Decorrelation characteristics of transverse blood flow along an intravascular array catheter

Abstract

In recent years, a new method to measure transverse blood flow based on the decorrelation of radio frequency (RF) signals has been introduced. In this paper, we investigated the decorrelation characteristics of transverse blood flow measurement using an intravascular ultrasound (IVUS) array catheter by means of computer modeling. Blood was simulated as a collection of randomly located point scatterers. Moving this scattering medium transversally across the acoustical beam represented flow. First-order statistics were evaluated, and the signal-to-noise ratio from the signals was measured. The correlation coefficient method was used to present the results. The decorrelation patterns for RF and for RF-envelope signals were studied. The decorrelation patterns from the RF signals were in good agreement with those obtained from theoretical beam profiles. This agreement suggests that the decorrelation properties of an IVUS array catheter for measuring quantitative transverse blood flow can be assessed by measuring the ultrasound beam. A line of point scatterers, moved transversally across the acoustical beam (line spread function), can determine this decorrelation behaviour.

Decorrelation-based blood flow velocity estimation: effect of spread of flow velocity, linear flow velocity gradients, and parabolic flow

“…In order to perform this study, a computer simulation program extended from Lupotti et al [13] and Borsboom et al [19] was used. In the computer simulation program, four elements were considered as one curved (convex) single element, and its area was divided into a grid of small areas with dimensions less than a quarter of a wavelength (17 µm for a wavelength of 75 µm).…”

“…In previous studies [13], [14], the transverse decorrelation pattern for plug blood flow was addressed. The present study evaluates the effect of random spread of blood-flow velocity, linear blood-flow velocity gradients, and parabolic blood flow on the decorrelation-based method.…”

“…With the advent of array technology in IVUS applications [12], this extra component of decorrelation is not present because the array transducer is capable of transmitting and receiving a multitude of echoes at exactly the same angle with respect to the array. Using a computer simulation program, Lupotti et al [13] assessed the decorrelation characteristics of the IVUS array catheter during transverse blood flow. The mean decorrelation pattern from scattering media containing only point scatterers, as RBCs, agreed with a reference curve based on the autoconvolution of the acoustical beam [13].…”

“…Using a computer simulation program, Lupotti et al [13] assessed the decorrelation characteristics of the IVUS array catheter during transverse blood flow. The mean decorrelation pattern from scattering media containing only point scatterers, as RBCs, agreed with a reference curve based on the autoconvolution of the acoustical beam [13]. Later results [14] showed the mean decorrelation pattern from scattering media containing strings of point scatterers with random angles and lengths, as aggregates of RBCs, in agreement with the autoconvolution of the acoustical beam.…”

Spatial anisotropic diffusion and local time correlation applied to segmentation of vessels in ultrasound image sequences

“…Some blood speed evaluation techniques were proposed by Lupotti [8] and Li [9], calculating the correlation between RF signals in order to estimate the longitudinal speed by correlating the displacement of ultrasound scatterers.…”