In-vivo clinical validation of cardiac deformation and strain measurements from 4D ultrasound

Abstract

An important goal in clinical cardiology is the non-invasive quantification of regional cardiac deformation. While many methods have been proposed for the estimation of 3D left ventricular deformation and strains derived from 4D ultrasound, currently there is a lack of in vivo clinical validation of these algorithms on humans. In this paper, we describe the experiments used in validating cardiac deformation and strain estimates of 4D ultrasound using correlation-based optical flow tracking on two different COPD patients with normal left ventricular function. Validation of the algorithm was done by 1) validation of cardiac volume across multiple scans of the same patient and 2) validation of the repeatability of cardiac displacement and strain results from multiple scan acquisitions of the same patient. The preliminary results are encouraging with our algorithm producing consistent cardiac volume and strain results across multiple acquisitions. Furthermore, our derived 4D cardiac strains showed qualitatively correct results. We also observed particularly interesting results in the radial displacements of the posterior and lateral walls of our COPD patients.

Fig. 2.1

Three cardiac views in (a) coronal plane, (b) sagittal plane, and (c) axial plane of the volumetric ultrasound data set at 50% sampling frequency.

Figure 2.2

Flowchart from data acquisition to strain computation.

Figure 3.1

Results of 3 cardiac volumes as computed from 3 different acquisitions during one examination of a COPD patient (AP0490).

Figure 3.2

Mean, first quartile, and third quartile temporal profiles of radial displacement of one patient over the course of two cardiac cycles. (a) The radial displacement of the base of the heart averaged over 6 sections expressed in cm (b) The radial displacement of the mid region of the heart averaged over 6 sections expressed in cm.

Figure 3.2

Mean, first quartile, and third quartile temporal profiles of radial displacement of one patient over the course of two cardiac cycles. (a) The radial displacement of the base of the heart averaged over 6 sections expressed in cm (b) The radial displacement of the mid region of the heart averaged over 6 sections expressed in cm.