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In vivo Sub-regional dGEMRIC Analysis and Contrast Distribution in Clinical Studies of Human Knee Cartilage

Hawezi, Zana LU (2013) In Lund University Faculty of Medicine Doctoral Dissertation Series 2013:62.
Abstract
Aims: This work was carried out to investigate whether considering cartilage depth in vivo dGEMRIC would provide additional information on the molecular content and changes in normal and diseased cartilage.



Methods: Study I was a longitudinal study on 23 healthy volunteers; Study II was a case-control study on 9 sedentary individuals and 8 elite runners. Study III was a longitudinal study on 30 patients with a history of medial meniscectomy. They were divided into three groups according to self-reported changes in level of physical activity. MRI measurements were performed in femoral knee cartilage pre- & post-injection of Gd-DTPA2-. Depth-wise times p.i. depending on the study group.



Results:... (More)
Aims: This work was carried out to investigate whether considering cartilage depth in vivo dGEMRIC would provide additional information on the molecular content and changes in normal and diseased cartilage.



Methods: Study I was a longitudinal study on 23 healthy volunteers; Study II was a case-control study on 9 sedentary individuals and 8 elite runners. Study III was a longitudinal study on 30 patients with a history of medial meniscectomy. They were divided into three groups according to self-reported changes in level of physical activity. MRI measurements were performed in femoral knee cartilage pre- & post-injection of Gd-DTPA2-. Depth-wise times p.i. depending on the study group.



Results: Studies I and II: before contrast injection, T1 was higher in the superficial region than in the deep regions of the cartilage. Bulk gadolinium concentration was negatively related to cartilage thickness. Gd-DTPA2- uptake was significantly slower in the deep region than in the superficial region of the cartilage. Gd concentration in the superficial region was independent of cartilage thickness. A trend was seen towards lower Gd concentration in the superficial layer of weight-bearing cartilage in elite runners, than in sedentary individuals. More contrast agent seen in superficial non-weight-bearing cartilage than weight-bearing cartilage. In Study III, those who increased their physical activity showed a significant increase in dGEMRIC index in both superficial and deep layers in lateral weight-bearing cartilage. Those who decreased their physical activity showed a significant decrease in dGEMRIC index in the medial weight-bearing cartilage.



Conclusions: The higher pre-contrast T1 in the superficial region than in the deep region is an indication of a higher water content in superficial cartilage. The uptake of contrast agent was found to be from the superficial region of the cartilage, with diffusion into the deeper parts, and this affects the interpretation of bulk dGEMRIC measurements. The Gd concentration in the superficial layer supports dGEMRIC findings that cartilage has an adaptive capacity to exercise, leading to increased glycosaminoglycan (GAG) content throughout the cartilage. Decreasing physical activity leads to a decrease in GAG content in the cartilage. Variation in cartilage thickness is a source of error in dGEMRIC that should be considered when analysing bulk values. (Less)
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author
supervisor
opponent
  • Mwale, Fackson, Orthopaedics Research LAB, McGill University, Lady Davis Institute, 3755 Chemin Cote Ste Catherine, Montreal QC H3T 1E2 Canada
organization
publishing date
type
Thesis
publication status
published
subject
keywords
MRI, dGEMRIC, sub-regional, knee, cartilage, GAG, meniscus injury, osteoarthritis, exercise.
in
Lund University Faculty of Medicine Doctoral Dissertation Series
volume
2013:62
pages
104 pages
publisher
Joint and Soft Tissue Unit
defense location
Lecture Hall, Department Of Orthopedics, Inga Marie Nilssons gata 22, 4th floor, Skane University Hospital, Malmo.
defense date
2013-06-10 01:00:00
ISSN
1652-8220
ISBN
978-91-87449-32-1
language
English
LU publication?
yes
id
d58dcc44-8694-4039-8f81-f2afe547cffe (old id 3798267)
date added to LUP
2016-04-01 14:14:41
date last changed
2019-05-22 04:28:21
@phdthesis{d58dcc44-8694-4039-8f81-f2afe547cffe,
  abstract     = {{Aims: This work was carried out to investigate whether considering cartilage depth in vivo dGEMRIC would provide additional information on the molecular content and changes in normal and diseased cartilage.<br/><br>
<br/><br>
Methods: Study I was a longitudinal study on 23 healthy volunteers; Study II was a case-control study on 9 sedentary individuals and 8 elite runners. Study III was a longitudinal study on 30 patients with a history of medial meniscectomy. They were divided into three groups according to self-reported changes in level of physical activity. MRI measurements were performed in femoral knee cartilage pre- &amp; post-injection of Gd-DTPA2-. Depth-wise times p.i. depending on the study group.<br/><br>
<br/><br>
Results: Studies I and II: before contrast injection, T1 was higher in the superficial region than in the deep regions of the cartilage. Bulk gadolinium concentration was negatively related to cartilage thickness. Gd-DTPA2- uptake was significantly slower in the deep region than in the superficial region of the cartilage. Gd concentration in the superficial region was independent of cartilage thickness. A trend was seen towards lower Gd concentration in the superficial layer of weight-bearing cartilage in elite runners, than in sedentary individuals. More contrast agent seen in superficial non-weight-bearing cartilage than weight-bearing cartilage. In Study III, those who increased their physical activity showed a significant increase in dGEMRIC index in both superficial and deep layers in lateral weight-bearing cartilage. Those who decreased their physical activity showed a significant decrease in dGEMRIC index in the medial weight-bearing cartilage.<br/><br>
<br/><br>
Conclusions: The higher pre-contrast T1 in the superficial region than in the deep region is an indication of a higher water content in superficial cartilage. The uptake of contrast agent was found to be from the superficial region of the cartilage, with diffusion into the deeper parts, and this affects the interpretation of bulk dGEMRIC measurements. The Gd concentration in the superficial layer supports dGEMRIC findings that cartilage has an adaptive capacity to exercise, leading to increased glycosaminoglycan (GAG) content throughout the cartilage. Decreasing physical activity leads to a decrease in GAG content in the cartilage. Variation in cartilage thickness is a source of error in dGEMRIC that should be considered when analysing bulk values.}},
  author       = {{Hawezi, Zana}},
  isbn         = {{978-91-87449-32-1}},
  issn         = {{1652-8220}},
  keywords     = {{MRI; dGEMRIC; sub-regional; knee; cartilage; GAG; meniscus injury; osteoarthritis; exercise.}},
  language     = {{eng}},
  publisher    = {{Joint and Soft Tissue Unit}},
  school       = {{Lund University}},
  series       = {{Lund University Faculty of Medicine Doctoral Dissertation Series}},
  title        = {{In vivo Sub-regional dGEMRIC Analysis and Contrast Distribution in Clinical Studies of Human Knee Cartilage}},
  url          = {{https://lup.lub.lu.se/search/files/3863354/3802150.pdf}},
  volume       = {{2013:62}},
  year         = {{2013}},
}