Quantitative 3D and 4D skeletal imaging

Skeletal imaging plays an increasingly important role in diagnosis, decision making and treatment of skeletal disorders. When skeletal imaging is used to quantify 3D geometric and kinematic (3D in motion) bone properties, we refer to quantitative skeletal imaging. Quantitative information helps us getting a better diagnosis, and provides more accurate treatment planning in the fields of orthopedics, traumatology and hand surgery.

Our group is devoted to research and development of novel CT-based methods for quantitative analysis of the skeletal system in general, with focus on surgical planning and kinematics of the wrist joint.

Focus

1. 4D-CT of the wrist joint

In a longstanding cooperation with the departments of Radiology, Plastic & Reconstructive and Hand Surgery, and Orthopedics of the AMC we develop, evaluate and clinically apply 4D-imaging for analysis of 3D motion patterns of the moving wrist. This novel technology adds dynamic information to the diagnosis, which facilitates decision making, treatment and post-operative evaluation of wrist disorders. Our approach focuses on using 4D images to quantify motion and to establish disorders in an objective fashion, mostly applied to the wrist. Divergent carpal kinematics can be observed by comparing motion patterns between an affected wrist and the patient’s contralateral side, or by presenting the joint space as a heat map on the dynamic wrist bones to visualize regions afflicted by osteoarthritis. 4D-CT is utilized in pre-clinical and clinical studies on early diagnosis of wrist trauma, evaluation of surgical procedures, and development of wrist implants.

Wrist joint kinematics

Heatmap representing dynamic distances

2. Planning of corrective surgery

As a second quantitative imaging application, we investigate and develop novel techniques for image-based preoperative planning of corrective osteotomy surgery, and intraoperative image analysis methods to perform this procedure in a minimally invasive way. A multitude of applications have emerged, such as using patient-specific osteosynthesis material, which snugly fit the patient’s bone anatomy while perfectly restoring anatomic bone alignment. Another example is achievement of perfect rotational alignment by calculating an oblique osteotomy plane and a single in-plane bone rotation. This procedure automatically finds the optimal cutting position to further optimize bone alignment. These sophisticated types of surgical planning have been implemented in software, developed in our group, and is continuously being extended for treatment planning of the upper and lower extremities.

Drill and cut guide

Reduction through temporary wedge

Fixation through standard plate and drilled holes

Optimization of an oblique osteotomy

Evaluating bone collision by simulation

3. Measurement of knee prosthesis loosening

Annually, more than 2.2 million people worldwide undergo Total Knee Arthroplasty (TKA) surgery to replace an osteoarthritic or severely damaged knee by an artificial knee joint. This knee replacement aims at removing pain, and recovering or enhancing the function of the knee. About 25% of patients return to the hospital with recurrent pain, which may be related to a aseptic loosening of the implant. In close collaboration with the Orthopedics department we have developed a noninvasive, image-based method, implemented in software called DisJoint, which allows us to determine whether or not a knee prosthesis is loose. With this method we aim to measure sub-millimeter displacements, and hence establish implant loosening in a noninvasive fashion. Research activities in this research line are devoted to optimization of image acquisition and image analysis methods and clinical evaluation in clinical trials.

Output

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