Table 4.
Estimated intercept and slope for the power analysis and sample size estimation for caudate and putamen in left and right hemisphere.
Method | Side | Structure | Intercept [Vp = VROI/ICV (%)] | Slope [Vp/Year] |
---|---|---|---|---|
MALF | Left | Putamen | 0.2748 | −0.0026 |
Caudate | 0.1989 | −0.0014 | ||
Right | Putamen | 0.2672 | −0.0023 | |
Caudate | 0.1992 | −0.0014 | ||
BRAINSCut | Left | Putamen | 0.2894 | −0.0038 |
Caudate | 0.2123 | −0.0029 | ||
Right | Putamen | 0.2767 | −0.0031 | |
Caudate | 0.2204 | −0.0041 |
The power and sample size analysis performed on data expressed as a percent of total intercranial volume along years offollow-up. Note that slope magnitude from BRAINSCut is larger than that estimated by MALF. These slopes and intercepts were utilized as population parameters in the sample size estimation with 80% power. (Vp, Percent volume of total ICV; VROI, Volume of region of interest; ICV, intercranial volume).