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At least 631 records · Page 35Linked to original sources
PubMed1995

Thickness of patellofemoral articular cartilage as measured on MR imaging: sequence comparison of accuracy, reproducibility, and interobserver variation.

OBJECTIVE: Since the thickness of cartilage is an important indicator of the status, progression and response to therapy of articular disorders, assessment of it is desirable. This study was undertaken to assess the accuracy, precision, and reliability of magnetic resonance (MR) measurements of articular cartilage. METHODS: Fifteen cadaveric patellas were imaged in the axial plane at 1.5 T. Gradient echo and fat-suppressed FSE, T2-weighted, proton density, and T1-weighted sequences were performed. We measured each 5-mm section separately at three standardized positions, giving a total of 900 measurements. These findings were correlated with independently performed measurements of the corresponding anatomic sections. A hundred random measurements were also evaluated for reproducibility and interobserver variation. RESULTS: Although all sequences were highly accurate (range r = 0.78-0.82), the T1-weighted images were the most accurate, with a mean difference of 0.25 mm and a correlation coefficient of 0.85. All sequences were also highly reproducible (mean difference between -0.09 and 0.05 mm) with little inter-observer variation (mean difference -0.04 and 0.11 mm). In an attempt to improve the accuracy of the MR measurements further, we retrospectively evaluated all measurements with discrepancies greater than 1 mm from the specimen. All these differences were attributable to focal defects causing exaggeration of the thickness on MR imaging. CONCLUSION: MR imaging is accurate, precise, and reliable as a basis for measuring articular cartilage and may potentially be usable to monitor progression of articular disorders. Care must be taken not to overestimate the thickness of areas with surface defects.

Adult↗
PubMed1990

Assessment of congestive heart failure in chest radiographs. Observer performance with two common film-screen systems.

The effect of observer variations and film-screen quality on the diagnosis of congestive heart failure based on chest radiographs was studied in 27 patients. For each patient, two films were exposed, one with the Kodak Lanex Medium system and one with the Agfa MR 400 system. The films were presented to three observers who assessed the presence of congestive heart failure on a three-graded scale. The results showed no significant difference between the two systems but large systematic differences between the observers. There were also differences between the two ratings by the same observer that could not be explained by the film-screen factor. It is concluded that the choice between these two systems is of little importance in view of the interobserver and intraobserver variability that can exist within the same department.

Heart Failure↗
PubMed1992

Postprandial gallbladder emptying is related to intestinal motility at the time of meal ingestion.

The characteristics of meal-induced gallbladder emptying in healthy individuals are subject to wide variation. We hypothesized that some of the observed variation might relate to ingestion of the meal during different phases of the migrating motor complex (MMC). Recording of gastrointestinal pressure was combined with scintigraphic recording of bile kinetics during infusion of 99mTc-HIDA. The material consisted of 12 healthy men. Group 1 (n = 6) had a fat-rich meal in phase I, and group 2 (n = 6) had the meal in a phase II. With the end of the meal ingestion as zero, the following results emerged. The subjects in group 1 had a median (range) lag period before beginning of gallbladder emptying of 13.5 (9.0-22.5) min. In group 2 gallbladder emptying began during the meal ingestion in four subjects, and the median lag period was 0 min (minimum, -9.0; maximum, 13.5 (p = 0.02)). The median percentage change of gallbladder counts during the observation period of 54 min in group 1 was 11.5% (from 19% filling to 25% emptying). The corresponding figures in group 2 were 41% (from 2% to 91% emptying (p less than 0.05)). This difference was due to the difference in duration of lag periods, as the emptying rates measured from the end of the lag periods were equal. In conclusion, the onset of postprandial gallbladder emptying relates to the phase activity of the MMC at the time of ingestion.

Adult↗
PubMed2003

Radiographic assessment of the marginal bone level after implant treatment: a comparison of periapical and Scanora detailed narrow beam radiography.

OBJECTIVES: To compare assessments of the marginal bone level around dental implants in the mandible using periapical radiography and Scanora detailed narrow beam (DNB) radiography. METHODS: Forty patients treated with Brnemark dental implants in the lower jaw were examined with periapical and Scanora DNB radiography. Ten implants were selected from each of the four dental regions (molar, incisor, canine, premolar), and no more than one implant was selected from the same patient. Seven observers assessed the level of the marginal bone on the mesial and distal surfaces of the implants. Three of the observers made all the assessments twice. RESULTS: Agreement between the methods was 61%. The highest agreement was found in the molar region. In DNB radiography the marginal bone level was observed to be situated more "coronally" in 17% and more "apically" in 22% compared with periapical radiography. The kappa value for interobserver agreement for all observers was 0.33 for periapical radiography and 0.27 for DNB radiography. The weighted kappa value for intraobserver agreement ranged from 0.75 to 0.99 for DNB radiography and from 0.94 to 0.98 for periapical radiography. CONCLUSIONS: Scanora multimodal radiography simplifies examination of implants in the mandible, and observer variation is comparable with that in intraoral periapical radiography.

Aged↗
PubMed1995

Rotator cuff disorders: interobserver and intraobserver variation in diagnosis with MR imaging.

PURPOSE: To determine interobserver and intraobserver variation in the interpretation of magnetic resonance (MR) images in rotator cuff disorders. MATERIALS AND METHODS: MR images of the shoulder in 97 patients were retrospectively reviewed twice, with a 3-week interval. Surgical findings indicated a full-thickness tear in 29 patients, grade 1 impingement in 19 (tendinitis), and grade 2 impingement (partial tear) in 26. The control population comprised 23 asymptomatic volunteers or patients. RESULTS: All observers were accurate in the diagnosis of a full-thickness tear (89%-98%), with good intraobserver (kappa = 0.67-0.84) and interobserver agreement (kappa = 0.74-0.92). In diagnoses of tendinitis, partial tear, and normal cuff, there were wide ranges of sensitivity (13%-74%) and specificity (72%-93%), as well as poor interobserver (kappa = 0.12-0.60) and intraobserver agreement (kappa = 0.35-0.78). CONCLUSION: Full-thickness tears of the rotator cuff can be accurately identified at MR imaging with little observer variation. Consistent differentiation of normal rotator cuff, tendinitis, and partial thickness tears is more difficult.

Female↗
PubMed1990

Differences between observers in blood pressure measurement with an automatic oscillometric recorder.

Blood pressure measurements made with a Dinamap oscillometric blood pressure recorder by two observers on a total of 2596 male and female subjects aged between 25 and 59 living in nine British towns were examined for evidence of observer differences. After adjusting for age, body mass index and town, significant differences between the two observers were found for systolic pressure, 3.07 mmHg (P = 0.001) for male subjects and 2.08 mmHg (P = 0.036) for female subjects. Observer differences for mean arterial pressure and diastolic pressure were less than 1 mmHg and were not significant. The magnitude of observer differences also varied between towns and, when tested statistically, was significant in male subjects for systolic (P = 0.011), mean arterial (P = 0.009) and diastolic pressure (P = 0.002); for female subjects it was significant only for diastolic pressure (P = 0.023). We conclude that although the highly automated Dinamap has kept observer variation within acceptably low limits in field study conditions, the problem has not been altogether eliminated.

Adult↗
PubMed2004

[Thinking about the evolution of caesarean section rate at University Teaching Hospital of Dakar between 1992 and 2001].

OBJECTIVE: The objective of this study is to answer the question: have we not been doing a lot of caesarean sections at University Teaching Hospital of Dakar? PATIENTS AND METHOD: This is an analytic study about caesarean section in 1992, 1996 and 2001; it was a prospective and longitudinal data collection from the epidemiological survey program carried through in Senegal about its obstetrical and surgical cover. For each year concerned, we have analysed caesarean section rate, maternal mortality rate and perinatal mortality rate. To eliminate the random part in observed variation, we used the comparison of proportions observed as a statistical test with a significant threshold less or equal to 5%. RESULTS: Caesarean section has gone from 12% in 1992 to 17.5 in 1996 and 25.2% in 2001. Operative indications are dominated by foeto-pelvic disproportion with an average of 31% and foetal suffering with an average of 25%. The increasing trend has been statistically significant for information's such as foeto-pelvic disproportion and maternal pathologies. The falling trend was statistically significant for indications in relation on relation to foetal suffering and scarred uterus. Gathering information has shown a stabilisation of "obligatory" caesarean rate around 41%, a decrease in "caution" caesarean rate from 50 to 37.2% and an increase in caesarean by "necessity" from 8.6 to 22.4%. The maternal mortality rate among women delivered has fallen from 1.4% to 0.8%, but postoperative surgery morbidity rate was still high around 10%, essentially due to infections. Reading of caesarean section rate has not a significant impact in perinatal prognosis. DISCUSSION AND CONCLUSION: Today there is an inflation of caesarean section at University Teaching Hospital of Dakar, without any significant loss of the maternal and perinatal mortality rate. The high level of complications due to surgery incite to reverse trends in order to get reasonable rate around 10 to 15% of childbirths.

Adult↗
PubMed2002

Can cardiovascular risk factors explain the association between education and cardiovascular disease in young women?

We sought to explain the observed variation in the relationship between education and cardiovascular disease (CVD) among young women in countries at different stages of economic development. Data comprised 2,478 cases of acute myocardial infarction (AMI) or stroke and 6,819 age-matched controls from Africa, Asia, Eastern Europe, and Latin America. The risks of AMI associated with lower education observed in Eastern Europe and higher education in non-European countries were reduced by 92% in Eastern Europe and totally abolished in non-European countries by adjustment for standard cardiovascular risk factors. The inverse associations between education and stroke risk in the three non-African regions were attenuated by 22, 47, and 60% after adjustment. In Africa, the slight inconsistent trend towards lower stroke risk in less well educated women was unaffected by adjustment. These data suggest that standard risk factors explain a substantial proportion if not all of the difference in AMI risk associated with education but a lesser proportion of educationally linked stroke risk.

Adult↗
PubMed1986

Digestion of milk, fish and soya-bean protein in the preruminant calf: flow of digesta, apparent digestibility at the end of the ileum and amino acid composition of ileal digesta.

1. Digesta were collected from eleven preruminant calves fitted with re-entrant (four calves in Expt 1 and three in Expt 2) or single cannulas (four calves in Expt 1) in the terminal ileum. Collection periods lasted 24 h (Expt 1) or 96 h (Expt 2). 2. Two milk-substitutes (fish and soya bean) and a control diet were given to the calves. In the control diet, protein was entirely provided by skim-milk powder. In the other two diets, protein was provided mainly by a partially hydrolysed white-fish protein concentrate or a soya-bean protein concentrate prepared by extracting soya-bean meal with hot aqueous ethanol. 3. In Expt 1, flow rates of fresh matter, dry matter, nitrogen and ash exhibited two maxima between 6 and 8 h after the morning meal and between 4 and 6 h (control and soya-bean diets) or 6 and 8 h (fish diet) after the evening meal. Minimum pH values were observed at times of maximum flow rate. Variations observed in the flow rates and pH values were larger with fish and especially soya-bean diets than with the control diet. 4. The apparent digestibility of the three diets in the terminal ileum was significantly higher in Expt 2 than in Expt 1: for N, the values were 0.92, 0.83 and 0.75 (Expt 1), and 0.94, 0.87 and 0.88 (Expt 2) with the control, fish and soya-bean diets respectively. 5. The amount of N apparently absorbed in the terminal ileum represented 90-96% of the amount that disappeared from the whole digestive tract in Expt 1 and 95-99% in Expt 2. 6. In Expt 1 the amino acid (AA) composition of digesta changed little with the flow rate when the calves were given the control diet (from 158 to 179 g glutamic acid/kg AA). With the fish and soya-bean diets the AA composition was similar to that observed with the control diet when the flow rate was minimum, but differences became apparent as the flow rate increased (281 and 161 g glutamic acid/kg AA for the soya-bean and control diets respectively with maximum flow rate). In Expt 2, the mean compositions of the digesta were very similar to the means obtained in Expt 1. 7. Different comparisons with dietary, endogenous and bacterial proteins indicated that for the three diets a common mixture containing approximately 65% endogenous and 35% bacterial proteins reached the terminal ileum.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗
PubMed1989

Comparisons of the structural proteins of avian infectious bronchitis virus as determined by western blot analysis.

The antigenic diversity of ten strains of avian infectious bronchitis virus (IBV) was examined by Western blot analyses using polyclonal antisera specific for the Massachusetts 41 (M41), Gray, Arkansas DPI (Ark DPI), Connecticut (Conn) and Australian T (Aust T) serotypes. Although antigenic variation was found in all three structural viral proteins, the matrix protein appeared to be antigenically the most highly variable. Four distinct antigenic groups, which did not correspond to virulence or pathotype, could be defined according to the variations observed in the matrix protein. Somewhat less variation was seen in the spike polypeptide. The only variation in the nucleocapsid protein was indicated by the lack of a detectable reaction between the Aust T antiserum and the Ark DPI nucleocapsid protein. Antisera made against M41 had the broadest reactivity while antisera against Aust T, the only strain tested which was exotic to the U.S.A., had the greatest specificity.

Animals↗
PubMed2005

A variability study of computerized sagittal spinopelvic radiologic measurements of trunk balance.

OBJECTIVE: The accurate measurement of spinal and pelvic alignment in the sagittal plane is of prime importance for various disorders. Pelvic incidence (PI) is a fundamental anatomic parameter that is specific and constant for each adult individual and is related to pelvic orientation as well as to the size of lumbar lordosis (LL). It is the summation of the sacral slope (SS) and pelvic tilt (PT), two position-dependent variables that determine pelvic orientation in the sagittal plane. The authors have proposed a computer software designed to measure PI, SS, PT, LL, and thoracic kyphosis (TK) on standardized standing lateral digitized x-rays of the spine and pelvis. The purpose of this study was to evaluate the inter- and intraobserver variability of measurements using this software, to determine if it can be used reliably in a clinical environment. METHODS: The standing lateral x-rays of 30 subjects were randomly selected from the database of two medical institutions. The normal population had standard radiographs on which the various pertinent landmarks were marked by one operator prior to digitization, whereas the scoliotic population had digital radiographs that obviated the need for prior marking of landmarks. Four individuals measured all variables on the 30 x-rays on two occasions, with a 15-day interval between the two sessions. Statistical analysis was done with intraclass correlation coefficients (ICCs). RESULTS: The ICC measured within observers was between 0.93 and 0.99, whereas the ICC between observers varied between 0.92 and 0.99. The variations observed were similar for normal and scoliotic subjects, and prior marking of the x-rays had no significant influence. CONCLUSION: We conclude that the variability of measurements with this method is lower than with similar radiologic measures done manually and that the use of this software can be recommended for future clinical and research studies of spinopelvic sagittal balance.

Adult↗
PubMed2003

Discrepancies between ordered and delivered concentrations of opiate infusions in critical care.

OBJECTIVES: We sought to test the assumption that the measured concentrations of medication infusions are within pharmaceutical standards (+/-10% of intended concentrations) and whether, at the time the infusion was mixed, the professional background of persons preparing the infusion or the unit for which the infusion was prepared were related to the observed variation. DESIGN, SETTING, AND PARTICIPANTS: This prospective, observational study was conducted in the neonatal and pediatric intensive care units of a university-affiliated tertiary pediatric center. Morphine infusions prepared for clinical use were randomly sampled over a 7-month period. Those with no error between labeled and ordered concentration were further analyzed. High-performance liquid chromatography was used to determine the concentration of morphine infusions. The primary outcome was a difference of >10% between ordered and measured concentrations. MEASUREMENTS AND MAIN RESULTS: The measured concentration of 65% of the 232 infusions was >10% different from the ordered concentration (95% confidence interval, 58-71%). The concentrations of 6% of infusions represented two-fold errors (95% confidence interval, 3-9%). The difference was normally distributed around zero, suggesting a cumulative effect of random errors, rather than a systematic bias. The time that the infusion was prepared, the professional background of the persons preparing the infusion, and the unit for which the infusion was mixed were not significant predictors of discrepancy (p =.74, analysis of variance). CONCLUSIONS: The concentration of two thirds of infusions prepared for clinical use was outside accepted industry standards. These findings are likely to be broadly representative of intravenous drug administration in hospitalized children and pediatric pharmacokinetic studies. Further study of the causes and clinical impact is required.

Critical Care↗
PubMed1992

Inadequacy of the WHO classification of the thyroid gland.

In order to evaluate the reproducibility of the WHO classification of goitre, the observer variation was estimated as kappa coefficients. Three observers independently inspected and palpated the thyroid gland of 53 patients twice and assessed the thyroid according to the five grades of the WHO classification. The thyroid volume was also measured by ultrasonography. We found kappa values from 0.15 to 0.70 in the interobserver study, and from 0.02 to 0.89 in the intraobserver study. Considerable overlap between the five grades was demonstrated when the assessments were related to volume estimated by ultrasonography. Description of the thyroid gland according to the WHO classification is inaccurate and not reproducible and is therefore of limited value.

Adult↗
PubMed1992

Relation between fibrositic and control site tenderness; effects of dolorimeter scale length and footplate size.

Recent data have suggested a correlation between the tenderness measured at tender and control sites, differing from earlier studies indicating site specific tenderness. In our study, the "constant control" model is tested against the "correlated control" model, in which control site tenderness varies with fibrositic site tenderness. Our study also addresses relevant technical issues in dolorimetry. We measured threshold of tenderness at 4 sites (2 fibrositic and 2 control) on 21 subjects, using dolorimeters with a 17 kg scale limit, and 3 different footplates, 0.7, 1.4 and 2.0 cm in diameter. To measure observer variation, we used multiple replications by multiple observers, obtaining in all 1,416 observations. There was a strong relationship between control and fibrositic site tenderness with control thresholds twice as high (half as tender). Scale length and dolorimeter footplate size each had important effects. The site specific approach is valuable diagnostically, but more broadly operative mechanisms should be the focus of research and therapy.

Adult↗
PubMed1981

Pharmacokinetic comparison of seven 8-methoxypsoralen brands.

The pharmacokinetics of seven 8-MOP brands were evaluated in 7 volunteers using an incomplete bloc design. After a single oral dose the 8-MOP plasma level was followed for 3 hours. The plasma concentration was measured with a gas chromatographic - mass spectrometric method, using an isotopic dilution technique. The different brands could be divided into three groups. Two gave a high maximum concentration, four a medium, and one a low concentration. The large interbrand variation observed in this study can explain the variations in the results of the treatment and the differing numbers of joules required to clear the patients in various PUVA centers.

Adult↗
PubMed1994

Comparative bioavailability of two suspension formulations of potassium diclofenac in healthy male volunteers.

The bioavailability of two suspension formulations of potassium diclofenac (Flogan, Merck and Cataflam, Ciba-Geigy) were compared in eighteen healthy male volunteers who received a single dose of 7 ml of each suspension (equivalent to 105 mg of potassium diclofenac) in an open randomized two period crossover design, with a fourteen-day washout period between doses. Serum samples were obtained over a 24 hour interval and diclofenac concentrations were determined by HPLC with ultraviolet detection. From the serum diclofenac concentration vs time curves, AUC[0-24] (area under the concentration vs time curves from 0-24 h), Cmax (maximum achieved concentration), Tmax (time to achieve Cmax) and Ke (terminal first order elimination constant) were obtained. Overlapping of Tmax intervals for both formulations was observed, but the important inter-subject variation observed in Cmax ratios did not allow equivalence conclusion for the rate of absorption. Equivalence in the extent of bioavailability between both potassium diclofenac suspension brands was concluded from the analysis of AUC[0-24] ratios.

Adult↗
PubMed1990

Effect of acquisition and analysis routines on gated blood pool measurements.

Results obtained from gated equilibrium blood pool (GBP) studies are not only dependent on intrinsic variations, but also on the way in which images are acquired and analysed. The aim of this study was to investigate factors which could affect left ventricular time-activity curves. Temporal resolution was studied by comparing studies of 20 and 40 frames beat-1. Forty frames per beat resulted in a mean left ventricular ejection fraction of 0.48 compared to 0.46 for 20 frames beat-1. The mean difference of 0.02 was significant (P less than 0.01) as was the mean difference in maximum emptying rate (MER = 0.28, P less than 0.01) and in maximum filling rate (MFR = 0.38, P less than 0.01). No significant differences in ejection fraction (EF) values were found between acquisitions made in list and frame mode, but the mean differences for MER = 0.03 (P less than 0.05) and MFR = 0.01 (P less than 0.02) were significant. For patient repositioning and intra-observer variations no significant differences were found. In patients with normal EF values (greater than 0.5) no significant differences were found in the inter-observer study. In patients with anterior myocardial infarction (AMI), significant differences were found in EF, MER and MFR (EF = 0.02, P less than 0.001; MER = 0.2, P less than 0.01; MFR = 0.24, P less than 0.01). Significant differences were found in all values when comparing a semi-automatic method of evaluation with two automatic methods. In conclusion the results from this study suggest that acceptable reproducibility can be achieved in GBP studies, provided the method of analysis is not changed between studies.

Coronary Circulation↗