Table 1.

CSF volume (ml) during forced breathing: aqueduct and upper thoracic spinal canal

Subject	Scan	Aqueduct			Th2			Th5
		Inspiration	Expiration	Net volume	Inspiration	Expiration	Net volume	Inspiration	Expiration	Net volume
#1	1	1.3	2.0	3.3	16.5	−1.4	15.1	20.5	−9.9	10.6
	2	1.8	1.5	3.3	16.8	0.1	16.9	16.1	−6.0	10.1
#2	1	0.2	0.3	0.5	0.7	0.4	1.1	0.2	−1.4	−1.2
	2	0.4	0.6	1.0	0.3	1.2	1.5	−0.4	−0.3	−0.7
#3	1	0.5	0.4	0.9	1.1	0.9	2.0	0.4	−0.8	−0.4
	2	0.7	0.3	1.0	1.8	0.6	2.4	1.9	−0.7	1.2
#4	1	0.2	0.1	0.3	1.8	−0.6	1.2	2.4	−3.5	−1.1
	2	0.2	0.1	0.3	2.0	−0.3	1.7	1.4	−2.7	−1.3
#5	1	1.3	1.0	2.3	−1.4	−1.0	−2.4	−0.4	−0.2	−0.6
	2	1.1	1.2	2.3	−3.1	−3.4	−6.5	−0.5	0.1	−0.4
#6	1	0.4	0.2	0.6	2.7	−0.4	2.3	2.6	−1.3	1.3
	2	0.3	0.2	0.5	1.4	0.1	1.5	2.9	−1.2	1.7
#7	1	0.4	0.3	0.7	0.2	1.3	1.5	0.0	0.0	0.0
	2	0.7	0.4	1.1	0.5	−0.2	0.3	0.3	−1.8	−1.5
#8	1	0.1	0.0	0.1	1.0	0.3	1.3	0.1	−1.5	−1.4
	2	0.2	0.0	0.2	0.7	1.4	2.1	1.6	−0.8	0.8
#9	1	1.0	−0.4	0.6	5.7	−1.3	4.4	2.0	−0.6	1.4
	2	1.9	−0.2	1.7	5.7	−1.1	4.6	1.7	−0.3	1.4
#10	1	0.4	0.1	0.5	4.7	0.5	5.2	1.9	−1.4	0.5
	2	0.4	0.1	0.5	2.8	−1.2	1.6	Not performed
#11	1	0.5	0.1	0.6	3.6	1.0	4.6	1.5	−2.0	−0.5
	2	0.4	0.1	0.5	3.2	0.6	3.8	2.3	−3.5	−1.2
#12	1	0.4	−0.2	0.2	1.6	−1.2	0.4	0.0	0.0	0.0
	2	0.5	−0.3	0.2	1.8	−1.1	0.7	1.1	−1.6	−0.5
Mean ± SDa		0.6 ± 0.5	0.3 ± 0.6	1.0 ± 0.9	3.0 ± 4.6	−0.2 ± 1.1	2.8 ± 4.7	2.6 ± 5.1	−1.8 ± 2.3	1.0 ± 3.2

^aAveraged across subjects.