Changes in internal carotid and vertebral arterial wall stiffness with head movement can be detected with shear wave elastography

Background: Safe practice is important for patients with neck pain, with the potential for injury to cervical arteries. Cervical manipulation or end range techniques/positions may place considerable strain on the arteries. Altered integrity of the arterial wall may render them more susceptible to minor trauma, particularly in the upper cervical region. Screening of blood flow velocity is limited for predicting those at risk. Examining properties of the cervical arterial wall (stiffness characteristics) and their response to head movement may provide an alternate measure of arterial susceptibility. Objectives: To investigate whether shear wave ultrasound elastography can detect any changes in internal carotid (ICA) and vertebral (VA) arterial wall stiffness in neutral compared with contralateral head rotation. Design: Observational study Methods: Shear wave ultrasound elastography was used to measure the stiffness of the ICA and VA. Shear wave velocity (m/s), indicative of arterial stiffness, was measured in both arteries proximally (C3-4) and distally (C1-2) in neutral and contralateral head rotation as were intimal thickness (mm) and flow velocity (cm/s). Results: Thirty participants (20-62 years) were successfully imaged. The VA was stiffer than ICA and it became significantly stiffer in contralateral rotation (p = 0.05). The ICA became significantly less stiff (p = 0.01). Effects were more apparent at C1-2 but significant in the ICA only (p = 0.03). Flow velocity and intimal thickness were unchanged in rotation. Conclusions: Changes in VA and ICA arterial wall stiffness can be measured with shear wave ultrasound elastography. This measure may ultimately help identify arteries with greater vulnerability to rotational stresses.