A fast and highly automated approach to myocardial motion analysis using phase contrast magnetic resonance imaging

Abstract

Purpose: To develop a fast and highly automated method for calculating two-dimensional myocardial motion and deformation using velocity encoded magnetic resonance imaging. Materials and Methods:Two-dimensional phase contrast magnetic resonance imaging was used to acquire time resolved velocity maps of the myocardium. Cardiac motion was calculated by an iterative integration-regularization scheme of low computational cost. Image segmentation was performed using active appearance models.Results: Validation of motion tracking was performed in N ϭ 47 subjects using saturation grid-tagging and closely followed "tag-lines." Image segmentation was validated vs. manual delineation. Conclusion:The speed and limited user interaction gives the method good potential for use in clinical practice.

Persistent decline in longitudinal and radial strain after coronary microembolization detected on velocity encoded phase contrast magnetic resonance imaging

“…Later noninvasive assessment was made possible using echocardiography (7), tagged MRI (10), displacement encoded (DENSE), and velocity-encoded PC-MRI (11,16,29,30). While tissue Doppler imaging (TDI) has a much higher temporal resolution than PC-MRI, and thus an inherent advantage in determining peak systole, TDI is limited by issues of three-dimensional coverage, operator dependence, and difficulties of obtaining quality images in obese patients.…”

“…While numerous studies have used tagged MR imaging to report on myocardial strain (10), this methodology is limited by low spatial and temporal resolution. Investigators found that the phase contrast method is less susceptible to operator interaction and provided higher spatial resolution than tagged MRI (16). While DENSE and velocity-encoded PC-MRI offer equivalent information about transmural regional myocardial strain over the course of the entire cardiac cycle, the former technique's computation of strain from position rather than velocity makes it more susceptible to noise than velocity-encoding modalities (11).…”

“…The ability of velocity-encoded phase contrast MRI (PC-MRI) to measure strain was described in the early 1990s (15), but was hindered by lengthy acquisition and postprocessing. A new fast and automated method to calculate two-dimensional strain has been introduced and compared with tagged MRI (16), and the results showed close agreement between the techniques. PC-MRI has also been validated in phantom (17).…”

“…The images were obtained in three long-axis views (two-, three-, and four-chamber), as earlier described (16). Velocity data was acquired in two in-plane directions (right-left, anterior-posterior, or feet-head) and used to calculate longitudinal and radial strain (see below).…”

“…Subsequently, automated myocardial contour tracking occurred through the remaining 15 time frames of the cardiac cycle using the acquired velocity data (16). Along the myocardial contour a set of 10 local spline basis functions were distributed with temporal dependent local deformation.…”