Evaluation of hydrocephalic periventricular radiolucency by dynamic computed tomography and xenon-computed tomography.

Objective: A common finding of computed tomography in a case of normal-pressure hydrocephalus (NPH) is periventricular radiolucency (PVL). We analyzed PVL for patients with hydrocephalus, using dynamic computed tomographic and xenon-computed tomographic techniques to differentiate NPH from similar diseases.
Methods: Dynamic computed tomography was evaluated as a method of diagnosing NPH in 14 patients with computed tomographic findings of both PVL and ventricular dilatation. Of the 14 patients, varying degrees of clinical improvement after shunt surgery were observed in 10 (shunt-effective group) but not in the remaining 4 (shunt-ineffective group). The difference in arrival time between PVL and thalamus, the difference in peak time between PVL and anterior cerebral artery, and cerebral blood flow in PVL by xenon-computed tomographic study were analyzed.
Results: The difference in arrival time between PVL and thalamus was significantly longer in the effective group than among the remaining patients. There was no significant difference in PVL/cerebral blood flow and the difference in peak time between PVL and the anterior cerebral artery between the two groups.
Conclusion: Dynamic computed tomographic analysis of the difference in arrival time between PVL and thalamus is useful for diagnosing NPH and predicting response to shunting.