Background:
Calcium-suppressed (CaSupp) technique involving spectral-based images has been used to
observe bone marrow edema by removing calcium components from the image.
Objective:
This study aimed to evaluate the knee articular cartilage using the CaSupp technique in dual-layer detector
computed tomography (DLCT).
Methods:
Twenty-eight healthy participants and two patients with osteoarthritis were enrolled, who underwent DLCT and
magnetic resonance imaging (MRI) examination. CaSupp images were reconstructed from spectral-based images using a
calcium suppression algorithm and were overlaid conventional CT images for visual evaluation. The morphology of the
knee cartilage was evaluated, and the thickness of the articular cartilage was measured on sagittal proton density–
weighted and CaSupp images in the patellofemoral compartment.
Results:
No abnormal signal or density, cartilage defect, and subjacent bone ulceration were observed in the lateral and
medial femorotibial compartments and the patellofemoral compartment on MRI images and CaSupp images for the 48
normal knee joints. CaSupp images could clearly identify cartilage thinning, defect, subjacent bone marrow edema, and
edema of the infrapatellar fat pad in the same way as MRI images in the three knee joints with osteoarthritis. A significant
difference was found in the mean thickness of the patellar cartilage between MRI images and CaSupp images, while the
femoral cartilage presented no significant difference in thickness between MRI images and CaSupp images over all 48
knee joints.
Conclusion:
The present study demonstrated that CaSupp images could effectively be used to perform the visual and
quantitative assessment of knee cartilage.
Validity of histopathological grading of articular cartilage from osteoarthritic knee joints
