Sub-Nyquist acquisition and constrained reconstruction in time resolved angiography

Area of Science:

• Medical Imaging
• Radiology
• Cardiovascular Imaging

Background:

• Digital subtraction angiography (DSA) revolutionized interventional radiology by providing real-time digital angiographic images, reducing risks.
• Initial limitations of 2D DSA included vessel overlap and the need for repeat injections, despite efforts to minimize complications through smaller catheters and reduced iodine doses.
• The development of time-resolved MR DSA yielded 3D time-series images, but faced tradeoffs in temporal and spatial resolution.

Purpose of the Study:

• To describe the evolution of DSA techniques from 2D to 4D imaging.
• To highlight advancements in undersampled acquisitions and constrained reconstruction methods.
• To showcase the benefits of 4D DSA in interventional radiology and medical imaging.

Main Methods:

• Implementation of undersampled non-Cartesian acquisitions (e.g., VIPR) and constrained reconstruction methods (e.g., HYPR) to overcome resolution tradeoffs.
• Application of these techniques to generate time-series 3D X-ray DSA volumes using rotational C-arm acquisition.
• Utilizing biplane systems for 4D fluoroscopy capabilities.

Main Results:

• Successful generation of 4D DSA volumes, representing a 30-year evolution from traditional DSA.
• Resolution of the vessel overlap problem inherent in 2D DSA, particularly for intravenous angiography.
• Demonstration of full time-dependent vascular behavior visualization in three dimensions.
• Enabling of 4D fluoroscopy for real-time device tracking in vascular structures from any angle.

Conclusions:

• 4D DSA volumes provide flexible, multi-dimensional roadmaps for interventional procedures.
• Constrained reconstruction methods are broadly applicable in medical imaging, enabling significant acceleration and dose reduction.
• The evolution to 4D DSA represents a major advancement in visualizing complex vascular dynamics for improved patient care.