Traumatic brain edema induced by ventricular puncture. A study by magnetic resonance imaging.

Magnetic resonance imaging demonstrates after ventricular catheterization a focal brain hypersignal corresponding to a parenchymal edema along the drain track. In the course of our daily clinical activity, this hypersignal extension seemed more pronounced when catheterizing the frontal area than the junctional parieto-temporo-occipital parenchyma (or trigonal area). In order to confirm this impression, we prospectively studied ten consecutive patients with normal pressure hydrocephalus in whom both of these brain regions were successively catheterized first by a frontal puncture for intracranial pressure monitoring and then by a trigonal one for a ventricular shunt. Each patient was evaluated by serial magnetic resonance imaging. The extension of the hypersignal induced by both catheterizations was estimated on a scale of five grades (0 to 4) of hypersignal extension. A statistically significant more important hypersignal extension was demonstrated at the level of frontal area when compared to the trigonal one. We discuss the likely underlying mechanisms of this phenomenon.