Purpose: 4D Digital Subtraction Angiography (4D-DSA) is a new imaging technology that provides both high spatial resolution and temporal resolution in one acquisition. It is a special new reconstruction algorithm that made this technology possible. Patients with various types of cerebrovascular diseases were evaluated with 4D-DSA, and its efficacy and limitations were assessed.
Methods: The 4D-DSA images of patients with different types of vascular malformations were evaluated. 6 seconds acquisitions were used for the evaluation of arterial phase dynamics and 12 seconds acquisitions for assessing the entire arterial-venous phase. The amount of contrast material and radiation dose used in each acquisition was compared with the conventional rotational 3D-DSA. The unique findings observed in the 4D-DSA in each type of vascular malformation were described, and whether or not the findings are useful for the pre-treatment planning was discussed.
Results: The 4D-DSA images of a total of 57 patients were evaluated. 33 aneurysm patients, 6 arteriovenous malformation (AVM) patients, 8 dural arteriovenous fistula (AVF) patients, as well as 4 spinal vascular malformation patients, and 6 others were included. The amount of contrast and radiation dose required for the 4D-DSA (6 seconds acquisition) was similar to the conventional 3D-DSA, whereas 12 seconds acquisitions required almost double the dose. Especially for the vascular malformations with arterio-venous shunting, the 4D-DSA helped understand the detailed vascular anatomy by breaking down the complex vascular structures into the different phases of contrast filling. Motion artifact due to the longer acquisition time, and metal artifact from deployed coils were observed.
Conclusions: The temporal information provided by 4D-DSA helps us understand the complex vascular structures and flow dynamics. 4D-DSA can be an effective assessment tool for the pre-treatment planning of brain vascular malformations.