4D Digital Subtraction Angiography for the Temporal Flow Visualization of Intracranial Aneurysms and Vascular Malformations

Purpose: To assess the benefit and radiation dose of four-dimensional (4D) digital subtraction angiography (DSA) a time resolved three-dimensional (3D) DSA application to evaluate the flow and architecture of aneurysms and vascular malformations. Methods: All patients with cerebrovascular disease were considered who underwent 4D-DSA at our institution between January 2015 and February 2016. For the aneurysm patients, we evaluated the image quality in terms of the visualization of contrast flow in the aneurysm on a 3-point scale (excellent, fair and poor). Interrater agreement between two raters was estimated using Cohen's Kappa statistics. For the shunt disease patients, the additional information obtained from the 4D-DSA was described for each disease. The median radiation dose and volume of contrast medium required for the acquisitions were estimated. Results: A total of 173 patients underwent 4D-DSA; 126 intracranial aneurysms, 10 arteriovenous malformations (AVM), 15 dural arteriovenous fistula (dAVF) and 22 other diseases. For aneurysm patients, excellent and fair visualization of the intra-aneurysmal flow was observed in 27.7%, 72.3%, and excellent (K = 0.9) agreement between the raters was found. For AVM and dAVF patients, 4DDSA clarified the complex vasculature by viewing the discrete time phase of contrast filling. Median radiation dose for intracranial lesions was 79.6 mGy for 6s 4D-DSA, and 175 mGy for 12s 4D-DSA. The median amount of contrast medium used was 18.0 ml for 6s 4D-DSA and 21.0 ml for 12s 4D-DSA. Conclusions: 4D-DSA provided additional information regarding intra-aneurysmal flow and contributed to detect different component of nidus or shunt points.