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Background: 18F-fluorodeoxyglucose positron-emitted tomography (FDG-PET) is a promising yet unexplored functional neuroimaging tool in the study and prognosis of hypoxic-ischemic encephalopathy (HIE) after cardiac arrest or respiratory failure. The present study aimed to correlate clinical data and FDG-PET scans for both analysis and prognostic use. Methods: 24 patients from an intensive rehabilitation ward were retrospectively evaluated. Data collected included age, gender, cause of anoxic event, length of stay in acute and rehabilitation units, discharge destination, and evaluation at admission and discharge using three clinical scales to assess cognitive function, independence and disability. Subjects were identified as good and bad performers on the basis of quantitative analysis of FDG-PET scans with the Cortex ID software. The relation between glucose uptake reduction and neurological outcome was evaluated. Results: good and bad performers presented no statistically significant difference regarding demographical data and in-hospital length of stay. The two categories significantly differed for impairment and disability levels both at admission and at discharge from the inpatient rehabilitation unit. Conclusions: FDG-PET considerably facilitates the early identification of patients with HIE who will have poor neurological outcome and could inform planning for their rehabilitation and care.

Advances in resuscitation techniques have resulted in more patients surviving cardio-circulatory arrest (CA) and consequently developing hypoxic/anoxic brain damage. The aim of this study is to evaluate the role of PET/CT (Positron Emission Tomography/Computerized Tomography scan) with F-18 FDG (F-18 fluorodeoxyglucose) during the early rehabilitative hospitalization phase in determining the V/C (Vermis/Cerebellar) ratio as a prognostic index to predict patient outcome, as defined by clinical evaluation scales.This is a single-center retrospective study of 37 consecutive adult patients admitted to the neurorehabilitation center between January 2011 and June 2019. Functional status was measured by the following clinical scales: FIM (Functional Indipendence Measure), LCFS (Levels of Cognitive Functioning Scale), GOS (Glasgow Outcome Scale) and CRS-R (Coma Recovery Scale-Revised). PET/CT with F-18 FDG as a functional imaging technique was used to calculate the V/C ratio as a ratio between the metabolism of the vermis and of the Cerebellar Hemisphere.A statistically significant correlation was observed between the V/C ratio and the delta values (difference between discharge and admission value) for each clinical evaluation scale (Delta FIM: P=0.0014; Delta LCFS P=0.0003). A statistically significant difference was observed between the V/C ratio of patients with LCFS ≥4 that showed an improved outcome (defined as an improvement of at least two points in LCFS), and that of patients with LCFS4 that did not improve (P=0.0011). A V/C ratio cut-off of 1.5 corresponded with a positive predictive power of 80% and a negative predictive power of 82%; a value1.5 predicted a better outcome.Clinical evaluation scales when associated with F-18 FDG PET/CT measurement of metabolism, provide a more reliable prognosis. This allows for more focused rehabilitation treatment and better management of family members' expectation.

We describe the first case report of pathology-proven brain infection by Mycobacterium chimaera (MC). A 35-year-old male, previously operated in 2010 of aortic valve and ascending aortic replacement, was addressed to our hospital for the acute onset of aphasia preceded by absence. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed multiple left frontal and temporal cortical-subcortical lesions. During hospitalization the patient never presented fever and cerebrospinal fluid (CSF), PCR, FilmArray and blood tests were within normal ranges. Transesophageal echocardiography showed no cardiac abnormalities. A thorax-abdomen CT scan was performed, revealing no extracranial abnormalities, and a whole body PET-CT scan showed a high uptake of brain lesions. Considering clinical results and the suspect of a tumoural lesion, the patient underwent surgery, where a left frontal enhanced nodular lesion was removed. Pathology finally revealed it was an abscess caused by Mycobacterium chimaera. This case confirms that Mycobacterium chimaera infection spread can be very subtle and diagnosis a real challenge, particularly years after surgery. We would like to underline the importance of suspecting an atypical infection source related to a history of cardiothoracic surgery, given a non-specific MR pattern and subtle clinical and laboratory findings.

Introduction: Medium cutoff (MCO) membranes represent an interesting innovation in the field of hemodialysis. Given the correlation between large (PM >25 kDa) middle molecules (LMM) and clinical outcomes, the possibility to broaden the spectrum of solutes removed in hemodialysis with MCO membranes introduces a new perspective for end-stage kidney disease patients. Due to low diffusion coefficients of LMM, the use of convection is required to maximize extracorporeal clearance. High convective rates are achieved with high-flux membranes in hemodiafiltration, a technique not available in the US. In case of the MCO membrane, remarkable clearances of LMM are achieved combining the permeability of the membrane with a significant amount of internal convection. The mechanism of filtration-backfiltration inside the dialyzer enables effective removal of LMM in a technique called expanded hemodialysis (HDx). Given such theoretical explanation, it is important to demonstrate the blood and ultrafiltration rheology inside the MCO dialyzer. Method: This study for the first time describes flow dynamic parameters and internal cross-filtration, thanks to specific radiology and nuclear imaging techniques. Results: Flow dynamic analysis of the blood and dialysate compartment confirms excellent distribution of velocities and an excellent matching of blood and dialysate. Average blood flow velocity allows for wall shear rates adequate to avoid protein stagnation at the blood membrane interface and increase in blood viscosity. Cross-filtration analysis demonstrates a remarkable filtration/backfiltration flux reaching values >30 mL/min at a blood flow of 300 mL/min and zero net filtration. Conclusion: The MCO dialyzer Theranova 400 appears to have a design optimized to perform expanded hemodialysis (HDx).

Purpose To assess the presence and pattern of incidental interstitial lung alterations suspicious of COVID-19 on fluorine-18-fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT) ([18F]FDG PET/CT) in asymptomatic oncological patients during the period of active COVID-19 in a country with high prevalence of the virus. Methods This is a multi-center retrospective observational study involving 59 Italian centers. We retrospectively reviewed the prevalence of interstitial pneumonia detected during the COVID period (between March 16 and 27, 2020) and compared to a pre-COVID period (January–February 2020) and a control time (in 2019). The diagnosis of interstitial pneumonia was done considering lung alterations of CT of PET. Results Overall, [18F]FDG PET/CT was performed on 4008 patients in the COVID period, 19,267 in the pre-COVID period, and 5513 in the control period. The rate of interstitial pneumonia suspicious for COVID-19 was significantly higher during the COVID period (7.1%) compared with that found in the pre-COVID (5.35%) and control periods (5.15%) (p

Spontaneous visual recovery is rare after cortical blindness. While visual rehabilitation may improve performance, no visual therapy has been widely adopted, as clinical outcomes are variable and rarely translate into improvements in activities of daily living (ADLs). We explored the potential value of a novel rehabilitation approach "cognitive therapeutic exercises" for cortical blindness.The subject of this case study was 48-year-old woman with cortical blindness and tetraplegia after cardiac arrest. Prior to the intervention, she was dependent in ADLs and poorly distinguished shapes and colors after 19 months of standard visual and motor rehabilitation. Computed tomographic images soon after symptom onset demonstrated acute infarcts in both occipital cortices.The subject underwent 8 months of intensive rehabilitation with "cognitive therapeutic exercises" consisting of discrimination exercises correlating sensory and visual information.Visual fields increased; object recognition improved; it became possible to watch television; voluntary arm movements improved in accuracy and smoothness; walking improved; and ADL independence and self-reliance increased. Subtraction of neuroimaging acquired before and after rehabilitation showed that focal glucose metabolism increases bilaterally in the occipital poles.This study demonstrates feasibility of "cognitive therapeutic exercises" in an individual with cortical blindness, who experienced impressive visual and sensorimotor recovery, with marked ADL improvement, more than 2 years after ischemic cortical damage.Video Abstract available for additional insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A173).

Background: Inadequate removal of molecules between 5 and 50 KDa may cause long-term complication in chronic hemodialysis. Medium cut-off (MCO) is a new class of membranes with enhanced sieving properties and negligible albumin loss. MCO membrane makes it possible to perform expanded hemodialysis (HDx), a technique based on high internal filtration (IF).The present study is designed to quantify IF in 2 MCO dialyzers (Theranova 400 and 500, Baxter, Deerfield, USA) using a nuclear imaging technique previously validated. Methods: Blood and dialysate compartment pressure drop along with transmembrane pressure; they were measured in a closed in vitro circuit with human blood (blood flow [QB] = 300 and 400 mL/min; dialysate flow 500 mL/min; net ultrafiltration rate 0 mL/min). A non-diffusible marker molecule (albumin macro-aggregates labeled with 99Tc metastable) was injected in the blood compartment and nuclear emission was recorded by a gamma camera. Relative variations in the concentration of the marker molecule along the length of the filter were used to calculate local cross filtration. Results: Based on marker concentration profiles, IF was estimated. For Theranova 400, IF were 29.7 and 41.6 mL/min for QB of 300 and 400 mL/min. For Theranova 500, IF were 31.6 and 53.1 mL/min for QB of 300 and 400 mL/min respectively. Conclusions: MCO membrane provides significant amounts of IF due to the particular combination between hydraulic permeability of the membrane and reduced inner diameter of the fibers. High IF combined with enhanced sieving profile of MCO membrane leads to improved removal of a wider spectrum of uremia retention molecules in HDx, without requiring complex equipment.

A fully automatic phenology-based synthesis (PBS) classification algorithm was developed to map land cover based on medium spatial resolution satellite data using the Google Earth Engine cloud computing platform. Vegetation seasonality, particularly in the tropical dry regions, can lead conventional algorithms based on a single date image classification to “misclassify” land cover types, as the selected date might reflect only a particular stage of the natural phenological cycle. The PBS classifier operates with occurrence rules applied to a selection of single date image classifications of the study area to assign the most appropriate land cover class. Since the launch of Landsat 8 in 2013, it has been possible to acquire imagery at any point on the Earth every 16 days with exceptional radiometric quality. The relatively high global acquisition frequency and the open data policy allow near-real-time land cover mapping and monitoring with automated tools such as the PBS classifier. We mapped four protected areas and their 20-km buffer zones from different ecoregions in Sub-Saharan Africa using the PBS classifier to present its first results. Accuracy assessment was carried out through a visual interpretation of very high resolution images using a Web geographic information system interface. The combined overall accuracy was over 90%, which demonstrates the potential of the classifier and the power of cloud computing in geospatial sciences.

Purpose: Both, the constant presence of apparent hypermetabolism of the vermis cerebelli compared to the cerebellar hemispheres in traumatic brain injury, and the presence of a good relationship between the intensity of this sign and the severity of the clinical conditions have been addressed in previous studies. Aim of the present paper is to evaluate the possible correlation between the intensity of the finding and the medium and long term outcome in a group of patients. Materials and Methods: A group of 105 patients consecutively admitted to the Brain Injury Rehabilitation Center of our Hospital between 2005 and 2012 was studied with a 18FDG-PET/CT study of the brain after head trauma; the metabolic activity of the cerebellar vermis was semiquantitatively assessed (vermis/cerebellum ratio, V/C). After that, all patients received systematic monitoring of their performance status via the timely administration of commonly used tests (DRS, LCF and GOS) during one whole year after the head trauma. The V/C parameter was compared with the evolution of performance abilities, as shown by the rating scales. Results: Statistical analysis showed a significant direct association between the V/C ratio and the DRS score at each time point (3 months: P

The East Africa IGAD (Intergovernmental Authority on Development in Eastern Africa) region with its great variety of ecological regions experienced major changes during the last decades. This study assesses and quantifies the land cover dynamics in the region by applying a systematic sampling of medium resolution Landsat and DMC Deimos imagery. 445 samples covering about 3% of the study area taken as a box of 20 km × 20 km around each 1 degree latitude and longitude intersects are processed and analyzed. Statistical estimates of land cover change are produced by means of an automatic object-based classification in seven broad classes for the years 1990–2000 and 2000–2010. Figures of change for the East Africa IGAD region are presented and land cover change processes such as loss of natural vegetation and increase of agriculture areas are analyzed. Results highlight the geographical distribution of land cover dynamics and show a 28% increase in agriculture area over the analyzed 20-year time frame. The yearly agriculture area increase rate is around 1.4% for both assessed decades, however a strong increase in yearly deforestation rate – from 0.2% in the first period to 0.4% in the second period – has been observed. These figures are discussed within the context of the drivers of changes and the resulting impact to the natural ecosystem.

Aim This study provides regional estimates of forest cover in dry African ecoregions and the changes in forest cover that occurred there between 1990 and 2000, using a systematic sample of medium-resolution satellite imagery which was processed consistently across the continent. Location The study area corresponds to the dry forests and woodlands of Africa between the humid forests and the semi-arid regions. This area covers the Sudanian and Zambezian ecoregions. Methods A systematic sample of 1600 Landsat satellite imagery subsets, each 20 km × 20 km in size, were analysed for two reference years: 1990 and 2000. At each sample site and for both years, dense tree cover, open tree cover, other wooded land and other vegetation cover were identified from the analysis of satellite imagery, which comprised multidate segmentation and automatic classification steps followed by visual control by national forestry experts. Results Land cover and land-cover changes were estimated at continental and ecoregion scales and compared with existing pan-continental, regional and local studies. The overall accuracy of our land-cover maps was estimated at 87%. Between 1990 and 2000, 3.3 million hectares (Mha) of dense tree cover, 5.8 Mha of open tree cover and 8.9 Mha of other wooded land were lost, with a further 3.9 Mha degraded from dense to open tree cover. These results are substantially lower than the 34 Mha of forest loss reported in the FAO's 2010 Global Forest Resources Assessment for the same period and area. Main conclusions Our method generates the first consistent and robust estimates of forest cover and change in dry Africa with known statistical precision at continental and ecoregion scales. These results reduce the uncertainty regarding vegetation cover and its dynamics in these previously poorly studied ecosystems and provide crucial information for both science and environmental policies.

Acute ingestion of MDMA (ecstasy) causes a transient marked increase in serotonin and dopamine at central synapses. Recent studies demonstrated that MDMA induces damage of serotonergic nerve terminals and alters hippocampal processing. Pronounced cognitive deficits in MDMA users affect learning and memory abilities. This pattern of predominant and long-lasting memory dysfunction suggests that the functioning of the hippocampus might be affected by the neurotoxic effects of MDMA. We present the case of a 16-year-old girl who developed an acute organic and psychotic syndrome caused by occasional use of low to moderate dose of MDMA. Serial neuroimaging ((18)F-FDG-PET and brain MRI) were correlated with her neurocognitive performance and clinical evolution. The structural and metabolic changes correlated with a severe cognitive impairment. After 16 months of intensive neuropsychological rehabilitation she showed significant improvement in hippocampal-related memory cognitive functions, which correlated with normalization of her (18)F-FDG-PET and remarkable hippocampal remodelling. This case report indicates that even non-chronic MDMA use may cause subacute toxic encephalopathy in which the clinical evolution is paralleled by neuroimaging changes in specific cerebral areas. The most relevant aspect is the reversibility of the volumetric changes, which may be the structural correlate of an ongoing hippocampal remodelling.

On October 2004, a sampling survey was carried out in Florence to estimate urban fine particle exposure concentrations inside commuting vehicles during workdays characterized by heavy traffic. Portable samplers were positioned inside four regularly scheduled diesel-powered buses and four taxis during eight weekdays. Each sampler consisted of a 2.5 μm size pre-separator cyclone, a direct-reading data logging photometer (pDR-1200), and a 4 L min−1 filter sampler for the determination of PM2.5 mass concentration. Based on reflectance analysis measurements, a PM2.5 Black Smoke Index was determined for each filter, and the elemental composition of the PM2.5 was analyzed by Particle Induced X-ray Emission (PIXE). PM2.5 mass concentrations inside the vehicles correlated well with the urban ambient air PM2.5 concentrations measured at the fixed-site monitoring stations. The PM2.5 excess above the urban ambient level was on average 32 μg m−3 (range: 22–52 μg m−3) and 20 μg m−3 (range: 11–29 μg m−3) in buses and taxis, respectively. The PM2.5-bound sulfur concentration was also higher in the buses than in the taxis. Based on daily Time-Microenvironment-Activity-Diary (TMAD) data, the Florentines spend on average 9.7% of their day in traffic, and the corresponding average exposure is approximately 12% of their daily PM2.5 personal exposure. The obtained data could be used to plan interventions to minimize the PM2.5 citizen exposures in commuting., This work is a part of the EU 5-FP funded and WHO/ECEH coordinated HEARTS-project.

Background. Hemodialysis using high flux membranes today is a commonly used therapy. The primary advantage is the larger spectrum of molecules removed with these membranes, and the mechanism of removal is in part due to a phenomenon of filtration and backfiltration along the length of the hollow fibers. We hypothesized that increasing the filtration and backfiltration fluxes by modifying the structure of the dialyzer could enhance the convective transport of various solutes. Methods. A modified high flux dialyzer was compared to the standard model in terms of pressure profiles, filtration-backfiltration rates and solute clearances. The modification consisted on the placement of a O-ring around the fiber bundle to create a resistance for the flow of the dialysis solution external to the fibers. The study on filtration fluxes was carried out using a scintigraphic method previously described, and solute clearances were studied during ultrafiltration-controlled hemodialysis sessions. Results. Utilizing a net filtration condition proximal to zero, the rates of proximal filtration and distal backfiltration in the experimental dialyzer were significantly enhanced in comparison with the standard dialyzer. The pressure drop in the dialysate compartment could be increased significantly, thus permitting an increase in the positive transmembrane pressure in the first half of the dialyzer and a parallel increase in the negative transmembrane pressure in the second half of the dialyzer. This resulted in a significant enhancement of the convective transport of middlelarge solutes as demonstrated by the increase in vitamin B12 and inulin clearances. Conclusions. This approach suggests that changes in design of the dialyzer may affect its performance. The use of internal filtration is suggested to improve convection and dialyzer efficiency for larger solutes without the requirement for high volumes of replacement fluid, as is the case for current hemodiafiltration techniques.

This paper presents a map of Africa's rainforests for 2005. Derived from moderate resolution imaging spectroradiometer data at a spatial resolution of 250 m and with an overall accuracy of 84%, this map provides new levels of spatial and thematic detail. The map is accompanied by measurements of deforestation between 1990, 2000 and 2010 for West Africa, Central Africa and Madagascar derived from a systematic sample of Landsat images—imagery from equivalent platforms is used to fill gaps in the Landsat record. Net deforestation is estimated at 0.28% yr −1 for the period 1990–2000 and 0.14% yr −1 for the period 2000–2010. West Africa and Madagascar exhibit a much higher deforestation rate than the Congo Basin, for example, three times higher for West Africa and nine times higher for Madagascar. Analysis of variance over the Congo Basin is then used to show that expanding agriculture and increasing fuelwood demands are key drivers of deforestation in the region, whereas well-controlled timber exploitation programmes have little or no direct influence on forest-cover reduction at present. Rural and urban population concentrations and fluxes are also identified as strong underlying causes of deforestation in this study.

Monitoring vegetation dynamics and land cover change in Kenya are essential for the sustainable management of natural resources and biodiversity conservation. However, accurate status of seasonal variation in vegetation and long-term land cover change data valid at the regional and country level generally do not exist or are hard to obtain. Here, we describe the various ecological regions of Kenya and the associated rainfall and land cover patterns of each ecological zone. This includes the use of low-resolution satellite data time series to characterise for each ecoregion and land cover type the interannual variability of the vegetation cycle, including the start-, mid- and end of the growing season. Seasonal variation in vegetation phenology is mapped to highlight the areas of greatest interannual variation and compared to rainfall patterns over the focal study period. Statistical estimates of land cover change are produced for six broad classes for the years 1990, 2000 and 2010, based on detailed land cover change assessed by a systematic sampling of high-resolution satellite imagery. Rates of change for Kenya are presented and discussed in light of the low-resolution time series analysis. Results highlight information on land cover change processes such as vegetation dynamics and deforestation. These are discussed within the context of the drivers of changes to the natural ecosystem—their potential impact on land availability for human activities such as agriculture and logging for timber and fire wood production on the one side and habitat and biodiversity conservation on the other side. Finally, biodiversity and habitat value, ecosystems and threats are analysed for Kenya’s conservation and protected areas so as to identify the status of and pressures on the country’s protected areas. Six indicators of species irreplaceability, habitat irreplaceability and the level of perceived threat to a protected area’s habitat and species from agriculture and human population are analysed. In addition, high-resolution satellite images taken over conservation areas are used for assessing land cover changes inside protected areas and in the surrounding 20 km buffer zone. The results show the importance and effectiveness of protected areas in reducing the loss of natural vegetation and hence protecting the habitats and biodiversity.

Assessing the status and monitoring the trends of land cover dynamics in and around protected areas is of utmost importance for park managers and decision makers. Moreover, to support the Convention on Biological Diversity (CBD)’s Strategic Action Plan including the Aichi Biodiversity Targets, such efforts are necessary to set a framework to reach the agreed national, regional or global targets. The integration of land use/cover change (LULCC) data with information on habitats and population density provides the means to assess potential degradation and disturbance resulting from anthropogenic activities such as agriculture and urban area expansion. This study assesses the LULCC over a 20 year (1990–2000–2010) period using freely available Landsat imagery and a dedicated method and toolbox for the Udzungwa Mountains National Park (UMNP) and its surroundings (20 km buffer) in Tanzania. Habitat data gathered from the Digital Observatory for Protected Areas (DOPA)’s eHabitat+ Web service were used to perform ecological stratification of the study area and to develop similarity maps of the potential presence of comparable habitat types outside the protected area. Finally, integration of the habitat similarity maps with the LULCC data was applied in order to evaluate potential pressures on the different habitats within the national park and on the linking corridors between UMNP and other protected areas in the context of wildlife movement and migration. The results show that the UMNP has not suffered from relevant human activities during the study period. The natural vegetation area has remained stable around 1780 km2. In the surrounding 20 km buffer area and the connecting corridors, however, the anthropogenic impact has been strong. Artificially built up areas increased by 14.24% over the last 20 years and the agriculture area increased from 11% in 1990 to 30% in the year 2010. The habitat functional types and the similarity maps confirmed the importance of the buffer zone and the connecting corridors for wildlife movements, while the similarity maps detected other potential corridors for wildlife.

Mutations within Presenilin 1 (PSEN1) represent the most common cause of monogenic Alzheimer Disease (AD). The clinical phenotype is highly variable, even if early onset disease with an autosomal dominant pattern of inheritance and presenting memory deficits usually occur. In the present work, we described the case of a late-onset AD patient, without any positive family history for dementia, and associated with seizures and behavioural symptoms. Structural and functional neuroimaging showed frontotemporal changes without posterior biparietal brain abnormalities. Cerebrospinal analysis was consistent with AD pattern, with decreased Aβ42 and increased Tau and phospho-Tau. A novel pathogenetic mutation within PSEN1 gene was detected within exon 8, leading to a substitution from arginine to tryptophan (AGG > TGG: R377W), affecting a splice junction and protein function. The case herein reported further confirms the heterogeneity of PSEN1 mutations and the need to take into account genetic screening in those cases with atypical presentation.

We describe a patient with persistent hyperthyroidism after total thyroidectomy for toxic multinodular goiter and without therapy with levothyroxine evaluated with I-131 whole-body scan and with F-18 FDG PET/CT scan. Scintigraphy performed 48 hours after radiopharmaceutical administration showed many areas of focal radioiodine uptake. A week later we performed a PET/CT scan to better localize the anatomic site of the iodine-positive lesions. Both scans, performed after methimazole withdrawal, visualized the same lesions, and these results were used as a guide for biopsy. Histologic examination was consistent with metastatic follicular thyroid carcinoma.

Respiratory gated PET/CT (positron emission tomography/computed tomography) of the lung is expected to increase the accuracy of quantitative determinations in lesional activities, regardless of the gating method used; reasonably, respiratory gating should increase standard uptake value (SUV; and possibly decrease lesional size), on the basis of the reduction of the "smearing effect." However, literature data are very limited, particularly for in vivo studies. The objective of this article is to test the SUV variations in a large group of lung lesion studies.A group of 26 consecutive positive studies (21 men, 5 women, age 36-84, mean 68), performed on patients referred to our institution for known or suspected lung cancer, are examined. All studies were performed both with conventional PET/CT total body scan and with Real-Time Position Management (RPM) triggered selective gated study of the thorax. Four studies were considered technically unsatisfactory and were discarded; the remaining 22 studies are the object of this work. Max lesional SUVs were evaluated in both settings by semi-automated algorithms; for the gated studies, both values of the bin that showed more relevant variations from the clinical routinary study ("best bin") and an average value that was calculated over all bins were determined. Results were compared on a one-to-one basis.In conventional, SUV showed a mean +/- standard deviation (SD) value of 9.2 +/- 6.9 (range 0.9-26). In the averaged gated studies, the mean +/- SD value was 13.4 +/- 11.7 (range 1.4-47); in the "best bin" dataset the mean +/- SD was 14.9 +/- 12.9, ranging from 1.6 to 53.1. In general, the use of respiratory trigger induced rather variable but overall consistent increases in SUV. If the percentage variations in the average trigger dataset are considered, there is an average increase of +60%, SD +/- 97 (P0.05). Similar results are found in the "best bin" dataset, the average percentage increase in SUV values being +77.2% (SD +/- 04.6).In lung cancer, triggering procedures increase the signal to noise ratio. The increase in SUV determined by gating is very variable, but generally relevant. This could lead to an SUV values cut-off revision, and may have an impact on smaller lesions detection.

The potential of convective solute transport for blood purification has been widely explored. New techniques (such as hemodiafiltration), based on a combination of diffusion and convection techniques, have been developed. Owing to the internal filtration/backfiltration (IF/BF) phenomenon, high-flux dialysis also relies on a convective component, which, however, is hard to quantify and thus optimize. In this work, we developed a mathematical model designed to supply the clinician with a quantification of the IF/BF fluxes taking place during high-flux dialysis. IF fluxes are predicted based on the machine settings and blood hematocrit/protein concentration. The hydraulic characteristics of commercial dialyzers were derived from bloodless bench tests. Moreover, an in vitro blood test was conducted on a 1.8 m2 polysulfone dialyzer using an established scintigraphic analysis, for verification of model prediction accuracy. Results of simulations show that the IF/BF rate is sensitive to the blood flow rate and (to a lesser extent) to the dialysate flow rate. Increasing net ultrafiltration rates resulted in parallel increases of direct filtration and simultaneous decreases of BF. IF/BF is rather influenced by blood composition, due to the complex dependence of oncotic pressure and blood viscosity upon hematocrit and plasma protein concentration. Simulation results showed an excellent agreement with the experimental results obtained with scintigraphy, with only a 3% prediction error. With respect to some previous works, this model is simpler in its theoretical approach. It allows implementation into a user-friendly software tool and might be used to predict the convective component in high-flux dialysis and possibly to optimize it.

Effects of a reduced inner diameter of hollow fibers in hemodia- crease of the blood compartment resistance. In turn, this results lyzers. in increased rates of internal filtration and backfiltration. The Background. The clearance of middle molecules in high-flux practical effect in clinical dialysis is demonstrated on middle hemodialyzers is due to the higher contribution of convection in molecules. While, in fact, the clearances for small solutes such the overall solute transport. Although net filtration can be maintained low by the machine control, internal filtration in as urea and creatinine are not affected, the clearances of larger the proximal part of the dialyzer remains high. The final fluid solutes such as vitamin B12 or inulin increase significantly balance is achieved by significant amounts of backfiltration (P , 0.01). in the distal part of the dialyzer. To increase further middle molecule clearance (MMK), hemodiafiltration has been used. This technique, however, requires complex machines and large Several lines of evidence demonstrate the importance amounts of substitution fluid. We present a novel solution to increase the convective transport of middle molecules in high of middle molecule removal in hemodialysis (1). The flux dialyzers without the need for substitution fluids. In partic- use of high-flux membranes and the increased use of ular, high-flux dialyzers with a reduced hollow fiber diameter convective techniques have permitted improvements in are compared with standard dialyzers in terms of internal fil- the efficiency of hemodialysis, leading to better removal tration and solute clearances. of solutes in the middle molecular weight range (2, 3). Methods. Hemodialyzers with 175 m inner diameter polysul- fone fibers were compared with standard 200 m polysulfone The improvement achieved with synthetic membranes hollow fiber dialyzers. The study was carried out in vitro using is mainly due to their higher hydraulic permeability and a previously published method to measure internal filtration their increased sieving capacity compared with classic and backfiltration rates. The method is based on the detection cellulose membranes. These properties result in higher by a g camera of segmental variations in concentration along middle molecule clearance. This clearance improvement the length of the dialyzer of a nondiffusable Tc99-labeled marker molecule injected in the blood in vitro circuit. At the is due to larger amounts of ultrafiltration per treatment same time, pressures were detected in the blood and dialysate and a more important contribution of convection to the compartment. The system was operated at zero net filtration overall transport process (4). maintaining volumetrically constant both dialysate and blood Synthetic high-flux membranes are used both in Eu- circuits. In vivo clearances were also measured for solutes with rope and the United States, with different modes of different molecular weight. Results. The pressure drop in the blood compartment at 300 application (5, 6). In Europe, high-flux dialysis and hemo- mL/min of blood flow passed from 112 to 159 mm Hg. At diafiltration (HFD and HDF) are used as treatment mo- the same blood flow, the internal filtration-backfiltration rates dalities for chronic renal failure. Conventional HDF uses increased from 23.1 to 48.2 mL/min. This resulted in a signifi- large convective transport with ultrafiltration rates of cant increase of in vivo in clearances of vitamin B12 and inulin of more than 30%. Urea, creatinine, and phosphate clearance more than 70 mL/min. Since the ultrafiltration rate ex- did not display any change. ceeds the rate of desired weight loss in the patient, sterile Conclusions. A reduction of the inner diameter of the hol- replacement fluid must be administered. Net ultrafiltra- tion rate in the patient will be equal to the difference between total ultrafiltration rate and reinfusion rate. To

Clotting of the filters in continuous arteriovenous hemofiltration (CAVH) has been frequently related to filtration pressure equilibrium (FPE). The geometry of the filter and the blood flow, together with filtration fraction, are the factors affecting FPE. A new method based on scintigraphic imaging of the filter is described to demonstrate FPE and identify the operational conditions influencing it. A radiolabelled marker molecule (albumin macroaggregates + Tc99) is added to the blood circulating at various flows through the filter. Changes in the concentration of this molecule detected by a gamma camera are used to calculate the water fluxes in different sections of the filter. When the curve reaches a plateau, no further changes occur and FPE is achieved. The study used Amicon D-30 hemofilters and FPE points were achieved for blood flows of 75, 110 and 150 ml/min respectively 8 cm, 12 cm and 18 cm from the inlet. The study not only demonstrates the occurrence of FPE, but also identifies the length of the filter required at a given blood flow to avoid FPE (achieving less clotting and lower heparin requirement). The Amicon diafilter family, having filters of different length, is useful for “personalizing” the filter in CAVH.