Viewpoint Planning for Quantitative Coronary Angiography

TL;DR

This paper presents an algorithm for optimal viewpoint planning in coronary angiography that improves visualization of arteries from single X-ray images by reducing foreshortening and enabling precise rotations around vessels.

Contribution

It introduces a novel method for determining optimal viewpoints based solely on 2-D images, eliminating the need for 3-D models in coronary artery assessment.

Findings

Substantial reduction in foreshortening compared to initial views

Complete elimination of foreshortening for 90-degree rotations

Provides bounds on maximal inaccuracies for off-centered vessels

Abstract

In coronary angiography the condition of myocardial blood supply is assessed by analyzing 2-D X-ray projections of contrasted coronary arteries. This is done using a flexible C-arm system. Due to the X-ray immanent dimensionality reduction projecting the 3-D scene onto a 2-D image, the viewpoint is critical to guarantee an appropriate view onto the affected artery and, thus, enable reliable diagnosis. In this work we introduce an algorithm computing optimal viewpoints for the assessment of coronary arteries without the need for 3-D models. We introduce the concept of optimal viewpoint planning solely based on a single angiographic X-ray image. The subsequent viewpoint is computed such that it is rotated precisely around a vessel, while minimizing foreshortening. Our algorithm reduces foreshortening substantially compared to the input view and completely eliminates it for 90 degree rotations. Rotations around iso-centered foreshortening-free vessels passing the isocenter are exact. The precision, however, decreases when the vessel is off-centered or foreshortened. We evaluate worst case boundaries, providing insight in the maximal inaccuracies to be expected. This can be utilized to design viewpoints guaranteeing desired requirements, e.g. a true rotation around the vessel of at minimum 30 degree.