Table 1.

Summary of the quantitative analysis of the biophysical characteristics and tract volumes of the delineated CSTs. Note that the coefficient of variation is very small (<10%), indicating minor variability of the results among our healthy subjects. Tract volume, by contrast, was the only parameter that was highly variable among the subjects.

	FA	RD	AD	Tract Volume (cm3)	Normalized Tract Volume (cm3)	Length (mm)
CST	Mean	Mean	Mean	Mean	Mean	Mean
	0.70808	285.78168	1265.76424	21.18664	0.01391	133.63757
	SD	SD	SD	SD	SD	SD
	0.01785	24.87915	57.36838	6.08293	0.00407	8.39159
	CV	CV	CV	CV	CV	CV
	0.02521	0.08706	0.04532	0.28711	0.29287	0.06279
Left CST	Mean	Mean	Mean	Mean	Mean	Mean
	0.70759	285.06082	1254.53178	11.08082	0.00725	133.52129
	SD	SD	SD	SD	SD	SD
	0.01750	24.19261	67.33187	3.75966	0.00235	9.41757
	CV	CV	CV	CV	CV	CV
	0.02474	0.08487	0.05367	0.33929	0.32454	0.07053
Right CST	Mean	Mean	Mean	Mean	Mean	Mean
	0.70504	287.09653	1264.45024	10.47865	0.00691	132.12170
	SD	SD	SD	SD	SD	SD
	0.02181	26.75149	58.84273	3.67042	0.00255	10.25023
	CV	CV	CV	CV	CV	CV
	0.03094	0.09318	0.04654	0.35028	0.36914	0.07758
SI CST	Mean	Mean	Mean	Mean	Mean	Mean
	0.00361	−0.00712	−0.00787	0.05586	0.04767	0.01054
	SD	SD	SD	SD	SD	SD
	−0.21919	−0.10046	0.13456	0.02402	−0.08102	−0.08467

Abbreviations used: CST: corticospinal tract, FA: fractional anisotropy, RD: radial diffusivity, AD: axial diffusivity, SD: standard deviation, CV: coefficient of variation, SI: symmetry index.