Magnetic resonance imaging of transfusional hemosiderosis complicating thalassemia major.

Abstract

Tissue deposits of hemosiderin, a paramagnetic iron-protein complex, resulted in marked abnormalities of magnetic resonance (MR) spin-echo signal intensity within the viscera of three children with transfusional hemosiderosis and thalassemia major. In all patients the liver and bone marrow demonstrated abnormally low spin-echo intensities and the kidneys and muscles had abnormally high intensities. These observations correlate with in vitro MR observations of ferric (Fe+3) solutions, in which concentrations of ferric salts greater than 20 mmol yielded a low MR intensity signal and ferric concentrations less than 15 mmol yielded higher intensities than did water alone. MR imaging is sensitive to the tissue deposition of hemosiderin, and MR intensity appears to provide a rough measure of the amount of iron deposited.

Evaluation of myocardial iron by magnetic resonance imaging during iron chelation therapy with deferrioxamine: indication of close relation between myocardial iron content and chelatable iron pool

“…Five patients (nos. 1,7,8,10,12) showed persistently, severely elevated myocardial iron estimates. We could distinguish 3 groups of patients: (1) group A (patients 1, 7, 8, 10, 12) with persistently elevated myocardial iron estimates, (2) group B (patients 2, 3, 4, 5, 9) with clearly elevated values only at the initial stage, and (3) group C (patients 6,11,13,14) with normal values throughout the entire follow-up period.…”

“…Clinically useful estimates of the hepatic iron content have been obtained by a superconducting quantum interference device (SQUID) 5,6 and by magnetic resonance imaging (MRI). [7][8][9][10][11][12][13] Estimation of myocardial iron by the SQUID has so far not been reported, but a few studies have explored the use of MRI for this purpose. [14][15][16][17][18] Except for 2 studies, 14,18 all studies demonstrated a significant correlation between the applied myocardial MRI index and the serum ferritin concentration by heart-to-muscle signal intensity ratio (SIR) measurements obtained from spin-echo images, 15,17 by T2 relaxometry, 15,16 or by magnetization transfer ratio measurements.…”

Çocukluk Çağı Kanserlerinde Tedaviye Bağlı Demir Yükü

“…Bu ölçüm sırasında dokulardaki su ve yağ miktarı arasındaki yapısal farktan kaynaklanan demir ile ilişkili kararma, T2 ve T2* gibi zaman sabitleri ile ya da R2 ve R2* gibi relaksasyon oranları ile karakterize edilebilir 40,41 . Dokuda aşırı miktardaki demir varlığı, demirin süper paramanyetik etkisi sonucu T2 relaksasyon zamanında kısalmaya sebep olarak, MRG ile ortaya konabilmektedir 36 . Demir yüklenmesinde MRG'nin etkinliği ferritin ve hemosiderin gibi yüksek moleküler ağırlıklı demir kompleksleri ile su molekülleri arasındaki etkileşimden kaynaklanan T2 relaksasyonun hızlanması temeline dayanır 38,39 .…”

Noninvasive MRI-Based Liver Iron Quantification: Methodic Approaches, Practical Applicability and Significance

“…Historically used first [12,13], this method was then further developed by St. Pierre [20] on the basis of the data of 40 patients into a validated, FDA-approved, CE-certified, feebased method under the name Ferriscan ® . The method is based on the fact that the liver signal decreases as the echo time (TE) increases as shown in • ▶ Fig.…”

“…With the introduction of MRI in the clinical routine, an effect of the liver iron content on the MR signal was identified [12,13]. The first systematic studies on this topic [14 -17] that qualitatively correlated the liver MRI signal with varying degrees of iron overload were published more than twenty years ago.…”