Optimisation of T2 and T2* sequences in MRI for better quantification of iron on transfused dependent sickle cell patients

Isam Salih,Amani Baldo,Fouad A Abolaban,Azza Ahmed,I I Suliman,A Sulieman,Hind Mirghani

doi:10.1038/s41598-021-88116-8

Abstract

This work aimed to investigate the effect of different shim techniques, voxel sizes, and repetition time (TR) on using theT2 and T2* sequences to determine their optimum settings to investigate the quantification of iron in transfused dependent sickle cell patients. The effect of each of these parameters was investigated on phantoms of different Gadolinium (Gd) concentrations, on 10 volunteers and 25 patients using a1 5T MRI Philips scanner. No significant difference between the three shim techniques was noticed in either T2 or T2* sequence measurements. Pixel sizes of 1 × 1 and 2 × 2 mm provided optimum results for T2 measurements. At 1 × 1 mm pixel size the T2* measurements experienced less error in measurements than the size of 2.5 × 2.5 mm used in the literature. Even though the slice thickness variation did not provide any changes in T2 measurements, the 12 mm provided optimum T2* measurements. TR variation did not yield significant changes on either T2 or T2* measurements. These results indicate that both T2 and T2* sequences can be further improved by providing more reliable measurements and reducing acquisition time.

Highlights

Sickle cell anaemia (SCA) is a haemoglobinopathy caused from a single point mutation in the β-chain of human haemoglobin[1] It causes rigid and sickle-shaped red blood cells, eventually ends up in anaemia, which leads to multiple complications, the most serious of which is the Overt stroke[2]
The effects of tested parameters were studied in terms of three performance indices: (i) The exponential decay curves of both T2 and T2*; (ii) the magnitude measurements of T2 or T2* values using Eq 1 and (iii) the correlation coefficient R 2, which determines the associated strength between two variables
The aim of this study was to investigate the effect of different shim techniques, voxel sizes, and repetition time (TR) on T2 and T2* sequences and to determine optimum settings for the evaluation of the amount of iron in the livers of transfusion dependent sickle cell patients

Summary

Introduction

Sickle cell anaemia (SCA) is a haemoglobinopathy caused from a single point mutation in the β-chain of human haemoglobin[1] It causes rigid and sickle-shaped red blood cells, eventually ends up in anaemia, which leads to multiple complications, the most serious of which is the Overt stroke[2]. In Africa, sickle cell disease is raising great health concerns, in the western part of Sudan among the Baggara (Misseriya tribe). The prevalence of patients with SCA in Sub-Saharan Africa ranges between 5 and 40%5. Their life expectancy is < 20 years old[6], and patients younger than 5 years are at high risk of death. Blood transfusions in sickle cell patients could lead to iron overload in the liver. The levels of iron in blood-transfusion patients are often monitored using the serum ferritin method. This method known to be an unreliable marker for assessing iron in organs such as the heart and liver[7]

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