Patient's posteroanterior chest radiographs are routinely displayed at different sizes on PACS: Cause and prevalence.

OBJECTIVE: Sequential posteroanterior chest radiographs (CXRs) on any one patient are commonly displayed at different sizes on PACS monitors. The purpose of this study was to determine the cause of these differences, the percentage of radiographs affected, the relative change in magnification seen and if radiologists were aware of this display difference. METHODS: Differences in routine radiographer collimation pre-acquisition and image cropping (shuttering) post acquisition were noted. From three different hospitals, 300 posteroanterior (PA) erect CXRs with prior comparative studies were viewed side-by-side on a standard landscape display monitor. Variation in display size was calculated using the number of detector elements in the autofitted axis of the radiograph, when compared with the prior study. Correlation between patient gender and extent of magnification between images was recorded. Following this, a national survey was circulated to see if radiologists were aware of this phenomenon. RESULTS: Large variations in display size were noted. The mean extent of magnification between sequential PA chest radiographs was ±6.8% (range 0-21.6%). 98% of CXRs had some degree of variability in display size. There was no significant difference in the extent of variation in magnification based on age or gender. 86% of the radiologists who responded to the survey (n = 132) were unaware of any display size variability. CONCLUSION: Sequential DR acquired chest radiographs are routinely displayed with varying degrees of magnification on PACS monitors due to differences in radiographer practice and auto-fit display settings. Most radiologists surveyed were unaware of these differences and their causation.

A computational model of neurodegeneration in Alzheimer's disease.

Disruption of mental functions in Alzheimer's disease (AD) and related disorders is accompanied by selective degeneration of brain regions. These regions comprise large-scale ensembles of cells organized into systems for mental functioning, however the relationship between clinical symptoms of dementia, patterns of neurodegeneration, and functional systems is not clear. Here we present a model of the association between dementia symptoms and degenerative brain anatomy using F18-fluorodeoxyglucose PET and dimensionality reduction techniques in two cohorts of patients with AD. This reflected a simple information processing-based functional description of macroscale brain anatomy which we link to AD physiology, functional networks, and mental abilities. We further apply the model to normal aging and seven degenerative diseases of mental functions. We propose a global information processing model for mental functions that links neuroanatomy, cognitive neuroscience and clinical neurology.

PE MIMICS: a structured approach for the emergency radiologist in the evaluation of chest pain.

Chest pain is a common reason for presentation to the emergency department. In many cases, a CTPA or CT thoracic aorta is performed during work up to assess for pulmonary embolism and aortic pathology, critical diagnoses that can be difficult to out rule clinically. However, the causes of chest pain are myriad. It is therefore crucial for the interpreting radiologist to be cognizant of other potential etiologies when interpreting these studies. The purpose of this pictorial essay is to highlight the causes of non-PE or aortic-related chest pain and provide radiologists with a structured approach to interpreting these studies, ensuring a comprehensive search strategy so that important pathologies are not missed.

Ultra-low-dose cone-beam CT compared to standard dose in the assessment for acute fractures.

PURPOSE: Multi-detector computed tomography (MDCT) is superior in fracture detection than conventional radiography; however, dose is increased. Cone-beam computed tomography (CBCT) offers higher spatial resolution and lower dose than MDCT. Manufacturers offer an ultra-low-dose algorithm. This study compares the diagnostic accuracy of the ultra-low-dose CBCT (ULDCBCT) with that of the standard-dose CBCT (SDCBCT). MATERIALS AND METHODS: In total, 64 patients were scanned with both the SDCBCT and the ULDCBCT protocols. Both studies were reported by two consultant radiologists with fellowship training in emergency radiology separated in time. The reporter recorded a diagnosis of fracture or normal and diagnostic confidence using a 5-point Likert scale. The gold standard was taken as the SDCBCT. Reporters were blinded to the indication and the SDCBCT report. Cases of discrepancy were resolved by consensus. RESULTS: There were 34 fractures and 30 cases had no fracture. Several fractures were missed using the UDCBCT, and there were also several cases of overdiagnosis. ULD was inferior to SD for fracture diagnosis (p < 0.00001). The diagnostic accuracy of ULDCBCT was 82.8% (75.1-88.9 CI). The diagnostic accuracy of plain radiograph was 64% (55.1-75.7% CI). Diagnostic confidence was reduced; the mean confidence for SDCBCT was 4.68 vs 4.12 for ULDCBCT (p < 0.001). The Kappa for interobserver agreement was 0.6. CONCLUSION: ULDCBCT is inferior to SDCBCT in fracture detection and confidence is reduced. For diagnostic studies, the standard dose should be used.

Changes in Ventricular and Cortical Volumes following Shunt Placement in Patients with Idiopathic Normal Pressure Hydrocephalus.

BACKGROUND AND PURPOSE: While changes in ventricular and extraventricular CSF spaces have been studied following shunt placement in patients with idiopathic normal pressure hydrocephalus, regional changes in cortical volumes have not. These changes are important to better inform disease pathophysiology and evaluation for copathology. The purpose of this work is to investigate changes in ventricular and cortical volumes in patients with idiopathic normal pressure hydrocephalus following ventriculoperitoneal shunt placement. MATERIALS AND METHODS: This is a retrospective cohort study of patients with idiopathic normal pressure hydrocephalus who underwent 3D T1-weighted MR imaging before and after ventriculoperitoneal shunt placement. Images were analyzed using tensor-based morphometry with symmetric normalization to determine the percentage change in ventricular and regional cortical volumes. Ventricular volume changes were assessed using the Wilcoxon signed rank test, and cortical volume changes, using a linear mixed-effects model (P < .05). RESULTS: The study included 22 patients (5 women/17 men; mean age, 73 [SD, 6] years). Ventricular volume decreased after shunt placement with a mean change of -15.4% (P < .001). Measured cortical volume across all participants and cortical ROIs showed a mean percentage increase of 1.4% (P < .001). ROIs near the vertex showed the greatest percentage increase in volume after shunt placement, with smaller decreases in volume in the medial temporal lobes. CONCLUSIONS: Overall, cortical volumes mildly increased after shunt placement in patients with idiopathic normal pressure hydrocephalus with the greatest increases in regions near the vertex, indicating postshunt decompression of the cortex and sulci. Ventricular volumes showed an expected decrease after shunt placement.

Gallstones top to toe: what the radiologist needs to know.

Gallstone-related disease can have significant associated morbidity and mortality worldwide. The incidence of gallstone-related disease in the Western world is on the increase. There are multiple different pathological manifestations of gallstone disease: the presentation, diagnosis and associated complications of which vary significantly depending on anatomical location. The role of imaging in gallstone-related disease is broad with radiology playing an essential role in the diagnosis, management and follow-up of gallstone-related pathologies. This paper distills the broad range of gallstone-related pathologies into an anatomical map, discussing the disease processes involved at each point along the biliary tree and reviewing the strengths and weaknesses of different imaging modalities for each distinct disease process.

Trapezium fracture: a common clinical mimic of scaphoid fracture.

PURPOSE: Fractures of the trapezium are rarely diagnosed on plain radiographs after acute wrist trauma. High-resolution cross-sectional imaging identifies fractures of the trapezium as the most common radiographically occult carpal bone fracture. We review the fracture frequency, mechanisms and patterns of trapezium fractures. METHODS: Cone beam CT was performed in patients with suspected radiographically occult radiocarpal fracture following acute injury. The frequency of carpal bone fractures was assessed and compared. RESULTS: Ninety-three radiographically occult wrist fractures were identified in 166 patients with acute trauma and negative radiographs. The trapezium was the most frequently fractured carpal bone, making up 20.4% of wrist fractures. Seventy-nine percent of trapezium fractures involved the volar ridge. The scaphoid was the clinically suspected fractured bone at initial assessment in 84% of patients with trapezium fractures. CONCLUSION: Fractures of the trapezium in acute wrist trauma are much more common than described in the literature. If initial radiographs are negative, a fracture of the trapezium is more likely to be present than one of the scaphoid, despite high levels of clinical suspicion for scaphoid injuries. Awareness of the types and mechanisms of trapezium fracture is important. Cross-sectional imaging should be considered in all cases of post-traumatic wrist pain with negative radiographs.

Identifying additional patients with diabetic nephropathy using the UK primary care initiative.

AIMS: The aim of this study was to use general practice data to estimate the prevalence of diabetic nephropathy within the registered diabetes patients and examine variation in practice prevalence and management performance since introduction of this initiative. METHODS: Reported quality indicators from the Northern Ireland General Practice Quality and Outcomes Framework were analysed for diabetes and diabetic nephropathy prevalence and management in the period 2004-2008. Variation in prevalence at practice level was assessed using multiple linear regression adjusting for age, practice size, deprivation and glycaemic control. RESULTS: In 2006-2007, 57,454 (4.1%) adult diabetic patients were registered in the denominator population of 1.4 million compared with 51,923 (3.8%) in 2004-2005 (mean practice range 0.5-7.7%). Diabetic nephropathy prevalence was 15.1 and 11.5%, respectively (8688 and 5955 patients). Documented diabetic nephropathy prevalence showed marked variation across practices (range 0-100%) and was significantly negatively correlated with diabetes list size, albumin creatinine ratio testing rates and renin-angiotensin-aldosterone system blockade use and positively correlated with exception reporting rates. Specifically, for every increase in 100 diabetic patients to a register, documented diabetic nephropathy prevalence reduced by 40% (P=0.003). On the positive side, median albumin-creatinine ratio testing rates doubled to 82% compared with figures in the pre-Framework era. CONCLUSIONS: Implementation of the Northern Ireland General Practice Quality and Outcomes Framework has positively benefitted testing for diabetic nephropathy and increased numbers of detected patients in a short space of time. Large variation in diabetic nephropathy prevalence remains and is associated with diabetes registry size, screening and treatment practices, suggesting that understanding this variation may help detect and better manage diabetic nephropathy.

A titer plate-based polymer microfluidic platform for high throughput nucleic acid purification.

A 96-well solid-phase reversible immobilization (SPRI) reactor plate was designed to demonstrate functional titer plate-based microfluidic platforms. Nickel, large area mold inserts were fabricated using an SU-8 based, UV-LIGA technique on 150 mm diameter silicon substrates. Prior to UV exposure, the prebaked SU-8 resist was flycut to reduce the total thickness variation to less than 5 mum. Excellent UV lithography results, with highly vertical sidewalls, were obtained in the SU-8 by using an UV filter to remove high absorbance wavelengths below 350 nm. Overplating of nickel in the SU-8 patterns produced high quality, high precision, metal mold inserts, which were used to replicate titer plate-based SPRI reactors using hot embossing of polycarbonate (PC). Optimized molding conditions yielded good feature replication fidelity and feature location integrity over the entire surface area. Thermal fusion bonding of the molded PC chips at 150 degrees C resulted in leak-free sealing, which was verified in leakage tests using a fluorescent dye. The assembled SPRI reactor was used for simple, fast purification of genomic DNA from whole cell lysates of several bacterial species, which was verified by PCR amplification of the purified genomic DNA.

Composition variability of spent mushroom compost in Ireland.

Spent mushroom compost (SMC) has proven to be an attractive material for improving soil structure in tilled soils and increasing dry matter production in grassland soils, owing to its high organic matter content and availability of essential plant nutrients. Because of this, it is important to identify the variability in composition of SMC in order to evaluate its merit as a fertilizer/soil conditioner. For this reason, a study was carried out involving the analysis of SMC samples obtained from five mushroom growers using compost from each of the 13 mushroom composting yards currently operating in both Northern Ireland (5 yd) and the Republic of Ireland (8 yd). The selected parameters measured include dry matter, organic matter, total N, P and K, C/N ratio; plant-available P and K, pH, EC, total Ca, Mg, Na, Cu, Zn, Fe, Mn, Cd, Cr, Ni, Pb; and cellulose, hemicellulose and lignin constituents. Yield of mushroom data were also collected from the selected growers. There were significant differences (P<0.05) within two compost production yards for some parameters, therefore, for the most part, the uniformity of SMC within each yard is relatively consistent. However, significant differences (P<0.05) were evident when comparing SMC obtained from growers supplied with compost from Northern Ireland and the Republic of Ireland independently, particularly among total and available phosphorus and potassium values. The results obtained show that, while SMC has fertilizer merit, its variability of composition must be taken into account when assessing this value. The variability of composition is also of particular interest in the context of recent emphasis on plant nutrient management in agriculture.

Implementing evidence-based guidelines:inpatient management of chronic obstructive pulmonary disease.

BACKGROUND: Evidence-based guidelines exist to guide inpatient management of chronic obstructive pulmonary disease (COPD) exacerbations, but we do not know how well these recommendations are adhered to. AIMS: The aims of this study were: (i) to examine concordance with evidence based guidelines for inpatient management of COPD and (ii)to address deficiencies in compliance with guidelines by feedback of audit results and distribution of an education package. METHODS: Retrospective chart reviews were performed using a data collection tool based on current guidelines. Forty-nine consecutive COPD admissions were audited, and results presented to medical staff. An education package was distributed directly after the presentation. One month later,35 consecutive separations were reviewed. Concordance with recommendations supported by the highest level of evidence was calculated. RESULTS: Data were complete for 84 cases. Concordance rates ranged from 0 to 100%. Apart from initiation of systemic steroids (80-83%)and avoidance of intravenous aminophylline (100%),concordance rates were less than 60%. The only significant improvement post-intervention was for steroid duration (10 vs 29%,95% confidence interval for difference (-36.2, -1.8)). CONCLUSION: Recommendations for steroid initiation and avoidance of aminophylline are well adhered to. Concordance rates for other recommendations were generally less than 60%. Concordance with recommendations for steroid duration was significantly improved by our intervention. The findings suggest that to facilitate evidence-based practice, alternative interventions should be evaluated.

Probing single-stranded DNA conformational flexibility using fluorescence spectroscopy.

Single-stranded DNA (ssDNA) is an essential intermediate in various DNA metabolic processes and interacts with a large number of proteins. Due to its flexibility, the conformations of ssDNA in solution can only be described using statistical approaches, such as flexibly jointed or worm-like chain models. However, there is limited data available to assess such models quantitatively, especially for describing the flexibility of short ssDNA and RNA. To address this issue, we performed FRET studies of a series of oligodeoxythymidylates, (dT)N, over a wide range of salt concentrations and chain lengths (10 < or = N < or = 70 nucleotides), which provide systematic constraints for testing theoretical models. Unlike in mechanical studies where available ssDNA conformations are averaged out during the time it takes to perform measurements, fluorescence lifetimes may act here as an internal clock that influences fluorescence signals depending on how fast the ssDNA conformations fluctuate. A reasonably good agreement could be obtained between our data and the worm-like chain model provided that limited relaxations of the ssDNA conformations occur within the fluorescence lifetime of the donor. The persistence length thus estimated ranges from 1.5 nm in 2 M NaCl to 3 nm in 25 mM NaCl.

Nutritional status in elderly female hip fracture patients: comparison with an age-matched home living group attending day centres.

Fractured neck of femur occurs mostly in the older female population and is generally caused by falls. Malnutrition has been postulated as a factor that increases the tendency to suffer falls. Nutritional status of older female hospital patients admitted for emergency surgery for fractured neck of femur recruited (n 75), was compared with an age-matched independent-living group of females attending one of three local day centres (n 50). Dietary assessment was undertaken using three consecutive 24 h dietary recalls and, in the hip fracture group, completed menu cards were used as memory prompts. Data concerning key lifestyle characteristics were obtained using a face-to-face administered questionnaire. Blood samples were taken to determine levels of plasma albumin, transferrin, C-reactive protein (CRP), cholesterol, vitamin C, Se, Zn and total antioxidant status. Haemolysate samples were analysed for Se-dependent glutathione peroxidase activity. There were no significant differences in age between the two groups, but the hip fracture patients had lower mean values for body weight (59.6 v. 67.5 kg; mindex (weight/demispan) (83.1 v. 94.4 kg/m; calculated BMI (24.1 v. 27.5 kg/m2 mid-upper arm circumference; 27.1 v. 31.3 cm, and triceps skinfold thickness; 17.0 v. 18.9 mm, than the home-living group. The hip fracture patients had lower intakes of energy (4.3 v. 5.4 MJ, fat carbohydrate protein thiamine vitamin B6 calcium K Mg P Fe Se and NSP Mean intakes of both groups were below the estimated average requirement for energy and below the reference nutrient intakes for folate, Ca, vitamin D, Mg, K, Se and Zn. In a high percentage of the hip fracture group the dietary intake of particular nutrients fell below the lower reference nutrient intake for Se (73 %), Mg (54 %) and Fe (19 %). As expected, the fracture patients had reduced plasma albumin and increased CRP values. They had higher plasma vitamin C levels and lower cholesterol levels than the day centre attendees. There were no significant differences in plasma levels of Se, Zn, transferrin or haemolysate glutathione peroxidase activity between the two groups. However, there was evidence of under-nutrition in both groups as key anthropometric values were low, plasma nutrient and metabolite levels were below the standard reference ranges and many individuals had low dietary intakes for specified nutrients.

Lack of association between lipaemia and central adiposity in subjects with an atherogenic lipoprotein phenotype (ALP).

OBJECTIVE: To investigate the associations between indices of adiposity and cardiovascular risk factors in individuals with an atherogenic lipoprotein phenotype (ALP). SUBJECTS: Fifty-five men, aged 34-69 y, body mass index (BMI) 22-35 kg/m2, with an ALP lipid profile (triglycerides (TG) 1.5-4.0 mmol/l, HDL<1.1 mmol/l; %LDL-3>40% total LDL). DESIGN: Each participant provided a fasting blood sample and underwent an 8 h postprandial assessment and had anthropometric measurements taken. OUTCOME MEASURES: BMI, waist circumference (W), waist-to-hip ratio (W/H), sum of skinfolds (SSK), fasting and postprandial concentrations of glucose, insulin and plasma lipids, post-heparin lipase activity, and apoE genotype. RESULTS: The expected positive associations between BMI, W and SSK and fasting and postprandial insulin were observed (r=0.42-0.65). Little association between glucose responses and any measures of adiposity was evident. Unexpectedly, there were no positive associations between measures of central adiposity (W and W/H) and fasting and postprandial TG responses, with a trend towards negative associations in this study group (TG AUC vs W, r=-0.23, P=0.097; TG IAUC vs W/H, r=-0.26, P=0.068). Subgroup analysis indicated that lack of a positive association between central adiposity and postprandial TG values was more evident in those with one E4 allele (r=-0.42, P=0.077) relative to non-E4 carriers (r=-0.16, P=0.430). The expected positive associations between insulin and TG responses were not observed (r=-0.03 to -0.36). CONCLUSION: In this ALP group the expected positive association between TG responses and a centralized distribution of body fat was not observed, particularly in individuals with an apoE4 genotype. Our findings are not in line with the view that there is a clear causal relationship between insulin resistance and the lipid abnormalities associated with ALP.

ApoE polymorphism and fish oil supplementation in subjects with an atherogenic lipoprotein phenotype.

The study assessed the efficacy of fish oil supplementation in counteracting the classic dyslipidemia of the atherogenic lipoprotein phenotype (ALP). In addition, the impact of the common apolipoprotein E (apoE) polymorphism on the fasting and postprandial lipid profile and on responsiveness to the dietary intervention was established. Fifty-five ALP males (aged 34 to 69 years, body mass index 22 to 35 kg/m(2), triglyceride [TG] levels 1.5 to 4.0 mmol/L, high density lipoprotein cholesterol [HDL-C] <1.1 mmol/l, and percent low density lipoprotein [LDL]-3 >40% total LDL) completed a randomized placebo-controlled crossover trial of fish oil (3.0 g eicosapentaenoic acid/docosahexaenoic acid per day) and placebo (olive oil) capsules with the 6-week treatment arms separated by a 12-week washout period. In addition to fasting blood samples, at the end of each intervention arm, a postprandial assessment of lipid metabolism was carried out. Fish oil supplementation resulted in a reduction in fasting TG level of 35% (P<0.001), in postprandial TG response of 26% (TG area under the curve, P<0.001), and in percent LDL-3 of 26% (P<0.05). However, no change in HDL-C levels was evident (P=0.752). ANCOVA showed that baseline HDL-C levels were significantly lower in apoE4 carriers (P=0.035). The apoE genotype also had a striking impact on lipid responses to fish oil intervention. Individuals with an apoE2 allele displayed a marked reduction in postprandial incremental TG response (TG incremental area under the curve, P=0.023) and a trend toward an increase in lipoprotein lipase activity relative to non-E2 carriers. In apoE4 individuals, a significant increase in total cholesterol and a trend toward a reduction in HDL-C relative to the common homozygous E3/E3 profile was evident. Our data demonstrate the efficacy of fish oil fatty acids in counteracting the proatherogenic lipid profile of the ALP but also that the apoE genotype influences responsiveness to this dietary treatment.

The use of the Mini-Nutritional Assessment (MNA) tool in elderly orthopaedic patients.

OBJECTIVE: To assess the use of the Mini-Nutritional Assessment (MNA) in elderly orthopaedic patients. DESIGN: An observation study assessing the nutritional status of female orthopaedic patients. SETTING: The orthopaedic wards of the Royal Surrey County Hospital. SUBJECTS: Forty-nine female patients aged 60-103 y; dietary records were obtained for 41 subjects and 36 subjects gave a blood sample for biochemical analysis. MAJOR OUTCOME METHODS: MNA questionnaire, anthropometry, plasma albumin, transferrin, C-reactive protein (CRP) levels and dietary analyses. RESULTS: The group as a whole had low mean values for body weight, albumin and transferrin and high CRP levels. In addition, the group had mean energy intakes well below the estimated average requirement (EAR) and mean intakes of vitamin D, magnesium, potassium, selenium and non-starch polysaccharides (NSP) were below the lower reference nutrient intakes (LRNI). The MNA screening section categorized 69% of the patients as requiring a full assessment (scored 11 or below), but for the purposes of the study the MNA was completed on all patients. The MNA assessment categorized 16% of the group as 'malnourished' (scored<17 points), 47% as 'at risk' (scored 17.5-23.5) and 37% as 'well nourished' (scored>23.5). Significant differences were found between the malnourished and well nourished groups for body weight (P<0.001), body mass index (BMI) (P<0.001), demiquet (P<0.001) and mindex (P<0. 001). Mean values for energy and nutrient intakes showed a clear stepwise increase across the three groups for all nutrients except sodium, with significant differences for protein (P<0.05), carbohydrate (P<0.05), riboflavin (P<0.05) niacin (P<0.05), pyridoxine (P<0.05), folate (P<0.05), calcium (P<0.05), selenium (P<0.05), iron (P<0.05) and NSP (P<0.05) intakes. Stepwise multiple regression analysis indicated that anthropometric assessments were the most predictive factors in the total MNA score. The sensitivity and specificity of the MNA was assessed in comparison with albumin levels, energy intake and mindex. The sensitivity of the MNA classification of those scoring less than 17 points in comparison with albumin levels, energy intake and mindex varied from 27 to 57% and the specificity was 66-100%. This was compared with the sensitivity and specificity of using a score of less than 23.5 on the MNA to predict malnourished individuals. Using this cut-off the sensitivity ranged from 75 to 100%, but the specificity declined to between 37 and 50%. CONCLUSIONS: The results suggest that the MNA is a useful diagnostic tool in the identification of elderly patients at risk from malnutrition and those who are malnourished in this hospital setting. SPONSORSHIP: Nestlé Clinical Nutrition, Croydon, Surrey.

Mixed chimerism and tolerance without whole body irradiation in a large animal model.

Mixed hematopoietic chimerism may provide a treatment for patients with nonmalignant hematologic diseases, and may tolerize patients to organ allografts without requiring chronic immunosuppression. However, the toxicity of the usual conditioning regimens has limited the clinical applicability of this approach. These regimens generally include some level of whole body irradiation (WBI), which is thought to facilitate engraftment either by making room for donor hematopoietic stem cells or by providing sufficient host immunosuppression to enable donor cells to engraft. Here, we have established mixed chimerism across both minor and major histocompatibility barriers in swine, by using high doses of peripheral blood stem cells in the absence of WBI. After mixed chimerism was established, swine leukocyte antigen-matched (SLA-matched) donor skin grafts were tolerated and maintained for a prolonged period, whereas third-party SLA-matched skin was rejected promptly. Donor-matched kidney allografts were also accepted without additional immunosuppression. Because of its low toxicity, this approach has potential for a wide range of clinical applications. Our data may indicate that niches for engrafting stem cells are filled by mass action and that WBI, which serves to empty some of these niches, can be omitted if the donor inoculum is sufficiently large and if adequate host T-cell depletion is achieved before transplant.