Magnetic resonance imaging and behavioral analysis of immature rats with kaolin-induced hydrocephalus: pre- and postshunting observations.
The motor and cognitive dysfunction associated with hydrocephalus remains a clinical problem in children. We hypothesized that young rats with hydrocephalus should exhibit similar dysfunction and that the dysfunction should be reversible by shunting. Hydrocephalus was induced in 3-week-old rats by injection of kaolin into the cisterna magna. Rats were assessed by T2-weighted images obtained with a 7-T magnetic resonance device and by repeated behavioral testing including ability to traverse a narrow beam and ability to find a hidden platform in a water pool. Some of the rats underwent a shunting procedure 1 or 4 weeks after kaolin injection. Magnetic resonance images were used to measure ventricle size. They clearly demonstrated increased signal in periventricular white matter, which corresponded to increased brain water content. A flow-void phenomenon was observed in the cerebral aqueduct. Ability to traverse the beam did not correlate with the degree of ventriculomegaly. Ability to swim to the hidden platform demonstrated a progressive impairment of learning function which may have been accentuated by motor disability. When rats were shunted after 1 week, the behavioral dysfunction was prevented. Late shunting after 4 weeks was associated with gradual recovery of the behavioral disability which was not complete after 4 weeks. We conclude that early shunting is superior to late shunting with regard to behavioral dysfunction. High-resolution MR imaging shows features in hydrocephalic rats similar to those found in hydrocephalic humans.
Del Bigio
M R
MR
Department of Pathology, University of Manitoba, Winnipeg, Canada.
Crook
C R
CR
Buist
R
R
D000818:Animals; D001522:Behavior, Animal; D001925:Brain Damage, Chronic / Q000209:etiology*; D002552:Cerebral Ventricles / Q000473:pathology; D002557:Cerebrospinal Fluid Shunts; D003072:Cognition Disorders / Q000209:etiology*; D006849:Hydrocephalus / Q000473:pathology* / Q000523:psychology / Q000601:surgery; D007616:Kaolin / Q000633:toxicity; D007859:Learning Disabilities / Q000209:etiology; D008279:Magnetic Resonance Imaging; D018782:Maze Learning; D009069:Movement Disorders / Q000209:etiology*; D011184:Postoperative Period; D011597:Psychomotor Performance; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D007616:Kaolin