Over-utilization of Advanced Imaging in the Hospital Setting: An Educational Approach to Reduce Unnecessary Inpatient Studies

By several measures, health care spending continues to rise, forcing businesses and families to cut back on operations and household expenses. In 2008, health care spending in the United States reached $2.4 trillion dollars, and is projected to reach$3.1 trillion in 2012.During the past decades, there has been a steady increase in the utilization of expensive inpatient imaging studies, with an overall increase in health care costs. In particular, advanced imaging includes CT, MRI and Nuclear Medicine, used for the diagnosis and management of hospitalized patients. The reasons for unnecessary imaging examinations include indirect financial benefit to physicians, medico-legal considerations, lack of accepted guidelines or failure to follow established ones. In the United States alone, it is estimated that CT testing accounts for around 6,000 additional cancers per year, with about half of those proving fatal. Each radiologic study using gadolinium presented a 2.4% risk of developing nephrogenic systemic fibrosis, with significant morbidity and mortality. We have shown that education of the ordering physicians is a feasible and cost effective means to decrease the over-otilization of advanced imaging in the inpatient setting

Added Value of Tomoelastography for Characterization of Pancreatic Neuroendocrine Tumor Aggressiveness Based on Stiffness

Simple Summary: The prediction of pancreatic neuroendocrine tumor (PNET) aggressiveness is important for treatment planning. The aim of this study was to evaluate the diagnostic performance of magnetic resonance elastography (MRE) with tomoelastography postprocessing (tomoelastography) in differentiating PNET from healthy pancreatic tissue and to correlate PNET stiffness with aggressiveness using asphericity derived from positron emission tomography (PET) as reference. In this prospective study we showed in a group of 13 patients with PNET that tomoelastography detected PNET by increased stiffness (p < 0.01) with a high diagnostic performance (AUC = 0.96). PNET was positively correlated with PET derived asphericity (r = 0.81). Tomoelastography provides quantitative imaging markers for the detection of PNET and the prediction of greater tumor aggressiveness by increased stiffness. Abstract: Purpose: To evaluate the diagnostic performance of tomoelastography in differentiating pancreatic neuroendocrine tumors (PNETs) from healthy pancreatic tissue and to assess the prediction of tumor aggressiveness by correlating PNET stiffness with PET derived asphericity. Methods: 13 patients with PNET were prospectively compared to 13 age-/sex-matched heathy volunteers (CTR). Multifrequency MR elastography was combined with tomoelastography-postprocessing to provide high-resolution maps of shear wave speed (SWS in m/s). SWS of pancreatic neuroendocrine tumor (PNET-T) were compared with nontumorous pancreatic tissue in patients with PNET (PNET-NT) and heathy pancreatic tissue (CTR). The diagnostic performance of tomoelastography was evaluated by ROC-AUC analysis. PNET-SWS correlations were calculated with Pearson’s r. Results: SWS was higher in PNET-T (2.02 ± 0.61 m/s) compared to PNET-NT (1.31 ± 0.18 m/s, p < 0.01) and CTR (1.26 ± 0.09 m/s, p < 0.01). An SWS-cutoff of 1.46 m/s distinguished PNET-T from PNET-NT (AUC = 0.89; sensitivity = 0.85; specificity = 0.92) and a cutoff of 1.49 m/s differentiated pancreatic tissue of CTR from PNET-T (AUC = 0.96; sensitivity = 0.92; specificity = 1.00). The SWS of PNET-T was positively correlated with PET derived asphericity (r = 0.81; p = 0.01). Conclusions: Tomoelastography provides quantitative imaging markers for the detection of PNET and the prediction of greater tumor aggressiveness by increased stiffness

Air-water CO 2 fluxes in the microtidal Neuse River Estuary, North Carolina

From June 2009 to July 2010, we conducted 27 continuous-flow surveys of surface water CO₂ partial pressure (pCO₂) along the longitudinal axis of the Neuse River Estuary (NRE), North Carolina ranging from the tidal freshwater region to the polyhaline border with the Pamlico Sound. Lateral transects were also conducted at the borders of each of three hydrologically distinct sections. The pCO₂ displayed considerable spatial-temporal variability. Likewise, net air-water CO₂ fluxes showed high spatial and temporal variability, with a maximum [release] of 271 mmol C m⁻² d⁻¹ during high river flow conditions in fall and minimum [uptake] of −38 mmol C m⁻² d⁻¹ during wind-driven, high primary productivity conditions in late spring. During high-flow conditions, pCO₂ generally decreased from the river mouth to the Pamlico Sound, similar to patterns seen in well-mixed systems. During warm, low-flow conditions, surface water pCO₂ distributions were spatially variable and dissimilar to those patterns seen in most macrotidal, well-mixed estuaries. The annual air-water CO₂ efflux from the study area was 4.7 mol C m⁻² yr⁻¹, an order of magnitude less than previously estimated for temperate estuaries. The CO₂ fluxes observed in the NRE highlight the contrasts between macrotidal and microtidal systems and suggest that global estuarine CO₂ emissions are likely overestimated by the current classification approaches. Scaling this lower efflux by the relative surface area of macrotidal and microtidal systems would reduce the global estuarine flux by 42%

Air-water CO₂ fluxes in the microtidal Neuse River Estuary, North Carolina

From June 2009 to July 2010, we conducted 27 continuous-flow surveys of surface water CO₂ partial pressure (pCO₂) along the longitudinal axis of the Neuse River Estuary (NRE), North Carolina ranging from the tidal freshwater region to the polyhaline border with the Pamlico Sound. Lateral transects were also conducted at the borders of each of three hydrologically distinct sections. The pCO₂ displayed considerable spatial-temporal variability. Likewise, net air-water CO₂ fluxes showed high spatial and temporal variability, with a maximum [release] of 271 mmol C m⁻² d⁻¹ during high river flow conditions in fall and minimum [uptake] of −38 mmol C m⁻² d⁻¹ during wind-driven, high primary productivity conditions in late spring. During high-flow conditions, pCO₂ generally decreased from the river mouth to the Pamlico Sound, similar to patterns seen in well-mixed systems. During warm, low-flow conditions, surface water pCO₂ distributions were spatially variable and dissimilar to those patterns seen in most macrotidal, well-mixed estuaries. The annual air-water CO₂ efflux from the study area was 4.7 mol C m⁻² yr⁻¹, an order of magnitude less than previously estimated for temperate estuaries. The CO₂ fluxes observed in the NRE highlight the contrasts between macrotidal and microtidal systems and suggest that global estuarine CO₂ emissions are likely overestimated by the current classification approaches. Scaling this lower efflux by the relative surface area of macrotidal and microtidal systems would reduce the global estuarine flux by 42%

An optimized imaging protocol for [99mTc]Tc-DPD scintigraphy and SPECT/CT quantification in cardiac transthyretin (ATTR) amyloidosis

Background: In [(99)mTc]Tc-DPD scintigraphy for myocardial ATTR amyloidosis, planar images 3 hour p.i. and SPECT/CT acquisition in L-mode are recommended. This study investigated if earlier planar images (1 hour p.i.) are beneficial and if SPECT/CT acquisition should be preferred in H-mode (180 degrees detector angle) or L-mode (90 degrees). Methods: In SPECT/CT phantom measurements (NaI cameras, N = 2; CZT, N = 1), peak contrast recovery (CRpeak) was derived from sphere inserts or myocardial insert (cardiac phantom; signal-to-background ratio [SBR], 10:1 or 5:1). In 25 positive and 38 negative patients reference: endomyocardial biopsy or clinical diagnosis), Perugini scores and heart-to-contralateral (H/CL) count ratios were derived from planar images 1 hour and 3 hour p.i. Results: In phantom measurements, accuracy of myocardial CRpeak at SBR 10:1 (H-mode, 0.95-0.99) and reproducibility at 5:1 (H-mode, 1.02-1.14) was comparable for H-mode and L-mode. However, L-mode showed higher variability of background counts and sphere CRpeak throughout the field of view than H-mode. In patients, sensitivity/specificity were >= 95% for H/CL ratios at both time points and visual scoring 3 hour. At 1 hour, visual scores showed specificity of 89% and reduced reader's confidence. Conclusions: Early DPD images provided no additional value for visual scoring or H/CL ratios. In SPECT/CT, H-mode is preferred over L-mode, especially if quantification is applied apart from the myocardium

Effects of external nutrient sources and extreme weather events on the nutrient budget of a Southern European coastal lagoon

The seasonal and annual nitrogen (N), phosphorus (P), and carbon (C) budgets of the mesotidal Ria Formosa lagoon, southern Portugal, were estimated to reveal the main inputs and outputs, the seasonal patterns, and how they may influence the ecological functioning of the system. The effects of extreme weather events such as long-lasting strong winds causing upwelling and strong rainfall were assessed. External nutrient inputs were quantified; ocean exchange was assessed in 24-h sampling campaigns, and final calculations were made using a hydrodynamic model of the lagoon. Rain and stream inputs were the main freshwater sources to the lagoon. However, wastewater treatment plant and groundwater discharges dominated nutrient input, together accounting for 98, 96, and 88 % of total C, N, and P input, respectively. Organic matter and nutrients were continuously exported to the ocean. This pattern was reversed following extreme events, such as strong winds in early summer that caused upwelling and after a period of heavy rainfall in late autumn. A principal component analysis (PCA) revealed that ammonium and organic N and C exchange were positively associated with temperature as opposed to pH and nitrate. These variables reflected mostly the benthic lagoon metabolism, whereas particulate P exchange was correlated to Chl a, indicating that this was more related to phytoplankton dynamics. The increase of stochastic events, as expected in climate change scenarios, may have strong effects on the ecological functioning of coastal lagoons, altering the C and nutrient budgets.Portuguese Science and Technology Foundation (FCT) [POCI/MAR/58427/2004, PPCDT/MAR/58427/2004]; Portuguese Science and Technology Foundation (FCT

Modeling the seasonal autochthonous sources of dissolved organic carbon and nitrogen in the upper Chesapeake Bay

In this paper we investigate the seasonal autochthonous sources of dissolved organic carbon (DOC) and nitrogen (DON) in the euphotic zone at a station in the upper Chesapeake Bay using a new mass-based ecosystem model. Important features of the model are: (1) carbon and nitrogen are incorporated by means of a set of fixed and varying C:N ratios; (2) dissolved organic matter (DOM) is separated into labile, semi-labile, and refractory pools for both C and N; (3) the production and consumption of DOM is treated in detail; and (4) seasonal observations of light, temperature, nutrients, and surface layer circulation are used to physically force the model. The model reasonably reproduces the mean observed seasonal concentrations of nutrients, DOM, plankton biomass, and chlorophyll a. The results suggest that estuarine DOM production is intricately tied to the biomass concentration, ratio, and productivity of phytoplankton, zooplankton, viruses, and bacteria. During peak spring productivity phytoplankton exudation and zooplankton sloppy feeding are the most important autochthonous sources of DOM. In the summer when productivity peaks again, autochthonous sources of DOM are more diverse and, in addition to phytoplankton exudation, important ones include viral lysis and the decay of detritus. The potential importance of viral decay as a source of bioavailable DOM from within the bulk DOM pool is also discussed. The results also highlight the importance of some poorly constrained processes and parameters. Some potential improvements and remedies are suggested. Sensitivity studies on selected parameters are also reported and discussed

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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