CT evaluation of lateral ventricular dilatation after subarachnoid hemorrhage: baseline bicaudate index balues

OBJECTIVES: To define baseline bicaudate index (BCI) values in patients with subarachnoid hemorrhage (SAH). METHODS: We reviewed the clinical and radiological information on consecutive adult patients admitted with acute SAH to our hospital between 1 January 2002 and 1 January 2008. Patients without diagnosis of acute hydrocephalus were entered into this study. Age-stratified BCI values were calculated. RESULTS: Our study cohort comprised 108 patients (66 women, 61%). The clinical status at presentation was excellent with a median score of 1 on the World Federation of Neurological Surgeons Scale. Cisternal blood burden was mild to moderate with a median Hijdra score of 17 (out of 30). The upper limits of normal (ninety-fifth percentile) for BCI were 0·12 at age 45 years and under, 0·14 at 55 years, 0·16 at 65 years, and 0·17 thereafter. CONCLUSION: Albeit not perfect, the BCI is a commonly used linear measure of the lateral ventricular size. We present baseline BCI values in a cohort of patients with acute SAH. A diagnosis of hydrocephalus can be made when the BCI value exceeds the upper limit of normal for age.