Hemodynamically independent analysis of intracranial cerebrospinal fluid dynamics using PC cine MRI

点击翻译按钮获取中文摘要

To clarify intracranial dynamical properties in normal pressure hydrocephalus (NPH), we assessed a spectral phase transfer function (PTF) calculated from the driving vascular pulsation and cerebrospinal fluid (CSF) flow in the aqueduct using phase contrast (PC) cine MRI.On a vertical plane against a mid-point on the long axis of the aqueduct, both CSF flow and blood flow waveforms were measured with cardiac triggered PC cine MRI. Taking the difference in each cardiac phase between arterial inflow and venous outflow in the brain as the input function (driving vascular pulsation), and the CSF flow in the aqueduct as the output function, the PTF related to the dynamical properties was calculated from both functions. The PTF was determined in patients with NPH after a subarachnoid hemorrhage (SAH-NPH), in an SAH-NPH post-shunt operation group, and in healthy volunteers (control group). The PTF(f)s were also measured 5 min after an intravenous injection of acetazolamide (increase of cerebral blood volume). The PTF was compared with the pressure volume response (PVR) as an index of the intracranial compliance.The PTF of the 1st harmonic in the SAH-NPH group was significantly larger than in the control group, and the PTF in the SAH-NPH post-shunt operation group tends to be closer to that in the control group than the SAH-NPH group. There was no significant difference in PTF before and after acetazolamide injection at any frequency ; independent of hemodynamics. A positive correlation was noted between the PTFPTF analysis with PC cine MRI makes it possible to obtain information noninvasively on intracranial dynamical properties in cases of NPH.