7 Tesla Chlorine (35Cl) and Sodium (23Na) MR Imaging of an Enchondroma

Abstract

We demonstrated the feasibility of 7 Tesla sodium (23 Na) and chlorine (35 Cl) MRI of a solitary enchondroma. For this, we established dedicated sequences on a 7-Tesla whole-body system with the following key parameters for 35 Cl MRI: TE/TR = 0.35/60 ms, T RO  = 5 ms, α = 90°, Δx 3  = (6 mm) 3, 3 averages, T acq  = 30 min and for 23 Na MRI: TE/TR = 0.4/101 ms, T RO  = 10ms; α = 90°; Δx 3  = (1.9 mm) 3, 3 averages, T acq  = 30 min 18 s. The measured apparent Na + concentration was 255 mmol/l and was approximately 7-fold higher than the apparent Cl - concentration with about 36 mmol/l. Additionally, repeated proton MRI examinations demonstrated constant but subtle growth (≈ 0.65 ml/year) over 14 years. In conclusion, enchondromas obviously have a high contrast-to-noise ratio when compared with the normal bone marrow in 23 Na and 35 Cl MRI, which may contribute to detection and differentiation in unclear or subtle cases. Key Points: High magnetic field strengths (e. g., 7 Tesla) enable sodium (23 Na) and chlorine (35 Cl) MRI of solitary cartilage-forming tumors like enchondromas with nominal spatial resolutions of (1.9 mm) 3 (23 Na MRI) and (6 mm) 3 (35 Cl MRI). Measured median tumoral apparent Na + and Cl - concentrations were nearly 13 times higher and 3 times higher than in normal muscle tissue, respectively. Enchondromas have a high contrast-to-noise-ratio when compared with the normal bone marrow in 23 Na and 35 Cl MRI, which may contribute to detection and differentiation in unclear or subtle cases. Citation Format Weber M, Seyler L, Nagel AM. 7 Tesla Chlorine (35 Cl) and Sodium (23 Na) MR Imaging of an Enchondroma. Fortschr Röntgenstr 2021; 193: 1207 - 1211.