Handedness and the geometry and hemodynamics of the branches of the aortic arch

Abstract

Asymmetry in the vasculature arising from the human aortic arch seems the obvious place to look for an anatomical basis for lateralized cerebral functions, but this relationship has never systematically been investigated. This study explored the relationship between handedness and the anatomical and hemodynamic characteristics of the carotid arteries, analysing potential asymmetries between the left and right common, internal and external carotid arteries in leftha-nded versus right-handed individuals. The study is separated into two chapters: geometric (n = 199) and hemodynamic (n = 234). A revised version of the Edinburgh Handedness Inventory classified all participants into relevant handedness preference categories. For the geometric study, detailed measurements of the common carotid arteries in computed tomography angiography scans were obtained using Radiant DICOM Viewer (64-bit) imaging software. Selected geometric parameters of the vessels measured included minimum, mean, and maximum diameters, length, angle and calculated resistance to blood flow. Cases of unconventional branching patterns were analysed separately. For the hemodynamic study, Speed and Accuracy Target Tests quantified the participants’ handedness performance. Doppler ultrasound was performed using the Vivid i GE Ultrasound system, on the common, internal and external carotid arteries. Hemodynamic parameters of the Doppler waveform were recorded, including Peak systolic and end-diastolic velocity, Resistive index, Pulsatility index, volume flow rate, and vessel diameter. The data was analysed with mixed design ANOVAs, discriminant function analyses, multiple regressions, and paired and independent t-tests, to investigate the asymmetries and predictive properties of the measured variables