Accuracy assessment of Tri-plane B-mode ultrasound for non-invasive 3D kinematic analysis of knee joints

Abstract

BackgroundCurrently the clinical standard for measuring the motion of the bones in knee joints with sufficient precision involves implanting tantalum beads into the bones. These beads appear as high intensity features in radiographs and can be used for precise kinematic measurements. This procedure imposes a strong coupling between accuracy and invasiveness. In this paper, a tri-plane B-mode ultrasound (US) based non-invasive approach is proposed for use in kinematic analysis of knee joints in 3D space.MethodsThe 3D analysis is performed using image processing procedures on the 2D US slices. The novelty of the proposed procedure and its applicability to the unconstrained 3D kinematic analysis of knee joints is outlined. An error analysis for establishing the method’s feasibility is included for different artificial compositions of a knee joint phantom. Some in-vivo and in-vitro scans are presented to demonstrate that US scans reveal enough anatomical details, which further supports the experimental setup used using knee bone phantoms.ResultsThe error between the displacements measured by the registration of the US image slices and the true displacements of the respective slices measured using the precision mechanical stages on the experimental apparatus is evaluated for translation and rotation in two simulated environments. The mean and standard deviation of errors are shown in tabular form. This method provides an average measurement precision of less than 0.1 mm and 0.1 degrees, respectively.ConclusionIn this paper, we have presented a novel non-invasive approach to measuring the motion of the bones in a knee using tri-plane B-mode ultrasound and image registration. In our study, the image registration method determines the position of bony landmarks relative to a B-mode ultrasound sensor array with sub-pixel accuracy. The advantages of our proposed system over previous techniques are that it is non-invasive, does not require the use of ionizing radiation and can be used conveniently if miniaturized.

In situ comparison of A-mode ultrasound tracking system and skin-mounted markers for measuring kinematics of the lower extremity

“…In principle that concept is different than our proposed A-mode ultrasound tracking system, since we employed multiple A-mode transducers at different anatomical locations for discrete point acquisition. Other researchers combined B-mode ultrasound transducer with a motion capture system, which could obtain one or multiple curves representing bone surfaces (Jia et al, 2017;Masum et al, 2014a). The potential of being less affected by STA has been validated in an in-vivo experiment by merely measuring the depth of bone surfaces on the greater trochanter with up to 16 mm measurement difference to skin marker measurement (Jia et al, 2017).…”

Method for Non-Invasive Skin Artifact-Free Spatial Bone Motion Tracking Using Pressure Sensor Foils

“…However, Masum et al note that marker-based fluoroscopy can only be applied in postoperative studies owing to the need of invasive marker implantation [47]. Furthermore, it was criticized by Karlsson and Tranberg that human exposure to ionizing radiation should be avoided as much as possible as it may increase the risk of cancer, thus limiting measurements to a minimal number of exposures per second, or even making them completely unacceptable for ethics committees [36].…”

Real-time target tracking of soft tissues in 3D ultrasound images based on robust visual information and mechanical simulation

“…This is therefore well suited to high speckle noise but is inefficient when large shadows occur. Multi-modal criteria have also been studied such as Mutual Information (MI) (Elen et al, 2008;Shekhar and Zagrodsky, 2002), or Sum of Conditional Variance (SCV) (Masum et al, 2014) since they are more robust to ultrasound gain variations. However, MI calculation is computationally expensive and is therefore not well suited for applications of real-time tracking in a sequence of 3D ultrasound images.…”