Optimization and comparison of two practical dual-tuned birdcage configurations for quantitative assessment of articular cartilage with sodium magnetic resonance imaging.

作者：Gunthard Lykowsky, Flavio Carinci, Markus Düring, Daniel L. Weber, Peter M. Jakob, Daniel Haddad · 发表于：PubMed · 年份：2015 · DOI：10.3978/j.issn.2223-4292.2015.11.06 · 被引用次数：6 · 研究领域：Osteoarthritis Treatment and Mechanisms、Advanced MRI Techniques and Applications、Nasal Surgery and Airway Studies

BACKGROUND: In this study, two practical dual-tuned birdcage configurations for quantitative assessment of articular cartilage with sodium magnetic resonance imaging (MRI) were designed and compared. METHODS: Two 1.5 T dual-tuned birdcages, a four-ring birdcage (FRB) and an alternating rungs birdcage (ARB), were built and then characterized by bench and MRI measurements. The relative uniformity (RU) and the efficiency of the coils were compared using (23)Na and (1)H B1 maps. In vivo images of a volunteer were acquired. RESULTS: Bench measurements showed matching and decoupling coefficients of the quadrature channels lower than -20 dB. The RUs and 180° pulse amplitudes of the FRB/ARB were determined as: (1)H RU =94.4/74.4%, (23)Na RU =95.2/93.6%, (1)H 180° pulse amplitude =69.2/75.4 V and (23)Na 180° pulse amplitude =45.1/45.9 V. The in vivo (23)Na images acquired with the FRB show a signal-to-noise ratio (SNR) of 6 to 14 in the cartilage. CONCLUSIONS: Due to its superior (1)H homogeneity and efficiency and its slightly better (23)Na homogeneity, the FRB is the overall preferred coil for the given requirements of this study. The achieved in vivo SNR is adequate for quantitative (23)Na and high resolution (1)H imaging.