Applying time-frequency analysis to assess cerebral autoregulation during hypercapnia.

Objective: Classic methods for assessing cerebral autoregulation involve a transfer function analysis performed using the Fourier transform to quantify relationship between fluctuations in arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV). This approach usually assumes the signals and the system to be stationary. Such an presumption is restrictive and may lead to unreliable results.

Assessment of cerebral blood flow during infusion test in the diagnosis of normal pressure hydrocephalus.

Background: Many studies indicate that the increase in intracranial pressure (ICP) leads to cerebral blood flow velocity (CBFV) changes. This relationship was accurately determined in patients with traumatic brain injury,

Objectives: The aim of this study was to determine how the changes in intracranial pressure induced during an infusion test influence cerebral blood flow.

Material And Methods: 40 patients with enlarged ventricular systems (Evan's ratio > 30%) who underwent a diagnostic lumbar infusion test (LIT) were included.