MDCT arthrography of the hip: value of the adaptive statistical iterative reconstruction technique and potential for radiation dose reduction.

OBJECTIVE: The purpose of this article is to assess the effect of the adaptive statistical iterative reconstruction (ASIR) technique on image quality in hip MDCT arthrography and to evaluate its potential for reducing radiation dose. SUBJECTS AND METHODS: Thirty-seven patients examined with hip MDCT arthrography were prospectively randomized into three different protocols: one with a regular dose (volume CT dose index [CTDIvol], 38.4 mGy) and two with a reduced dose (CTDIvol, 24.6 or 15.4 mGy). Images were reconstructed using filtered back projection (FBP) and four increasing percentages of ASIR (30%, 50%, 70%, and 90%). Image noise and contrast-to-noise ratio (CNR) were measured. Two musculoskeletal radiologists independently evaluated several anatomic structures and image quality parameters using a 4-point scale. They also jointly assessed acetabular labrum tears and articular cartilage lesions. RESULTS: With decreasing radiation dose level, image noise statistically significantly increased (p=0.0009) and CNR statistically significantly decreased (p=0.001). We also found a statistically significant reduction in noise (p=0.0001) and increase in CNR (p≤0.003) with increasing percentage of ASIR; in addition, we noted statistically significant increases in image quality scores for the labrum and cartilage, subchondral bone, overall diagnostic quality (up to 50% ASIR), and subjective noise (p≤0.04), and statistically significant reductions for the trabecular bone and muscles (p≤0.03). Regardless of the radiation dose level, there were no statistically significant differences in the detection and characterization of labral tears (n=24; p=1) and cartilage lesions (n=40; p≥0.89) depending on the ASIR percentage. CONCLUSION: The use of up to 50% ASIR in hip MDCT arthrography helps to reduce radiation dose by approximately 35-60%, while maintaining diagnostic image quality comparable to that of a regular-dose protocol using FBP.

Wood Volume Measurement Using Color Images

Tämä työ käsittelee puutukkien tilavuuden mittaamista värikonenäön avulla. Värikuvat on saatu Simpeleellä olevan metsäteollisuusyrityksen hiomosta. Työssä esitetään perusteellisesti matemaattinen teoria, joka liittyy käytettyihin kuvankäsittelymenetelmiin, kuten luokitteluun, kohinan poistoon ja tukkien segmentointiin. Esitetyt menetelmät implementointiin käytännössä ja eri menetelmillä saatuja tuloksia vertailtiin keskenään. Kuvankäsittelyalgoritmit on implementoitu Matlab 6.0:n avulla. Pääasiassa käytettiin uusinta Image Processing Toolboxia, joka on versio 3.0. Tämä työn näkökulma on pääasiassa käytäntöön soveltava, koska metsäteollsuus on korkealla tasolla Suomessa ja siellä on paljon alan yrityksiä, joissa tässä työssä kehitettyä menetelmää voidaan hyödyntää.

Combined T2 -preparation and two-dimensional pencil-beam inner volume selection.

PURPOSE: To improve coronary magnetic resonance angiography (MRA) by combining a two-dimensional (2D) spatially selective radiofrequency (RF) pulse with a T2 -preparation module ("2D-T2 -Prep"). METHODS: An adiabatic T2 -Prep was modified so that the first and last pulses were of differing spatial selectivity. The first RF pulse was replaced by a 2D pulse, such that a pencil-beam volume is excited. The last RF pulse remains nonselective, thus restoring the T2 -prepared pencil-beam, while tipping the (formerly longitudinal) magnetization outside of the pencil-beam into the transverse plane, where it is then spoiled. Thus, only a cylinder of T2 -prepared tissue remains for imaging. Numerical simulations were followed by phantom validation and in vivo coronary MRA, where the technique was quantitatively evaluated. Reduced field-of-view (rFoV) images were similarly studied. RESULTS: In vivo, full field-of-view 2D-T2 -Prep significantly improved vessel sharpness as compared to conventional T2 -Prep, without adversely affecting signal-to-noise (SNR) or contrast-to-noise ratios (CNR). It also reduced respiratory motion artifacts. In rFoV images, the SNR, CNR, and vessel sharpness decreased, although scan time reduction was 60%. CONCLUSION: When compared with conventional T2 -Prep, the 2D-T2 -Prep improves vessel sharpness and decreases respiratory ghosting while preserving both SNR and CNR. It may also acquire rFoV images for accelerated data acquisition.

Effect of pyloroplasty and fundectomy on the delay of gastric emptying and gastrointestinal transit of liquid elicited by acute blood volume expansion in awake rats

We evaluated the effects of fundectomy and pyloroplasty on the delay of gastric emptying (GE) and gastrointestinal (GI) transit of liquid due to blood volume (BV) expansion in awake rats. Male Wistar rats (N = 76, 180-250 g) were first submitted to fundectomy (N = 26), Heinecke-Mikulicz pyloroplasty (N = 25) or SHAM laparotomy (N = 25). After 6 days, the left external jugular vein was cannulated and the animals were fasted for 24 h with water ad libitum. The test meal was administered intragastrically (1.5 ml of a phenol red solution, 0.5 mg/ml in 5% glucose) to normovolemic control animals and to animals submitted to BV expansion (Ringer-bicarbonate, iv infusion, 1 ml/min, volume up to 5% body weight). BV expansion decreased GE and GI transit rates in SHAM laparotomized animals by 52 and 35.9% (P<0.05). Fundectomy increased GE and GI transit rates by 61.1 and 67.7% (P<0.05) and prevented the effect of expansion on GE but not on GI transit (13.9% reduction, P<0.05). Pyloroplasty also increased GE and GI transit rates by 33.9 and 44.8% (P<0.05) but did not prevent the effect of expansion on GE or GI transit (50.7 and 21.1% reduction, P<0.05). Subdiaphragmatic vagotomy blocked the effect of expansion on GE and GI transit in both SHAM laparotomized animals and animals submitted to pyloroplasty. In conclusion 1) the proximal stomach is involved in the GE delay due to BV expansion but is not essential for the establishment of a delay in GI transit, which suggests the activation of intestinal resistances, 2) pyloric modulation was not apparent, and 3) vagal pathways are involved

Decreased left temporal lobe volume of panic patients measured by magnetic resonance imaging

Reported neuroimaging studies have shown functional and morphological changes of temporal lobe structures in panic patients, but only one used a volumetric method. The aim of the present study was to determine the volume of temporal lobe structures in patients with panic disorder, measured by magnetic resonance imaging. Eleven panic patients and eleven controls matched for age, sex, handedness, socioeconomic status and years of education participated in the study. The mean volume of the left temporal lobe of panic patients was 9% smaller than that of controls (t21 = 2.37, P = 0.028). In addition, there was a trend (P values between 0.05 and 0.10) to smaller volumes of the right temporal lobe (7%, t21 = 1.99, P = 0.06), right amygdala (8%, t21 = 1.83, P = 0.08), left amygdala (5%, t21 = 1.78, P = 0.09) and left hippocampus (9%, t21 = 1.93, P = 0.07) in panic patients compared to controls. There was a positive correlation between left hippocampal volume and duration of panic disorder (r = 0.67, P = 0.025), with recent cases showing more reduction than older cases. The present results show that panic patients have a decreased volume of the left temporal lobe and indicate the presence of volumetric abnormalities of temporal lobe structures.

Methodological approaches to planar and volumetric scintigraphic imaging of small volume targets with high spatial resolution and sensitivity

Single-photon emission computed tomography (SPECT) is a non-invasive imaging technique, which provides information reporting the functional states of tissues. SPECT imaging has been used as a diagnostic tool in several human disorders and can be used in animal models of diseases for physiopathological, genomic and drug discovery studies. However, most of the experimental models used in research involve rodents, which are at least one order of magnitude smaller in linear dimensions than man. Consequently, images of targets obtained with conventional gamma-cameras and collimators have poor spatial resolution and statistical quality. We review the methodological approaches developed in recent years in order to obtain images of small targets with good spatial resolution and sensitivity. Multipinhole, coded mask- and slit-based collimators are presented as alternative approaches to improve image quality. In combination with appropriate decoding algorithms, these collimators permit a significant reduction of the time needed to register the projections used to make 3-D representations of the volumetric distribution of target’s radiotracers. Simultaneously, they can be used to minimize artifacts and blurring arising when single pinhole collimators are used. Representation images are presented, which illustrate the use of these collimators. We also comment on the use of coded masks to attain tomographic resolution with a single projection, as discussed by some investigators since their introduction to obtain near-field images. We conclude this review by showing that the use of appropriate hardware and software tools adapted to conventional gamma-cameras can be of great help in obtaining relevant functional information in experiments using small animals.

Potential reduction of concrete deterioration through controlled DEF in hydrated concrete

Delayed ettringite formation (DEF) is a chemical reaction with proven damaging effects on hydrated concrete. Ettringite crystals can cause cracks and their widening due to pressure on cracked walls caused by the positive volume difference in the reaction. Concrete may show improvements in strength at early ages but further growth of cracks causes widening and spreading through the concrete structure. In this study, finely dispersed crystallization nuclei achieved by adding air-entraining agent (AEA) and short vibration of specimens is presented as the main prerequisite for reducing DEF-induced deterioration of hydrated concrete. The study presents the method and mechanism for obtaining the required nucleation. Controlling long-term DEF by providing AEA-induced crystallisation nuclei, prevented excessive and rapid initial strength improvements, and resulted in a slight increase of compressive strength of fine grained concrete with only marginally lower density.

Secoiridoids delivered as olive leaf extract induce acute improvements in human vascular function and reduction of an inflammatory cytokine: a randomised, double-blind, placebo-controlled, cross-over trial

The leaves of the olive plant (Olea europaea) are rich in polyphenols, of which oleuropein and hydroxytyrosol (HT) are most characteristic. Such polyphenols have been demonstrated to favourably modify a variety of cardiovascular risk factors. The aim of the present intervention was to investigate the influence of olive leaf extract (OLE) on vascular function and inflammation in a postprandial setting and to link physiological outcomes with absorbed phenolics. A randomised, double-blind, placebo-controlled, cross-over, acute intervention trial was conducted with eighteen healthy volunteers (nine male, nine female), who consumed either OLE (51 mg oleuropein; 10mg HT), or a matched control (separated by a 4-week wash out) on a single occasion. Vascular function was measured by digital volume pulse (DVP), while blood collected at baseline, 1, 3 and 6 h was cultured for 24 h in the presence of lipopolysaccharide in order to investigate effects on cytokine production. Urine was analysed for phenolic metabolites by HPLC. DVP-stiffness index and ex vivo IL-8 production were significantly reduced (P < 0.05) after consumption of OLE compared to the control. These effects were accompanied by the excretion of several phenolic metabolites, namely HT and oleuropein derivatives, which peaked in urine after 8-24 h. The present study provides the first evidence that OLE positively modulates vascular function and IL-8 production in vivo, adding to growing evidence that olive phenolics could be beneficial for health.

Sequential injection analysis (SIA) and response surface methodology: A versatile small volume approach for optimization of photo-Fenton processes

Optimization of photo-Fenton degradation of copper phthalocyanine blue was achieved by response surface methodology (RSM) constructed with the aid of a sequential injection analysis (SIA) system coupled to a homemade photo-reactor. Highest degradation percentage was obtained at the following conditions [H(2)O(2)]/[phthalocyanine] = 7, [H(2)O(2)]/[FeSO(4)] = 10, pH = 2.5, and stopped flow time in the photo reactor = 30 s. The SIA system was designed to prepare a monosegment containing the reagents and sample, to pump it toward the photo-reactor for the specified time and send the products to a flow-through spectrophotometer for monitoring the color reduction of the dye. Changes in parameters such as reagent molar ratios. residence time and pH were made by modifications in the software commanding the SI system, without the need for physical reconfiguration of reagents around the selection valve. The proposed procedure and system fed the statistical program with degradation data for fast construction of response surface plots. After optimization, 97% of the dye was degraded. (C) 2009 Elsevier B.V. All rights reserved.

Volatility of returns, variations in prices and volume traded: evidence from the main stocks in Brazil

We study the relationship between the volatility and the price of stocks and the impact that variables such as past volatility, financial gearing, interest rates, stock return and turnover have on the present volatility of these securities. The results show the persistent behavior of volatility and the relationship between interest rate and volatility. The results also showed that a reduction in stock prices are associated with an increase in volatility. Finally we found a greater trading volume tends to increase the volatility.

Influence of fluid volume variations on the calculated value of the left ventricular mass measured by echocardiogram in patients submitted to hemodialysis

The left ventricular mass (LVM) measurement is of major importance for renal patients, as ventricular hypertrophy is an important prognostic index. The echo-cardiogram of the ventricular mass is larger before than it is after hemodialysis, which can confuse data interpretation. The aim of this work is to study the influence of alterations in fluid volume on the variations in measurements of ventricular mass observed during the course of a hemodialysis. Sixteen patients with chronic renal insufficiency in hemodialysis were evaluated at the Dialysis Unit of the University Hospital-UNESP, Botucatu, São Paulo State. The left ventricular mass was calculated from echocardiograms taken before and after hemodialysis and simultaneous ultra-filtration (12 patients: UF GROUP) and before and after hemodialysis isovolemic phase with sequential ultra-filtration (10 patients: ISO GROUP). Six of these patients were submitted to measurements of left ventricular mass before and after hemodialysis in both isovolemic and simultaneous ultra-filtration procedures. In the UF group, there was significant reduction in the following parameters before and after dialysis: diastolic diameter from 54.0 +/- 6.0 mm to 45.6 +/- 7.6 mm; left ventricular mass from 342 +/- 114 g to 265 +/- 117 g; and its respective index (IMVE) from 214 +/- 68 g/m(2) to 168 +/- 71 g/m(2). The ISO group showed no statistically significant variation. The behavior of the variables of six patients submitted to both observations confirm these results. In conclusion, the variations in echocardiogram measurements of the left ventricular mass relating to hemodialysis appear to be induced by alterations of the volemic condition.

Volume do recipiente, adubação e sua forma de mistura ao substrato no crescimento inicial de Peltophorum dubium (sprengel) taubert em viveiro

O ensaio comparou três volumes de recipientes, três tipos de adubação e duas formas de mistura do fertilizante ao substrato, no crescimento inicial de plântulas de Peltophorum dubium (Sprengel) Taubert (canafístula) em viveiro, num esquema fatorial 3 x 3 x 2. Foram utilizados tubetes de 100 e 180 cm³ preenchidos com substrato comercial e sacos plásticos de 10 x 15 cm cheios com mistura de solo e vermiculita em partes iguais, fertilizados com fertilizante de liberação lenta (FLL) nas dosagens de 1,75 e 3,5 kg m-3 e com formulação NPK a 1,0 kg m-3 de substrato. As formas de misturas adotadas foram aquelas com base por metro cúbico de substrato ou individualmente para cada recipiente. Na análise destrutiva realizada 12 semanas após a emergência, avaliaram-se o número de folhas, a altura da planta, o diâmetro do coleto e as massas secas da parte aérea, o sistema radicular e o total. Os resultados indicaram que a redução no volume do recipiente causou diminuição na massa seca, diâmetro e altura. O número de folhas, a massa seca da parte aérea e a massa seca total foram semelhantes nas plântulas sob fertilização com NPK, independentemente do volume do recipiente, o que não ocorreu naquelas sob FLL, onde esse parâmetro diminuiu com o volume do recipiente. O cálculo do índice de Dickson após 12 semanas indicou valores superiores em mudas com a forma de mistura convencional em relação à individual e maior naquelas sob fertilização com NPK, em comparação com as sob FLL.

Redução da dose e do volume de calda nas aplicações noturnas de herbicidas em pós-emergência na cultura de soja

O objetivo deste trabalho foi avaliar o efeito de reduções da dose e do volume de calda nas aplicações noturnas de herbicidas em pós-emergência sobre o controle de plantas daninhas e a seletividade para a cultura da soja. Dois experimentos foram conduzidos na Fazenda de Ensino e Pesquisa da FCAV/UNESP - Campus de Jaboticabal, durante os anos agrícolas de 94/95 e 95/96. As aplicações foram realizadas às 5, 9, 14, 17 e 22h e o volume de calda de 300 l/ha foi reduzido para 75 e 150l/ha. No primeiro experimento foram aplicadas as doses de 432 g de bentazon/ha e 90 g de lactofen/ha, correspondentes a 60% das recomendações de rótulo desses herbicidas, e no segundo, 60 g lactofen/ha e 157,5 g de fomesafen/ha + 2 % de adjuvante (v/v), correspondentes a 40% e 70% das recomendações. Também foram incluídos nos experimentos tratamentos com as recomendações dos rótulos e testemunhas com e sem capina das plantas daninhas durante todo o ciclo da cultura. As aplicações noturnas, realizadas às 5 e 22h, favoreceram significativamente a ação do lactofen com 60% da dose recomendada e desfavoreceram a do fomesafen no controle das plantas daninhas. Não ocorreram diferenças significativas entre os volumes de aplicação estudados, possibilitando o uso de 75 ou 150 l de calda/ha aplicados nos horários mais favoráveis a cada um dos herbicidas. A maior eficiência das aplicações dos herbicidas bentazon, lactofen e fomesafen depende, além das condições ambientais favoráveis no período noturno, das interações específicas entre os herbicidas e as plantas daninhas.

High volume peritoneal dialysis for acute renal failure

Background. Peritoneal dialysis (PD) is still widely used for acute renal failure (ARF) in developing countries despite concerns about its inadequacy. Continuous PD has been evaluated in ARF by analyzing the resolution of metabolic abnormality and normalization of plasma pH, bicarbonate, and potassium.Methodology: A prospective study was performed on 30 ARF patients who were assigned to high-dose continuous PD (Kt/V = 0.65 per session) via a flexible catheter (Tenckhoff) and automated PD with a cycler. Fluid removal, pH and metabolic control, protein Loss, and patient outcome were evaluated.Results: Patients received 236 continuous PD sessions; 76% were admitted to ICUs. APACHE II score was 32.2 +/- 8.65. BUN concentrations stabilized after 3 sessions, creatinine after 4, and bicarbonate and pH after 2. Fluid removal was 2.1 +/- 0.62 L/day. Creatinine and urea clearances were 15.8 +/- 4.16 and 17.3 +/- 5.01 mL/minute respectively. Normalized creatinine clearance and urea Kt/V values were 110.6 +/- 22.5 L/week/1.73 m(2) body surface area and 3.8 +/- 0.6 respectively. Solute reduction index was 41% +/- 6.5% per session. Serum albumin values remained stable in spite of considerable protein tosses (median 21.7 g/day, interquartile range 9.1 - 29.8 g/day). Regarding ARF outcome, 23% of patients presented renal function recovery, 13% remained on dialysis after 30 days of follow-up, and 57% died.Conclusion: High-dose continuous PD by flexible catheter and cycler was an effective treatment for ARF. It provided high solute removal, allowing appropriate metabolic and pH control, and adequate dialysis dose and fluid removal. Continuous PD can therefore be considered an alternative to other forms of renal replacement therapy in ARF.

Reduction in size of the ovulatory follicle reduces subsequent luteal size and pregnancy rate

We hypothesized that reducing the size of the ovulatory follicle using aspiration and GnRH would reduce the size of the resulting CL, reduce circulating progesterone concentrations, and alter conception rates. Lactating dairy cows (n=52) had synchronized ovulation and AI by treating with GnRH and PGF(2 alpha) as follows: Day -9, GnRH (100 mug); Day -2, PGF(2 alpha) (25 mg); Day 0, GnRH (100 mug); Day 1, AI. Treated cows (aspirated group; n=29) had all follicles > 4 mm in diameter aspirated on Days -5 or -6 in order to start a new follicular wave. Control cows (nonaspirated group; n=23) had no follicle aspiration. The size of follicles and CL were monitored by ultrasonography. The synchronized ovulation rate (ovulation rate to second GnRH injection; 42/52=80.8%) and double ovulation rate of synchronized cows (6/42=14.3%) did not differ (P > 0.05) between groups. Aspiration reduced the size of the ovulatory follicle (P < 0.0001; 11.5 +/- 0.2 vs 14.5 +/- 0.4 mm), and serum estradiol concentrations at second GnRH treatment (P < 0.0002; 2.5 +/- 0.4 vs 5.7 +/- 0.6 pg/mL). The volume of CL was less (P < 0.05) for aspirated than nonaspirated cows on Day 7 (2,862 +/- 228 vs 5,363 +/- 342 mm(3)) or Day 14 (4,652 +/- 283 vs 6,526 +/- 373 mm(3)). Similarly, serum progesterone concentrations were less on Day 7 (P < 0.05) and Day 14 (P < 0.10) for aspirated cows. Pregnancy rate per AI for synchronized cows was lower (P < 0.05) for aspirated (3/21=14.3%) than nonaspirated (10/21=47.6%) cows. In conclusion, ovulation of smaller follicles produced lowered fertility possibly because development of smaller CL decreased circulating progesterone concentrations. (C) 2001 by Elsevier B.V.