AngioVis: Advanced Visualization Techniques in Peripheral CT-Angiography

Modern multiple-detector row helical CT scanners allow fast and precise volumetric imaging of the patient body. With simultaneous application of contrast media they are well-suited for CT-Angiography. Due to the presence of bones in extremities and curved course of the vessels, visualization of the vascular tree and its assesment is a challenging task.

This web summarized results of a series of three research projects aimed on clinical processing and visualization of peripheral CTA datasets:

These research projects were carried out in an interdisciplinary environment involving both radiologists and computer scientists of four reseasrch institutions: Austrian Academy of Sciences, Vienna University of Technology, Medical University of Vienna and Stanford University Medical Center (USA). Within this environment, the clinical usability of new reformation techniques was confirmed which enabled us to integrate the new tools into the infrastructure in the daily routine of a radiological department of a hospital. Altogether 600 cases are currently processed by these tools per year at various hospitals.

Advanced Peripheral CT-Angiography

Vascular diseases are the most frequent cause of death in developed countries. Atherosclerosis in various forms influences mainly elderly people. Higher age, suboptimal diet, lack of exercise and pre-cursors as smoking result in pathologic changes in the vascularity, main in the form of hardening arteries. Atherosclerotic plaque deposits in the vessel walls narrow the blood flow lumen and thus diminish blood flow, what can result in incomfort, interminent claudication and in final stage can cause gangrene.

Atherosclerotic diseases, as e.g. Peripheral Arterial Occlusive Disease (PAOD) are in later stages treated surgically. To allow  planning of the treatment, stage of the pathology must be precisely assessed. Within the recent years, helical, multiple-detector row CT (MDCT) scanners (MDCT) has evolved in precise, effective and easy to use tool in clinical praxis. The actual speeds and resolution of the MDCT scanner allow fast volumetric imaging of the entire human body. With injection of contrast-medium, the acquired 3D data are well suited for angiographic purposes. Due to its quality, 3D modality and efficiency it might outperform traditional techniques, as e.g. Digital-Subtraction-Angiography (DSA). In such way, the MDCT is modality very useful for extremities.
Due to the anatomy, the vessel are in the extremities are in a complex relationship with human body skeleton. This, together with the nature of CT acquisition makes proper clinical vessel visualization from 3D CT-A datasets (in case of extremities) challenging, because the bone occlude the vessels in Maximum-Intensity-Projection (MIP) images and does not allow assess the blood flow lumen together with plaque and occluded parts of the vessel in Volume-Rendered (VR) images.

AngioVis offers a novel approach for visualization of the vessel and diagnostic of the PAOD based on pre-processing of the 3D dataset. Main vessel are identified and modeled in the data using fast and user-friendly semi-automatic algorithm. The derived models of the vessel then served for resampling of the dataset along the vessel paths, thus allowing to see the vessel, its course and eventual pathology in longitudinal cuts, in so called Curved-Planar-Reformation (CPR) images.

The AngioVis ToolBox is a software aimed on pre-processing of the peripheral CT-A datasets in form of CPR images. The software is used regularly for clinical and research purposes. Read more about AngioVis and peripheral CT-A data visualization.