Surface roughness and thickness analysis of contrast-enhanced articular cartilage using mesh parameterization

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• 作者：T. Maerz^&dagger ; ; ^&Dagger ; ; ^§ ; ; M.D. Newton^&dagger ; ; H.W.T. Matthew^§ ; ; ^‖ ; K.C. Baker^&dagger ; ; ^&Dagger ; ; ^{kevin.baker@beaumont.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Post-traumatic osteoarthritis ; Image analysis ; Contrast-enhanced μCT ; Cartilage morphology ; Mesh parameterization ; Surface roughness
• 刊名：Osteoarthritis and Cartilage
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：24
• 期：2
• 页码：290-298
• 全文大小：2720 K

文摘

Articular cartilage (AC) morphology is an important metric for characterizing degeneration. We propose a novel morphologic analysis using mesh parameterization, enabling the use of surface roughness and thickness metrics to characterize degeneration in a rodent model of post-traumatic osteoarthritis.

Methods

Six rats underwent anterior cruciate ligament transection (ACL-T) and six were controls (Control). At 4-weeks, femora and tibiae were harvested and imaged using contrast-enhanced micro-computed tomography (μCT). Cartilage surfaces were manually outlined, and 2-dimensional thickness maps were generated using mesh parameterization and analyzed by thickness and surface roughness (S_a). The parameterization technique was validated against the direct distance transform (DDT) and histologic AC thickness from sagittal Safranin-O/Fast-Green sections. Parameterization and DDT measurements were also validated using known, virtual shapes with zero, one, and two planes of curvature.

Results

Parameterization had 0.00–6.26% error and DDT had 5.06–12.02% error in determining thicknesses of known shapes. Parameterization thickness correlated highly to DDT thickness (femur: r = 0.978, P < 0.001; tibia: r = 0.992, P < 0.001) and histologic thickness (femur: r = 0.952, P < 0.001; tibia: r = 0.959, P < 0.001). Thickness maps enabled visualization and quantification of AC degeneration. ACL-T samples displayed general thickening of cartilage, with adjacent regions of thickening and thinning on the medial femoral condyle. Compared to Control, ACL-T thickness was higher in the whole femur, whole tibia, and all compartments and sub-compartments. S_a was higher in the whole femur and medial and lateral condyle, and the whole tibia and medial and lateral plateau. The largest increases in S_a were observed on the medial femoral condyle.

Conclusions

Cartilage analysis using parameterization effectively characterized early degeneration in AC, including sub-compartmental thickening/thinning, and is a powerful tool for assessing degeneration in preclinical osteoarthritis.