METHOD FOR QUANTITATIVE ASSESSMENT OF HEPATIC IRON OVERLOAD IN CHILDREN

摘要

FIELD: medicine.;SUBSTANCE: invention refers to medicine, namely to radiation diagnostics, and can be used for quantitative assessment of hepatic iron overload in children. Magnetic resonance imaging is performed with magnetic field strength of 3 T in three orthogonal planes in T2WI TSE scanning mode with TR=1,800 ms, TE=80 ms, angle=0. To obtain the T2*-map, a fast gradient echo sequence with a Cartesian filling of k-space is used, TR=350 ms, TE=0.9 ms, ΔTE=0.9 ms, resolution – 1.5 mm×1.5 mm×7 mm and suppression of fat tissue signal. Selection of ROI interest zones in the liver is carried out taking into account absence of small and large vessels, absence of fibrosis. Data selected for these ROI criteria are collected by T2* using a tomography software. Calculation of average values of T2* and root-mean-square deviations in ROI is performed automatically by approximation of attenuation curve by maximum likelihood method. Examination is carried out without respiratory arrest in the patient. Relative relaxation rate R2* is calculated by formula in scanning in mode T2*:R2*=1,000/T2av*, where T2*av is average value of T2* signal, ms. Concentration of iron in liver is calculated, mg/g, C=1.24+0.012×R2*, where R2* is relaxation rate during scanning in T2* mode, 1.24 and 0.012 are experimentally obtained coefficients. Concentration of iron in the liver is evaluated. If C=0.1–2 mg/g of dry substance of liver of corresponding histological degree of haemosiderosis Grade 1. If C=2.1–7 mg/g of the corresponding histological degree of hemodesidosis Grade 2. If C=7.1–15 mg/g of the corresponding histological degree of hemosiderosis Grade 3. If C15 mg/g of corresponding histological degree of hemodesidosis Grade 4.;EFFECT: method enables performing a non-invasive quantitative assessment of hepatic iron overload in children by converting the MR signal using the MRI T2*-mapping.;1 cl, 5 dwg, 4 ex