[Roentgenological aspect of the basilar artery and its significance in clinical diagnosis--angiographical study a of the basilar artery (author's transl)].

Topometric study of basilar arteries was performed, using 130 normal vertebral angiograms of cases consisting of 83 males and 47 females aged 2 to 67 (mean = 38.1). The cases having clinically and/or neuroradiologically had obvious positive findings such as cerebral atrophies, cerebrovascular diseases and space-taking lesions were excluded. Selective vertebral angiography using Seldinger's technique in 120 cases and retrograde brachial angiography in remaining 10 cases was carried out. The following results were obtained. 1) The position of vertebrobasilar junction was almost at the midline in frontal view with a mean distance of 0.3 mm +/- 3.6 leftward from the midline. 2) The length of basilar artery was 25.5 mm +/- 6.6 in frontal view and 32.8 mm +/- 5.8 in lateral view. 3) The position of basilar bifurcation was almost at the midline in frontal view with a mean of 0.0 mm +/- 2.0 from the midline, and 9.3 mm +/- 4.7 above the Twining's line and 24.5 mm +/- 3.4 posterior from tuberculum sellae in lateral view. 4) As for the configulation of basilar artery in frontal view, 'straight type' was common in young age and 'curved type' in old age. 'Curved type' was divided into four subtypes. The concave rightwards curved type and/ or the reversed S-formed tortuous type were almost twice many as the concave leftwards curved type and/or the S-formed tortuous type. This result seemed to support the reports on the hemodynamic mechanism of verteral arteries that the dominant flow was present on the left side at the rate of 50 to 80%. 5) Internal diameter of basilar artery at the point of 1 cm proximal to the apex was measured. The mean value was 3.3 mm +/- 0.6 in frontal view and 3.2 mm +/- 0.5 in lateral view. Maximum diameter of basilar artery was 3.5 mm +/- 0.7 in frontal view and 3.6 mm +/- 0.6 in lateral view.