The Use of MRI for Sternocleidomastoid Muscle Volume Measurement and its Association with Internal Carotid Artery Velocity in a Healthy Cohort

Impairments or changes in the neck musculatures functional capacity has been shown to lead to cervicogenic symptoms (Rubin et al., 1995; Ryan & Cope., 1955; Wrisley et al., 2000). This study measured the sternocleidomastoid muscle (SCMM) volume to explore sex-related differences and its relationship with internal carotid artery (ICA) blood flow velocity (BFV). Imaging of the SCMM was conducted using Phase-Contrast Magnetic Resonance Imaging (PC-MRI) and the ICA BFV was examined by Doppler Ultrasound (DU) of 34 healthy participants (19 females, 15 males). Significant sex differences were established in SCMM volumes (p<0.05). There was excellent absolute agreement amongst raters measuring SCMM volume (ICC=0.916). Body Mass Index (BMI) was significantly correlated with females right SCMM volume and ICA BFV (p<0.005). Overall bilateral and particularly the right males SCMM volume was significantly correlated with ICA BFV (p< 0.05). These results will be an essential comparison group of healthy SCMM volume values for patients suffering from concurrent concussion and whiplash-related injuries.