Proportion of Variant Anatomy of the Circle of Willis and Association with Vascular Anomalies on Cerebral CT Angiography

Table 3

Proportion of posterior circulation variants.

POSTERIOR CW	FREQUENCY
TYPE A	27.7% (26)
TYPE B	4.3% (4)
TYPE C	7.4% (7)
TYPE D	4.3% (4)
TYPE E	41.5% (39)
TYPE F	2.1% (2)
TYPE G	7.4% (7)
TYPE H	0% (0)
TYPE I	0% (0)
TYPE J	5.3% (5)