In-vivo cerebral artery pulsation assessment with Dynamic Computed Tomography Angiography

Four-Dimensional Computed Tomography Angiography (4D CTA) seems a promising technique for capturing vessel motion of cerebral arteries, which may help to assess pathological conditions such as intracranial aneurysms. The goal of our current study is to capture the lumen diameter of cerebral arteries during three subsequent cardiac cycles with 4D CTA and to assess vessel motion, anticipating consistent expansion patterns within each cardiac cycle. Eighteen adult patients with unruptured and untreated intracranial aneurysms were recruited at Radboud University Medical Center. Three cardiac cycles were captured, on a wide detector CT system, using ECG-gated 4D CTA. To reduce the impact of small head movements during the acquisition, a rigid-body registration was employed. Three 10 mm segments of cerebral arteries were selected. The total deformation of the vessel lumen was calculated using a deformable registration algorithm and was used as a substitute measure for vessel motion. No pulsations could be registered, which was probably caused by pulsation motion below threshold of detection in combination with insufficient Signal-to-Noise Ratio. Further studies need to investigate if large intracranial structures can be evaluated and if using a novel scanner with a high spatial resolution would result in reproducible measurements of arteries this size.