37 research outputs found

    Iterative reconstruction incorporating background correction improves quantification of [18F]-NaF PET/CT images of patients with abdominal aortic aneurysm

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    Background A confounding issue in [18F]-NaF PET/CT imaging of abdominal aortic aneurysms (AAA) is the spill in contamination from the bone into the aneurysm. This study investigates and corrects for this spill in contamination using the background correction (BC) technique without the need to manually exclude the part of the AAA region close to the bone. Methods Seventy-two (72) datasets of patients with AAA were reconstructed with the standard ordered subset expectation maximization (OSEM) algorithm incorporating point spread function (PSF) modelling. The spill in effect in the aneurysm was investigated using two target regions of interest (ROIs): one covering the entire aneurysm (AAA), and the other covering the aneurysm but excluding the part close to the bone (AAAexc). ROI analysis was performed by comparing the maximum SUV in the target ROI (SUVmax(T)), the corrected cSUVmax (SUVmax(T) − SUVmean(B)) and the target-to-blood ratio (TBR = SUVmax(T)/SUVmean(B)) with respect to the mean SUV in the right atrium region. Results There is a statistically significant higher [18F]-NaF uptake in the aneurysm than normal aorta and this is not correlated with the aneurysm size. There is also a significant difference in aneurysm uptake for OSEM and OSEM + PSF (but not OSEM + PSF + BC) when quantifying with AAA and AAAexc due to the spill in from the bone. This spill in effect depends on proximity of the aneurysms to the bone as close aneurysms suffer more from spill in than farther ones. Conclusion The background correction (OSEM + PSF + BC) technique provided more robust AAA quantitative assessments regardless of the AAA ROI delineation method, and thus it can be considered as an effective spill in correction method for [18F]-NaF AAA studies

    The Impact of Mobile Phone Penetration on African Inequality

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    The aim of this paper is to complement theoretical and qualitative literature with empirical evidence on the income-redistributive effect of mobile phone penetration in 52 African countries. It deviates from mainstream country-specific and microeconomic survey-based approaches in the literature and provides the first macroeconomic assessment of the ‘mobile phone’-inequality nexus. The findings suggest that mobile penetration is pro-poor, as it has a positive income equality effect. ‘Mobile phone’-oriented poverty reduction channels are discussed

    Orlistat vs Placebo in the Inhibition of Dietary Fat in Obese Adult Nigerian Volunteers

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    Objective: To compare the efficacy and safety of orlistat (120mg tid) versus placebo in the inhibition of dietary fat absorption in healthy adult Nigerian volunteers. Method: This was a double blind randomised cross-over study, with each arm of the cross-over lasting 4 weeks with a one week placebo run-in period before and in-between treatment. Four males and 16 females, with a mean BMI of 35.1 and a mean age of 40.08 years, participated in the study. Prior to allocation to treatment, subjects were given placebo for a 7-day period, while receiving a moderate hypocaloric supporting diet as prescribed for each individual by the dietician. During this period, a 72-hour faeces was collected from each subject for estimation of baseline faecal fat excretion. Additionally blood and urine samples were collected for evaluation of plasma lipid profile, haemogram, blood chemistry and urinalysis. Subjects were assigned to treatment according to their enrolment number i. e. subject no. 1 received treatment labelled DBN 1. Each subject was given a weekly pack of medication as specified in the label. The subjects took one capsule three times a day with the prescribed diet. At the end of each week of treatment, subjects were required to submit 24-hr faeces for faecal fat estimation. Blood samples were collected at week 5 and week 10 for haematological profile, lipid profile, blood chemistry and liver function tests. At each weekly clinical visit, subjects were questioned closely on the incidence of any adverse event, they also discussed their diet with the dietician. At the end of the study the emergency code envelopes were opened and the subjects were assigned into groups according to the treatment sequence, the sequence Placebo/ Orlistat were assigned group 1 and Orlistat/ Placebo group 2. Results: The difference in faecal fat excretion with orlistat compared to placebo was significant (
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