Iron overload syndrome. Ethiopatogenesis. magnetic resonance imaging techniques for quantitative assessment of iron overload status: a review

Abstract

INTRODUCTION: The development of iron overload syndrome may be due to both hereditary and acquired factors. The danger of this condition is manifested in the irreversible loss of parenchymatous pool as a result of cirrhotic transformation and marked fibrosis, caused by the consequent accumulation of iron complexes, of such important internal organs as the liver and heart. The amount of iron in the body is assessed by detecting serum ferritin concentration or by measuring liver and heart iron concentration by biopsy (LIC — liver iron concentration; HIC — heart iron concentration). Insufficient diagnostic significance of the serum ferritin concentration criterion, as well as the invasiveness and traumatization of biopsies, are limitations to the widespread use of these methods.OBJECTIVE: The purpose of this review is to present the main etio-pathogenetic factors of iron overload, the impact of this metabolic disorder on the body, and to reflect the basic principles of diagnosis and the leading role of quantitative MRI in the assessment of iron overload of vital internal organs.MATERIALS AND METHODS: Performed literature search in Russian and English languages for the period from 2001 to 2022 years in Medline/PubMed, RINC/Elibrary, CyberLeninka, Google Scholar databases by keywords: iron overload syndrome, liver, liver cirrhosis, ferritin, hemosiderin, MR diagnostics iron overload, MR relaxometry, R2*/T2*, thesaurismoses, magnetic resonance tomography, SIR (signal intensity ratio), LIC (liver iron concentration), biopsy, chronic diffuse liver diseases, DIOS.RESULTS: The final analysis included 27 publications devoted to various etio-pathogenetic aspects of iron overload syndrome. The forms of iron complexes residence in liver parenchymatous tissue are presented. Characteristics of MR-signal behavior depending on the severity of inhomogeneity of the magnetic field created by iron complexes are characterized. The areas of application of magnetic resonance imaging scanning modes for detection and quantitative diagnostics of iron overload are reflected.CONCLUSION: The ferritin-iron complex, also called ferrihydride, has high paramagnetic properties that provide high contrast MR images in the state of tissue iron overload. The leading methods for quantitative assessment of iron overload are the signal intensity ratio (SIR) method and T2*/R2*-relaxometry. Advantages and disadvantages of these methods, consisting in the limits of determining the degree of overload, make it possible to cover a wide range of overload values by complementing each other. Also the influence of parenchyma architectonics disturbances and concomitant accumulation diseases contribute to the formation of diagnostic inaccuracies. Therefore, the development of complex qualitative-quantitative MR diagnostics in order to isolate highly selective biomarkers will play an important role in MR diagnostics of iron overload syndrome.