Re: Further Evidence Supporting the Accuracy of Quantitative Magnetic Resonance Imaging for Evaluating Iron Load in Dialysis Patients

In his editorial accompanying our article, Daniel Coyne raises important issues regarding the validity of magnetic resonance imaging (MRI) for quantifying iron load in dialysis patients.1Coyne D.W. Iron overload in dialysis patients: rust or bust?.Kidney Int Rep. 2017; 2: 995-997Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar, 2Issad B. Ghali N. Beaudreuil S. et al.Hepatic iron load at magnetic resonance imaging is normal in most patients receiving peritoneal dialysis.Kidney Int Rep. 2017; 2: 1219-1222Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar We are disappointed that he did not analyze our article devoted to this topic, published in January 2017.3Rostoker G. Laroudie M. Blanc R. et al.Signal-intensity-ratio MRI accurately estimates hepatic iron load in hemodialysis patients.Heliyon. 2017; 3: e00226Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar There is indeed a need to validate these MRI techniques in dialysis patients, notably by comparison with liver biopsy.3Rostoker G. Laroudie M. Blanc R. et al.Signal-intensity-ratio MRI accurately estimates hepatic iron load in hemodialysis patients.Heliyon. 2017; 3: e00226Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar However, liver biopsy is an invasive and risky procedure, especially in frail patients with end-stage renal disease, and such studies therefore raise ethical concerns.3Rostoker G. Laroudie M. Blanc R. et al.Signal-intensity-ratio MRI accurately estimates hepatic iron load in hemodialysis patients.Heliyon. 2017; 3: e00226Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar In a pilot study, on the advice of ethicists, we compared the classic Scheuer score and Deugnier and Turlin histological classification of iron overload (Perls staining of hemosiderin deposits) with signal-intensity-ratio MRI values obtained with the Rennes University algorithm in 11 hemodialysis patients in whom liver biopsy was formally indicated for their medical follow-up.3Rostoker G. Laroudie M. Blanc R. et al.Signal-intensity-ratio MRI accurately estimates hepatic iron load in hemodialysis patients.Heliyon. 2017; 3: e00226Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar For Scheuer’s histological classification, the Wilcoxon matched-pairs test showed no significant difference in the ranking of iron overload by histology and MRI (summary of ranks = 1.5; P = 1) (Figure 1).3Rostoker G. Laroudie M. Blanc R. et al.Signal-intensity-ratio MRI accurately estimates hepatic iron load in hemodialysis patients.Heliyon. 2017; 3: e00226Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar The MRI and Scheuer histological classifications were strongly correlated (rho = 0.866, P = 0.0035, Spearman coefficient), as were the absolute liver iron concentrations on MRI (rho = 0.860, P = 0.0013, Spearman coefficient).3Rostoker G. Laroudie M. Blanc R. et al.Signal-intensity-ratio MRI accurately estimates hepatic iron load in hemodialysis patients.Heliyon. 2017; 3: e00226Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar The absolute liver iron concentrations on MRI also correlated strongly with the Deugnier-Turlin histological score (rho = 0.841, P = 0.0033, Spearman coefficient).3Rostoker G. Laroudie M. Blanc R. et al.Signal-intensity-ratio MRI accurately estimates hepatic iron load in hemodialysis patients.Heliyon. 2017; 3: e00226Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar We think these recent findings in the field of dialysis-related iron overload warrant the attention of the broad readership of Kidney International Reports. Hepatic Iron Load at Magnetic Resonance Imaging Is Normal in Most Patients Receiving Peritoneal DialysisKidney International ReportsVol. 2Issue 6PreviewOver the past 3 decades, the routine use of erythropoeisis-stimulating agents (ESA) has enabled the correction of anemia in most patients with end-stage renal disease (ESRD), reducing the need for blood transfusions and improving the quality of life of severely anemic patients.1 Almost all ESA-treated hemodialysis patients receive parenteral iron to ensure sufficient available iron for ESA therapy.1–4 Iron deficiency is common in hemodialysis patients due to inadequate iron mobilization from repleted storage sites (functional iron deficiency) and blood loss related to the hemodialysis procedure itself, to routine blood sampling for laboratory tests (especially for monitoring of uremia), and to occult fecal bleeding due to uremic enteropathy. Full-Text PDF Open AccessOther Estimation of Blood Losses in Hemodialysis and Formula for Translating Liver Iron Concentration From Iron Balance Calculation Based on Iron Removal by PhlebotomyKidney International ReportsVol. 3Issue 1PreviewIn his recent editorial, Daniel Coyne1 raises concerns regarding iron overload detection in dialysis patients by quantitative magnetic resonance imaging (MRI). Using the equation established by Barry2 in 1974 (based on the relationship between liver iron content [LIC] and stored iron mobilized by phlebotomy in 12 patients with genetic hemochromatosis, where 30 μmol/g dry liver LIC equals 1 g of iron), Daniel Coyne calculates that the decline in LIC on MRI found by Rostoker et al.3 in their iron-overloaded hemodialysis patients after iron withdrawal (17.9 μmol/g dry liver/month or 215 μmol/g dry liver per year) “cannot match blood losses (7.16 g of iron lost per year with Barry’s formula). Full-Text PDF Open AccessThe Author RepliesKidney International ReportsVol. 3Issue 1PreviewRostoker and colleagues1 do not contest my conclusion that applying the ratio of magnetic resonance imaging (MRI) estimate of liver iron content (LIC) to total body iron observed in hereditary and transfusional overload overestimates total body iron by a factor of 3 to 6 in dialysis patients.2 Unfortunately, this letter title states MRI-LIC is accurate for “evaluating iron load in dialysis patients.”1 A high MRI-LIC score is not the same as iron overload in dialysis patients.1,2 Based on the rate of decline in high MRI-LIC scores after halting iron therapy, most dialysis patients appear to have normal or mildly elevated total body iron. Full-Text PDF Open AccessIron Overload in Dialysis Patients: Rust or Bust?Kidney International ReportsVol. 2Issue 6PreviewA recent study using magnetic resonance imaging (MRI) to assess liver iron content (LIC) by Issad and colleagues provides observational data from prevalent peritoneal dialysis patients, showing that few have iron overload.1 These results complement earlier MRI studies in hemodialysis patients by Rostoker et al. and other groups showing high MRI-estimated LIC in hemodialysis patients and a high incidence of moderate to severe iron overload. The discussions in these reports, and in several editorials and commentaries, have warned that our present i.v. Full-Text PDF Open Access