Estimation of Blood Flow Parameters in the Left Atrial Appendage from 4DCT Dynamic Contrast Enhancement

TL;DR

This paper presents a method to estimate blood flow parameters in the left atrial appendage using high-resolution 4DCT imaging and dynamic contrast enhancement maps, providing detailed flow visualization.

Contribution

The study introduces a novel approach to quantify and visualize blood flow in the LAA using 4DCT and contrast enhancement modeling, advancing non-invasive cardiac flow assessment.

Findings

Successful acquisition of 4DCT contrast enhancement data across multiple heartbeats.

Generation of spatial-temporal flow parameter maps from contrast enhancement.

Enhanced visualization of blood flow dynamics in the LAA.

Abstract

Cardiac CT is often used clinically in electrophysiology to evaluate cardiac morphology. One such case is to evaluate patients with Atrial Fibrillation (AF). AF can cause regions of slow blood flow and blood stasis through the left atrial appendage (LAA), and therefore, it may be preferable to evaluate blood flow through the LAA in addition to morphology. Although CT cannot measure flow directly, CT data has been used to estimate flow using modeling approaches such as Computational Fluid Dynamics, which take into account the cardiac geometry to simulate flow. Advances in CT technology now enable high-resolution imaging of the whole heart with low radiation doses. With multi-heartbeat imaging during a contrast injection, we can obtain 4-dimentional CT (4DCT) images to measure dynamic contrast enhancement directly. In this study, we use high-resolution 4DCT to acquire images of contrast enhancement across the LAA over multiple heartbeats. The CT contrast signal at each voxel over time is used to create dynamic contrast enhancement maps of parameters derived from a gamma-variate fit. These contrast enhancement maps enable quantification and visualization of spatial-temporal characteristics of flow parameters across the LAA.