Blake's pouch cyst-like imaging abnormalities in idiopathic normal pressure hydrocephalus

Abstract

Objective: Blake's pouch cyst is a cause of congenital non-communicating hydrocephalus. Recent study revealed that adult onset communicating normal pressure hydrocephalus sometimes accompanied by Blake's pouch cyst-like imaging abnormalities. However, relationships between two disease entities remains uncovered. The aim of this study was to investigate the prevalence of Blake's pouch cyst-like imaging abnormalities in idiopathic normal pressure hydrocephalus and their impact on the clinical features. Methods: First, we investigated the existence of Blake's pouch cyst-like imaging abnormalities in 46 idiopathic normal pressure hydrocephalus patients (mean age 76.8 ± 5.2 years old; 28 women) and 247 normal controls (mean age 65.2 ± 4.0 years old; 120 women). Second, the demographic, clinical and imaging characteristics were compared between idiopathic normal pressure hydrocephalus with and without Blake's pouch cyst-like imaging abnormalities. Results: Blake's pouch cyst-like imaging abnormalities were more prevalent in idiopathic normal pressure hydrocephalus patients (17.4 %) than in the normal population (2.4 %). Idiopathic normal pressure hydrocephalus with Blake's pouch cyst-like imaging abnormalities showed a trend toward a younger onset than those without Blake's pouch cyst-like imaging abnormalities, while clinical features, including the response to cerebrospinal fluid tap test and shunt treatment, did not differ between two groups. Conclusions: Incomplete cerebrospinal fluid obstruction associated with Blake's pouch cyst-like imaging abnormalities may be a cause of idiopathic normal pressure hydrocephalus.

Keywords

• Blake's pouch cyst (BPC)
• Idiopathic normal pressure hydrocephalus (INPH)