23Na Magnetic Resonance Imaging of the Lower Leg of Acute Heart Failure Patients during Diuretic Treatment.
OBJECTIVE
Na+ can be stored in muscle and skin without commensurate water accumulation. The aim of this study was to assess Na+ and H2O in muscle and skin with MRI in acute heart failure patients before and after diuretic treatment and in a healthy cohort.


METHODS
Nine patients (mean age 78 years; range 58-87) and nine age and gender-matched controls were studied. They underwent 23Na/1H-MRI at the calf with a custom-made knee coil. Patients were studied before and after diuretic therapy. 23Na-MRI gray-scale measurements of Na+-phantoms served to quantify Na+-concentrations. A fat-suppressed inversion recovery sequence was used to quantify H2O content.


RESULTS
Plasma Na+-levels did not change during therapy. Mean Na+-concentrations in muscle and skin decreased after furosemide therapy (before therapy: 30.7±6.4 and 43.5±14.5 mmol/L; after therapy: 24.2±6.1 and 32.2±12.0 mmol/L; p˂0.05 and p˂0.01). Water content measurements did not differ significantly before and after furosemide therapy in muscle (p = 0.17) and only tended to be reduced in skin (p = 0.06). Na+-concentrations in calf muscle and skin of patients before and after diuretic therapy were significantly higher than in healthy subjects (18.3±2.5 and 21.1±2.3 mmol/L).


CONCLUSIONS
23Na-MRI shows accumulation of Na+ in muscle and skin in patients with acute heart failure. Diuretic treatment can mobilize this Na+-deposition; however, contrary to expectations, water and Na+-mobilization are poorly correlated.
Department of Radiology, University Hospital Erlangen, Erlangen, Germany.
Matthias
M
Hammon
Department of Radiology, University Hospital Erlangen, Erlangen, Germany.
Susan
S
Grossmann
Department of Nephrology and Hypertension, University Hospital Erlangen, Erlangen, Germany.
Peter
P
Linz
Department of Nephrology and Hypertension, University Hospital Erlangen, Erlangen, Germany.
Christoph
C
Kopp
Department of Nephrology and Hypertension, University Hospital Erlangen, Erlangen, Germany.
Anke
A
Dahlmann
Department of Cardiology, University Hospital Erlangen, Erlangen, Germany.
Christoph
C
Garlichs
Department of Radiology, University Hospital Erlangen, Erlangen, Germany.
Rolf
R
Janka
Department of Radiology, University Hospital Erlangen, Erlangen, Germany.
Alexander
A
Cavallaro
Experimental and Clinical Research Center, Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany; Department of Medicine, Vanderbilt University, Nashville, Tennessee, United States of America.
Friedrich C
FC
Luft
Department of Radiology, University Hospital Erlangen, Erlangen, Germany.
Michael
M
Uder
Department of Medicine, Vanderbilt University, Nashville, Tennessee, United States of America.
Jens
J
Titze
D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D004232:Diuretics / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D006333:Heart Failure / Q000209:etiology* / Q000378:metabolism*; D006801:Humans; D007866:Leg / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism; D011446:Prospective Studies; D012867:Skin / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D014867:Water / Q000378:metabolism
D004232:Diuretics; D014867:Water; D012964:Sodium