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At least 307 records · Page 17Linked to original sources
PubMed2006

Accuracy of endoscopic ultrasound staging of gastric cancer in routine clinical practice in Singapore.

OBJECTIVE: Endoscopic ultrasound has emerged as the leading modality to assess the T and N stage in gastric cancer. This study aimed to assess the accuracy of TN staging by endoscopic ultrasound in routine clinical practice in Singapore. METHODS: Over a period of 7 years, 77 patients (male: 70%; median age 62.8 years) with gastric cancer underwent preoperative staging with endoscopic ultrasound. Fifty-seven patients eventually underwent surgery with tissues available for histopathological staging and comparison. RESULTS: The tumor locations were: cardia: 13; corpus: 20; incisura: 19; antrum: 25. The majority was poorly differentiated (57.1%); 26% were moderately differentiated and 16.9% were well differentiated adenocarcinoma. Compared to pathological staging, the overall accuracy of T staging by endoscopic ultrasound was 77.2% (17.5% under-staged: 5.3% over-staged). The staging accuracy of T1 (92.9%) and T3 (81.8%) was higher than T2 (57.1%) and T4. For N staging, the accuracy of endoscopic ultrasound was 59.6% (26.3% under-staged; 14% over-staged); this was significantly superior to computer tomography (43.9%). CONCLUSION: Endoscopic ultrasound is useful for the T staging of gastric cancer, with an overall accuracy rate of 77%, and up to 93% for T1 lesions. Under-staging may occur due to microscopic tumor infiltration, while over-staging may arise due to inflammatory reactions. The accuracy of N staging is lower at 60%, but could be further improved with the use of fine needle aspiration.

Adult↗
PubMed2006

Brief report: beyond clinical experience: features of data collection and interpretation that contribute to diagnostic accuracy.

BACKGROUND: Clinical experience, features of data collection process, or both, affect diagnostic accuracy, but their respective role is unclear. OBJECTIVE, DESIGN: Prospective, observational study, to determine the respective contribution of clinical experience and data collection features to diagnostic accuracy. METHODS: Six Internists, 6 second year internal medicine residents, and 6 senior medical students worked up the same 7 cases with a standardized patient. Each encounter was audiotaped and immediately assessed by the subjects who indicated the reasons underlying their data collection. We analyzed the encounters according to diagnostic accuracy, information collected, organ systems explored, diagnoses evaluated, and final decisions made, and we determined predictors of diagnostic accuracy by logistic regression models. RESULTS: Several features significantly predicted diagnostic accuracy after correction for clinical experience: early exploration of correct diagnosis (odds ratio [OR] 24.35) or of relevant diagnostic hypotheses (OR 2.22) to frame clinical data collection, larger number of diagnostic hypotheses evaluated (OR 1.08), and collection of relevant clinical data (OR 1.19). CONCLUSION: Some features of data collection and interpretation are related to diagnostic accuracy beyond clinical experience and should be explicitly included in clinical training and modeled by clinical teachers. Thoroughness in data collection should not be considered a privileged way to diagnostic success.

Clinical Competence↗
PubMed1989

Effect of disinfecting solutions on accuracy of alginate and elastomeric impressions.

The effect of immersion in six disinfecting solutions on the accuracy of 10 impression materials was investigated. Impressions were taken of a truncated steel cone. After setting, the impressions were either stored at room temperature for 24 h, for control, or immediately immersed in a disinfecting agent for 60 min (in one case 10 min), and after 24 h poured with gypsum. A steel ring fitting the steel cone was placed on the resulting dies, and the discrepancy between the top surface of the ring and the die was measured. From these measurements the deviation between the base diameter of the die and of the impression was calculated to express the inaccuracy. All impressions except some in Blueprint exhibited a net shrinkage, giving rise to too large die stones and incomplete seating of the steel ring. Blueprint impressions, however, occasionally swelled and resulted in too small die stones and "overseating" of the steel ring. The disinfecting solutions had no significant impact on two impression materials. For the remaining eight materials the accuracy was decreased, increased, or unaffected by the immersion. Generally, the accuracy of the alginates investigated were more affected by the disinfecting solutions than were the elastomeric impression materials. The accuracy of the three alginates was drastically impaired by immersion in 70% ethanol, whereas the remaining five disinfecting solutions had a smaller, though sometimes statistically significant, effect on the accuracy. For the elastomeric materials only a few specific combinations of impression material and disinfecting solution reduced the accuracy.(ABSTRACT TRUNCATED AT 250 WORDS)

Alginates↗
PubMed2001

Accuracy limits in the determination of absolute optical properties using time-resolved NIR spectroscopy.

We assess typical systematic experimental errors involved in a time-resolved measurement as applied to NIR diffuse optical spectroscopy and investigate their effect on the quantification accuracy of the absorption and the reduced scattering coefficient. We demonstrate that common systematic experimental uncertainties may lead to quantification errors of 10% or more, even when excellent signal to noise ratio conditions exist and accurate photon propagation models are employed. We further demonstrate that the accuracy of the calculation depends nonlinearly on the optical properties of the medium measured. High scattering and low absorbing media can be quantified more accurately than media with low scattering or high absorption using measurements of the same signal to noise ratio. We further discuss curve-shape fitting schemes that aid in improving the quantification accuracy in the presence of experimental errors. Finally, we identify uncertainties that set quantification accuracy limits and we find temporal resolution as the ultimate limiting factor in the quantification accuracy achieved. Our findings suggest that temporal resolution of the order of 10 ps is necessary for quantifying the absorption and reduced scattering coefficient of diffuse media with accuracy better than 5% using curve fitting methods. In that sense this analysis can be used in time-resolved system design and in predicting the expected errors given the technology selected for time-resolved measurements.

Biophysical Phenomena↗
PubMed2006

Accuracy of treatment planning based on stereolithography in computer assisted surgery.

Three-dimensional stereolithographic models (SL models), made of solid acrylic resin derived from computed-tomography (CT) data, are an established tool for preoperative treatment planning in numerous fields of medicine. An innovative approach, combining stereolithography with computer-assisted point-to-point navigation, can support the precise surgical realization of a plan that has been defined on an SL model preoperatively. The essential prerequisites for the application of such an approach are: (1) The accuracy of the SL models (including accuracy of the CT scan and correspondence of the model with the patient's anatomy) and (2) the registration method used for the transfer of the plan from the SL model to the patient (i.e., whether the applied registration markers can be added to the SL model corresponding to the markers at the patient with an accuracy that keeps the "cumulative error" at the end of the chain of errors, in the order of the accuracy of contemporary navigation systems). In this study, we focus on these two topics: By applying image-matching techniques, we fuse the original CT data of the patient with the corresponding CT data of the scanned SL model, and measure the deviations of defined parameter (e.g., distances between anatomical points). To evaluate the registration method used for the planning transfer, we apply a point-merge algorithm, using four marker points that should be located at exactly corresponding positions at the patient and at connective bars that are added to the surface of the SL model. Again, deviations at defined anatomical structures are measured and analyzed statistically. Our results prove sufficient correspondence of the two data sets and accuracy of the registration method for routine clinical application. The evaluation of the SL model accuracy revealed an arithmetic mean of the relative deviations from 0.8% to 5.4%, with an overall mean deviation of 2.2%. Mean deviations of the investigated anatomical structures ranged from 0.8 mm to 3.2 mm. An overall mean (comprising all structures) of 2.5 mm was found. The fiducial registration error of the point-merge algorithm ranged from 1.0 mm to 1.4 mm. The evaluated chain of errors showed a mean deviation of 2.5 mm. This study verifies that preoperative planning on SL models and intraoperative transfer of this plan with computer assisted navigation is a suitable and sufficiently reliable method for clinical applications.

Algorithms↗
PubMed2004

A multicentre randomised controlled trial of an intervention to improve the accuracy of linear growth measurement.

AIMS: To evaluate linear growth assessment and the effect of an intervention on measurement accuracy in primary care practices (PCP) within eight US geographical areas. METHODS: In this multicentre randomised controlled intervention study, paediatric endocrine nurses as site coordinators (SC) visited 55 randomly assigned PCP to evaluate growth assessment of staff performing linear measurements. SC observed 127 measurers assessing a total of 878 children: 307 (baseline), 282 (3 months), and 289 (6 months). Accuracy was determined by SC re-measuring each child with correct technique and equipment. State of the art equipment and a standardised growth training session were provided to the intervention group (IG) following the baseline visit. SC repeated data collection at all PCP at 3 and 6 months. RESULTS: There were no baseline differences between IG and CG equipment, technique, or accuracy; only 30% of measurements were accurate (< or =0.5 cm from SC). Post-intervention, significantly more IG measurements were accurate: IG = 55%, CG = 37% at 3 months; IG = 70%, CG = 34% at 6 months. Odds ratio of accuracy for IG versus CG was 2.1 at 3 months and 4.5 at 6 months. At 6 months, mean difference from the SC measurements was 0.5 cm in IG and 1.1 cm in CG. CONCLUSIONS: In PCP, children are measured inaccurately. Our intervention significantly improved measurement accuracy. Improved accuracy could yield more rapid detection and diagnosis of paediatric growth disorders.

Adolescent↗
PubMed2005

Effect of one or more co-morbid conditions on diagnostic accuracy of coronary flow velocity reserve for detecting significant left anterior descending coronary stenosis.

OBJECTIVE: To determine the effect of one or multiple co-morbid conditions on the diagnostic accuracy of coronary flow velocity reserve (CFVR) in a heterogeneous patient population. METHODS: CFVR was measured in the left anterior descending coronary artery (LAD) by transthoracic Doppler echocardiography (TTDE) in 318 consecutive patients before elective coronary angiography. CFVR was calculated as the average peak diastolic velocity during intravenous ATP infusion divided by baseline flow velocity. All patients underwent coronary angiography within 48 hours. Significant LAD stenosis was defined as > 50% luminal narrowing. Diagnostic accuracy of CFVR was analysed according to the type and number of risk factors that may adversely affect microvascular function. RESULTS: CFVR was measured in 309 patients, of whom 105 were found to have significant LAD stenosis based on coronary angiography. CFVR < 2.0 had a sensitivity of 86% and a specificity of 77% for predicting significant LAD stenosis. Left ventricular hypertrophy (LVH) was the only factor that significantly lowered diagnostic accuracy (61% with LVH v 84% without LVH, p < 0.001). Diagnostic accuracy was not affected by increasing number of risk factors. CONCLUSIONS: The diagnostic accuracy of CFVR by TTDE for detecting significant LAD stenosis remains high in a more clinically relevant population with multiple cardiovascular co-morbidities. Only the presence of LVH adversely affected diagnostic accuracy.

Adult↗
PubMed2002

Shoulder instability: accuracy of MR imaging performed after surgery in depicting recurrent injury--initial findings.

PURPOSE: To analyze a series of postoperative magnetic resonance (MR) images obtained in patients with recurrent signs or symptoms of instability in whom subsequent surgical correlation was performed to determine the accuracy in diagnosing recurrent injury. MATERIALS AND METHODS: The authors identified 24 patients who underwent MR imaging after shoulder instability surgery and had recurrent instability requiring repeat surgery. Twelve nonenhanced MR images and six indirect and six direct MR arthrograms were retrospectively reviewed with consensus to determine the presence or absence of recurrent labral or rotator cuff tear. Operative reports were reviewed to confirm the presence or absence of labral or rotator cuff tear. The mean interval between initial surgery and MR imaging was 10 months. The mean interval until repeat surgery was 2 months. RESULTS: Overall, the accuracy of postoperative MR imaging was 79% in depicting recurrent labral tear and 88% in depicting recurrent rotator cuff tear. Indirect MR arthrography had 100% accuracy for recurrent labral tear detection, whereas direct MR arthrography and nonenhanced MR imaging had accuracies of 67% and 75%, respectively. Direct MR arthrography was more sensitive, 100% versus 71%, but less specific, 60% versus 80%, than nonenhanced MR imaging in depicting recurrent labral tears. Direct MR arthrography had 100% accuracy in depicting rotator cuff tear, whereas both indirect MR arthrography and nonenhanced MR imaging had 83% accuracy. CONCLUSION: MR imaging, indirect MR arthrography in particular, appears to be an accurate means of evaluating the shoulder following instability surgery.

Adult↗
PubMed2005

Association between compliance with methodological standards of diagnostic research and reported test accuracy: meta-analysis of focused assessment of US for trauma.

PURPOSE: To study whether compliance with methodological standards affected the reported accuracy of screening ultrasonography (US) for trauma. MATERIALS AND METHODS: Meta-analysis was conducted of prospective investigations in which US was compared with any diagnostic reference test in patients with suspected abdominal injury. Reports were retrieved from electronic databases without language restrictions; added information was gained with manual search. Two reviewers independently assessed methodological rigor by using 27 items contained in the Standards for Reporting of Diagnostic Accuracy (STARD) checklist and the Quality Assessment of Studies of Diagnostic Accuracy included in Systematic Reviews (QUADAS) instrument. Inconsistencies were resolved by means of consensus. Summary receiver operating characteristics and random-effects meta-regression were used to model the effect of methodological standards and other study features on US accuracy. RESULTS: A total of 62 trials, which included a total of 18,167 participants, were eligible for meta-analysis. The average proportion of men or boys was 71.7%, the mean age was 30.6 years +/- 10.8 (standard deviation), and the mean injury severity score was 16.7 +/- 8.3. The prevalence of abdominal trauma was 25.1% (95% confidence interval [CI]: 21.1%, 29.1%). Pooled overall sensitivity and specificity of US were 78.9% (95% CI: 74.9%, 82.9%) and 99.2% (95% CI: 99.0%, 99.4%), respectively. Varying end points (hemoperitoneum or organ damage) did not change these results. US accuracy was much lower in children (sensitivity, 57.9%; specificity, 94.3%). Strong heterogeneity was observed in sensitivity, whereas specificity remained constant across trials. There was evidence of publication bias. Initial interobserver agreement with methodological standards ranged from poor (kappa = 0.03, independent verification of US findings) to perfect (kappa = 1.00, sufficiently short interval between US and reference test). By consensus, studies fulfilled a median of 13 methodological criteria (range, five to 20 criteria). In investigations that lacked individual methodological standards, researchers overestimated pooled sensitivity, with predicted differences of 9%-18%. The use of a single reference test, specification of the number of excluded patients, and calculation of CIs independently contributed to predicted sensitivity in a multivariate model. In 16 investigations (1309 subjects), a single reference test was used, which provided a combined sensitivity of 66.0% (95% CI: 56.2%, 75.8%). CONCLUSION: Bias-adjusted sensitivity of screening US for trauma is low. Adherence to methodological standards included in appraisal instruments like STARD and QUADAS is crucial to obtain valid estimates of test accuracy.

Abdominal Injuries↗
PubMed2006

Abdominal and iliac arterial stenoses: comparative double-blinded randomized study of diagnostic accuracy of 3D MR angiography with gadodiamide or gadopentetate dimeglumine.

PURPOSE: To prospectively evaluate accuracy of gadolinium-enhanced three-dimensional (3D) magnetic resonance (MR) angiography with gadodiamide and gadopentetate dimeglumine (0.1 mmol/kg), with intraarterial DSA as reference standard, for imaging abdominal and iliac arterial stenoses. MATERIALS AND METHODS: The study was approved by all institutional review boards; informed consent was obtained from each subject before procedures. Two hundred forty-seven subjects were included; 240 received either contrast agent and were available for safety analysis; 222 were available for accuracy analysis. Enhanced 3D MR angiography and DSA were performed; image data were evaluated in a double-blinded randomized study. Stenoses were classified as not relevant (<50% stenosis) or relevant (> or =50%). For detection of main stenosis, accuracy with enhanced 3D MR angiography compared with that with DSA was determined. RESULTS: The difference in accuracy for imaging with gadodiamide and gadopentetate was 3.6%. Noninferiority was inferred because the lower bound of the exact two-sided 95% confidence interval was -10.1 and was above the noninferiority margin (-15%). Accuracy for detection of the main stenosis was low, 56.4% for gadodiamide and 52.8% for gadopentetate group. Subgroup analysis with exclusion of inferior mesenteric artery and internal iliac arteries and the most false-positive stenosis classifications yielded better results: 76.6% and 71.6%, respectively. Sensitivity, specificity, and negative and positive predictive values did not differ substantially between study groups. In the main analysis, values were 44%, 96%, 35%, and 97% for gadodiamide and 44%, 83%, 30%, and 90% for gadopentetate, respectively. In the subgroup analysis, values were 66%, 95%, 61%, and 96% for gadodiamide and 63%, 86%, 58%, and 88% for gadopentetate, respectively. CONCLUSION: Noninferiority of gadodiamide versus gadopentetate was verified based on the primary end point, which was accuracy for detection of the main stenosis with enhanced 3D MR angiography compared with DSA.

Abdomen↗
PubMed1981

Lymphographic accuracy in 632 consecutive, previously untreated cases of Hodgkin disease and non-Hodgkin lymphoma.

The accuracy of lymphography was prospectively evaluated in a series of 632 consecutive, unselected patients with Hodgkin disease and non-Hodgkin lymphoma. The cases were newly diagnosed and previously untreated. The following five parameters of lymphographic accuracy were achieved: sensitivity 91%, specificity 91%, overall accuracy 91%, accuracy of positive diagnosis 84%, and accuracy of negative diagnosis 95%. Before this useful imaging modality is prematurely abandoned, comparable studies of the accuracy of ultrasound and computed tomography, perhaps with a less extensive series, should be carried out.

Evaluation Studies as Topic↗
PubMed1998

Comparison of S-T segment/heart rate slope with exercise thallium imaging and conventional S-T segment criteria in detecting coronary artery disease: effect of exercise level on accuracy.

The S-T segment/heart rate (ST/HR) slope has been proposed as a more accurate electrocardiographic criterion for the diagnosis of coronary artery disease, but studies comparing the diagnostic value of the ST/HR slope with exercise thallium imaging are scant. The aims of this study were to assess the diagnostic accuracy of the ST/HR slope, conventional S-T segment criteria and exercise thallium imaging in detecting coronary artery disease and to evaluate the effect of exercise level on the sensitivity and specificity of these three techniques. Ninety consecutive patients underwent treadmill testing and exercise thallium single-photon emission computed tomography (SPECT) simultaneously. All 90 patients also underwent coronary angiography within 1 month of the exercise test. We found that exercise thallium SPECT had a significantly higher diagnostic accuracy than either the ST/HT slope or conventional S-T segment criteria (thallium imaging 82%, ST/HR slope 67%, conventional S-T segment criteria 63%). The overall accuracy of the ST/HR slope was slightly but insignificantly greater than conventional S-T segment criteria (ST/HR slope 67%, conventional S-T segment criteria 63%; p = 0.639). In 50 patients with a lower exercise level, defined as not achieving 85% of their maximal predicted heart rate, the accuracy of the ST/HR slope was insignificantly greater (ST/HR slope 72%, conventional S-T segment criteria 66%; p = 0.517). In 40 patients with adequate exercise, the accuracy rate was the same (60%) for both the ST/HR slope and conventional S-T segment criteria. We conclude that exercise thallium imaging is more accurate than the ST/HR slope in diagnosing coronary artery disease and that the accuracy of the ST/HR slope is marginally better than conventional S-T segment criteria only in patients with a lower exercise level, and not in those with adequate exercise.

Cardiac Catheterization↗
PubMed2006

The scaling of winner-takes-all accuracy with population size.

Empirical studies seem to support conflicting hypotheses with regard to the nature of the neural code. While some studies highlight the role of a distributed population code, others emphasize the possibility of a "single-best-cell" readout. One particularly interesting example of single-best-cell readout is provided by the winner-takes-all (WTA) approach. According to the WTA, every cell is characterized by one particular preferred stimulus, to which it responds maximally. The WTA estimate for the stimulus is defined as the preferred stimulus of the cell with the strongest response. From a theoretical point of view, not much is known about the efficiency of single-best-cell readout mechanisms, in contrast to the considerable existing theoretical knowledge on the efficiency of distributed population codes. In this work, we provide a basic theoretical framework for investigating single-best-cell readout mechanisms. We study the accuracy of the WTA readout. In particular, we are interested in how the WTA accuracy scales with the number of cells in the population. Using this framework, we show that for large neuronal populations, the WTA accuracy is dominated by the tail of the single-cell-response distribution. Furthermore, we find that although the WTA accuracy does improve when larger populations are considered, this improvement is extremely weak compared to other types of population codes. More precisely, we show that while the accuracy of a linear readout scales linearly with the population size, the accuracy of the WTA readout scales logarithmically with the number of cells in the population.

Action Potentials↗
PubMed2003

Accuracy of a system for creating 3D computer models of dental arches.

Three-dimensional imaging of dental tissues will have a major impact in dentistry if the images are accurate. The purpose of this study was to measure the accuracy and precision of a system for creating three-dimensional images of dental arches. Using vinyl polysiloxane impression materials and improved dental stone, we made 10 stone casts of a "dental" standard with known dimensions. The impressions and casts were scanned by means of a Comet 100 optical scanner. Custom software created three-dimensional images (computer models) from the scanned data. Accuracy was defined as the average of the absolute differences between the computer models and the standard. Precision was the standard deviation of accuracy over 10 repeated measures. Software processing improved the accuracy of the scanner data. Accuracy +/- precision for the casts and impressions was 0.024 +/- 0.002 mm and 0.013 +/- 0.003 mm, respectively. The system produced computer models with sufficient accuracy for clinical application.

Algorithms↗
PubMed2006

Metabolomic database annotations via query of elemental compositions: mass accuracy is insufficient even at less than 1 ppm.

BACKGROUND: Metabolomic studies are targeted at identifying and quantifying all metabolites in a given biological context. Among the tools used for metabolomic research, mass spectrometry is one of the most powerful tools. However, metabolomics by mass spectrometry always reveals a high number of unknown compounds which complicate in depth mechanistic or biochemical understanding. In principle, mass spectrometry can be utilized within strategies of de novo structure elucidation of small molecules, starting with the computation of the elemental composition of an unknown metabolite using accurate masses with errors <5 ppm (parts per million). However even with very high mass accuracy (<1 ppm) many chemically possible formulae are obtained in higher mass regions. In automatic routines an additional orthogonal filter therefore needs to be applied in order to reduce the number of potential elemental compositions. This report demonstrates the necessity of isotope abundance information by mathematical confirmation of the concept. RESULTS: High mass accuracy (<1 ppm) alone is not enough to exclude enough candidates with complex elemental compositions (C, H, N, S, O, P, and potentially F, Cl, Br and Si). Use of isotopic abundance patterns as a single further constraint removes >95% of false candidates. This orthogonal filter can condense several thousand candidates down to only a small number of molecular formulas. Example calculations for 10, 5, 3, 1 and 0.1 ppm mass accuracy are given. Corresponding software scripts can be downloaded from http://fiehnlab.ucdavis.edu. A comparison of eight chemical databases revealed that PubChem and the Dictionary of Natural Products can be recommended for automatic queries using molecular formulae. CONCLUSION: More than 1.6 million molecular formulae in the range 0-500 Da were generated in an exhaustive manner under strict observation of mathematical and chemical rules. Assuming that ion species are fully resolved (either by chromatography or by high resolution mass spectrometry), we conclude that a mass spectrometer capable of 3 ppm mass accuracy and 2% error for isotopic abundance patterns outperforms mass spectrometers with less than 1 ppm mass accuracy or even hypothetical mass spectrometers with 0.1 ppm mass accuracy that do not include isotope information in the calculation of molecular formulae.

Algorithms↗
PubMed2004

The urine dipstick test useful to rule out infections. A meta-analysis of the accuracy.

BACKGROUND: Many studies have evaluated the accuracy of dipstick tests as rapid detectors of bacteriuria and urinary tract infections (UTI). The lack of an adequate explanation for the heterogeneity of the dipstick accuracy stimulates an ongoing debate. The objective of the present meta-analysis was to summarise the available evidence on the diagnostic accuracy of the urine dipstick test, taking into account various pre-defined potential sources of heterogeneity. METHODS: Literature from 1990 through 1999 was searched in Medline and Embase, and by reference tracking. Selected publications should be concerned with the diagnosis of bacteriuria or urinary tract infections, investigate the use of dipstick tests for nitrites and/or leukocyte esterase, and present empirical data. A checklist was used to assess methodological quality. RESULTS: 70 publications were included. Accuracy of nitrites was high in pregnant women (Diagnostic Odds Ratio = 165) and elderly people (DOR = 108). Positive predictive values were >/=80% in elderly and in family medicine. Accuracy of leukocyte-esterase was high in studies in urology patients (DOR = 276). Sensitivities were highest in family medicine (86%). Negative predictive values were high in both tests in all patient groups and settings, except for in family medicine. The combination of both test results showed an important increase in sensitivity. Accuracy was high in studies in urology patients (DOR = 52), in children (DOR = 46), and if clinical information was present (DOR = 28). Sensitivity was highest in studies carried out in family medicine (90%). Predictive values of combinations of positive test results were low in all other situations. CONCLUSIONS: Overall, this review demonstrates that the urine dipstick test alone seems to be useful in all populations to exclude the presence of infection if the results of both nitrites and leukocyte-esterase are negative. Sensitivities of the combination of both tests vary between 68 and 88% in different patient groups, but positive test results have to be confirmed. Although the combination of positive test results is very sensitive in family practice, the usefulness of the dipstick test alone to rule in infection remains doubtful, even with high pre-test probabilities.

Adult↗
PubMed2005

Accuracy of body composition measurements by dual energy x-ray absorptiometry in underweight patients with chronic intestinal disease and in lean subjects.

BACKGROUND: To assess the accuracy of Dual-energy X-ray absorptiometry (DXA) in underweight patients with chronic gastrointestinal disease, we investigated the ability of DXA to detect variations in body composition induced by infusion of parenteral nutrition (PN). Furthermore, the influence of a low body weight per se on the accuracy of DXA was studied by placing packets of lard on lean healthy subjects. METHODS: The hydration study included 11 patients with short bowel syndrome on long-term home parenteral nutrition (9 women and 2 men), and (mean +/- SD) 49.5 +/- 17.1 yr., 19.3 +/- 3.1 kg/m2. The lard study, where packets of lard were placed either over the thighs or the trunk region, was performed in 8 healthy lean male volunteers, 26.4 +/- 7.4 yr., and 21.0 + 0.9 kg/m2. Body composition, including measures of the total mass (TM), soft tissue mass (STM), lean tissue mass (LTM), fat mass (FM), and total body mineral content (TBBMC), was assessed by DXA. The fat fraction of the lard packets (3.49 kg), measured in triplicate by chemical fat extraction, was 52.2%. RESULTS: Hydration study; The increase in scale weight (BW) of approximately 0.90 kg due to infusion of PN correlated significantly to the increase in TM (R-square = 0.72, SEE 0.36 kg, p < 0.01), and the increase in STM (R-square = 0.69, SEE 0.38 kg, p < 0.01), however not with the increase LTM (R-square = 0.30, SEE 1.06 kg, p = 0.08). Mean changes in TM (0.88 kg), STM (0.88 kg), and LTM (0.81 kg) were not significantly different from changes in BW (p > 0.05). Lard study; Regardless of position, measurements of FM and LTM of the added lard were not significantly different from expected values. However, the composition of the lard packets into FM and LTM was more accurately detected when the packets were placed over the thighs than over the trunk region. The accuracy of DXA in individual subjects, expressed as the SD of the difference between expected and measured values, was 1.03 kg and 1.06 kg for the detection of changes in LTM and FM, respectively, and 0.18 kg for the detection of changes in STM and TM. CONCLUSIONS: On a group level, DXA provided sufficient accuracy to detect small changes in body composition in underweight patients with chronic gastrointestinal disease. However, the accuracy errors were higher than reported in normal weight subjects. The accuracy was not influenced by a low body weight per se.

Journal Article↗
PubMed2000

Accuracy of physical and occupational therapists' early predictions of recovery after severe middle cerebral artery stroke.

INTRODUCTION: The ability of physical therapists (PTs) and occupational therapists (OTs) to predict level of outcome accurately was investigated prospectively in 91 severely disabled stroke patients with a first-ever middle cerebral artery (MCA) stroke. METHODS: Within the second and fifth week after stroke onset, 364 predictions were made by 59 PTs and 47 OTs about walking ability, dexterity, activities of daily living (ADL), need for additional care in ADL, time required to achieve independent walking ability and maximal level of ADL, and destination of discharge at six months after stroke. The functional recovery patterns of stroke patients were assessed by an independent observer. The accuracy of the therapists' predictions was compared with that of derived prediction models. In addition, the influence of characteristics of patients and therapists on the accuracy of the predictions was investigated. RESULTS: Compared to observed outcomes at six months after stroke, therapists' lowest accuracies of prediction were found for the moment at which maximal ADL score was achieved (rs = 0.07; p = NS), and highest accuracy was for level of dexterity of the hemiplegic arm (rs = 0.78; p <0.01). Therapists' predictions of functional outcome at six months tended to be too pessimistic. No significant differences were observed for dexterity and walking ability when the predictions by PTs and OTs were compared with those of regression models, whereas significant differences were found for the accuracies of OTs' and PTs' first prediction of destination of discharge and second predictions of outcome in ADL and need for additional care in ADL. No significant differences were found between the accuracy of PTs' and OTs' predictions, and their ability to predict functional outcome was not significantly influenced by the characteristics of patient and therapists. CONCLUSIONS: At two and five weeks after stroke, OTs and PTs can accurately predict level of walking ability and dexterity at six months. The prediction of time required for achieving maximal level of recovery, destination of discharge, outcome of ADL as well as need for additional care in ADL leaves room for improvement.

Activities of Daily Living↗