Table 3

Intrarater and interrater precision and reliabilty for measurements of change in lesion volume for all 16 patients

Manual outliningContour
Repeatability
coefficient (cm3)
ICCRepeatability
coefficient (cm3)
ICC
Intrarater3.30.9392.60.945
Interrater3.70.9212.80.944
  • ICC=Intraclass correlation coefficient, a measure of reliability. The intrarater precision (repeatability coefficient) and reliability for the change in lesion volume were calculated by pooling data acquired from the replicated measurements of all three raters on the 16 patients. The interrater precision and reliability for the change in lesion volume were averaged across the two sets of measurements with each technique. The coefficient of variation was not used to define precision in measuring change in lesion volume as its value is too heavily dependent on the magnitude of the measured change. Repeatability coefficients were therefore used as a measure of precision. The difference between two measurements for the same subject is expected to be less than the repeatability coefficient in 95% of observations.