Fludeoxyglucose Positron Emission Tomography Research Articles

Predictive Value of Preoperative 18 Fludeoxyglucose Positron Emission Tomography–Computed Tomography for Survival in Liver Transplantation Due to Hepatocellular Cancer

We aimed to study the predictive value of preoperative perform [18F] Fludeoxyglucose positron emission tomography-computed tomography ([18] FDG PET-CT) for survival in liver transplantation due to hepatocellular cancer. Ninety-six patients who underwent liver transplantation for hepatocellular cancer (HCC) after preoperative PET-CT evaluation were examined for the study. All patients' ages, genders, body mass index, blood groups, Child-Pugh and Model for End-Stage Liver Disease scores, etiologies, median Alpha Fetoprotein values, Milan Criteria and T stages, grades, macrovascular and microvascular invasions, multicentricities, maximum and total tumor sizes, tumor number findings in explant specimens, and recurrence rates were analyzed statistically. Statistically, microvascular (P = .002) and macrovascular invasions (P = .034) were observed more frequently in patients who are PET-CT (+) compared with patients who are PET-CT (-). PET-CT positivity was associated with shortened disease-free survival (DFS) statistically (P = .004). Positron emission tomography-CT positivity may be important for predicting prognostic markers such as DFS and vascular invasion in the preoperative evaluation. Before transplantation, PET-CT should be applied to all patients with HCC.

Cardiac fludeoxyglucose-18 positron emission tomography in genotype-positive arrhythmogenic cardiomyopathy

BackgroundMyocardial inflammation contributes to the pathogenesis of arrhythmogenic cardiomyopathy (ACM), a clinically and genetically heterogenous disorder. Due to phenotypic overlap, some patients with genetic ACM may be evaluated for an underlying inflammatory cardiomyopathy. However, the cardiac fludeoxyglucose (FDG) positron emission tomography (PET) findings in ACM patients have not been elucidated. MethodsAll genotype-positive patients in the Mayo Clinic ACM registry (n = 323) who received a cardiac FDG PET were included in this study. Pertinent data were extracted from the medical record. ResultsCollectively, 12/323 (4%; 67% female) genotype-positive ACM patients received a cardiac PET FDG scan as part of their clinical evaluation (median age at scan 49 ± 13 years). Amongst these patients, pathogenic/likely pathogenic variants were detected in LMNA (n = 7), DSP (n = 3), FLNC (n = 1) and PLN (n = 1). Of note, 6/12 (50%) had abnormal myocardial FDG uptake, including diffuse (entire myocardium) uptake in 2/6 (33%), focal (1–2 segments) uptake in 2/6 (33%) and patchy (3+ segments) in 2/6 (33%). Median myocardial standardized uptake value ratio was 2.1. Interestingly, LMNA-positive patients accounted for 3 out of 6 (50%) positive studies (diffuse uptake in 2 and focal uptake in 1). ConclusionAbnormal myocardial FDG uptake is common in genetic ACM patients undergoing cardiac FDG PET. This study further supports the role of myocardial inflammation in ACM. Further investigation is needed to determine role of FDG PET in diagnosis and management of ACM and investigate the role of inflammation in ACM.

Disseminated Nocardia farcinica Infection and Treatment Response on F-18 Fludeoxyglucose Positron Emission Tomography Computed Tomography.

We report a rare case of nocardiosis with increased F-18 Fludeoxyglucose (F-18 FDG) uptake in widespread abscess foci of Nocardia farcinica infection in an immunocompromised patient on positron emission tomography computed tomography (PET/CT) imaging. A relatively infrequent cause of nocardiosis, N. farcinica is an opportunistic infection that may present with clinically aggressive disseminated disease. Whole-body F-18 FDG-PET/CT allows identifying the extent of disease, as well as monitoring response to therapy in patients with nocardiosis especially the disseminated form.

Different metabolic and clinical profiles between patients with pure Alzheimer dementia and epileptic Alzheimer dementia: a metabolic study

Aim: To investigate the clinical characteristics and cerebral FDG PET metabolisms of dementia patients who were also diagnosed with epilepsy and compare the differences with pure Alzheimer dementia patients.Methods: In this case-control study, a total of 14 patients, 7 patients with pure Alzheimer disease as a control group and 7 age and gender-matched patients with Alzheimer disease and concomitant epilepsy as a study group, were included. Detailed neurocognitive battery and brain fludeoxyglucose positron emission tomography (FDG PET-CT) were performed for all subjects.Results: In comparison of neurocognitive test scores, there was no significant difference between the study and control groups. However, geriatric depression scale scores were significantly lower in study group than the controls (p= 0.026). In cerebral FDG-PET CT profiles of subjects we detected significantly lower metabolism in left and right cerebellum, left lentiform nucleus, right thalamus and vermis in the study group (p=0.008, p=0.023, p=0.003, p=0.002, p=0.002, respectively). In the right parietotemporal cortex and right and left associative visual cortex, we found higher metabolism in the study group than controls (p=0.023, p=0.012, p=0.003, respectively).Conclusion: Epileptic patients with Alzheimer’s dementia may have distinct clinical and metabolic profiles, than pure Alzheimer’s disease patients. Even if there is no difference in the neurocognitive clinical scores of the patients, depression and related functional abnormalities may be a biomarker of epileptic AD.

Abstract 12736: Cardiac Fludeoxyglucose-18 Positron Emission Tomography in Genotype-Positive Arrhythmogenic Cardiomyopathy

Introduction: Myocardial inflammation likely contributes to the pathogenesis of arrhythmogenic cardiomyopathy (ACM), a clinically and genetically heterogenous disorder characterized by ventricular dysfunction and potentially life-threatening ventricular arrhythmias. Due to phenotypic overlap, some patients with genetic ACM may have been evaluated for an underlying inflammatory cardiomyopathy, namely cardiac sarcoidosis. However, the cardiac fludeoxyglucose (FDG) positron emission tomography (PET) findings in ACM patients have not been assessed systematically. Methods: All genotype-positive patients in the Mayo Clinic ACM registry who received a cardiac FDG PET were included in this study. The cardiac FDG PET scan consisted of a resting myocardial perfusion scan with N13-ammonia as well as a F18-FDG scan after a high-fat diet to suppress physiologic FDG uptake. Pertinent demographic, genetic, imaging, and outcome data were extracted from the medical record. Results: Collectively, 12 (75% female) genotype-positive ACM patients received a cardiac PET FDG scan as part of their clinical evaluation (median age at scan 45.3 years [IQR 38.9-62.1]). Amongst these patients, pathogenic/likely pathogenic variants were detected in LMNA (n=7), DSP (n=3), FLNC (n=1), and PLN (n=1). Of note, 6/12 (50%) had abnormal myocardial FDG uptake, including diffuse (entire myocardium) uptake in 2/6 (33%), focal (1-2 segments) uptake in 2/6 (33%) and patchy (3+ segments) in 2/6 (33%). Median myocardial standardized uptake value ratio was 2.1 (IQR 1.5-2.6). Interestingly, LMNA -positive patients accounted for 3 out of 6 (50%) positive studies (diffuse uptake in 2 and focal uptake in 1). Conclusion: Myocardial FDG uptake is common in genetic ACM patients undergoing cardiac FDG PET. This finding further supports the role of myocardial inflammation in genetic ACM and demonstrates the ability of cardiac FDG PET to readily detect this phenomenon. Further investigation is needed to determine (i) the role of cardiac FDG PET in the evaluation of genetic ACM, (ii) if FDG uptake in genetic ACM has prognostic value and (iii) whether the attenuation of myocardial inflammation with immunosuppressive agents can impact the clinical course of inflammatory genetic ACMs.

Serum Sirtuin-1, HMGB1-TLR4, NF-KB and IL-6 levels in Alzheimer's: The Relation Between Neuroinflammatory Pathway and Severity of Dementia.

In this study, serum Sirtuin-1(SIRT-1), High Mobility Group Box 1 (HMGB1), Toll-Like Receptor-4 (TLR4), Nuclear Factor Kappa B (NF-kB), Interleukine-6 (IL-6), Amyloid βeta-42 (Aβ-42), and p-tau181 levels in patients diagnosed with AD according to NINCS-ADRA criteria were studied. We investigated the inflammatory pathways that lead to progressive neuronal loss and highlight their possible relationship with dementia severity in the systemic circulation. Patients over 60 years of age were grouped according to their Standard Mini Mental Test results, MRI, and/or Fludeoxyglucose positron emission tomography or according to their CT findings as Control n:20; AD n:32; Vascular Dementia (VD) n:17; AD + VD; n=21. Complete blood count, Glucose, Vitamin B12, Folic Acid, Enzymes, Urea, Creatinine, Electrolytes, Bilirubin, and Thyroid Function tests were evaluated. ELISA was used for the analysis of serum SIRT1, HMGB1, TLR4, NF-kB, IL-6, Aβ-42, and p-tau181 levels. Levels of serum Aβ-42, SIRT1, HMGB1, and IL-6 were significantly higher (p˂0.001, p<0.01, p<0.001, and p<0.001, respectively), and TLR4 levels were significantly lower (p˂0.001) in the dementia group than in the control group. No significant difference was observed between dementia and control groups for serum NF-kB and p-tau181 levels. Our results show that the levels of the Aβ42, SIRT 1, HMGB1, and TLR4 pathways are altered in AD and VD. SIRT 1 activity plays an important role in the inflammatory pathway of dementia development, particularly in AD.

The Value of Neuroimaging in Dementia Diagnosis.

This article discusses neuroimaging in dementia diagnosis, with a focus on new applications of MRI and positron emission tomography (PET). Although the historical use of MRI in dementia diagnosis has been supportive to exclude structural etiologies, recent innovations allow for quantification of atrophy patterns that improve sensitivity for supporting the diagnosis of dementia causes. Neuronuclear approaches allow for localization of specific amyloid and tau neuropathology on PET and are available for clinical use, in addition to dopamine transporter scans in dementia with Lewy bodies and metabolic studies with fludeoxyglucose PET (FDG-PET). Using computerized software programs for MRI analysis and cross-sectional and longitudinal evaluations of hippocampal, ventricular, and lobar volumes improves sensitivity in support of the diagnosis of Alzheimer disease and frontotemporal dementia. MRI protocol requirements for such quantification are three-dimensional T1-weighted volumetric imaging protocols, which may need to be specifically requested. Fluid-attenuated inversion recovery (FLAIR) and 3.0T susceptibility-weighted imaging (SWI) sequences are useful for the detection of white matter hyperintensities as well as microhemorrhages in vascular dementia and cerebral amyloid angiopathy. PET studies for amyloid and/or tau pathology can add additional specificity to the diagnosis but currently remain largely inaccessible outside of research settings because of prohibitive cost constraints in most of the world. Dopamine transporter PET scans can help identify Lewy body dementia and are thus of potential clinical value.

Diagnostic test accuracies of F-18 FDG PET for characterisation of cardiac masses compared to conventional imaging techniques: systematic review and meta-analysis.

The present systematic review and meta-analysis compared the diagnostic performance of F-18 fludeoxyglucose positron emission tomography (18F-FDG PET) and conventional imaging, including MRI, echocardiography, and CT, in characterising cardiac masses. A literature search of the PubMed, Cochrane, and EMBASE databases for studies comparing the diagnostic accuracies of 18F-FDG PET and conventional imaging in characterising cardiac masses, from inception of indexing to 31 July 2020, was performed. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess study quality. Sensitivity and specificity across the studies were determined, positive and negative likelihood ratios (LR+ and LR-, respectively) were calculated, and summary receiver operating characteristic curves were constructed. Of six included studies (n = 212 patients), 18F-FDG PET demonstrated a pooled sensitivity of 0.89 (95% confidence interval [CI] 0.81-0.94) and a pooled specificity of 0.89 (95% CI 0.80-0.94). LR syntheses yielded an overall LR+ of 7.9 (95% CI 4.3-14.6) and LR- of 0.12 (95% CI 0.07-0.22). The calculated pooled diagnostic odds ratio (DOR) was 64 (95% CI 23-181). For conventional imaging, the pooled sensitivity was 0.70 (95% CI 0.57-0.81) and the pooled specificity was 0.96 (95% CI 0.88-0.98). LR syntheses yielded an overall LR+ of 16.1 (95% CI 5.8-44.5) and LR- of 0.31 (95% CI 0.21-0.46). The evaluated pooled DOR was 52 (95% CI 17-155). 18F-FDG PET and conventional imaging demonstrated comparable diagnostic accuracies for the characterisation of cardiac masses. Further large multicentre studies are, however, required to corroborate the diagnostic performances of 18F-FDG PET and conventional imaging for the characterisation of cardiac masses. No previous studies have comprehensively analysed the diagnostic performance of 18F-FDG PET/CT compared with conventional imaging techniques including echocardiography, CT, and MRI. According to the current study, 18F-FDG PET/CT yielded a pooled DOR of 64, whereas other conventional imaging techniques demonstrated a DOR of 52. As such, 18F-FDG PET/CT demonstrated sensitivity and specificity, with a high pooled DOR comparable with other conventional imaging modalities.

Skeletal Metastases of Unknown Primary: A Rare Presentation of Carcinoma Pancreas on Fludeoxyglucose Positron Emission Tomography-Computed Tomography.

Skeletal metastases of unknown primary represent skeletal metastases where primary tumors remain obscure. They usually arise from lung and prostate cancer. We present a case of a young male who presented with severe bone pains, weight loss, and generalized weakness. Fludeoxyglucose positron emission tomography–computed tomography reveals extensive skeletal metastases, a mass in the pancreas tail, and other metastatic lesions. He had no liver or lung metastases. This case presents a rare presentation of carcinoma pancreas.

Intranasal Administration of Chitosan-Nanoparticles Conjugated with Imipramine and its Effect on Stroke-Induced Secondary Neurodegeneration: A Research Protocol

Introduction: Stroke is the second leading cause of death and the third leading cause of permanent disability worldwide. Notably, the recovery period post-stroke is crucial as there is a risk of stroke-induced secondary neurodegeneration. Stroke-induced secondary neurodegeneration is the inevitable loss of viable brain tissue at sites distal from the initial infarct. It shares similarities with neurodegenerative diseases and results in neurological deficits, further complicating stroke recovery. Intranasal administration of chitosan-nanoparticles conjugated with imipramine will be tested to determine if they elicit a synergistic effect in mitigating disease processes associated with stroke-induced secondary neurodegeneration. Methods: Treatment and testing will be conducted in 30 male Wistar rats aged 12 months. Stroke will be induced by occluding the middle cerebral artery. Rats will be divided into three groups of 10 and will receive an intranasal dose of either saline (Control, C), 20mg/kg of imipramine (Treatment 1, T1), or 20mg/kg of chitosan-nanoparticles conjugated with imipramine (Treatment 2, T2). Statistical analysis using analysis of variance will determine if chitosan-nanoparticles conjugated with imipramine can mitigate the effects of stroke-induced secondary neurodegeneration determined by the proposed tests. Results: T2 given 20mg/kg of chitosan-nanoparticles conjugated with imipramine is proposed to spend more time exploring the unfamiliar object in the novel object recognition test. Lesser evidence of Alzheimer’s disease in T2 is expected, as measured by the fludeoxyglucose positron emission tomography imaging. A higher serum brain-derived neurotrophic factor measured by an enzyme-linked immunosorbent assay is also expected to be present in T2. Discussion: It is anticipated that chitosan-nanoparticles conjugated with imipramine will exhibit a synergistic effect in mitigating disease processes accompanying stroke-induced secondary neurodegeneration because of properties associated with neuroplasticity and enhanced drug targeting efficacy. Conclusion: This research protocol aims to elucidate a novel treatment that can be applied to stroke recovery to mitigate stroke-induced secondary neurodegeneration, which tends to complicate this crucial period. Our proposal could have implications in the prognosis and management of stroke and post-stroke recovery, respectively, and inspire a framework for the discovery of novel post-stroke therapeutic interventions.

Clinical usefulness of 18F-FDG PET in patients with hepatocellular carcinoma undergoing surgical resection

The diagnosis and staging hepatocellular carcinoma (HCC) is important because of the different treatment methods and the prognosis. [18F]fludeoxyglucose positron emission tomography/computed tomography ([18F]FDG-PET/CT) has been suggested as a diagnostic modality in HCC. The aim of this study is to evaluate the accuracy of [18F]FDG-PET for staging of HCC after surgical resection and histological confirmation. We retrospectively collected data of 56 patients who underwent [18F]FDG-PET before surgical resection for HCC from March 2011 to May 2017. All of whom were suitable for resection by conventional HCC staging. The results of maximal standardized uptake value (SUVmax) was compared with histological confirmation. A larger tumor size was related with a higher SUV (≥ 4.9) and also serum alpha-feto protein was associated with SUV. The recurrence rate was higher in patients with a higher SUV and the patients with lower SUV had better survival rate. HCC, [18F]fludeoxyglucose positron emission tomography, standardized uptake value (SUV).

Role of F-18 FDG PET/CT in Patients with Suspected Recurrent Breast Cancer: Additional Value over Conventional Imaging Modalities

Background: The aim of the present study was to investigate the added value of F-18 fludeoxyglucose (FDG) positron-emission tomography (PET)/computed tomography (CT) compared with conventional imaging modalities for the evaluation of locoregional and distant sites of recurrence in breast cancer patients. Methods: From May 2013 to September 2016, 109 patients with suspected recurrent breast cancer who underwent conventional imaging and F-18 FDG PET/CT with an interval of 6 weeks were consecutively enrolled (mean age: 52.66 years; range: 29?79). Histopathologic results and clinical follow up based on the gold-standard imaging modality or serial imaging were considered as the reference for verification of F-18 FDG PET/CT findings. Results: Of 109 patients, 81 were found to have at least one site of recurrence (74.31%). Local recurrence was correctly identified in 32/32 patients following PET/CT, which was higher than that on conventional imaging (20/32, 62.5%). PET/CT detected 27 additional nodal metastases compared with conventional imaging (59 vs. 32, 45.76%), most frequently in the hilar/mediastinal region (n=27), followed by the supraclavicular lymph nodes (n=20, 62.5%), internal mammary lymph nodes (n=6, 18.77%), and axillary basin (n=6, 18.77%). Additional sites of distant metastasis were identified in 41 patients (37.61%) following F-18 FDG PET/CT imaging, 48.78% of which were localized in the skeletal system (n=20), 21.95% in the liver (n=9), 12.19% in the lungs (n=5), 12.19% in the brain (n=5), and 4.87% in the adrenal glands (n=2). Conclusion: F-18 FDG PET/CT serves as a useful supplement to conventional imaging techniques by identifying additional sites of disease recurrence in patients with breast cancer, which may change the preferred treatment strategy, particularly in regions that are not routinely evaluated by conventional imaging.

Comparison of different diagnostic approaches in the management of the clinically negative neck in early oral cancer patients

In clinically node‐negative patients with early oral cavity cancer, [18F]fludeoxyglucose (FDG) positron emission tomography–computed tomography (PET‐CT) should be compared with sentinel node biopsy. Cost effectiveness is one of the important aspects for implementation of FDG/PET‐CT in clinical practice for this patient population.

Glioma surveillance imaging: current strategies, shortcomings, challenges and outlook.

Inaccurate assessment of surveillance imaging to assess response to glioma therapy may have life-changing consequences. Varied management plans including chemotherapy, radiotherapy or immunotherapy may all contribute to heterogeneous post-treatment appearances and the overlap between the morphological features of pseudoprogression, pseudoresponse and radiation necrosis can make their discrimination very challenging. Therefore, there has been a drive to develop objective strategies for post-treatment assessment of brain gliomas. This review discusses the most important of these approaches such as the RANO “Response Assessment in Neuro-Oncology”, iRANO “Immunotherapy Response Assessment in Neuro-Oncology” and RAPNO “Response Assessment in Paediatric Neuro-Oncology” models.In addition to these systematic approaches for glioma surveillance, the relatively limited information provided by conventional imaging modalities alone has motivated the development of novel advanced magnetic resonance (MR) and metabolic imaging methods for further discrimination between viable tumour and treatment induced changes. Multiple clinical trials and meta-analyses have investigated the diagnostic performance of these novel techniques in the follow up of brain gliomas, including both single modality descriptive studies and comparative imaging assessment. In this manuscript, we review the literature and discuss the promises and pitfalls of frequently studied modalities in glioma surveillance imaging, including MR perfusion, MR diffusion and MR spectroscopy. In addition, we evaluate other promising MR techniques such as chemical exchange saturation transfer as well as fludeoxyglucose and non-FDG positron emission tomography techniques.

Coregistration of Magnetic Resonance and [18F] Fludeoxyglucose–Positron Emission Tomography Imaging for Stereotactic Radiation Therapy Planning: Case Report in a Previously Irradiated Brain Metastasis With Recurrent Tumor and Radiation Necrosis

Stereotactic radiosurgery (SRS) or radiotherapy (SRT) is commonly used to treat brain metastasis (BM). While effective in achieving tumor control, a significant number of BM patients exhibit lesion growth on follow-up MR imaging after SRS which cannot reliably distinguish between tumor growth, radiation necrosis (RN) or a mixture of both. SRS retreatment is a therapeutic option for tumor regrowth but contraindicated for RN. Here, we describe an instructive case of MRI progression of a breast BM previously treated by SRS where [18F] fludeoxyglucose-positron emission tomography (FDG-PET) proved useful to anatomically delineate metabolically active tumor from RN for re-treatment planning. Post-treatment FDG-PET and MRI studies indicated decreased uptake and enhancement respectively following treatment. This case study underscores the biological heterogeneity underlying MRI based BM progression after prior SRS and the potential utility of FDG-PET to guide treatment planning for repeat SRS.

Role of FDG PET/CT to Detect Bone Marrow Involvement in the Initial Staging of Aggressive Non-Hodgkin Lymphoma

BACKGROUND: According to the Lugano classification (Cheson et al., JCO 2014, 32: 3059-3067) fludeoxyglucose positron emission tomography combined with computed tomography (FDG PET/CT) is the standard for evaluation and staging of aggressive non-Hodgkin Lymphoma (NHL). It is a matter of debate whether FDG PET/CT is sufficient to determine bone marrow (BM) involvement. We performed a pooled analysis of data from the PETAL (EudraCT 2006-001641-33) and OPTIMAL&gt;60 trials (EudraCT 2010-019587-36) as prospective, open-label, randomized, multicenter Phase-III trials to determine whether initial staging with FDG PET/CT would allow non-invasive diagnosis of BM involvement and thus could avoid established but potentially painful and unpleasant BM biopsy (BMB). PATIENTS AND METHODS: Patients treated within the trials were included if both FDG PET/CT and BMB were performed during initial staging. Only patients with a biopsy-proven, centrally confirmed diagnosis of diffuse large B-cell lymphoma, primary mediastinal B-cell lymphoma or follicular lymphoma grade 3b were included. FDG PET/CT images and BM findings were blinded for central review by board certified PET/CT readers. Discordant findings were documented and resolved after unblinding by interdisciplinary discussion using findings of complementary imaging and/or subsequent PET examinations. Based on literature (Berthet et al., J Nucl Med 2013), a newly defined gold standard was used to confirm BM involvement. It includes a positive BMB or a positive FDG PET confirmed by targeted biopsy, complementary CT imaging or targeted MRI, or concurrent disappearance of focal FDG-avid BM lesions with other lymphoma manifestations during immunochemotherapy. RESULTS: Out of 1,976 patients a total of 930 patients met the inclusion criteria. BMB confirmed BM involvement in 85 of 930 patients (9%). According to FDG PET/CT, BM was involved in 185 out of 930 patients (20%) with 36 discordances (4%) between negative initial FDG PET/CT and positive BMB ("false negatives" with respect to previous reference standard, PRS). Discordances between positive initial FDG PET/CT and negative BMB ("false positives" by PRS) occurred in 136 patients (15%). If only BMB is used as in the PRS, the negative predictive value (NPV) of FDG PET/CT was 709/745=95% (95% confidence interval [95%CI]: 93%-97%) with a sensitivity (Sens) of 58% (95%CI: 46%-68%) and a specificity (Spec) of 84% (95%CI: 81%-86%). After discussion of these cases, 185 out of 221 cases with BM involvement were identified as true positive, resulting in a Sens of 84% for FDG PET/CT (95%CI: 78%-88%). By means of FDG PET/CT 745 cases were negative of which 709 were confirmed as true negatives, resulting in an NPV of 95% (95%CI: 93%-97%). All 185 cases with positive FDG PET/CT were evaluated as true positive for BM involvement in the unblinded synopsis of all findings, resulting in a positive predictive value (PPV) of 100% (95%CI: 98%-100%). All 709 negative FDG PET/CT findings were finally confirmed as such, so Spec was 100% (95%CI: 99%-100%). Thus, the prevalence in our total cohort analyzed was 24%, since 221 out of 930 cases had confirmed BM involvement. Diagnostic performance parameters for BMB as compared to the newly defined gold standard were Sens 85/221=38% (95%CI: 32%-45%), Spec 709/709=100% (95%CI: 99%-100%), PPV 85/85=100% (95%CI: 96%-100%) and NPV 709/845=84% (95%CI: 81%-86%), respectively. Differences between the PRS in the diagnosis of BM involvement by only BMB and the newly defined gold standard result mainly from false negative BMB due to sampling errors, which are detected by FDG PET/CT. DISCUSSION: In the majority of patients with aggressive B-cell lymphoma, routine BMB does not give any additional relevant diagnostic or prognostic information over FDG PET/CT alone and could therefore be omitted. BMB should only be performed if results would have direct therapeutic impact e.g. in patients with limited stage disease and lack of further risk factors according to the international prognostic index (IPI). Disclosures Held: MSD: Consultancy; Bristol-Myers Squibb: Consultancy, Other: Travel support, Research Funding; Roche: Consultancy, Other: Travel support, Research Funding; Amgen: Research Funding; Acrotech: Research Funding. Stilgenbauer:Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Research Funding, Speakers Bureau; GSK: Consultancy, Honoraria, Research Funding, Speakers Bureau; Hoffmann La-Roche: Consultancy, Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Duehrsen:Amgen: Consultancy; University Hospital Essen, Germany: Employment; Takeda: Consultancy; Novartis: Consultancy; Gilead: Honoraria; Janssen: Honoraria; Gilead: Consultancy; AbbVie: Consultancy; Celgene: Research Funding; CPT: Consultancy; Takeda: Honoraria; Novartis: Honoraria; Amgen: Research Funding; Roche: Research Funding; AbbVie: Honoraria; Amgen: Honoraria; CPT: Honoraria. Hüttmann:University Hospital Essen: Employment; Takeda: Honoraria; Gilead: Honoraria. Poeschel:Amgen: Other: Travel, accommodations, expenses; Abbvie: Other: Travel, accomodations, expenses; Roche: Other: Travel, accomodations, expenses; Hexal: Speakers Bureau.

FDG PET-CT in pediatric Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) in pediatric patients presents with single-system or multisystem disease. Accurate staging is essential for selecting the most appropriate therapy ranging from local surgery to chemotherapy. A retrospective review was undertaken of reported fludeoxyglucose (FDG) positron emission tomography - computed tomography (PET-CT) scans performed in children with LCH from June 2006 to February 2017. Findings were compared with a reference standard of biopsy or informed clinical follow-up. One hundred nine scans were performed in 33 patients (age 7weeks to 18 years). Nineteen patients had single-system, bone unifocal disease; seven patients had single-system, bone multifocal disease; four patients had single-system, skin unifocal disease; two patients had multisystem disease; and one patient had single-system, lymph node disease. Twenty-six scans were performed to stage biopsy-proven LCH, and 83 scans were performed during follow-up to assess treatment response or recurrence after therapy completion. At staging, FDG PET-CT detected all sites of biopsy-proven LCH (except where bone unifocal disease had been resected). There was one false-positive thymic finding that resolved without therapy. The per-patient false-positive rate of FDG PET-CT at staging was 4% (1/26). During follow-up, five LCH recurrences and one case of progressive disease on therapy occurred, all positive on FDG PET-CT. During follow-up two patients had FDG PET-CT scans with false-positive findings and one patient with a magnetic resonance imaging false-positive finding. The per-scan false-positive rate of FDG PET-CT during follow-up was 2% (2/83). FDG PET-CT is highly sensitive for the staging and follow-up of pediatric patients with LCH, and has a very low false-positive rate.

Application of T1-/T2-Weighted Ratio Mapping to Elucidate Intracortical Demyelination Process in the Alzheimer's Disease Continuum.

Background The biological diagnosis criteria of the Alzheimer’s disease (AD) suggests that previous work may misclassify the cognitive impairment caused by other factors into AD. Consequently, re-assessing the imaging profile of AD continuum is needed. Considering the high vulnerability of cortical association fibers, we aimed to elucidate the cortical demyelination process in the AD continuum biologically defined.Methods According to the biological diagnosis criteria, we determined the positive amyloid status (A+) as cerebrospinal fluid (CSF) amyloid1–42 < 192 pg/ml, Florbetapir Positron emission tomography (PET) composite standardized uptake value ratio (SUVR) >1.11. Also, the positive Tau status (T+) was determined as p-Tau181 > 23 pg/ml. Based on the cognitive characterization, we further categorized 252 subjects into 27 cognitively unimpaired with normal AD biomarkers (A−T−, controls), 49 preclinical AD (A+T+), 113 AD with mild cognitive impairment (MCI) (A+T+), and 63 AD dementia (A+T+). We estimated the intracortical myelin content used the T1- and T2-weighted (T1W/T2W) ratio mapping. To investigate the sensitivity of the ratio mapping, we also utilized well-validated AD imaging biomarkers as the reference, including gray matter volume and Fludeoxyglucose PET (FDG-PET). Based on the general linear model, we conducted the voxel-wise two-sample T-tests between the controls and each group in the AD continuum.Results Compared to the controls, the results showed that the preclinical AD patients exhibited decreased T1W/T2W ratio value in the right inferior parietal lobule (IPL); as the disease progresses, the prodromal AD patients demonstrated lower ratio value in bilateral IPL, with hippocampus (HP) atrophy. Lastly, the AD dementia patients exhibited decreased ratio value in bilateral IPL and hippocampus; also, we observed the bilateral temporal cortices atrophy and widespread decreased metabolism in the AD dementia patients. After corrected with gray volume, the results remained mostly unchanged.Conclusion Our study implied the decreased right IPL T1W/T2W ratio might represent early AD-related demyelination in disease continuum. Additionally, we demonstrated that the T1W/T2W ratio mapping is an easy-to-implement and sensitive metric to assess the intracortical myelin content in AD, particularly in the early stage.

Interregional causal influences of brain metabolic activity reveal the spread of aging effects during normal aging.

During healthy brain aging, different brain regions show anatomical or functional declines at different rates, and some regions may show compensatory increases in functional activity. However, few studies have explored interregional influences of brain activity during the aging process. We proposed a causality analysis framework combining high dimensionality independent component analysis (ICA), Granger causality, and least absolute shrinkage and selection operator regression on longitudinal brain metabolic activity data measured by Fludeoxyglucose positron emission tomography (FDG-PET). We analyzed FDG-PET images from healthy old subjects, who were scanned for at least five sessions with an averaged intersession interval of 1 year. The longitudinal data were concatenated across subjects to form a time series, and the first-order autoregressive model was used to measure interregional causality among the independent sources of metabolic activity identified using ICA. Several independent sources with reduced metabolic activity in aging, including the anterior temporal lobe and orbital frontal cortex, demonstrated causal influences over many widespread brain regions. On the other hand, the influenced regions were more distributed, and had smaller age-related declines or even relatively increased metabolic activity. The current data demonstrated interregional spreads of aging on metabolic activity at the scale of a year, and have identified key brain regions in the aging process that have strong influences over other regions.

Discrepancy between significant fibrosis and active inflammation in patients with cardiac sarcoidosis: combined and image fusion analysis of cardiac magnetic resonance and 18F fluorodeoxyglucose positron emission tomography

BackgroundDiagnosis and evaluation of cardiac sarcoidosis (CS) are mainly based on the combined use of cardiac magnetic resonance imaging (CMR) and 18F fludeoxyglucose positron emission tomography (FDG). Though these modalities can detect the pathological feature of the disease, combined assessment has not been fully examined. Multimodality image fusion is known to be useful for further comprehension, while most image interpretation is performed with a side by side comparison in clinical routine. We investigated the similarity and discrepancy of active inflammation, regional fibrosis, and wall function by image fusion of CMR and FDG.MethodsPatients with CS who underwent both CMR and FDG were retrospectively enrolled. The extent of myocardial late gadolinium enhancement (LGE) in left ventricle (LGE volume), cardiac function, and volume (left ventricular ejection fraction, LVEF; end-diastolic volume, EDV) was measured from CMR. The FDG uptake in whole myocardium (whole SUVmax), cardiac metabolic volume (CMV), and cardiac metabolic activity (CMA) was calculated from FDG. CMR and FDG were fused and divided into AHA 17 model for segmental analysis. Wall motion, the magnitude of LGE in myocardial wall (LGE%wall), and corresponding FDG uptake (segmental SUVmax) were analyzed.ResultsForty-one patients were retrospectively enrolled. In patients with FDG uptake, LVEF inversely correlated to LGE volume and positively correlated to SUVmax (r = − 0.56, p < 0.0001, and r = 0.08, p = 0.048, respectively). Discrepancy between LGE volume and CMV showed a significant positive correlation to whole SUVmax and CMA (r = 0.49, p < 0.0001, and r = 0.96, p < 0.0001, respectively). In image fusion analysis, segmental SUVmax showed a significant inverse correlation to LGE%wall (Spearman’s rank correlation coefficient; r = − 0.15, p = 0.008). LGE%wall also showed significant inverse correlation to wall motion (r = − 0.13, p = 0.0011).ConclusionCombined and fusion analysis with CMR and FDG demonstrated the discrepancy of myocardial inflammation and extensive fibrosis. Active inflammation was present in the earlier stage of myocardial fibrosis and was found to be less in the wall with advanced fibrosis and remodeling. Combined analysis of CMR and FDG can incrementally reclassify the pathological stage of CS.