In vivo sodium (23Na) imaging of the human kidneys at 7 T: Preliminary results

• Published in: European radiology 2014-02, Vol.24 (2), p.494-501
• Main Authors: Haneder, Stefan, Juras, Vladimir, Michaely, Henrik J, Deligianni, Xeni, Bieri, Oliver, Schoenberg, Stefan O., Trattnig, Siegfried, Zbýň, Štefan
• Format: Article
• Language: English
• Subjects: Adult; Diagnostic Radiology; Feasibility; Feasibility Studies; Female; Healthy Volunteers; Humans; Imaging; Imaging, Three-Dimensional - methods; Internal Medicine; Interventional Radiology; Kidney - anatomy & histology; Kidney Cortex - anatomy & histology; Kidney Medulla - anatomy & histology; Kidneys; Least-Squares Analysis; Magnetic Resonance; Magnetic Resonance Imaging - methods; Male; Medicine; Medicine & Public Health; Morphology; Neuroradiology; Prospective Studies; Radiology; Sodium; Ultrasound; Whole Body Imaging - methods; Young Adult
• ISSN: 0938-7994; 1432-1084
• DOI: 10.1007/s00330-013-3032-6

Objective To evaluate the feasibility of in vivo 23 Na imaging of the corticomedullary 23 Na gradient and to measure 23 Na transverse relaxation times (T2*) in human kidneys. Methods In this prospective, IRB-approved study, eight healthy volunteers (4 female, 4 male; mean age 29.4 ± 3.6 years) were examined on a 7-T whole-body MR system using a 23 Na-only spine-array coil. For morphological 23 Na-MRI, a 3D gradient echo (GRE) sequence with a variable echo time scheme (vTE) was used. T2* times were calculated using a multiecho 3D vTE-GRE approach. 23 Na signal-to-noise ratios (SNR) were given on a pixel-by-pixel basis for a 20-mm section from the cortex in the direction of the medulla. T2* maps were calculated by fitting the 23 Na signal decay monoexponentially on a pixel-by-pixel basis, using least squares fit. Results Mean corticomedullary 23 Na-SNR increased from the cortex (32.2 ± 5.6) towards the medulla (85.7 ± 16.0). The SNR increase ranged interindividually from 57.2 % to 66.3 %. Mean 23 Na-T2* relaxation times differed statistically significantly ( P