Imaging biopsy composition at ACL reconstruction

Douglas R Pedersen,1,2 James A Martin,1,2 Daniel R Thedens,3 Noelle F Klocke,1,2 Nathaniel H Roberts,1 Jessica E Goetz,1 Annunziato Amendola1 1Department of Orthopaedics and Rehabilitation, 2Department of Biomedical Engineering, 3Department of Radiology, University of Iowa, Iowa City, IA, USA Purpos...

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Main Authors: Pedersen DR, Martin JA, Thedens DR, Klocke NF, Roberts NH, Goetz JE, Amendola A
Format: Article
Language:English
Published: Dove Medical Press 2013-04-01
Series:Orthopedic Research and Reviews
Online Access:http://www.dovepress.com/imaging-biopsy-composition-at-acl-reconstruction-a12780
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author Pedersen DR
Martin JA
Thedens DR
Klocke NF
Roberts NH
Goetz JE
Amendola A
author_facet Pedersen DR
Martin JA
Thedens DR
Klocke NF
Roberts NH
Goetz JE
Amendola A
author_sort Pedersen DR
collection DOAJ
description Douglas R Pedersen,1,2 James A Martin,1,2 Daniel R Thedens,3 Noelle F Klocke,1,2 Nathaniel H Roberts,1 Jessica E Goetz,1 Annunziato Amendola1 1Department of Orthopaedics and Rehabilitation, 2Department of Biomedical Engineering, 3Department of Radiology, University of Iowa, Iowa City, IA, USA Purpose: Early-stage osteoarthritis (OA) includes glycosaminoglycan (GAG) loss and collagen disruption that cannot be seen on morphological magnetic resonance imaging (MRI). T1ρ MRI is a measurement that probes the low-frequency rate of exchange between protons of free water and those from water associated with macromolecules in the cartilage's extracellular matrix. While it has been hypothesized that increased water mobility resulting from early osteoarthritic changes cause elevated T1ρ MRI values, there remain several unknown mechanisms influencing T1ρ measurements in cartilage. The purpose of this work was to relate histological and biochemical metrics directly measured from osteochondral biopsies and fluid specimens with quantitative MRI-detected changes of in vivo cartilage composition. Patients and methods: Six young patients were enrolled an average of 41 days after acute anterior cruciate ligament (ACL) rupture. Femoral trochlear groove osteochondral biopsies, serum, and synovial fluid were harvested during ACL reconstruction to complement a presurgery quantitative MRI study (T1ρ, T2, delayed gadolinium-enhanced MRI of cartilage [dGEMRIC] relaxation times). A high-resolution MRI scan of the excised osteochondral biopsy was also collected. Analyses of in vivo T1ρ images were compared with ex vivo T1ρ imaging, GAG assays and histological GAG distribution in the osteochondral biopsies, and direct measures of bone and cartilage turnover markers and "OA marker" 3B3 in serum and synovial fluid samples. Conclusion: T1ρ relaxation times in patients with a torn ACL were elevated from normal, indicating changes consistent with general fluid effusion after blunt joint trauma. Increased chondrogenic progenitor cell (CPC) production of chondroprotective lubricin may relate to cartilage surface disruption by blunt trauma and CPC amplification of joint inflammation. Disparity between ex vivo and matched in vivo MRI of trochlear cartilage suggests MRI signal differences that may be related to the synovial fluid environment. T1ρ is emerging as a promising MRI biomarker to relate noninvasive measures of whole-joint condition and cartilage composition to direct measures of cartilage changes in the acute phase of joint injuries. Keywords: proteoglycan, osteochondral biopsy, T1ρ, biomarker
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spelling doaj.art-ace93b5370ab4df0ac67566f2bffcf8d2022-12-21T22:25:04ZengDove Medical PressOrthopedic Research and Reviews1179-14622013-04-012013default3541Imaging biopsy composition at ACL reconstructionPedersen DRMartin JAThedens DRKlocke NFRoberts NHGoetz JEAmendola ADouglas R Pedersen,1,2 James A Martin,1,2 Daniel R Thedens,3 Noelle F Klocke,1,2 Nathaniel H Roberts,1 Jessica E Goetz,1 Annunziato Amendola1 1Department of Orthopaedics and Rehabilitation, 2Department of Biomedical Engineering, 3Department of Radiology, University of Iowa, Iowa City, IA, USA Purpose: Early-stage osteoarthritis (OA) includes glycosaminoglycan (GAG) loss and collagen disruption that cannot be seen on morphological magnetic resonance imaging (MRI). T1ρ MRI is a measurement that probes the low-frequency rate of exchange between protons of free water and those from water associated with macromolecules in the cartilage's extracellular matrix. While it has been hypothesized that increased water mobility resulting from early osteoarthritic changes cause elevated T1ρ MRI values, there remain several unknown mechanisms influencing T1ρ measurements in cartilage. The purpose of this work was to relate histological and biochemical metrics directly measured from osteochondral biopsies and fluid specimens with quantitative MRI-detected changes of in vivo cartilage composition. Patients and methods: Six young patients were enrolled an average of 41 days after acute anterior cruciate ligament (ACL) rupture. Femoral trochlear groove osteochondral biopsies, serum, and synovial fluid were harvested during ACL reconstruction to complement a presurgery quantitative MRI study (T1ρ, T2, delayed gadolinium-enhanced MRI of cartilage [dGEMRIC] relaxation times). A high-resolution MRI scan of the excised osteochondral biopsy was also collected. Analyses of in vivo T1ρ images were compared with ex vivo T1ρ imaging, GAG assays and histological GAG distribution in the osteochondral biopsies, and direct measures of bone and cartilage turnover markers and "OA marker" 3B3 in serum and synovial fluid samples. Conclusion: T1ρ relaxation times in patients with a torn ACL were elevated from normal, indicating changes consistent with general fluid effusion after blunt joint trauma. Increased chondrogenic progenitor cell (CPC) production of chondroprotective lubricin may relate to cartilage surface disruption by blunt trauma and CPC amplification of joint inflammation. Disparity between ex vivo and matched in vivo MRI of trochlear cartilage suggests MRI signal differences that may be related to the synovial fluid environment. T1ρ is emerging as a promising MRI biomarker to relate noninvasive measures of whole-joint condition and cartilage composition to direct measures of cartilage changes in the acute phase of joint injuries. Keywords: proteoglycan, osteochondral biopsy, T1ρ, biomarkerhttp://www.dovepress.com/imaging-biopsy-composition-at-acl-reconstruction-a12780
spellingShingle Pedersen DR
Martin JA
Thedens DR
Klocke NF
Roberts NH
Goetz JE
Amendola A
Imaging biopsy composition at ACL reconstruction
Orthopedic Research and Reviews
title Imaging biopsy composition at ACL reconstruction
title_full Imaging biopsy composition at ACL reconstruction
title_fullStr Imaging biopsy composition at ACL reconstruction
title_full_unstemmed Imaging biopsy composition at ACL reconstruction
title_short Imaging biopsy composition at ACL reconstruction
title_sort imaging biopsy composition at acl reconstruction
url http://www.dovepress.com/imaging-biopsy-composition-at-acl-reconstruction-a12780
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AT goetzje imagingbiopsycompositionataclreconstruction
AT amendolaa imagingbiopsycompositionataclreconstruction