PET brain imaging in HIV-associated neurocognitive disorders (HAND) in the era of combination antiretroviral therapy

Effective combination antiretroviral therapy (cART) has lead to a significant reduction in the prevalence and incidence of central nervous system (CNS) HIV-associated brain disease, particularly CNS opportunistic infections and HIV encephalitis. Despite this, cognitive deficits in people living with HIV, also known as HIV-associated neurocognitive disorders (HAND) have become more prevalent in recent years. The pathogenesis of HAND is likely to be multifactorial, however recent evidence suggests that brain microglial activation is the most likely pathogenic mechanism. Recent developments in positron emission tomography (PET) brain neuroimaging using novel brain radioligands targeting a variety of physiological changes in the brains of HIV-positive individuals have improved our understanding of the mechanisms associated with the development of HAND. This review will highlight recent PET brain neuroimaging studies in the cART era, focusing on physiological and neurochemical changes associated with HAND in people living with HIV

In vivo characterization of [18F]AVT-011 as a radiotracer for PET imaging of multidrug resistance

Multidrug resistance (MDR) impedes cancer treatment. Two efflux transporters from the ATP-binding cassette (ABC) family, ABCB1 and ABCG2, may contribute to MDR by restricting the entry of therapeutic drugs into tumor cells. Although a higher expression of these transporters has been correlated with an unfavorable response to chemotherapy, transporter expression does not necessarily correlate with function. In this study, we characterized the pharmacological properties of [18F]AVT-011, a new PET radiotracer for imaging transporter-mediated MDR in tumors.AVT-011 was radiolabeled with 18F and evaluated with PET imaging in preclinical models. Transport of [18F]AVT-011 by ABCB1 and/or ABCG2 was assessed by measuring its uptake in the brains of wild-type, Abcb1a/b-/-, and Abcg2-/- mice at baseline and after administration of the ABCB1 inhibitor tariquidar (n = 5/group). Metabolism and biodistribution of [18F]AVT-011 were also measured. To measure ABCB1 function in tumors, we performed PET experiments using both [18F]AVT-011 and [18F]FDG in mice bearing orthotopic breast tumors (n = 7-10/group) expressing clinically relevant levels of ABCB1.At baseline, brain uptake was highest in Abcb1a/b-/- mice. After tariquidar administration, brain uptake increased 3-fold and 8-fold in wild-type and Abcg2-/- mice, respectively, but did not increase further in Abcb1a/b-/- mice. At 30 min after injection, the radiotracer was > 90% in its parent form and had highest uptake in organs of the hepatobiliary system. Compared with that in drug-sensitive tumors, uptake of [18F]AVT-011 was 32% lower in doxorubicin-resistant tumors with highest ABCB1 expression and increased by 40% with tariquidar administration. Tumor uptake of [18F]FDG did not significantly differ among groups.[18F]AVT-011 is a dual ABCB1/ABCG2 substrate radiotracer that can quantify transporter function at the blood-brain barrier and in ABCB1-expressing tumors, making it potentially suitable for clinical imaging of ABCB1-mediated MDR in tumors

Dynamic contrast-enhanced CT compared with positron emission tomography CT to characterise solitary pulmonary nodules: the SPUtNIk diagnostic accuracy study and economic modelling

BACKGROUND: Current pathways recommend positron emission tomography-computerised tomography for the characterisation of solitary pulmonary nodules. Dynamic contrast-enhanced computerised tomography may be a more cost-effective approach. OBJECTIVES: To determine the diagnostic performances of dynamic contrast-enhanced computerised tomography and positron emission tomography-computerised tomography in the NHS for solitary pulmonary nodules. Systematic reviews and a health economic evaluation contributed to the decision-analytic modelling to assess the likely costs and health outcomes resulting from incorporation of dynamic contrast-enhanced computerised tomography into management strategies. DESIGN: Multicentre comparative accuracy trial. SETTING: Secondary or tertiary outpatient settings at 16 hospitals in the UK. PARTICIPANTS: Participants with solitary pulmonary nodules of ≥ 8 mm and of ≤ 30 mm in size with no malignancy in the previous 2 years were included. INTERVENTIONS: Baseline positron emission tomography-computerised tomography and dynamic contrast-enhanced computer tomography with 2 years' follow-up. MAIN OUTCOME MEASURES: Primary outcome measures were sensitivity, specificity and diagnostic accuracy for positron emission tomography-computerised tomography and dynamic contrast-enhanced computerised tomography. Incremental cost-effectiveness ratios compared management strategies that used dynamic contrast-enhanced computerised tomography with management strategies that did not use dynamic contrast-enhanced computerised tomography. RESULTS: A total of 380 patients were recruited (median age 69 years). Of 312 patients with matched dynamic contrast-enhanced computer tomography and positron emission tomography-computerised tomography examinations, 191 (61%) were cancer patients. The sensitivity, specificity and diagnostic accuracy for positron emission tomography-computerised tomography and dynamic contrast-enhanced computer tomography were 72.8% (95% confidence interval 66.1% to 78.6%), 81.8% (95% confidence interval 74.0% to 87.7%), 76.3% (95% confidence interval 71.3% to 80.7%) and 95.3% (95% confidence interval 91.3% to 97.5%), 29.8% (95% confidence interval 22.3% to 38.4%) and 69.9% (95% confidence interval 64.6% to 74.7%), respectively. Exploratory modelling showed that maximum standardised uptake values had the best diagnostic accuracy, with an area under the curve of 0.87, which increased to 0.90 if combined with dynamic contrast-enhanced computerised tomography peak enhancement. The economic analysis showed that, over 24 months, dynamic contrast-enhanced computerised tomography was less costly (£3305, 95% confidence interval £2952 to £3746) than positron emission tomography-computerised tomography (£4013, 95% confidence interval £3673 to £4498) or a strategy combining the two tests (£4058, 95% confidence interval £3702 to £4547). Positron emission tomography-computerised tomography led to more patients with malignant nodules being correctly managed, 0.44 on average (95% confidence interval 0.39 to 0.49), compared with 0.40 (95% confidence interval 0.35 to 0.45); using both tests further increased this (0.47, 95% confidence interval 0.42 to 0.51). LIMITATIONS: The high prevalence of malignancy in nodules observed in this trial, compared with that observed in nodules identified within screening programmes, limits the generalisation of the current results to nodules identified by screening. CONCLUSIONS: Findings from this research indicate that positron emission tomography-computerised tomography is more accurate than dynamic contrast-enhanced computerised tomography for the characterisation of solitary pulmonary nodules. A combination of maximum standardised uptake value and peak enhancement had the highest accuracy with a small increase in costs. Findings from this research also indicate that a combined positron emission tomography-dynamic contrast-enhanced computerised tomography approach with a slightly higher willingness to pay to avoid missing small cancers or to avoid a 'watch and wait' policy may be an approach to consider. FUTURE WORK: Integration of the dynamic contrast-enhanced component into the positron emission tomography-computerised tomography examination and the feasibility of dynamic contrast-enhanced computerised tomography at lung screening for the characterisation of solitary pulmonary nodules should be explored, together with a lower radiation dose protocol

18FDG PET/CT in the qualitative and quantitative evaluation of the therapeutic response in Hodgkin’s lymphoma

info:eu-repo/semantics/publishedVersio

Defining the future of quantitative SPECT/CT

Single photon emission tomography computed tomography (SPECT/CT) imaging, with its innate ability to detect and characterise abnormalities in their earliest forms, can be a meaningful tool for determining prompt diagnoses and developing personalised treatment strategies. Such a tool is invaluable as we move towards precision medicine, and the significant addition of reliable quantitative measurements only enhances SPECT/CT’s opportunities. Quantitative SPECT/CT looks to establish an active role in the next era of healthcare, but the extent of its impact continues to be defined

Untersuchungen zur Moeglichkeit der Reduzierung von Fegedampfverlusten bei der thermischen Entgasung von Kesselspeisewasser Abschlussbericht

SIGLEAvailable from TIB Hannover: F02B585 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDeutsche Bundesstiftung Umwelt, Osnabrueck (Germany)DEGerman

Use of 18F-FDG-PET-CT in glioma surveillance: A single centre experience

INTRODUCTION Radiological surveillance in glioma surgery is primarily with MRI. Differentiating between disease progression and radionecrosis can be challenging. In our unit, in selected cases when there is suspicion of radiological recurrence, progression or to aid in differentiating progression from radionecrosis, we have augmented our surveillance with 18F-FDG-PET-CT which can highlight areas of metabolic activity which correlate with increased tumour activity. RESULTS We identified 19 cases of PET imaging for glioma surveillance of whom we could assess 17 notes and images. Mean age was 45.06 (30–67) with male: female ratio 9:8. 15 /17(88.2%) patients had surgery and 2 declined surgery(7 biopsy only, 8 debulk and 2 declined surgery). Initial histology was pilocytic astrocytoma (1), grade II (4, 26.7%), grade III (6, 40%), GBM (3) and non-specific tissue (1). 5 patients had evidence of increased uptake on PET and all showed clinical progression, with only 3 clinically fit for surgery (histology showed 2 recurrence, 1 transformation). 10 patients had no increased uptake on FDG with 4 on on-going surveillance for an average of 8.5 years (7–12), 2 clinically progressed at 2 and 8 years after initial presentation at the point of PET imaging and received palliative chemotherapy, 1 had concurrent inoperable lung cancer and was palliated, 1 patient had transformation from glioma grade II - III, 1 had grade 2 histology, and 1 had only gliotic tissue on re-operation CONCLUSIONS A positive FDG PET has a positive correlation with disease progression and may be considered as an adjunct test in glioma surveillance

Incidence of prediabetes and risk of developing cardiovascular disease in women with polycystic ovary syndrome

Our aim was to determine the incidence of prediabetes and risk of developing cardiovascular disease (CVD) in women with polycystic ovary syndrome (PCOS). This prospective, observational study included 148 women with PCOS, without Type 2 diabetes mellitus (T2DM) and CVD present at baseline. In the fasting blood samples, we measured lipids, glucose, and insulin levels during oral glucose tolerance test, levels of C-reactive protein (CRP), steroids, 25-hydroxyvitamin D (25-OHD), prolactin, thyroid-stimulating hormone, and parathyroid hormone. The follow-up period was 3 years. At baseline, prevalent prediabetes was present in 18 (12%) of PCOS cases and it progressed to T2DM in 5 (3%) of the cases. Incident prediabetes during the follow-up was noted in 47 (32%) women or 4.7 per 1000 persons/year. Prediabetes was associated with elevated body mass index (BMI) (odds ratio [OR] = 1.089, confidence interval [CI]: 1.010; 1.174, p = 0.026), high baseline levels of CRP (OR = 3.286, CI: 1.299; 8.312, p = 0.012), homeostatic model assessment - insulin resistance (IR) (OR = 2.628, CI: 1.535; 4.498, p < 0.001), and high lipid accumulation product (LAP) (OR = 1.009, CI: 1.003; 1.016, p = 0.005). Furthermore, prediabetes was associated with low 25-OHD (OR = 0.795, CI: 0.724; 0.880, p ≤ 0.05). In addition, cardiovascular risk in PCOS women with prediabetes was high (hazard ratio = 1.092, CI: 1.036; 1.128, p < 0.001). We showed association of prediabetes with high BMI, IR, markers of inflammation, LAP, and low serum 25-OHD concentration. IR appears to be more relevant than the other predictors of prediabetes risk in this study. PCOS women are considered as a high-risk population for prediabetes

Use of FDG PET/CT in identification of bone marrow involvement in diffuse large B cell lymphoma and follicular lymphoma: comparison with iliac crest bone marrow biopsy

Background: Non-Hodgkin's lymphoma (NHL) accounts for around 4% of new cancer cases annually. Bone marrow involvement is important for staging and management. Fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) is used increasingly to identify this, in addition to bone marrow biopsy (BMB), which is seen as "gold" reference standard. Purpose: To compare determination of bone marrow involvement by FDG PET/CT against BMB in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). Material and Methods: This was a retrospective study of patients with histologically confirmed NHL at a single UK cancer center undergoing pre-treatment FDG PET/CT and BMB between June 2010 and February 2013. Information was collected from patient notes, cancer registry, histological and imaging reports. Diagnostic accuracy of FDG PET/CT was determined, compared to BMB as the reference standard. Results: Twenty-four patients with DLBCL and 12 with FL were included. Five DLBCL patients had bone marrow involvement on PET/CT; all were confirmed on BMB. Three FL patients had marrow involvement on PET/CT but not on BMB; one FL patient had positive BMB but negative PET/CT. Using BMB as the reference standard, the sensitivity and specificity of FDG PET/CT for detecting bone marrow involvement in DLBCL were 100% and 100%, respectively, and in FL were 0% and 72.7%, respectively. Conclusion: FDG PET/CT is accurate for detection of bone marrow involvement in newly diagnosed DLBCL, but not FL. In DLBCL, positive FDG PET/CT may negate the need for routine BMB, although BMB in addition or combination may be appropriate if this would influence management or prognosis