Table 2. Intra- and inter-observer agreement evaluation of peak velocity at 3 ROIs.

	Ventral SAS at the FM level	Dorsal SAS at the FM level	Cerebral aqueduct
ICC (Intra-observer)	0.900	0.970	0.974
ICC (Inter-observer)	0.841	0.900	0.822

Reliability level: 0.800–1.000 (high reliability), 0.600–0.790 (moderate reliability), and ≤ 0.590: (unreliable).

ROIs, regions of interest; SAS, subarachnoid space; FM, foramen magnum; ICC, intra- or inter-observer correlation coefficient.