SHUNT TREATMENT AT 2 POSTNATAL AGES IN HYDROCEPHALIC H-TX RATS QUANTIFIED USING MR-IMAGING

The H-Tx rat has inherited hydrocephalus with an onset in late gestati on. Ventriculosubcutaneous shunts were placed in a group of hydrocepha lic pups at 3-6 days after birth and in another group at 8-12 days aft er birth. Multislice proton magnetic resonance (MR) images were taken of shunt-treated pups at 7, 14, or 21 days and of age-matched control and untreated hydrocephalic rats and were subjected to quantitative an alysis. Some rats were also imaged before surgery. The volume of the v entricles of untreated hydrocephalic pups increased linearly with age at a rate of 52 mu l/day. The ventricles of shunted pups were reduced from the preshunt condition and were around 20% of age-matched hydroce phalic rats. There was no significant difference in the post-shunt vol ume between early and late shunt groups. The cortical mantle thickness in both groups of shunt-treated rats was significantly thicker than i n untreated pups and close to that of control rats. It is concluded th at shunt treatment at both ages reversed the hydrocephalus as measured from MR images, although other evidence from fixed brains suggests th at normal morphology may not be achieved at the cellular level even fo r early shunts. (C) 1995 Academic Press,Inc.