23NA MRI accurately measures fixed charge density in articular cartilage

Erik M. Shapiro, Arijitt Borthakur, Alexander Gougoutas, Ravinder Reddy

Research output: Research - peer-reviewArticle

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Abstract

One of the initiating steps of osteoarthritis is the loss of proteoglycan (PG) molecules from the cartilage matrix. One method for assessing cartilage integrity, therefore, is to measure the PG content or fixed charge density (FCD) of cartilage. This report shows the feasibility of calculating FCD by 23Na MRI and introduces MRI protocols for human studies, in vivo. 23Na MRI was used to measure the sodium concentration inside bovine patellar cartilage. The sodium concentration was then converted to FCD (mM) by considering ideal Donnan equilibrium. These FCD measurements were compared to FCD measurements obtained through standard dimethylmethylene blue PG assays. There was a high correlation (slope = 0.89, r2 = 0.81) between the FCD measurements obtained by 23Na MRI and those obtained by the PG assays. These methods were then employed in quantifying the FCD of articular cartilage of human volunteers in vivo. Two imaging protocols were compared: one using a birdcage coil, the other using a transmit/receive surface coil. Both methodologies gave similar results, with the average sodium concentration of normal human patellar cartilage ranging from ∼240 to 260 mM. This corresponds to FCDs of -158 mM to -182 mM.

LanguageEnglish (US)
Pages284-291
Number of pages8
JournalMagnetic Resonance in Medicine
Volume47
Issue number2
DOIs
StatePublished - 2002
Externally publishedYes

Profile

Articular Cartilage
Cartilage
Proteoglycans
Sodium
Osteoarthritis
Volunteers
dimethylmethylene blue

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

Cite this

23NA MRI accurately measures fixed charge density in articular cartilage. / Shapiro, Erik M.; Borthakur, Arijitt; Gougoutas, Alexander; Reddy, Ravinder.

In: Magnetic Resonance in Medicine, Vol. 47, No. 2, 2002, p. 284-291.

Research output: Research - peer-reviewArticle

Shapiro, Erik M. ; Borthakur, Arijitt ; Gougoutas, Alexander ; Reddy, Ravinder. / 23NA MRI accurately measures fixed charge density in articular cartilage. In: Magnetic Resonance in Medicine. 2002 ; Vol. 47, No. 2. pp. 284-291
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