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Variation in MR signal intensity across normal human knee cartilage
Author(s) -
Paul Pradip K.,
Kris Jasani M.,
Sebok David,
Rakhit Ashok,
Dunton Alan W.,
Douglas Frank L.
Publication year - 1993
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.1880030404
Subject(s) - flip angle , cartilage , nuclear magnetic resonance , proteoglycan , sagittal plane , anatomy , magnetic resonance imaging , pulse sequence , osteoarthritis , intensity (physics) , sequence (biology) , materials science , chemistry , biology , physics , medicine , optics , pathology , radiology , biochemistry , alternative medicine
Signal intensity(SI) of individual pixels on sagittal magnetic resonance (MR)images of normal human knee cartilage was quantified to investigate whether it was related to cartilage proteoglycan content. In five subjects, images were acquired with spin‐echo sequences with a TR msec/TE msec ofl,OOO or 7OO/2O and a three‐dimensional gradient‐echo(GRE)sequence (60/15). In a sixth subject, the GRE sequence alone was used with 15°,30°,and 50° flip angles. In all subjects, SI was maximal in pixel layers of the medial zone and minimal at both cartilage edges, resulting in the presence of a bell‐shaped curve of interpixel(zonal) SI variation across the cartilage thickness. The magnitude of SI was dependent on the pulse sequence and flip angle, but the bell shape of the SI variation curve was independent of them. For example, in the medial tibial cartilage, the peak SI was highest with the 1,000/20 spin‐echo sequence, intermediate with the 7OO/2O sequence, and lowest with the GRE sequence. The differences were statistically significant. The bell‐shaped SI variation curve resembled the curve for zonal variation in cartilage proteoglycan content but not the curves for collagen or free water content. The physiologic basis for this resemblance and the potential usefulness of the findings for early diagnosis of diseases such as osteoarthritis are discussed.