Variation of T2 times of central aspect of lumbar IVDs from various normative reference T2 times^a

	Mean (ms)	SD (ms)	Ib	Inpb	Xb	Xnpb	Xsb	Xsnpb	Xcb	Xcnpb	Xcsb	Xcsnpb
I	9.8	10.7
Inp	11.7	13.4	<.001
X	15.8	16.0	<.001	<.001
Xnp	18.6	19.3	<.001	<.001	<.001
Xs	15.5	15.3	<.001	<.001	.123	<.001
Xsnp	18.3	18.6	<.001	<.001	<.001	.27	<.001
Xc	17.2	17.3	<.001	<.001	<.001	.003	<.001	.027
Xcnp	20.2	20.9	<.001	<.001	<.001	.001	<.001	<.001	<.001
Xcs	21.8	20.7	<.001	<.001	<.001	.002	<.001	<.001	<.001	.031
Xcsnp	25.7	25.2	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001

^aVariability parameters represent the difference between T2 times of the central aspect of the index IVD from the mean T2 times of the other healthy IVDs from same individual (I), the mean of T2 times of all other healthy lumbar IVDs (X), the mean T2 times of all other healthy lumbar IVDs at the same segmental level as the index IVD (Xs), T2 time of a randomly selected healthy IVD from a different individual but at the same segmental level as the index IVD (Xcs), the mean T2 times of 6 randomly selected healthy discs from different individuals (Xc), each representing a particular segmental level between the T12 through S1 levels. Inp, Xnp, Xsnp, Xcnp, and Xcsnp indicate corresponding values calculated using 52.4% of the central IVD regions with highest T2 values.

^bP values based on a paired Student t test.