Spatial Compounding of Ultrasonic Diagnostic Images for Rotating Linear Probe with Geometric Parameter Error Compensation

Abstract

-In ultrasonic medical imaging, spatial compounding of images is a technique where ultrasonic beam is steered to examine patient tissues in multiple angles. In the conventional ultrasonic diagnostic imaging, the steering of the ultrasonic beam is achieved electronically using the phased array transducer elements. In this paper, a spatial compounding approach is presented where the ultrasonic probe element is rotated mechanically and the beam steering is achieved mechanically. In the spatial compounding, target position is computed using the value of the rotation axis and the transducer array angular position. However, in the process of the rotation mechanism construction and the control system there arises the inevitable uncertainties in these values. These geometric parameter errors result in the target position error, and the consequence is a blurry compounded image. In order to reduce these target position errors, we present a spatial compounding scheme where error correcting transformation matrices are computed and applied to the raw images before spatial compounding to reduce the blurriness in the compounded image. The proposed scheme is illustrated using phantom and live scan images of human knee, and it is shown that the blurriness is effectively reduced.

Spatial Angular Compounding ofPhotoacoustic Images

“…Contrary to US imaging, where the success of spatial compounding relies on the combination of fully decorrelated speckle patterns, which can be achieved with large relative translations [10] or rotations [41], the background noise of PA images rapidly decorrelates (e.g., NCC < 0.5), with minimal perturbation from an initial probe position, as shown in Fig. 7, whereas ultrasound speckle correlation is greater than 0.9 for similar values of probe perturbation [10], [49].…”

“…The concept is similar to spatial compounding methods for improving the quality of US B-mode [10], [34]–[36], quantitative US [37], [38] and US strain [11], [39], [40] images. The success of spatial compounding of US images relies on the combination of fully decorrelated speckle patterns, which may be achieved with large relative translations [10] or rotations [41], deformation [26], or variations in transmit parameters, such as frequency [42] and beem steering [43]. Images containing any one of these variations are then registered and summed to create a compounded image.…”

Rotation Elastogram Estimation Using Mechanical Assisted Spatial Compounding: An Experimental Validation Study

“…Similar beamsteering [2], in which the ultrasound beam is electronically steered by conveniently changing the phase of the emitted pulse for each element, our method proposes physical rotations of the US probe to change the ultrasound beam angle. Simultaneously, a quasi-static and small compression is applied for each ultrasound probe angle to obtain the displacement images [20]. First, we performed Finite Element Method (FEM) simulations in ANSYS software (ANSYS, Inc. Headquarters, Canonsburg, PA, USA) for a loosely-bond inclined elliptical inclusion, using a simple friction model without dependence on the pre-stress distribution.…”