Intracranial blood-flow velocity and pressure measurements using an intra-arterial dual-sensor guidewire

Abstract

Hemodynamics is thought to play a role in the growth and rupture of intracranial aneurysms. In 4 patients, we obtained local pressure and BFV by using a dual-sensor pressure and Doppler velocity wire within and in vessels surrounding unruptured aneurysms. Local BFVs can serve as boundary conditions for computational fluid dynamics, whereas pressure recordings provide direct information on the mechanical load imposed on the aneurysm. Both measurements may thus add to patient-specific rupture-risk assessment.

Fig 1.

Detail of the ComboWire. Reprinted with permission of Volcano Therapeutics. PTFE indicates polytetrafluoroethylene.

Fig 2.

BFV and pressure measurements using the ComboWire in the ICA at the cervical level (A), proximal to the aneurysm (B), intra-aneurysmally (C), and distal to the aneurysm (D). The graphs show matching flow velocity and pressure waveforms extracted from the ComboMap recordings. The upper part of each panel depicts pressure (mm Hg): systemic pressure measured in the radial artery (Pa) and intracranial pressure measured at the tip of the wire (Pd). The lower part of the graphs show flow velocity (centimeters per second). Sec indicates seconds.

Fig 3.

Maximal BFV in centimeters per second measured with the ComboWire in the ICA at the cervical level (Cervical), proximal to the aneurysm (Proximal), and distal to the aneurysm (Distal). Intra-aneurysmal measurements are not plotted here because we considered them to be less accurate (see “Data Analysis”). Maximal BFV was calculated by averaging 5 consecutive peaks of the ComboMap flow signal. One measurement is lacking because the wire could not be placed distal to the aneurysm in patient 1 due to unfavorable geometry.