Advanced Vascular Imaging

4D CT Angiography (4D CTA)

At Spectrum Interventional Radiology, our team under Dr Hao Xiang has refined 4D CT Angiography (4D CTA) to give clearer answers for patients with complex problems of the aorta.

Unlike a standard CT scan that takes one snapshot in time, 4D CTA records a rapid series of images so we can watch how blood actually flows through the vessels — almost like a short movie of the circulation. This extra “time” dimension reveals important flow details that static scans miss.

We use it especially for aortic dissection, where a tear in the aortic wall creates a false channel. 4D CTA shows us exactly where the tear starts and ends, how blood is entering and filling the false channel, and the flow patterns that help decide the safest treatment approach.

It is also very useful after endovascular stent-graft repair of an abdominal aortic aneurysm (AAA). 4D CTA can detect and fully characterise endoleaks — leaks of blood back into the aneurysm sac — by showing the precise source, timing, and type of leak as the contrast flows in real time.

By evaluating these flow characteristics, our specialists can make more accurate diagnoses, plan treatment or surveillance with greater confidence, and monitor patients more effectively. The technique is performed with modern low-dose protocols, making it a safe and powerful tool for understanding these challenging vascular conditions.