Subchondral bone and cartilage thickness from MRI: effects of chemical-shift artifact |
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Authors: | Email author" target="_blank">Chris?A?McGibbonEmail author Jenny?Bencardino William?E?Palmer |
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Affiliation: | (1) Department of Orthopaedics, Biomotion Laboratory, Massachusetts General Hospital, Ruth Sleeper Hall 010, 40 Parkman St., 02114, Boston, MA, USA,;(2) Department of Radiology, Bone and Joint Radiology, Massachusetts General Hospital, 02114, Boston, MA, USA, |
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Abstract: | Magnetic resonance imaging (MRI) is the modality of choice for visualizing and quantifying articular cartilage thickness.
However, difficulties persist in MRI of subchondral bone using spoiled gradient-echo (SPGR) and other gradient-echo sequences,
primarily due to the effects of chemical-shift artifact. Fat-suppression techniques are often used to reduce these artifacts,
but they prevent measurement of bone thickness. In this report, we assess the magnitude of chemical-shift effects (phase-cancellation
and misregistration artifacts) on subchondral bone and cartilage thickness measurements in human femoral heads using a variety
of pulse sequence parameters. Phase-cancellation effects were quantified by comparing measurements from in-phase images (TE=13.5 ms)
to out-of-phase images (TE=15.8 ms). We also tested the assumption of the optimal in-phase TE by comparing thickness measures
at small variations on TE (13.0, 13.5 and 14.0 ms). Misregistration effects were quantified by comparing measurements from
water+fat images (water-only+fat-only images) to the measurements from in-phase (TE=13.5) images. A correction algorithm was
developed and applied to the in-phase measurements and then compared to measurements from water+fat images. We also compared
thickness measurements at different image resolutions. Results showed that both phase-cancellation artifact and misregistration
artifact were significant for bone thickness measurement, but not for cartilage thickness measurement. Using an in-phase TE
and correction algorithm for misregistration artifact, the errors in bone thickness relative to water+fat images were non-significant.
This information may be useful for developing pulse sequences for optimal imaging of both cartilage and subchondral bone.
Electronic Publication |
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Keywords: | Subchondral bone Articular cartilage Chemical-shift artifact Thickness Magnetic resonance imaging |
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