title: Magnetic resonance detection of kidney iron deposition in sickle cell disease: a marker of chronic hemolysis.
abstract: OBJECTIVE
  To study the pattern, etiology, and significance of renal iron accumulation in chronically transfused sickle cell disease (SCD) and thalassemia major (TM) patients using magnetic resonance imaging (MRI).
  
  
  METHODS
  Magnetic resonance imaging (MRI) was performed in 75 SCD patients, 73 TM patients, and 16 healthy controls. Multiecho gradient echo protocols were used to measure T2* reciprocals (R2*) in the kidney, liver, and heart. Kidney R2* was compared to tissue iron estimates, serum iron markers, and surrogates of intravascular hemolysis by univariate regression.
  
  
  RESULTS
  Mean R2* in SCD patients was 55.3+/-45.3 Hz, compared with 22.1+/-11 Hz in TM patients and 21.3+/-5.8 Hz in control subjects (P<0.001). Kidney R2* decreased with advancing age (R2=0.09, P<0.02). Kidney R2* correlated strongly with increased serum lactate dehydrogenase levels found in SCD (R2=0.55, P<0.001), but was independent of hepatic iron concentration and cardiac R2*. Kidney R2* did not correlate with blood pressure, creatinine, cardiac index, or right and left ejection fraction.
  
  
  CONCLUSIONS
  Intravascular hemolysis, not chronic transfusion, causes renal hemosiderosis in SCD. Prospective trials are necessary to determine whether kidney R2* is a biomarker for hemolysis-mediated vascular complications in SCD.
authors.affiliation: Department of Diagnostic Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90027, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Schein
authors.forename: Cathleen
authors.initials: C
authors.lastname: Enriquez
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Coates
authors.forename: John C
authors.initials: JC
authors.lastname: Wood
mesh_terms: D000293:Adolescent; D000465:Algorithms; D000743:Anemia, Hemolytic / Q000175:diagnosis* / Q000378:metabolism*; D000755:Anemia, Sickle Cell / Q000175:diagnosis* / Q000378:metabolism*; D015415:Biomarkers / Q000032:analysis; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007501:Iron / Q000032:analysis*; D019190:Iron Overload / Q000175:diagnosis* / Q000378:metabolism*; D007668:Kidney / Q000737:chemistry; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D015415:Biomarkers; D007501:Iron
references.citation: Radiology. 1996 Apr;199(1):13-22
references.pmid: 8633135
references.citation: N Engl J Med. 2000 Aug 3;343(5):327-31
references.pmid: 10922422
references.citation: J Am Soc Nephrol. 2007 Feb;18(2):414-20
references.pmid: 17229906
references.citation: Radiology. 2005 Sep;236(3):911-9
references.pmid: 16118170
references.citation: Ultrastruct Pathol. 1993 Mar-Apr;17(2):169-83
references.pmid: 8316965
references.citation: Blood. 1981 Jan;57(1):83-9
references.pmid: 7448417
references.citation: Magn Reson Med. 2006 Sep;56(3):681-6
references.pmid: 16888797
references.citation: Kidney Int. 2006 Apr;69(7):1276-80
references.pmid: 16482096
references.citation: J Am Soc Nephrol. 2002 Feb;13(2):423-430
references.pmid: 11805171
references.citation: JAMA. 2005 Jul 6;294(1):81-90
references.pmid: 15998894
references.citation: Clin Nephrol. 2006 Sep;66(3):210-3
references.pmid: 16995344
references.citation: Abdom Imaging. 1994 Mar-Apr;19(2):168-73
references.pmid: 8199554
references.citation: Pediatr Radiol. 1985;15(1):38-43
references.pmid: 3881724
references.citation: J Comput Assist Tomogr. 1994 Jan-Feb;18(1):63-7
references.pmid: 8282886
references.citation: J Am Soc Nephrol. 1999 Jan;10(1):187-92
references.pmid: 9890326
references.citation: N Engl J Med. 2004 Feb 26;350(9):886-95
references.pmid: 14985486
references.citation: Annu Rev Nutr. 1987;7:485-508
references.pmid: 3300744
references.citation: Intern Med. 1993 Sep;32(9):686-90
references.pmid: 8142671
references.citation: Medicine (Baltimore). 2005 Nov;84(6):363-376
references.pmid: 16267411
references.citation: J Magn Reson Imaging. 2006 Jan;23(1):9-16
references.pmid: 16329085
references.citation: Exp Pathol. 1983;23(4):227-35
references.pmid: 6683665
references.citation: Blood. 2006 Mar 15;107(6):2279-85
references.pmid: 16291595
references.citation: Lab Invest. 2000 Dec;80(12):1905-14
references.pmid: 11140702
references.citation: Kidney Int. 2006 Jun;69(11):2037-42
references.pmid: 16501491
references.citation: Eur J Pediatr. 1997 Aug;156(8):602-4
references.pmid: 9266189
references.citation: Circulation. 2005 Jul 26;112(4):535-43
references.pmid: 16027257
references.citation: Nephron. 1998;78(2):156-61
references.pmid: 9496731
references.citation: Radiology. 1986 Feb;158(2):379-83
references.pmid: 3941863
references.citation: Arch Intern Med. 1974 Apr;133(4):660-9
references.pmid: 4594399
references.citation: Stroke. 2006 Jun;37(6):1424-6
references.pmid: 16627796
references.citation: J Comput Assist Tomogr. 1999 May-Jun;23(3):445-7
references.pmid: 10348453
references.citation: Radiographics. 2002 Jul-Aug;22(4):833-46
references.pmid: 12110713
references.citation: Blood. 2005 Aug 15;106(4):1460-5
references.pmid: 15860670
references.citation: Blood. 2003 Jan 1;101(1):15-9
references.pmid: 12393526
references.citation: Pediatr Nephrol. 2000 Nov;15(1-2):109-12
references.pmid: 11095025
references.citation: Circulation. 1996 Dec 15;94(12):3271-5
references.pmid: 8989140
references.citation: Clin Nephrol. 2002 Feb;57(2):127-30
references.pmid: 11863122
references.citation: Blood. 1995 Jun 1;85(11):3283-8
references.pmid: 7756661
references.citation: Clin Lab Haematol. 2003 Apr;25(2):105-9
references.pmid: 12641614
references.citation: Blood. 1997 Feb 1;89(3):739-61
references.pmid: 9028304
references.citation: Ann N Y Acad Sci. 1998 Jun 30;850:251-69
references.pmid: 9668547
references.citation: Proc Natl Acad Sci U S A. 1975 Oct;72(10):3853-7
references.pmid: 1060068