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

One of the earliest changes in osteoarthritis (OA) is a surface discontinuity of the articular cartilage (AC), and these surface changes become gradually more complex with OA progression. We recently developed a contrast enhanced micro‐computed tomography (μCT) method for visualizing AC surface in detail. The present study aims to introduce a μCT analysis technique to parameterize these complex AC surface features and to demonstrate the feasibility of using these parameters to quantify degenerated AC surface. Osteochondral plugs ( n = 35) extracted from 19 patients undergoing joint surgery were stained with phosphotungstic acid and imaged using μCT. The surface micro‐topography of AC was analyzed with developed method. Standard root mean square roughness (R q ) was calculated as a reference, and the Area Under Curve (AUC) for receiver operating characteristic analysis was used to compare the acquired quantitative parameters with semi‐quantitative visual grading of μCT image stacks. The parameters quantifying the complex micro‐topography of AC surface exhibited good sensitivity and specificity in identifying surface continuity (AUC: 0.93, [0.80 0.99]), fissures (AUC: 0.94, [0.83 0.99]) and fibrillation (AUC: 0.98, [0.88 1.0]). Standard R q was significantly smaller compared with the complex roughness (CR q ) already with mild surface changes with all surface reference parameters − continuity, fibrillation, and fissure sum. Furthermore, only CR q showed a significant difference when comparing the intact surface with lowest fissure sum score. These results indicate that the presented method for evaluating complex AC surfaces exhibit potential to identify early OA changes in superficial AC and is dynamic throughout OA progression. © 2019 The Authors. Journal of Orthopaedic Research ® Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. Society. 9999:1–12, 2019.

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confidence: 99%

“…As mentioned above, studies quantifying the micro‐topography of the AC surface have attempted to characterize the apparent simple surface of AC. Thus, in an orthogonal coordinate system, on the AC surface for every lateral coordinate ( x , y ), there is only one z‐value , where ( x , y , z ) represents a coordinate on AC surface (Fig.…”

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confidence: 99%

Quantifying Complex Micro‐Topography of Degenerated Articular Cartilage Surface by Contrast‐Enhanced Micro‐Computed Tomography and Parametric Analyses

Ylitalo

Finnilä

Gahunia³

et al. 2019

“…Femoral and tibial cartilage volumes were segmented from each 3D MRI stack in a blinded fashion using MATLAB (Mathworks Inc., Natick, MA). The MRI stack was resampled to 0.37 mm isotropic voxels and displayed in a custom multi‐plane viewing interface, and a volume of interest (VOI) composed of articular cartilage, the bone‐cartilage interface (BCI), and a thin layer of subchondral bone (excluding bone marrow) was manually outlined, as previously demonstrated for the isolation of articular cartilage . Briefly, a single author (KG) performed manual outlining of individual, spaced sagittal slices, and a morphing algorithm (MATLAB File Exchange, http://www.mathworks.com/matlabcentral/fileexchange/61313-morph-binary-images) was used to interpolate the slices between manually contoured slices to produce the 3D VOI.…”

Section: Methodsmentioning

confidence: 99%

“…Cartilage thickness maps were computed for each sample based on a previously described and validated algorithm . The overall process of mesh parameterization analysis is demonstrated in Figure .…”

Section: Methodsmentioning

confidence: 99%

“…Mesh parameterization, a type of 3D‐to‐2D image processing transformation, was applied to convert 3D femoral and tibial cartilage volumes into 2D cartilage thickness maps for subsequent calculation of 2D surface roughness, representing the variation in cartilage thickness across the surface. The study demonstrated that while overall mean cartilage thickness changed by ∼50%, surface roughness increased by over 250% …”

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confidence: 97%

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Articular cartilage surface roughness as an imaging‐based morphological indicator of osteoarthritis: A preliminary investigation of osteoarthritis initiative subjects

Newton

Osborne

Gawronski

et al. 2017

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Current imaging-based morphometric indicators of osteoarthritis (OA) using whole-compartment mean cartilage thickness (MCT) and volume changes can be insensitive to mild degenerative changes of articular cartilage (AC) due to areas of adjacent thickening and thinning. The purpose of this preliminary study was to evaluate cartilage thickness-based surface roughness as a morphometric indicator of OA. 3D magnetic resonance imaging (MRI) datasets were collected from osteoarthritis initiative (OAI) subjects with Kellgren-Lawrence (KL) OA grades of 0, 2, and 4 (n = 10/group). Femoral and tibial AC volumes were converted to two-dimensional thickness maps, and MCT, arithmetic surface roughness (S ), and anatomically normalized S (normS ) were calculated. Thickness maps enabled visualization of degenerative changes with increasing KL grade, including adjacent thinning and thickening on the femoral condyles. No significant differences were observed in MCT between KL grades. S was significantly higher in KL4 compared to KL0 and KL2 in the whole femur (KL0: 0.55 ± 0.10 mm, KL2: 0.53 ± 0.09 mm, KL4: 0.79 ± 0.18 mm), medial femoral condyle (KL0: 0.42 ± 0.07 mm, KL2: 0.48 ± 0.07 mm, KL4: 0.76 ± 0.22 mm), and medial tibial plateau (KL0: 0.42 ± 0.07 mm, KL2: 0.43 ± 0.09 mm, KL4: 0.68 ± 0.27 mm). normS was significantly higher in KL4 compared to KL0 and KL2 in the whole femur (KL0: 0.22 ± 0.02, KL2: 0.22 ± 0.02, KL4: 0.30 ± 0.03), medial condyle (KL0: 0.17 ± 0.02, KL2: 0.20 ± 0.03, KL4: 0.29 ± 0.06), whole tibia (KL0: 0.34 ± 0.04, KL2: 0.33 ± 0.05, KL4: 0.48 ± 0.11) and medial plateau (KL0: 0.23 ± 0.03, KL2: 0.24 ± 0.04, KL4: 0.40 ± 0.10), and significantly higher in KL2 compared to KL0 in the medial femoral condyle. Surface roughness metrics were sensitive to degenerative morphologic changes, and may be useful in OA characterization and early diagnosis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2755-2764, 2017.

Traumatic joint injury induces acute catabolic bone turnover concurrent with articular cartilage damage in a rat model of posttraumatic osteoarthritis

Maerz

Newton

Fleischer

et al. 2020

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Objective: Assess acute alterations in bone turnover, microstructure, and histomorphometry following noninvasive anterior cruciate ligament rupture (ACLR).Methods: Twelve female Lewis rats were randomized to receive noninvasive ACLR or Sham loading (n=6/group). In vivo μCT was performed at 3, 7, 10, and 14 days post-injury to quantify compartmentdependent subchondral (SCB) and epiphyseal trabecular bone remodeling. Near-infrared (NIR) molecular imaging was used to measure in vivo bone anabolism (800 CW BoneTag) and catabolism (Cat K 680 FAST). Metaphyseal bone remodeling and articular cartilage morphology was quantified using ex vivo μCT and contrast-enhanced µCT, respectively. Calcein-based dynamic histomorphometry was used to quantify bone formation. OARSI scoring was used to assess joint degeneration, and osteoclast number was quantified on TRAP stained-sections.Results: ACLR induced acute catabolic bone remodeling in subchondral, epiphyseal, and metaphyseal compartments. Thinning of medial femoral condyle (MFC) SCB was observed as early as 7 days postinjury, while lateral femoral condyles (LFC) exhibited SCB gains. Trabecular thinning was observed in MFC epiphyseal bone, with minimal changes to LFC. NIR imaging demonstrated immediate and sustained reduction of bone anabolism (~15-20%), and a ~32% increase in bone catabolism at 14 days, compared to contralateral limbs. These findings were corroborated by reduced bone formation rate and increased osteoclast numbers, observed histologically. ACLR-injured femora had significantly elevated OARSI score, cartilage thickness, and cartilage surface deviation. Conclusion:ACL rupture induces immediate and sustained reduction of bone anabolism and overactivation of bone catabolism, with mild-to-moderate articular cartilage damage at 14 days postinjury..