Aortic Centerline Extraction in 4D-Flow MRI: Effect of Threshold Selection and Subsampling

Arterial centerline is a simplified and topologically equivalent representation of the vascular structure. The objective of this study was to obtain the centerline of the thoracic aorta in 4D Flow MRI images through iterative thinning, analyzing the variations in the results caused by the application of different thresholds for vascular segmentation and the reduction of voxel quantity through subsampling. The results were acceptable for thresholds below 60% of the maximum value of the angiogram in the aorta, with average differences below 2 pixels. Subsampling significantly accelerated the processing times but nearly doubled average and maximum distances from the reference line, especially in the descending aorta. These preliminary results will allow for future standardization of the positioning of regions of interest in the aorta using this modality.