FlexTrac + TriFlow: CT-Compatible Knee Imaging System
Stanford Soft Tissue Biomechanics Lab
Osteoarthritis usually shows up on standard imaging only after the cartilage is already breaking down. Dynamic CT arthrography could catch it earlier by tracking how an iodine contrast agent moves through the joint. The method needs two things the clinic does not have yet: a way to hold the knee steady under controlled traction during a scan, and a way to deliver the contrast at known, changing concentrations. Over a ten-week summer project in the Soft Tissue Biomechanics Lab, our team built two devices to close those gaps.
FlexTrac
A CT-compatible device that holds the knee in flexion and applies steady, adjustable traction during a scan. A modular frame and a weight-based pulley add axial load in set increments, so the setup stays consistent from one patient to the next.
ResultOn a porcine knee, traction opened the medial joint space by two to three millimeters, a clear and measurable change.
TriFlow
A programmable flow system that controls how much contrast agent moves through a joint model over time. Peristaltic pumps mix and drive the fluid, so the concentration can follow a set curve instead of staying flat the way current irrigation systems do.
ResultThe first prototype held its programmed flow rates to within about five milliliters of target and produced a clean, repeatable dilution curve.
I was first author on FlexTrac and a co-author on TriFlow, and I worked on both across the ten weeks. The project ran through the Mechanical Engineering Summer Undergraduate Research Institute, and we presented it at the Stanford SURI and Bio-X poster sessions.
