Positioning Laser Doppler Probe: A Technique to Implant Probe Over Middle Cerebral Artery for Blood Flow Measurement in Murine Model

The middle cerebral artery, or M-C-A, is a prominent brain vessel that supplies oxygenated blood to the cerebrum.

To measure the blood flow within the MCA, place an anesthetized mouse in the prone position. Make a small incision on the scalp between the left ear and the left eye to locate the temporal skull bone. Cut the adjacent muscle layers and retract them to visualize the MCA beneath the skull bone.

Position the probe holder containing the laser Doppler probe over the MCA. This step allows the probe to be implanted close to the artery. Apply surgical glue to restrain the probe in its position. Using more glue, close the skin around the implanted probe and cover the wound site.

Connect the probe to a laser Doppler device. The probe focuses a laser beam at a particular frequency on a narrow region of the MCA. Subsequently, the red blood cells flowing in the artery absorb the laser beam.

Being in motion, these cells scatter the laser, causing a Doppler shift—an apparent change in the frequency of the emitted waves. The detector captures these minute frequency shifts to measure blood flow within the artery.