Intracranial B waves simulation

This simulation is designed to help visualize the steps utilized in recording intracranial B waves using transcranial Doppler (TCD) ultrasound. An example is given of recording of the middle cerebral artery (MCA) spectral signal via a right trans-temporal window, to which a spectral outline signal (white fine line, following the upper outline of the spectral signal) is assigned. This fine white line is then recorded below in the later frames( beginning at second 26 in the simulation) as a green trend line labeled FV (flow velocity). The simulation illustrates a classic intracranial B wave pattern of the flow velocity oscillating at slightly less than 1 cycle per minute. B waves of the intracranial pressure were first defined as occurring at frequencies of 0.5-2 per minute. Other signals displayed include the arterial blood pressure (ABP) in red, the intracranial pressure (ICP) in blue, and the end-tidal carbon dioxide (ET-CO2) concentration which is measure from the exhaled breath.

The other simulation box displayed in the middle left location after the first 26 seconds of the simulation, represents an axial brain slice with the dark butterfly appearance in the center representing the cerebrospinal fluid in the cerebral ventricles (which have no blood flow). The colored areas(orange/yellow) highest, green lower, blue lowest) represent the regional cerebral blood flow (r CBF) in milliliters/minute. The numerical averages are displayed on the outside, and constantly change in synchrony with corresponding changes in the MCA velocity spectrum. The colors in the brain axial slice, representing blood flow levels in the brain tissue, and the green FV tracing reflecting the MCA arterial blood flow changes over time reveals the oscillations known as intracranial B waves.

Intracranial B waves recorded using TCD, have been shown to occur during deep resting and sleep, as also after brain injury, ruptured brain aneurysm, and sedation and certain types of anesthesia, as well as other conditions which cause a decreased level of consciousness. These waves share similar features to cerebral blood flow slow waves which are associated with glymphatic flow in the brain.

For additional details of brain blood flow simulation and the simulator used to create this example of Intracranial B waves, see also:

https://www.hemodynamic.com/

For other additional published information, and lecture see also:

https://www.frontiersin.org/articles/...

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