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Quantitative in vivo diffusion imaging of cartilage using double echo steady‐state free precession
Author(s) -
Bieri Oliver,
Ganter Carl,
Scheffler Klaus
Publication year - 2012
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.23275
Subject(s) - steady state free precession imaging , dephasing , nuclear magnetic resonance , steady state (chemistry) , spin echo , relaxation (psychology) , diffusion , echo planar imaging , chemistry , diffusion mri , precession , magnetic resonance imaging , physics , radiology , medicine , quantum mechanics , astronomy , thermodynamics
Single‐shot echo‐planar imaging techniques are commonly used for diffusion‐weighted imaging (DWI) but offer rather poor spatial resolution and field‐of‐view coverage for species with short T 2 . In contrast, steady‐state free precession (SSFP) has shown promising results for DWI of the musculoskeletal system, but quantification is generally hampered by its prominent sensitivity on relaxation times. In this work, a new and truly diffusion‐weighted (that is relaxation time independent) SSFP DWI technique is introduced using a double‐echo steady‐state approach. Within this framework (and this is in contrast to common SSFP DWI techniques using SSFP‐Echo) both primary echo paths of nonbalanced SSFP are acquired, namely the FID and the Echo. Simulations and in vitro measurements reveal that the ratio of the Echo/FID signal ratios of two double‐echo steady‐state scans acquired with and without diffusion sensitizing dephasing moments provides a highly relaxation independent quantity for diffusion quantification. As a result, relaxation‐independent high‐resolution (0.4 × 0.4 − 0.6 × 0.6 mm 2 in‐plane resolution) quantitative in vivo SSFP DWI is demonstrated for human articular cartilage using diffusion‐weighted double‐echo steady‐state scans in the knee and ankle joint at 3.0 T. The derived diffusion coefficients for cartilage ( D ∼ 1.0–1.5 μm 2 /ms) and synovial fluid ( D ∼ 2.6 μm 2 /ms) are in agreement with previous work. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.