Feldkamp-type reconstruction algorithms for spiral cone-beam CT with variable pitch

Abstract

Bolus-chasing CT angiography is an important new imaging mode for imaging cardiovascular structures and peripheral vessels. The adaptive bolus-chasing method implies a variable pitch spiral cone-beam CT scan. In this paper, we extend 2D-weighted, 3D-weighted and tilted plane FDK algorithms for variable pitch spiral cone-beam CT. Numerical simulation tests with high pitches and large cone angles are performed. Our results demonstrate that the tilted plane Feldkamp-type reconstruction algorithm shows the highest tolerance to the data incompleteness, the 3D-weighted half-scan FDK algorithm is the best choice for the practical variable pitch cone-beam CT, and the exact reconstruction algorithms perform less satisfactorily when a dataset is incomplete. However, the exact algorithms can be used for high accuracy reconstruction offline if a dataset is complete. Our work may facilitate development of practical variable pitch helical cone-beam CT.