title: Sodium MRI of the human kidney at 3 Tesla.
abstract: The sodium concentration gradient in the kidney (from the cortex to the medulla) serves to regulate fluid homeostasis and is tightly coupled to renal function. It was previously shown that renal function and pathophysiology can be characterized in rat kidneys by measuring the sodium gradient with (23)Na MRI. This study demonstrates for the first time the ability of (23)Na MRI to map the distribution of sodium in the human kidney and to quantify the corticomedullary sodium gradient. The study was performed on a 3T Signa LX scanner (GE) using an in-house-built quadrature surface coil. (23)Na images of volunteers were acquired using a 3D coronal gradient-echo sequence at a spatial resolution of 0.3 x 0.3 x 1.5 cm(3) in a 25-min scan time. The signal intensity (relative to the noise) increased linearly from the cortex to each of the medullae with a mean slope of 1.6 +/- 0.2 in relative arbitrary units per mm (Rel.u./mm, N = 6) and then decreased, as expected, toward the renal pelvis. Water deprivation (12 hr) induced a significant increase of 25% (P < 0.05) in this gradient. Based on these results, we suggest that sodium MRI can serve as a valuable noninvasive method for functional imaging of the human kidney.
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
authors.forename: Nimrod
authors.initials: N
authors.lastname: Maril
authors.forename: Yael
authors.initials: Y
authors.lastname: Rosen
authors.forename: Glenn H
authors.initials: GH
authors.lastname: Reynolds
authors.forename: Alex
authors.initials: A
authors.lastname: Ivanishev
authors.forename: Long
authors.initials: L
authors.lastname: Ngo
authors.forename: Robert E
authors.initials: RE
authors.lastname: Lenkinski
mesh_terms: D000328:Adult; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007668:Kidney / Q000033:anatomy & histology* / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D012964:Sodium / Q000378:metabolism*; D012979:Sodium Radioisotopes; D014018:Tissue Distribution
chemical_list: D012979:Sodium Radioisotopes; D012964:Sodium