Operational definitions improve reliability of the age-related white matter changes scale
1Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
Background And Purpose:
Although the age-related white matter changes (ARWMC) scale has been advocated to be applicable to both MRI and CT for assessing the severity of WMC, its inter-rater reliability on CT is only fair. We aimed to operationalize the ARWMC scale and investigate the effect of this operationalization on the reliability and validity on MRI and CT.
Methods:
Operational definitions of the ARWMC scale were derived from Erkinjuntti research criteria for subcortical vascular dementia and Scheltens scale. Using original and operationalized ARWMC scale, eight observers recorded the time for rating per MRI and per CT. We investigated the inter-rater and intrarater reliability as well as validity against volume using data from 97 stroke patients.
Results:
Inter-rater reliability of the operationalized scale on CT (0.874, 95% confidence interval [0.780-0.934]) was better than the original scale (0.569, 95% confidence interval [0.247-0.775]). Its intrarater reliability on CT (0.869) and reliability on MRI (inter-rater: 0.860; intrarater: 0.838) was comparable with the original scale (CT intrarater: 0.750 and on MRI inter-rater: 0.845; intrarater: 0.853). The time required to administer the operationalized scale (4'2″ for MRI and 1'18″ for CT) was similar to that of the original scale (3'56″ for MRI and 1'16″ for CT). The original scale and operationalized scale also significantly correlated with WMC volume (operationalized scale ρ = 0.613, P < 0.001, original scale ρ = 0.638, P < 0.001).
Conclusion:
Operational definitions improve the inter-rater reliability of ARWMC scale on CT, and it correlates with volumetric measurement.
Insights
Operational definitions improved the age-related white matter changes (ARWMC) scale's reliability on CT scans. This enhanced scale also showed good validity, correlating with white matter changes volume.
Area of Science:
- Neuroradiology
- Medical Imaging Analysis
Background:
- The age-related white matter changes (ARWMC) scale assesses white matter changes (WMC) severity on MRI and CT.
- Current inter-rater reliability of the ARWMC scale on CT is only fair.
Purpose of the Study:
- To operationalize the ARWMC scale for improved reliability and validity.
- To assess the impact of operationalization on ARWMC scale performance on MRI and CT.
Main Methods:
- Developed operational definitions for the ARWMC scale based on existing research criteria.
- Eight observers rated WMC using both original and operationalized ARWMC scales on MRI and CT data from 97 stroke patients.
- Evaluated inter-rater and intrarater reliability and validity against WMC volume.
Main Results:
- Operationalized ARWMC scale significantly improved inter-rater reliability on CT (0.874) compared to the original scale (0.569).
- Reliability of the operationalized scale on MRI and intrarater reliability on CT were comparable to the original scale.
- Administration time for the operationalized scale was similar to the original scale.
- Both scales demonstrated significant correlation with WMC volume.
Conclusions:
- Operational definitions enhance the inter-rater reliability of the ARWMC scale on CT.
- The operationalized ARWMC scale maintains good reliability and validity, correlating with volumetric measurements.
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