Observer Variation: The failure by the observer to measure or identify a phenomenon accurately, which results in an error. Sources for this may be due to the observer's missing an abnormality, or to faulty technique resulting in incorrect test measurement, or to misinterpretation of the data. Two varieties are inter-observer variation (the amount observers vary from one another when reporting on the same material) and intra-observer variation (the amount one observer varies between observations when reporting more than once on the same material).Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Genetic Variation: Genotypic differences observed among individuals in a population.
(1/5805) Integrated visualization of functional and anatomic brain data: a validation study.
Two-dimensional SPECT display and three methods for integrated visualization of SPECT and MRI patient data are evaluated in a multiobserver study to determine whether localization of functional data can be improved by adding anatomical information to the display. METHODS: SPECT and MRI data of 30 patients were gathered and presented using four types of display: one of SPECT in isolation, two integrated two-dimensional displays and one integrated three-dimensional display. Cold and hot spots in the peripheral cortex were preselected and indicated on black-and-white hard copies of the image data. Nuclear medicine physicians were asked to assign the corresponding spots in the image data on the computer screen to a lobe and a gyrus and give a confidence rating for both localizations. Interobserver agreement using kappa statistics and average confidence ratings were assessed to interpret the reported observations. RESULTS: Both the interobserver agreement and the confidence of the observers were greater for the integrated two-dimensional displays than for the two-dimensional SPECT display. An additional increase in agreement and confidence was seen with the integrated three-dimensional display. CONCLUSION: Integrated display of SPECT and MR brain images provides better localization of cerebral blood perfusion abnormalities in the peripheral cortex in relation to the anatomy of the brain than single-modality display and increases the confidence of the observer. (+info)
(2/5805) The Sock Test for evaluating activity limitation in patients with musculoskeletal pain.
BACKGROUND AND PURPOSE: Assessment within rehabilitation often must reflect patients' perceived functional problems and provide information on whether these problems are caused by impairments of the musculoskeletal system. Such capabilities were examined in a new functional test, the Sock Test, simulating the activity of putting on a sock. SUBJECTS AND METHODS: Intertester reliability was examined in 21 patients. Concurrent validity, responsiveness, and predictive validity were examined in a sample of 337 patients and in subgroups of this sample. RESULTS: Intertester reliability was acceptable. Sock Test scores were related to concurrent reports of activity limitation in dressing activities. Scores also reflected questionnaire-derived reports of problems in a broad range of activities of daily living and pain and were responsive to change over time. Increases in age and body mass index increased the likelihood of Sock Test scores indicating activity limitation. Pretest scores were predictive of perceived difficulties in dressing activities after 1 year. CONCLUSION AND DISCUSSION: Sock Test scores reflect perceived activity limitations and restrictions of the musculoskeletal system. (+info)
(3/5805) Identifying homologous anatomical landmarks on reconstructed magnetic resonance images of the human cerebral cortical surface.
Guided by a review of the anatomical literature, 36 sulci on the human cerebral cortical surface were designated as homologous. These sulci were assessed for visibility on 3-dimensional images reconstructed from magnetic resonance imaging scans of the brains of 20 normal volunteers by 2 independent observers. Those sulci that were found to be reproducibly identifiable were used to define 24 landmarks around the cortical surface. The interobserver and intraobserver variabilities of measurement of the 24 landmarks were calculated. These reliably reproducible landmarks can be used for detailed morphometric analysis, and may prove helpful in the analysis of suspected cerebral cortical structured abnormalities in patients with such conditions as epilepsy. (+info)
(4/5805) Venous duplex scanning of the leg: range, variability and reproducibility.
Despite the many studies on venous haemodynamics using duplex, only a few evaluated the normal values, variability and reproducibility. Therefore, the range and variability of venous diameter, compressibility, flow and reflux were measured. To obtain normal values, 42 healthy individuals (42 limbs, 714 vein segments) with no history of venous disease were scanned by duplex. To determine the reproducibility the intra-observer variability was measured in 11 healthy individuals (187 vein segments) and the inter-observer variability in 15 healthy individuals (255 vein segments) and 13 patients (169 vein segments) previously diagnosed with deep venous thrombosis. Of the 714 normal vein segments, 708 (99%) were traceable, including the crural veins. Of the traceable vein segments, 675 (95%) were compressible and in 696 (98%) flow was present. Of the 42 common femoral vein segments, in 25 (60%) the reflux duration exceeded 1.0 s, but in the other proximal vein segments the reflux duration was less than 1.0 s (95% confidence interval 3.0-10.0). With the exception of the distal long saphenous vein, in the distal vein segments the reflux duration was less than 0.5 s (95% confidence interval 3.5-8.2). The coefficient of variation of the diameter measurements ranged from 14 to 50% and that of the reflux measurements from 28 to 60%. The kappa-coefficient of the inter-observer variability in the classification of compressibility measurements in the patients was 0. 77 and that of the reflux measurements was 0.86. This study shows that almost all veins were compressible in healthy individuals, except the distal femoral veins. In healthy individuals the duration of reflux of the proximal veins was less than 1.0 s and in the distal veins it was less than 0.5 s. The inter-observer variability of the reflux and compressibility measurements in the patients was good. (+info)
(5/5805) Computed radiography dual energy subtraction: performance evaluation when detecting low-contrast lung nodules in an anthropomorphic phantom.
A dedicated chest computed radiography (CR) system has an option of energy subtraction (ES) acquisition. Two imaging plates, rather than one, are separated by a copper filter to give a high-energy and low-energy image. This study compares the diagnostic accuracy of conventional computed radiography to that of ES obtained with two radiographic techniques. One soft tissue only image was obtained at the conventional CR technique (s = 254) and the second was obtained at twice the radiation exposure (s = 131) to reduce noise. An anthropomorphic phantom with superimposed low-contrast lung nodules was imaged 53 times for each radiographic technique. Fifteen images had no nodules; 38 images had a total of 90 nodules placed on the phantom. Three chest radiologists read the three sets of images in a receiver operating characteristic (ROC) study. Significant differences in Az were only found between (1) the higher exposure energy subtracted images and the conventional dose energy subtracted images (P = .095, 90% confidence), and (2) the conventional CR and the energy subtracted image obtained at the same technique (P = .024, 98% confidence). As a result of this study, energy subtracted images cannot be substituted for conventional CR images when detecting low-contrast nodules, even when twice the exposure is used to obtain them. (+info)
(6/5805) Tomatoes, tomato-based products, lycopene, and cancer: review of the epidemiologic literature.
The epidemiologic literature in the English language regarding intake of tomatoes and tomato-based products and blood lycopene (a compound derived predominantly from tomatoes) level in relation to the risk of various cancers was reviewed. Among 72 studies identified, 57 reported inverse associations between tomato intake or blood lycopene level and the risk of cancer at a defined anatomic site; 35 of these inverse associations were statistically significant. No study indicated that higher tomato consumption or blood lycopene level statistically significantly increased the risk of cancer at any of the investigated sites. About half of the relative risks for comparisons of high with low intakes or levels for tomatoes or lycopene were approximately 0.6 or lower. The evidence for a benefit was strongest for cancers of the prostate, lung, and stomach. Data were also suggestive of a benefit for cancers of the pancreas, colon and rectum, esophagus, oral cavity, breast, and cervix. Because the data are from observational studies, a cause-effect relationship cannot be established definitively. However, the consistency of the results across numerous studies in diverse populations, for case-control and prospective studies, and for dietary-based and blood-based investigations argues against bias or confounding as the explanation for these findings. Lycopene may account for or contribute to these benefits, but this possibility is not yet proven and requires further study. Numerous other potentially beneficial compounds are present in tomatoes, and, conceivably, complex interactions among multiple components may contribute to the anticancer properties of tomatoes. The consistently lower risk of cancer for a variety of anatomic sites that is associated with higher consumption of tomatoes and tomato-based products adds further support for current dietary recommendations to increase fruit and vegetable consumption. (+info)
(7/5805) The psychometric properties of clinical rating scales used in multiple sclerosis.
OullII;l y Many clinical rating scales have been proposed to assess the impact of multiple sclerosis on patients, but only few have been evaluated formally for reliability, validity and responsiveness. We assessed the psychometric properties of five commonly used scales in multiple sclerosis, the Expanded Disability Status Scale (EDSS), the Scripps Neurological Rating Scale (SNRS), the Functional Independence Measure (FIM), the Ambulation Index (AI) and the Cambridge Multiple Sclerosis Basic Score (CAMBS). The score frequency distributions of all five scales were either bimodal (EDSS and AI) or severely skewed (SNRS, FIM and CAMBS). The reliability of each scale depended on the definition of 'agreement'. Inter-and intra-rater reliabilities were high when 'agreement' was considered to exist despite a difference of up to 1.0 EDSS point (two 0.5 steps), 13 SNRS points, 9 FIM points, 1 AI point and 1 point on the various CAMBS domains. The FIM, AI, and the relapse and progression domains of the CAMBS were sensitive to clinical change, but the EDSS and the SNRS were unresponsive. The validity of these scales as impairment (SNRS and EDSS) and disability (EDSS, FIM, AI and the disability domain of the CAMBS) measures was established. All scales correlated closely with other measures of handicap and quality of life. None of these scales satisfied the psychometric requirements of outcome measures completely, but each had some desirable properties. The SNRS and the EDSS were reliable and valid measures of impairment and disability, but they were unresponsive. The FIM was a reliable, valid and responsive measure of disability, but it is cumbersome to administer and has a limited content validity. The AI was a reliable and valid ambulation-related disability scale, but it was weakly responsive. The CAMBS was a reliable (all four domains) and responsive (relapse and progression domains) outcome measure, but had a limited validity (handicap domain). These psychometric properties should be considered when designing further clinical trials in multiple sclerosis. (+info)
(8/5805) Cephalometric abnormalities in non-obese and obese patients with obstructive sleep apnoea.
The aim of this work was to comprehensively evaluate the cephalometric features in Japanese patients with obstructive sleep apnoea (OSA) and to elucidate the relationship between cephalometric variables and severity of apnoea. Forty-eight cephalometric variables were measured in 37 healthy males and 114 male OSA patients, who were classed into 54 non-obese (body mass index (BMI) <27 kg x m(-2), apnoea-hypopnoea index (AHI)=25.3+/-16.1 events x h(-1)) and 60 obese (BMI > or = 27 kg x m(-2), AHI=45.6+/-28.0 events h(-1)) groups. Diagnostic polysomnography was carried out in all of the OSA patients and in 19 of the normal controls. The non-obese OSA patients showed several cephalometric defects compared with their BMI-matched normal controls: 1) decreased facial A-P distance at cranial base, maxilla and mandible levels and decreased bony pharynx width; 2) enlarged tongue and inferior shift of the tongue volume; 3) enlarged soft palate; 4) inferiorly positioned hyoid bone; and 5) decreased upper airway width at four different levels. More extensive and severe soft tissue abnormalities with a few defects in craniofacial bony structures were found in the obese OSA group. For the non-obese OSA group, the stepwise regression model on AHI was significant with two bony structure variables as determinants: anterior cranial base length (S-N) and mandibular length (Me-Go). Although the regression model retained only linear distance between anterior vertebra and hyoid bone (H-VL) as an explainable determinant for AHI in the obese OSA group, H-VL was significantly correlated with soft tissue measurements such as overall tongue area (Ton), inferior tongue area (Ton2) and pharyngeal airway length (PNS-V). In conclusion, Japanese obstructive sleep apnoea patients have a series of cephalometric abnormalities similar to those described in Caucasian patients, and that the aetiology of obstructive sleep apnoea in obese patients may be different from that in non-obese patients. In obese patients, upper airway soft tissue enlargement may play a more important role in the development of obstructive sleep apnoea, whereas in non-obese patients, bony structure discrepancies may be the dominant contributing factors for obstructive sleep apnoea. (+info)
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