort

BackgroundIsolated subjective cognitive impairment (SCI) and mild cognitive impairment (MCI) are the prodromal phases of dementia with Lewy bodies (DLB). MEMENTO is a nationwide study of patients with SCI and MCI with clinic, neuropsychology, biology, and brain imaging data. We aimed to compare SCI and MCI patients with symptoms of prodromal DLB to others in this study at baseline.MethodsParticipants of the French MEMENTO cohort study were recruited for either SCI or MCI. Among them, 892 were included in the Lewy sub-study, designed to search specifically for symptoms of DLB. Probable prodromal DLB diagnosis (pro-DLB group) was done using a two-criteria cutoff score among the four core clinical features of DLB. This Pro-DLB group was compared to two other groups at baseline: one without any core symptoms (NS group) and the one with one core symptom (1S group). A comprehensive cognitive battery, questionnaires on behavior, neurovegetative and neurosensory symptoms, brain 3D volumetric MRI, CSF, FDG PET, and amyloid PET were done.ResultsThe pro-DLB group comprised 148 patients (16.6%). This group showed more multidomain (59.8%) MCI with slower processing speed and a higher proportion of patients with depression, anxiety, apathy, constipation, rhinorrhea, sicca syndrome, and photophobia, compared to the NS group. The pro-DLB group had isolated lower P-Tau in the CSF (not significant after adjustments for confounders) and on brain MRI widening of sulci including fronto-insular, occipital, and olfactory sulci (FDR corrected), when compared to the NS group. Evolution to dementia was not different between the three groups over a median follow-up of 2.6 years.ConclusionsPatients with symptoms of prodromal DLB are cognitively slower, with more behavioral disorders, autonomic symptoms, and photophobia. The occipital, fronto-insular, and olfactory bulb involvement on brain MRI was consistent with symptoms and known neuropathology. The next step will be to study the clinical, biological, and imaging evolution of these patients.Trial registrationClinicaltrials.gov, NCT01926249

Identification and validation of Alzheimer’s disease-related metabolic brain pattern in biomarker confirmed Alzheimer’s dementia patients

Metabolic brain biomarkers have been incorporated in various diagnostic guidelines of neurodegenerative diseases, recently. To improve their diagnostic accuracy a biologically and clinically homogeneous sample is needed for their identification. Alzheimer’s disease-related pattern (ADRP) has been identified previously in cohorts of clinically diagnosed patients with dementia due to Alzheimer’s disease (AD), meaning that its diagnostic accuracy might have been reduced due to common clinical misdiagnosis. In our study, we aimed to identify ADRP in a cohort of AD patients with CSF confirmed diagnosis, validate it in large out-of-sample cohorts and explore its relationship with patients’ clinical status. For identification we analyzed 2-[18F]FDG PET brain scans of 20 AD patients and 20 normal controls (NCs). For validation, 2-[18F]FDG PET scans from 261 individuals with AD, behavioral variant of frontotemporal dementia, mild cognitive impairment and NC were analyzed. We identified an ADRP that is characterized by relatively reduced metabolic activity in temporoparietal cortices, posterior cingulate and precuneus which co-varied with relatively increased metabolic activity in the cerebellum. ADRP expression significantly differentiated AD from NC (AUC = 0.95) and other dementia types (AUC = 0.76–0.85) and its expression correlated with clinical measures of global cognition and neuropsychological indices in all cohorts.

Novel App knock-in mouse model shows key features of amyloid pathology and reveals profound metabolic dysregulation of microglia

BackgroundGenetic mutations underlying familial Alzheimer’s disease (AD) were identified decades ago, but the field is still in search of transformative therapies for patients. While mouse models based on overexpression of mutated transgenes have yielded key insights in mechanisms of disease, those models are subject to artifacts, including random genetic integration of the transgene, ectopic expression and non-physiological protein levels. The genetic engineering of novel mouse models using knock-in approaches addresses some of those limitations. With mounting evidence of the role played by microglia in AD, high-dimensional approaches to phenotype microglia in those models are critical to refine our understanding of the immune response in the brain.MethodsWe engineered a novel App knock-in mouse model (AppSAA) using homologous recombination to introduce three disease-causing coding mutations (Swedish, Arctic and Austrian) to the mouse App gene. Amyloid-β pathology, neurodegeneration, glial responses, brain metabolism and behavioral phenotypes were characterized in heterozygous and homozygous AppSAA mice at different ages in brain and/ or biofluids. Wild type littermate mice were used as experimental controls. We used in situ imaging technologies to define the whole-brain distribution of amyloid plaques and compare it to other AD mouse models and human brain pathology. To further explore the microglial response to AD relevant pathology, we isolated microglia with fibrillar Aβ content from the brain and performed transcriptomics and metabolomics analyses and in vivo brain imaging to measure energy metabolism and microglial response. Finally, we also characterized the mice in various behavioral assays.ResultsLeveraging multi-omics approaches, we discovered profound alteration of diverse lipids and metabolites as well as an exacerbated disease-associated transcriptomic response in microglia with high intracellular Aβ content. The AppSAA knock-in mouse model recapitulates key pathological features of AD such as a progressive accumulation of parenchymal amyloid plaques and vascular amyloid deposits, altered astroglial and microglial responses and elevation of CSF markers of neurodegeneration. Those observations were associated with increased TSPO and FDG-PET brain signals and a hyperactivity phenotype as the animals aged.DiscussionOur findings demonstrate that fibrillar Aβ in microglia is associated with lipid dyshomeostasis consistent with lysosomal dysfunction and foam cell phenotypes as well as profound immuno-metabolic perturbations, opening new avenues to further investigate metabolic pathways at play in microglia responding to AD-relevant pathogenesis. The in-depth characterization of pathological hallmarks of AD in this novel and open-access mouse model should serve as a resource for the scientific community to investigate disease-relevant biology.

Comparison of dynamic susceptibility contrast enhanced MR and FDG-PET brain studies in patients with Alzheimer’s disease and amnestic mild cognitive impairment

BackgroundThe aim of this study was to compare Dynamic Susceptibility Contrast Enhanced MRI (DSC-MRI) and PET with [18F]flurodeoxyglucose (FDG-PET) in the diagnosis of Alzheimer’s Disease (AD) and amnestic Mild Cognitive Impairment (aMCI).MethodsTwenty-seven age-and sex-matched patients with AD, 39 with aMCI and 16 controls underwent brain DSC-MRI followed by FDG-PET. Values of relative Cerebral Blood Volume (rCBV) and rCBV z-scores from frontal, temporal, parietal and PCG cortices were correlated with the rate of glucose metabolism from PET. Sensitivity, specificity and accuracy of DSC-MRI and FDG-PET in the diagnosis of AD and aMCI were assessed and compared.ResultsIn AD, hypoperfusion was found within all the examined locations, while in aMCI in both parietal and temporal cortices and left PCG. FDG-PET showed the greatest hypometabolism in parietal, temporal and left PCG regions in both AD and aMCI. FDG-PET was more accurate in distinguishing aMCI from the controls than DSC-MRI. In the AD and combined group (AD + aMCI) there were numerous correlations between DSC-MRI and FDG-PET results.ConclusionsIn AD the patterns of hypoperfusion and glucose hypometabolism are similar, thus DSC-MRI may be a competitive method to FDG-PET. FDG-PET is a more accurate method in the diagnosis of aMCI.

Abnormal metabolic covariance patterns associated with multiple system atrophy and progressive supranuclear palsy

PurposeDifferentiation between neurodegenerative parkinsonisms, whose early clinical presentation is similar, may be improved with metabolic brain imaging. In this study we applied a specific network analysis to 2-[18F]FDG PET brain scans to identify the characteristic metabolic patterns for multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) in a new European cohort. We also developed a new tool to recognize and estimate patients’ metabolic brain heterogeneity. Methods20 MSA-P patients, 20 PSP patients and 20 healthy controls (HC) underwent 2-[18F]FDG PET brain imaging. The scaled subprofile model/principal component analysis was applied to identify MSA/PSP-related patterns; MSARP and PSPRP. Additional, 56 MSA, 45 PSP, 116 PD and 61 HC subjects were analyzed for validation. We innovatively applied heat-map analysis to extract and graphically display the pattern’s regional sub-scores in individual subjects. ResultsMSARP was characterized by hypometabolism in cerebellum and putamen, and PSPRP by hypometabolism in medial prefrontal cortices, nucleus caudatus, frontal cortices and mesencephalon. Patterns’ expression discriminated between MSA/PSP patients and HCs as well as between different parkinsonian cohorts (p < 0.001). Both patterns were sensitive and specific (AUC for MSARP/PSPRP: 0.96/0.99). Heat-map analysis showed differences within MSA/PSP subjects and HCs consistent with clinical presentation. ConclusionsReplication and validation of MSARP and PSPRP confirms robustness of these metabolic biomarkers and supports its application in clinical and research practice. Heat-map analysis gives us an insight into the contribution of various pattern’s regions to patterns’ expression in individual subjects, which improves our insight into the heterogeneity of studied syndromes.

Genetic Algorithms for Optimized Diagnosis of Alzheimer's Disease and Frontotemporal Dementia Using Fluorodeoxyglucose Positron Emission Tomography Imaging.

Genetic algorithms have a proven capability to explore a large space of solutions, and deal with very large numbers of input features. We hypothesized that the application of these algorithms to 18F-Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) may help in diagnosis of Alzheimer’s disease (AD) and Frontotemporal Dementia (FTD) by selecting the most meaningful features and automating diagnosis. We aimed to develop algorithms for the three main issues in the diagnosis: discrimination between patients with AD or FTD and healthy controls (HC), differential diagnosis between behavioral FTD (bvFTD) and AD, and differential diagnosis between primary progressive aphasia (PPA) variants. Genetic algorithms, customized with K-Nearest Neighbor and BayesNet Naives as the fitness function, were developed and compared with Principal Component Analysis (PCA). K-fold cross validation within the same sample and external validation with ADNI-3 samples were performed. External validation was performed for the algorithms distinguishing AD and HC. Our study supports the use of FDG-PET imaging, which allowed a very high accuracy rate for the diagnosis of AD, FTD, and related disorders. Genetic algorithms identified the most meaningful features with the minimum set of features, which may be relevant for automated assessment of brain FDG-PET images. Overall, our study contributes to the development of an automated, and optimized diagnosis of neurodegenerative disorders using brain metabolism.