Correspondence

Hemochromatosis

N Engl J Med 1997; 336:1531May 22, 1997

Article

To the Editor:

In my opinion, the first of the two images provided by Wortsman in Images in Clinical Medicine (Dec. 12 issue)1 is really “useful and clinically important.” 2 In a 62-year-old woman with hemochromatosis, magnetic resonance imaging (MRI) shows a dark liver, even darker than the hepatic veins.

The meaning of the second image is less clear. Wortsman states that it shows “almost complete resolution of the abnormality” after 32 phlebotomies, when the serum ferritin concentration was 606 ng per milliliter and thus when the hepatic iron stores were not yet completely removed. Why did the patient undergo a second MRI study at that time? Iron depletion is considered complete only when the serum ferritin concentration falls to a level less than 30 to 50 ng per milliliter.3 The message of the second picture could be misleading. This picture shows that MRI, at least as currently and usually used, cannot detect a moderate hepatic iron overload (roughly between 3 and 4 g). In fact, noninvasive laboratory or imaging studies are regarded as inefficient in detecting and quantifying iron overload.4 Only the results of dedicated gradient-echo MRI studies seem promising.5

Agostino Colli, M.D.
Ospedale Civile, 23017 Morbegno, Italy

5 References

1. 1

   Wortsman J. Hemochromatosis. N Engl J Med 1996;335:1815-1815
   Full Text | Web of Science | Medline

2. 2

   Kassirer JP. Images in clinical medicine. N Engl J Med 1992;326:829-830
   Full Text | Web of Science | Medline

3. 3

   Tavill AS, Bacon BR. Hemochromatosis: iron metabolism and the iron overload syndromes. In Zakim D, Boyer TD, eds. Hepatology: a textbook of liver disease. 2nd ed. Philadelphia: W.B. Saunders, 1990:1273-99.
   

4. 4

   Bonkovsky HL, Slaker DP, Bills EB, Wolf DC. Usefulness and limitations of laboratory and hepatic imaging studies in iron-storage disease. Gastroenterology 1990;99:1079-1091
   Web of Science | Medline

5. 5

   Gandon Y, Guyader D, Heautot JF, et al. Hemochromatosis: diagnosis and quantification of liver iron with gradient-echo MR imaging. Radiology 1994;193:533-538
   Web of Science | Medline

Author/Editor Response

Dr. Wortsman replies:

To the Editor: The timing of the second scan was determined largely by the patient's infrequent visits to the clinic where hemochromatosis had been diagnosed, because she was living in another city, where the phlebotomies were performed. The sole purpose of the imaging procedure was to document that iron, removed by the closely sequenced phlebotomies, was responsible for the abnormalities observed. The pictures were intended to show the change in the hepatic MRI images in two widely different states of iron repletion (not necessarily maximal and normal or reduced).

Jacobo Wortsman, M.D.
Southern Illinois University, Springfield, IL 62794-9230