Table 1:

Total flow (mL/cardiac cycle), delineated by side, measurement level, and scan, in all volunteers

Volunteer	Left IJV						Right IJV
	Upper		Mid		Lower		Upper		Mid		Lower
	S1	S2	S1	S2	S1	S2	S1	S2	S1	S2	S1	S2
1	0	0	0	0	0	0	1.90	8.36	2.00	7.15	3.95	3.07
2	4.36	4.42	4.45	2.80	4.63	4.11	6.03	6.40	4.56	3.34	9.59	8.47
3	3.35	2.63	4.39	1.41	1.99	0.31	0	0	0	0	0	0
4	2.09	2.82	0.80	3.34	2.14	3.70	3.40	3.02	2.99	6.53	2.78	8.75
5	3.89	2.03	1.84	1.74	2.46	1.09	2.37	0.46	2.73	1.86	1.47	0.37
6	1.00	1.68	0.98	1.44	2.26	2.82	3.53	5.37	2.90	4.27	1.39	3.48
7	0.49	0.46	0.82	0.33	0.57	0.50	6.35	4.31	4.91	2.82	5.25	3.63
8	4.18	4.77	3.60	4.01	2.95	4.24	4.54	5.39	3.42	5.72	2.69	5.53
9	2.87	0.74	2.54	1.14	0.64	0.34	0	0	0	0	0	0
10	3.09	3.25	2.60	2.59	1.03	0.99	3.99	3.33	3.75	2.35	1.28	1.19
Average/Max %RF	0.79/6.15		2.98/14.39		6.02/24.59		0.30/4.83		1.19/12.31		3.52/29.46

Note:—Average and maximum retrograde flow percentages are presented (bottom row).