Table 3.

Frequency of adequate contrast opacification of the major intracranial venous structures in first-pass CTAs performed for evaluation of intracerebral hemorrhage^a

Venous Structure	All CTAs (%) (n = 170)	16-Section CTAs (%) (n = 58)	64-Section CTAs (%) (n = 112)	P Value^{^b}
Deep cerebral veins^{^c}	88	95	84	.03
Straight sinus	85	93	80	.03
Superior sagittal sinus	81	97	72	<.001
Right transverse sinus	66	83	58	.001
Left transverse sinus	63	81	54	<.001
Right sigmoid sinus	49	62	42	.012
Left sigmoid sinus	48	71	36	<.001
Right cavernous sinus	11	16	8	.13
Left cavernous sinus	7	12	4	.11
All noncavernous venous structures	42	60	33	<.001

a Adequate contrast opacification defined as homogeneous contrast opacification within the venous structure examined.
b P value is for the difference between 16- and 64-section CTAs using the Pearson χ² test.
c Includes internal cerebral veins and the vein of Galen.