The Bicaudate Index (BCI) can be used to evaluate a patient for lateral ventricular dilatation.
Exam: head CT in the transverse plane
Measurement taken along lines perpendicular to midline of the brain:
(1) minimum distance between the two caudate nuclei in mm
(2) internal skull diameter along the same line in mm
bicarudate index =
= (bicaudate distance) / (internal skull diameter)
Interpretation:
• The ratio is analyzed against tables of the age-appropriate reference range (see Table 11 of Wilk et al).
• A value above the upper limit of normal for age may indicate the presence of hydrocephalus.
