Optimization of High-Frequency Ultrasound Imaging to Detect Incremental Changes in Mineral Content at the Cartilage–Bone Interface Ex Vivo

(1) Background: Osteoarthritis is a degenerative disease of the whole joint marked by cartilage–bone interface (CBI) remodeling, but methods to monitor subtle changes in mineralization are lacking. We optimized a non-destructive ultrasound imaging method to monitor incremental shifts in mineralizati...

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Main Authors: Akshay Charan, Parag V. Chitnis, Caroline D. Hoemann
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Biomimetics
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Online Access:https://www.mdpi.com/2313-7673/10/3/160
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author Akshay Charan
Parag V. Chitnis
Caroline D. Hoemann
author_facet Akshay Charan
Parag V. Chitnis
Caroline D. Hoemann
author_sort Akshay Charan
collection DOAJ
description (1) Background: Osteoarthritis is a degenerative disease of the whole joint marked by cartilage–bone interface (CBI) remodeling, but methods to monitor subtle changes in mineralization are lacking. We optimized a non-destructive ultrasound imaging method to monitor incremental shifts in mineralization, using brief decalcification as a mimetic of CBI remodeling. (2) Methods: We used a 35-MHz transducer to scan 3 mm diameter bovine osteochondral explants wrapped with parafilm to produce surface-directed decalcification and dedicated 3D-printed holders to maintain sample orientation. Customized MATLAB codes and a matched pair design were used for quantitative hypothesis testing. (3) Results: Optimal scan precision was obtained when the High-Frequency Ultrasound (HFUS) focal distance was trained at the CBI. HFUS cartilage thickness increased by 53 ± 21 µm or 97 ± 28 µm after three or seven hours of ethylene diamine tetra-acetic acid (EDTA) (but not PBS), respectively, and was highly correlated with histological cartilage thickness (R = 0.98). The en face CBI backscatter pattern was irregular and shifted after the EDTA-displacement of the mineral front. Collective data suggested that the −10 dB echogenic CBI signal originated from the mineral front and varied topographically with undulating mineral thickness. (4) Conclusions: This imaging approach could be used to monitor tidemark remodeling in live explant cultures, toward identifying new treatments that inhibit tidemark advancement and slow osteoarthritis progression.
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spelling doaj-art-b1e816e4b4bb46c09b759917a6a37dcf2025-08-20T02:42:45ZengMDPI AGBiomimetics2313-76732025-03-0110316010.3390/biomimetics10030160Optimization of High-Frequency Ultrasound Imaging to Detect Incremental Changes in Mineral Content at the Cartilage–Bone Interface Ex VivoAkshay Charan0Parag V. Chitnis1Caroline D. Hoemann2Department of Bioengineering, George Mason University, Manassas, VA 20110, USADepartment of Bioengineering, George Mason University, Manassas, VA 20110, USADepartment of Bioengineering, George Mason University, Manassas, VA 20110, USA(1) Background: Osteoarthritis is a degenerative disease of the whole joint marked by cartilage–bone interface (CBI) remodeling, but methods to monitor subtle changes in mineralization are lacking. We optimized a non-destructive ultrasound imaging method to monitor incremental shifts in mineralization, using brief decalcification as a mimetic of CBI remodeling. (2) Methods: We used a 35-MHz transducer to scan 3 mm diameter bovine osteochondral explants wrapped with parafilm to produce surface-directed decalcification and dedicated 3D-printed holders to maintain sample orientation. Customized MATLAB codes and a matched pair design were used for quantitative hypothesis testing. (3) Results: Optimal scan precision was obtained when the High-Frequency Ultrasound (HFUS) focal distance was trained at the CBI. HFUS cartilage thickness increased by 53 ± 21 µm or 97 ± 28 µm after three or seven hours of ethylene diamine tetra-acetic acid (EDTA) (but not PBS), respectively, and was highly correlated with histological cartilage thickness (R = 0.98). The en face CBI backscatter pattern was irregular and shifted after the EDTA-displacement of the mineral front. Collective data suggested that the −10 dB echogenic CBI signal originated from the mineral front and varied topographically with undulating mineral thickness. (4) Conclusions: This imaging approach could be used to monitor tidemark remodeling in live explant cultures, toward identifying new treatments that inhibit tidemark advancement and slow osteoarthritis progression.https://www.mdpi.com/2313-7673/10/3/160cartilage–bone interfacehigh frequency ultrasoundtidemarkdecalcificationhard/soft interface remodelingnon-decalcified histology
spellingShingle Akshay Charan
Parag V. Chitnis
Caroline D. Hoemann
Optimization of High-Frequency Ultrasound Imaging to Detect Incremental Changes in Mineral Content at the Cartilage–Bone Interface Ex Vivo
Biomimetics
cartilage–bone interface
high frequency ultrasound
tidemark
decalcification
hard/soft interface remodeling
non-decalcified histology
title Optimization of High-Frequency Ultrasound Imaging to Detect Incremental Changes in Mineral Content at the Cartilage–Bone Interface Ex Vivo
title_full Optimization of High-Frequency Ultrasound Imaging to Detect Incremental Changes in Mineral Content at the Cartilage–Bone Interface Ex Vivo
title_fullStr Optimization of High-Frequency Ultrasound Imaging to Detect Incremental Changes in Mineral Content at the Cartilage–Bone Interface Ex Vivo
title_full_unstemmed Optimization of High-Frequency Ultrasound Imaging to Detect Incremental Changes in Mineral Content at the Cartilage–Bone Interface Ex Vivo
title_short Optimization of High-Frequency Ultrasound Imaging to Detect Incremental Changes in Mineral Content at the Cartilage–Bone Interface Ex Vivo
title_sort optimization of high frequency ultrasound imaging to detect incremental changes in mineral content at the cartilage bone interface ex vivo
topic cartilage–bone interface
high frequency ultrasound
tidemark
decalcification
hard/soft interface remodeling
non-decalcified histology
url https://www.mdpi.com/2313-7673/10/3/160
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