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  • Key words Multiple sclerosis  (3)
  • disability evaluation  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Visual analysis of serial T2-weighted MRI in multiple sclerosis: intra- and interobserver reproducibility (1999)
    Springer
    Neuroradiology 41 (1999), S. 882-888 
    Details
    ISSN: 1432-1920
    Schlagwort(e): Key words Multiple sclerosis ; Magnetic resonance imaging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We evaluated the effect of consensus formation and training on the agreement between observers in scoring the number of new and enlarging multiple sclerosis (MS) lesions on serial T2-weighted MRI studies. The baseline and month 9 MRI studies of 16 patients with a range of MRI activity were used (dual-echo conventional spin-echo sequence, TR 2000, TE 34 and 90 ms, 5 mm contiguous slices, in-plane resolution 1 mm). First, the serial studies were visually analysed for the presence of new and enlarging lesions, on two occasions, by five experienced observers, without adopting any consensus strategy and in isolation. Next, the observers met to identify the common sources of inconsistencies in reporting between observers and formulate consensus rules. Finally, a further independent reading session was performed on the same MRI dataset, this time applying the consensus rules. Agreement between observers was assessed using kappa scores. Without the consensus rules, interobserver kappa scores for the first and second reading sessions for new lesions were only 0.51 and 0.39 respectively; agreement for enlarging lesions was even worse. The mean intraobserver kappa score for new lesions was higher at 0.72, reflecting the fact that the observers were consistently applying their individual assessment strategies. Application of the consensus rules did not lead to a significant improvement in inter observer kappas; the kappa scores adopting the guidelines were 0.46 and 0.21 for new and enlarging lesions respectively. Consensus guidelines thus did not improve the reproducibility of visual analysis of serial T2-weighted MRI, and the level of agreement between observers remained only moderate. Suboptimal repositioning is likely to be a major source of residual variability and this suggests a future role for image registration strategies; until then, a single observer, or pair of observers working in consensus, should be used in MS studies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002340050860
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  • 2
    Digitale Medien
    Digitale Medien
    Interobserver agreement for diagnostic MRI criteria in suspected multiple sclerosis (1999)
    Springer
    Neuroradiology 41 (1999), S. 347-350 
    Details
    ISSN: 1432-1920
    Schlagwort(e): Key words Multiple sclerosis ; Magnetic resonance imaging ; Interobserver variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract MRI is the paraclinical test most widely used to support the diagnosis of multiple sclerosis (MS). We evaluated interobserver agreement in applying diagnostic criteria to MRI obtained at first presentation. Five experienced observers scored 25 sets of images consisting of unenhanced T2- and gadolinium-enhanced T1-weighted images (approximately half the sets were normal). We scored frontal, parietal, temporal, occipital, infratentorial and basal ganglia lesions and the total number of lesions on T2-weighted images; periventricular, callosal, juxtacortical and ovoid lesions and those 〉 5 mm in maximum diameter; contrast-enhancing and hypointense lesions. Based on a combination of imaging findings patients were classified as compatible or not compatible with MS according to composite criteria. Observer concordance was characterised by weighted kappa values (ϰ) and mean average difference to the median (MADM) scores. Using the raw scores, there was poor agreement for the total number of lesions on T2-weighted images, and for occipital, oval, juxtacortical and hypointense lesions. Moderate agreement was found for frontal, callosal, basal ganglia and large lesions on T2 weighting. Good agreement was attained for parietal, temporal, infratentorial and periventricular lesions. After dichotomisation according to accepted cut-off values, most criteria performed better, especially the number of lesions on T2-weighted images (P 〈 0.05). Good agreement was found for the criteria of Paty and Fazekas and moderate agreement for those of Barkhof. While experienced observers may not agree on the total number of lesions, they show quite good agreement for commonly used cut-off points and elements in the composite criteria. This validates the use of MRI in the diagnosis of MS, and the use of dichotomised and composite criteria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002340050762
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  • 3
    Digitale Medien
    Digitale Medien
    The use of magnetic resonance imaging in multiple sclerosis treatment trials: power calculations for annual lesion load measurement (2000)
    Springer
    Journal of neurology 247 (2000), S. 34-40 
    Details
    ISSN: 1432-1459
    Schlagwort(e): Key words Multiple sclerosis ; Treatment trial ; Power calculations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Phase III definitive treatment trials of new multiple sclerosis (MS) therapies now routinely incorporate an annual magnetic resonance imaging protocol, with change in T2-weighted brain lesion load providing an important outcome measure. To date the accepted strategy has been to perform a core imaging protocol on all patients in such studies. The aim of this study was to provide power calculations based on this MRI endpoint. Serial MRI data from 128 patients with either relapsing remitting (RR) or secondary progressive (SP) MS were used to calculate sample size requirements using a repeated measures analysis of variance design. We provide sample size calculations based on various follow-up intervals and effect sizes. Sample sizes for the SPMS cohort were substantially larger than for the RRMS group, reflecting the greater variance in lesion load changes between patients in the SPMS group. With a follow-up of 3 years, we estimate that only 12 and 33 patients per arm are needed to show stabilisation of MRI lesion load in the RRMS and SPMS groups, respectively. Our results suggest that ongoing phase III treatment trials are more than adequately powered to detect even subtle treatment effects, and indicate that incorporating measurements from longer follow-up durations increases power substantially. We conclude that an annual imaging protocol provides a robust and powerful tool for assessing effects on the radiological appearance of the disease process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004150050007
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  • 4
    Digitale Medien
    Digitale Medien
    Factor structure of the Disability and Impact Profile in patients with multiple sclerosis (1999)
    Springer
    Quality of life research 8 (1999), S. 141-150 
    Details
    ISSN: 1573-2649
    Schlagwort(e): Quality of life ; multiple sclerosis ; disability evaluation ; questionnaires ; factor analysis ; statistical.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The Disability and Impact Profile (DIP) is used for the measurement of quality of life in multiple sclerosis (MS) patients. Data from 211 persons with definite MS from Belgium, Denmark and the Netherlands were used to address three questions. To what extent do the impairment ratings and their complementary weighted scores share common variance? What is the factor structure of the weighted scores? To what extent do disease-related information and information from psychological questionnaires offer concurrent validity for the factors? Correlations between impairment ratings and the weighted item scores were high; for most items the complementary ratings of impact do not supplement information provided by impairment ratings. The DIP weighted scores can be represented to some extent by three independent dimensions: a motor (skeletal movement) or displacement ability factor, a factor relating to sensory–cognitive intactness and a psychological well-being factor. A two-factor solution provides a first factor identical to that of the three-factor solution and a second factor representing psychological well-being. The two factors correlate well with instruments measuring disability and with satisfaction versus emotional distress. Provisional scales based on the factors were constructed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1026481029191
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