Impedance changes detected by electrical impedance tomography during acute and chronic hydrocephalus progression: an experimental animal study

To examine the impedance changes and imaging characteristics of electrical impedance tomography (EIT) for continuous monitoring of acute and chronic hydrocephalus progression. Twenty-four New Zealand rabbits were randomly assigned to an experimental group ( n = 18) and a control group ( n = 6). The experimental group was further divided into subgroup A ( n = 6) and subgroup B ( n = 12). In subgroup A, acute hydrocephalus was induced by intraventricular injection of 0.9% saline, and EIT monitoring was performed concurrently with invasive intracranial pressure (ICP) measurements. In subgroup B, chronic hydrocephalus was induced by intracisternal injection of kaolin, and EIT monitoring was conducted daily, with magnetic resonance imaging (MRI) conducted 2 weeks after injection to confirm model establishment. Rabbits in the control group received no intervention. In subgroup A, ICP increased from 5.0 ± 1.0 mmHg to 14.3 ± 0.6 mmHg after injection, whereas EIT values decreased by approximately 2.25% ( P < 0.05). A strong negative correlation was observed between ICP and EIT values ( r = − 0.949). EIT images revealed changes corresponding to the injection site. In subgroup B, 6 rabbits exhibited marked ventricular dilation on MRI, indicating successful establishment of the hydrocephalus model. These animals showed a mean decrease in EIT values of approximately 0.75%. No substantial EIT changes were observed in the control group and failed group. These findings suggest that EIT holds promise for the continuous, dynamic monitoring of hydrocephalus progression while also providing valuable spatial information on disease-related pathophysiological changes.