PURPOSE: To qualitatively and quantitatively assess the corticomedullary sodium 23 ((23)Na) concentration in human kidneys before and after oral administration of a water load by using 3-T magnetic resonance (MR) imaging. MATERIALS AND METHODS: Fourteen healthy volunteers (mean age, 28 years; range, 24-34 years) were included in this institutional review board-approved study between July and December 2009. For (23)Na MR imaging, a density-adapted three-dimensional radial gradient echo sequence (echo time, 0.55 msec; repetition time, 120 msec; spatial resolution, 5 × 5 × 5 mm) was used with a dedicated (23)Na-tuned coil. Beforehand, the coil profile was assessed by using phantom measurements, and the volunteer images were mathematically corrected accordingly. Images of the volunteers were obtained before and 30 minutes after oral ingestion of 1 L of water. As internal reference, (23)Na concentration of the cerebrospinal fluid (CSF) was calculated. Well-defined corticomedullary complexes in each kidney were assessed, with (23)Na concentrations in the cortex and medulla assessed at various standardized points. From these values, quantitative (23)Na concentrations were derived, and the slopes of the linear portion of the concentration gradient were calculated. Paired t tests were performed. RESULTS: Mean calculated (23)Na concentrations of CSF before (135.2 mmol/L ± 10.4) and after water load (135.5 mmol/L ± 11.0) fell within physiologic ranges (P = .95). An increase in average (23)Na concentration from 63.5 mmol/L ± 9.3 in the cortex to 108.0 mmol/L ± 10.9 in the medulla was identified. After the water load, this gradient was preserved, although (23)Na concentrations decreased significantly (P < .0001) to 48.6 mmol/L ± 5.3 in the cortex and 81.9 mmol/L ± 10.1 in the medulla-declines of 23.4% and 24.7%, respectively. CONCLUSION: This study demonstrates the physiologic evaluation of human kidneys with 3-T (23)Na MR imaging. The (23)Na imaging technique used allows the quantification of the corticomedullary (23)Na concentration and the assessment of its change with differing physiologic conditions.
PURPOSE: To qualitatively and quantitatively assess the corticomedullary sodium 23 ((23)Na) concentration in human kidneys before and after oral administration of a water load by using 3-T magnetic resonance (MR) imaging. MATERIALS AND METHODS: Fourteen healthy volunteers (mean age, 28 years; range, 24-34 years) were included in this institutional review board-approved study between July and December 2009. For (23)Na MR imaging, a density-adapted three-dimensional radial gradient echo sequence (echo time, 0.55 msec; repetition time, 120 msec; spatial resolution, 5 × 5 × 5 mm) was used with a dedicated (23)Na-tuned coil. Beforehand, the coil profile was assessed by using phantom measurements, and the volunteer images were mathematically corrected accordingly. Images of the volunteers were obtained before and 30 minutes after oral ingestion of 1 L of water. As internal reference, (23)Na concentration of the cerebrospinal fluid (CSF) was calculated. Well-defined corticomedullary complexes in each kidney were assessed, with (23)Na concentrations in the cortex and medulla assessed at various standardized points. From these values, quantitative (23)Na concentrations were derived, and the slopes of the linear portion of the concentration gradient were calculated. Paired t tests were performed. RESULTS: Mean calculated (23)Na concentrations of CSF before (135.2 mmol/L ± 10.4) and after water load (135.5 mmol/L ± 11.0) fell within physiologic ranges (P = .95). An increase in average (23)Na concentration from 63.5 mmol/L ± 9.3 in the cortex to 108.0 mmol/L ± 10.9 in the medulla was identified. After the water load, this gradient was preserved, although (23)Na concentrations decreased significantly (P < .0001) to 48.6 mmol/L ± 5.3 in the cortex and 81.9 mmol/L ± 10.1 in the medulla-declines of 23.4% and 24.7%, respectively. CONCLUSION: This study demonstrates the physiologic evaluation of human kidneys with 3-T (23)Na MR imaging. The (23)Na imaging technique used allows the quantification of the corticomedullary (23)Na concentration and the assessment of its change with differing physiologic conditions.
Authors: Stefan Haneder; Vladimir Juras; Henrik J Michaely; Xeni Deligianni; Oliver Bieri; Stefan O Schoenberg; Siegfried Trattnig; Štefan Zbýň Journal: Eur Radiol Date: 2013-10-02 Impact factor: 5.315
Authors: Stefan Haneder; Paul Kettnaker; Simon Konstandin; John N Morelli; Lothar R Schad; Stefan O Schoenberg; Henrik J Michaely Journal: MAGMA Date: 2013-03-09 Impact factor: 2.310
Authors: Stefan Haneder; Johannes Michael Budjan; Stefan Oswald Schoenberg; Simon Konstandin; Lothar Rudi Schad; Ralf Dieter Hofheinz; Veronika Gramlich; Frederik Wenz; Frank Lohr; Judit Boda-Heggemann Journal: Strahlenther Onkol Date: 2014-12-02 Impact factor: 3.621