Quantitative T2* Magnetic Resonance Imaging for Evaluation of Iron Deposition in the Brain of β-Thalassemia Patients

Cognitive impairment and hippocampal neuronal damage in β-thalassaemia mice

β-Thalassaemia is one of the most common genetic diseases worldwide. During the past few decades, life expectancy of patients has increased significantly owing to advance in medical treatments. Cognitive impairment, once has been neglected, has gradually become more documented. Cognitive impairment in β-thalassaemia patients is associated with natural history of the disease and socioeconomic factors. Herein, to determined effect of β-thalassaemia intrinsic factors, 22-month-old β-thalassaemia mouse was used as a model to assess cognitive impairment and to investigate any aberrant brain pathology in β-thalassaemia. Open field test showed that β-thalassaemia mice had decreased motor function. However, no difference of neuronal degeneration in primary motor cortex, layer 2/3 area was found. Interestingly, impaired learning and memory function accessed by a Morris water maze test was observed and correlated with a reduced number of living pyramidal neurons in hippocampus at the CA3 region in β-thalassaemia mice. Cognitive impairment in β-thalassaemia mice was significantly correlated with several intrinsic β-thalassaemic factors including iron overload, anaemia, damaged red blood cells (RBCs), phosphatidylserine (PS)-exposed RBC large extracellular vesicles (EVs) and PS-exposed medium EVs. This highlights the importance of blood transfusion and iron chelation in β-thalassaemia patients. In addition, to improve patients' quality of life, assessment of cognitive functions should become part of routine follow-up.

Brain iron content and cognitive function in patients with β-thalassemia

Patients with β-thalassemia (β-TM) may have brain iron overload from long-term blood transfusions, ineffective erythropoiesis, and increased intestinal iron absorption, leading to cognitive impairment. Brain magnetic resonance imaging (MRI) methods such as the transverse relaxation rate, susceptibility-weighted imaging, and quantitative susceptibility mapping can provide quantitative, in vivo measurements of brain iron. This review assessed these MRI methods for brain iron quantification and the measurements for cognitive function in patients with β-TM. We aimed to identify the neural correlates of cognitive impairment, which should help to evaluate therapies for improving cognition and quality of life in patients with β-TM.

RANK/RANKL/OPG axis genes relation to cognitive impairment in children with transfusion-dependent thalassemia: a cross-sectional study

Background

RANK/RANKL/OPG axis was implicated in many pathological conditions. The study aimed to assess the relationship between the studied RANK, RANKL, and OPG polymorphisms and alleles and cognitive impairment in children with transfusion-dependent thalassemia (TDT).

Methods

This study included 60 TDT children. Real-time PCR was done for: rs1805034, rs1245811, and rs75404003 polymorphisms for the RANK gene, rs9594782 and rs2277438 polymorphisms for the RANKL gene, and rs207318 polymorphism for the OPG gene. The intelligence quotient (IQ) was assessed using the Wechsler Intelligence Scale for Children-Third Edition.

Results

TDT children had a low average total IQ, verbal IQ, and borderline performance IQ. RANK rs1805034 (C > T) had a significant effect on total IQ (p = 0.03). Its TT polymorphism and the CT polymorphism of RANKL rs9494782 (C > T) had a significantly lower total IQ (p = 0.01 for both). The G allele of the RANKL rs2277438 (G > A) had a significantly lower total IQ (p = 0.02). RANK rs1805034 (C > T) and RANKL rs2277438 (G > A) significantly affected verbal IQ (p = 0.01 and 0.03). TT genotype of RANK rs1805034 (C > T) had significantly lower verbal IQ (p = 0.002). Furthermore, the GG genotype of RANKL rs2277438 (G > A) had a significantly lower verbal and performance IQ than the AA genotype (p = 0.04 and 0.01 respectively), and its G allele had a significantly lower performance IQ than the A allele (p = 0.02).

Conclusion

TDT children had low average total and verbal IQ while their performance IQ was borderline. The RANK/RANKL/OPG pathway affects cognition in TDT children, as some of the studied genes’ polymorphisms and alleles had significant effects on total, verbal, and performance IQ of the studied TDT children.

Neuroimaging Findings in Pediatric Patients with Thalassemia Major

Background: Cranial magnetic resonance imaging (MRI) studies about iron accumulation in children with thalassemia major are quite limited. Aim: This study aimed to detect neurological findings with cranial MRIs in the pediatric patients with thalassemia major who did not develop any neurological complications. Materials and Methods: Pediatric patients with thalassemia major who followed in the Pediatric Hematology Unit between 1 July 2017 and 1 January 2019 were included in the study. The patients underwent cranial MRI scans. Results: A total of 30 patients were included. The median age was 15 (range from 4–18) years old. We found that 7 patients had a splenectomy and 19 of the remaining 23 patients had splenomegaly. In addition, 13 of the patients had hepatomegaly, 10 had skeletal deformities, and 17 had growth retardation. The mean ferritin level was 3772.3 ± 2524.8. We detected various pathologies on cranial MRI images of 10 (33.3%) patients. In 3 of these patients, millimeter-sized ischemia-compatible lesions were found in the cerebral white matter, which did not fit any arterial area, and 5 patients had hyperintense lesions in the basal ganglia. Conclusion: Our study is valuable since 1/3 of our pediatric patients with thalassemia major were detected with intracranial pathology.

Destructive effect of iron overload in brain tissue of albino rats: Ameliorative role of silver immobilized organo-modified casein nanocomposite as co-treating agent with Deferasirox

BACKGROUND

Iron (Fe) is one of the most essential trace elements in the body that play crucial role in organisms' survival, however, excess deposition of it puts patients at higher risk of iron overload and tissue injury through production of reactive oxygen species (ROS), elevation of oxidative stress, development of endocrine disorders among which hypogonadism, and increased incidence of cells damage in vital organs. As deferasirox (DFX) is an approved Fe chelator drug, its inability to cross blood brain barrier (BBB) remains a definite obstacle against its use as Fe chelator in the brain. Lately, attention to nanoparticles usage in researches has been widely grown since their role in improving drug therapeutic effects and scavenging free radicals make them good candidates as chelating and antioxidant agents.

AIMS

Herein, after induction of iron overload, organo-modified casein immobilized silver nanocomposite (Ag@Tr-CA) was designed and explored as combined therapy with DFX drug to develop its penetrating efficiency toward BBB and its Fe chelating affinity. Moreover, to distinguish the advanced antioxidant character as well as the beneficial impact of it on lowering brain's oxidative stress. Meanwhile, its capability in regulating serum pituitary hormones such as follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), and testosterone (T), ameliorating DNA damage, and improving brain's histopathological alterations was also assessed.

METHODS

The physicochemical characteristics of Ag@Tr-CA was carried out using X-ray powder diffractometry (XRD), Fourier transform infrared (FTIR), dynamic light scattering (DLS), field emission scanning electron microscope (FE-SEM), and high-resolution transmission electron microscope (HR-TEM) analyses. Effect of iron overload and subsequent treatment with DFX + Ag@Tr-CA on brain of adult male albino rats were evaluated using colorimetric methods to determine brain Fe concentration and brain oxidative stress biomarkers. Assessment of serum Fe indices and serum pituitary hormones (FSH, LH, PRL) and T were estimated by ELISA technique. Determination of DNA damage in cerebral cortex cells was accomplished using the alkaline version of comet assay, while detection of brain's histopathological alterations was performed by examination of H&E sections under light microscope.

RESULTS

The physicochemical characteristics of Ag@Tr-CA showing the proficiency of Ag nanoparticles (∼35 nm) in creating highly-ordered negatively charged micro-sized casein particles (∼450 μm). After induction of iron overload, DFX + Ag@Tr-CA combination efficiently down brain Fe concentration, brain oxidative stress markers, and DNA damage in cerebral cortex cells linked with improvements in brain histopathological alterations. Comparing DFX therapeutic action alone to its combination to whether Ag@Tr-CA or Tr-CA (organo-modified cross-linked casein nanoparticles) as co-treating agents revealed no significant effect on serum Fe indices, FSH, LH, PRL, and T against iron overload disease.

CONCLUSION

The present results showed that combination of Ag@Tr-CA nanocomposite with DFX makes it a promising co-treating agent against iron overload through improving the physiological, molecular, and histological structure of the brain in iron overloaded rats.

Hidden brain iron content in sickle cell disease: impact on neurocognitive functions

Children with sickle cell disease (SCD) are at a high risk for neurocognitive impairment. We aim to quantitatively measure cerebral tissue R2* to investigate the brain iron deposition in children and young adults with SCD in comparison to beta thalassemia major (BTM) and healthy controls and evaluate its impact on neurocognitive functions in patients with SCD. Thirty-two SCD, fifteen BTM, and eleven controls were recruited. Multi-echo fast-gradient echo sequence brain MRI was performed, and brain R2* values of both caudate and thalamic regions were calculated. SCD patients were examined for the neurocognitive functions. SCD had high iron overload 0.30 ± 0.12 mg/kg/day. 68.9% of SCD had under-threshold IQ, 12.5% had moderate to severe anxiety, and 60.8% had depression. There were no differences between SCD, BTM, and controls in brain MRI except that left thalamus R2* higher in BTM than both SCD and controls (p = 0.032). Mean right caudate R2* was higher in female than male (p = 0.044). No significant association between brain R2* and LIC or heart R2* values in SCD. Left caudate R2* directly correlate with age and HbS%, and negatively correlate with HbA% while right thalamus R2* negatively correlate with transfusion index and among SCD patients.Conclusion: Neurocognitive dysfunction in SCD could not be explained solely by brain iron overload. What is Known: • Children with sickle cell disease are at great risk of brain damage due to their irregularly shaped red blood cells that can interrupt blood flow to the brain. • There are a number of factors that have negative brain effects that result in learning difficulties, and this not only due to increase brain iron content. What is New: • Assessment of quantitative brain iron content using MRI R2* in children and young adults with SCD in comparison to beta thalassemia major and healthy controls. • Impact of brain iron content on neurocognitive functions of children and young adults with SCD.

Absence of T1 Hyperintensity in the Brain of High-risk Patients After Multiple Administrations of High-dose Gadobutrol for Cardiac Magnetic Resonance

PURPOSE

A prospective study was conducted to evaluate signal changes in the dentate nucleus, globus pallidus, pons, and thalamus (normalized to the deep cerebellum white matter) in T1-weighted magnetic resonance (MR) images after serial injections of gadobutrol in patients with thalassemia without neurological lesions.

METHODS

In this study three groups were scanned at both 1.5 T and 3 T: 15 thalassemia patients transfused and chelated with ≥4 gadobutrol administrations at a high dose (0.2 mmol/kg per scan) for late gadolinium enhancement (LGE) cardiovascular MR, 8 thalassemia patients and 13 healthy subjects who had never received gadolinium-based contrast agents (GBCA).

RESULTS

Signal intensity (SI) ratios at 1.5 T in all regions were comparable among the three groups and were not correlated with the number of gadobutrol administrations. In healthy subjects SI ratios were significantly different among the 4 regions, being higher in the pallidus. The SI ratios at 1.5 T were significantly higher and not correlated with SI ratios at 3 T or with iron overload in the same regions assessed by the T2* technique.

CONCLUSION

This article describes the lack of increased SI in T1-weighted MR images after repeated administration of gadobutrol for cardiovascular MR studies in a high-risk population (high dose per scan, iron overload that can facilitate the transmetalation of gadolinium) scanned at 3 T and 1.5 T.

Brain iron content in systemic iron overload: A beta-thalassemia quantitative MRI study

•

Iron overload is a life-threatening condition in beta-thalassemia.

•

Data on brain involvement in systemic iron overload are conflicting.

•

MRI quantification of brain tissue iron content is feasible in a voxel-based approach.

•

No iron tissue excess is evident in beta-thalassemia but in the choroid plexuses.

Objective

Multisystem iron poisoning is a major concern for long-term beta-thalassemia management. Quantitative MRI-based techniques routinely show iron overload in heart, liver, endocrine glands and kidneys. However, data on the brain are conflicting and monitoring of brain iron content is still matter of debate.

Methods

This 3T-MRI study applied a well validated high-resolution whole-brain quantitative MRI assessment of iron content on 47 transfusion-dependent (mean-age: 36.9 ± 10.3 years, 63% females), 23 non-transfusion dependent (mean-age: 29.2 ± 11.7 years, 56% females) and 57 healthy controls (mean-age: 33.9 ± 10.8 years, 65% females). Clinical data, Wechsler Adult Intelligence Scale scores and treatment regimens were recorded. Beside whole-brain R2* analyses, regional R2*-values were extracted in putamen, globus pallidum, caudate nucleus, thalamus and red nucleus; hippocampal volumes were also determined.

Results

Regional analyses yielded no significant differences between patients and controls, except in those treated with deferiprone that showed lower R2*-values (p<0.05). Whole-brain analyses of R2*-maps revealed strong age-R2* correlations (r²=0.51) in both groups and clusters of significantly increased R2*-values in beta-thalassemia patients in the hippocampal formations and around the Luschka foramina; transfusion treatment was associated with additional R2* increase in dorsal thalami. Hippocampal formation R2*-values did not correlate with hippocampal volume; hippocampal volume did not differ between patients and controls. All regions with increased R2*-values shared a strict anatomical contiguity with choroid plexuses suggesting a blooming effect as the likely cause of R2* increase, in agreement with the available histopathologic literature evidence.

Conclusion

According to our MRI findings and the available histopathologic literature evidence, concerns about neural tissue iron overload in beta-thalassemia appear to be unjustified.

Increased Iron Deposition on Brain Quantitative Susceptibility Mapping Correlates with Decreased Cognitive Function in Alzheimer's Disease

The excessive accumulation of iron in deep gray structures is an important pathological characteristic in patients with Alzheimer's disease (AD). Quantitative susceptibility mapping (QSM) is more specific than other imaging-based iron measurement modalities and allows noninvasive assessment of tissue magnetic susceptibility, which has been shown to correlate well with brain iron levels. This study aimed to investigate the correlations between the magnetic susceptibility values of deep gray matter nuclei and the cognitive functions assessed by mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA) in patients with mild and moderate AD. Thirty subjects with mild and moderate AD and 30 age- and sex-matched healthy controls were scanned with a 3.0 T magnetic resonance imaging (MRI) scanner. The magnetic susceptibilities of the regions of interest (ROIs), including caudate nucleus (Cd), putamen (Pt), globus pallidus (Gp), thalamus (Th), red nucleus (Rn), substantia nigra (Sn), and dentate nucleus (Dn), were quantified by QSM. We found that the susceptibility values of the bilateral Cd and Pt were significantly higher in AD patients than the controls ( P < 0.05). In contrast, bilateral Rn had significantly lower susceptibility values in AD than the controls. Regardless of gender and age, the increase of magnetic susceptibility in the left Cd was significantly correlated with the decrease of MMSE scores and MoCA scores ( P < 0.05). Our study indicated that magnetic susceptibility value of left Cd could be potentially used as a biomarker of disease severity in mild and moderate AD.

Acinetobacter baumannii Infection in Transfusion Dependent Thalassemia Patients with Sepsis

PURPOSE

To identify the Acinetobacter baumannii infection among transfusion dependent thalassemia patients.

METHODS

A quantitative approach was employed to assess Acinetobacter baumannii infection in transfusion dependent thalassemia patients. Samples were collected from 916 patients, which have shown bacterial growth on MacConkey and blood agar culture media. A. baumannii strains were identified by microbiological methods and Gram's staining. API 20 E kit (Biomerieux, USA) was used for final identification.

RESULTS

From 916 cultured blood specimens, 107 (11.6%) showed growth of A. baumannii. Serum ferritin in thalassemic patients without bacterial infections was 3849.5 ± 1513.5 µg/L versus 6413.5 ± 2103.9 µg/L in those with bacterial infections (p = 0.0001). Acinetobacter baumannii infected patients have shown higher serum ferritin levels (p = 0.0001). Serum ferritin in thalassemic patients was 3849.5 ± 1513.5 µg/L versus 6413.5 ± 2103.9 µg/L in those with bacterial infections (p = 0.0001). Acinetobacter baumannii infected patients showed high serum ferritin levels (p = 0.0001). The clinical symptoms have been found with A. baumannii +ve with a mean and standard deviation of 47 (5.1%) and A. baumannii -ve with mean and standard deviation of 60 (6.5%).

CONCLUSION

Isolation of asymptomatic A. baumannii from the thalassemia patients shows an alarming situation of bacterial infections. A continuous surveillance of transfusion dependent thalassemia patients is recommended for bacterial sepsis.

The utility of susceptibility-weighted imaging to evaluate the extent of iron accumulation in the choroid plexus of patients with β-thalassaemia major

AIM

To assess iron accumulation in the choroid plexus of β-thalassaemia patients using fast spin echo (FSE) T2-weighted, gradient echo (GRE) T2*-weighted, susceptibility-weighted imaging (SWI) and compare the results.

MATERIALS AND METHODS

Eighteen patients with transfusion-dependent β-thalassaemia and the control group underwent magnetic resonance imaging (MRI) examinations. Signal intensities were separately evaluated using a "number of hypointensity in the choroid plexus" (NHICP) grading system on axial FSE T2-weighted, GRE T2*-weighted, and SWI images. The NHICP grading system scores were compared using the chi-squared test. Spearman's correlation analysis was used to explore relationships between the variables and NHICP grading system scores.

RESULTS

The sensitivity of each technique was calculated: FSE T2-weighted imaging=0.17, GRE T2*-weighted imaging=0.48, and SWI=0.81. Three-sample test for equality of proportions showed that chi-squared=74.85, df=2, p<0.0001. All of the FSE T2-weighted, GRE T2*-weighted, and SWI images differed significantly in terms of their capacity to reveal iron accumulation in the choroid plexus. Of the three methods, SWI was the most sensitive.

CONCLUSIONS

SWI is useful for revealing iron deposition in the brains of β-thalassaemia patients, especially those in the early stages of disease, and it can be used to predict disease prognosis. The present study contributes to an understanding of the important role played by the choroid plexus in brain iron metabolism.

Restless legs syndrome/Willis-Ekbom disease prevalence in beta thalassemia patients

PURPOSE

Both beta thalassemia and restless legs syndrome (RLS) patients share some common pathophysiological characteristics related to iron handling. In the present study, the aim was to explore the prevalence of RLS as well as to explore potential association between the syndrome and various quality of life-related parameters in a sample of beta thalassemia patients.

METHODS

One hundred fourteen (age 40 ± 11 yr, 59 M/55F) beta thalassemia patients participated in this cross-sectional descriptive study. Patients were screened for RLS based on the international RLS study group diagnostic criteria as well as a battery of validated questionnaires.

RESULTS

The prevalence of RLS in this sample of beta thalassemia patients was zero. The quality of life score was low (78 ± 18). Iron levels were within normal range (191 ± 66 mcg/dL) while ferritin levels were high as expected (1836 ± 225 ng/dL).

CONCLUSIONS

Our sample of patients comes from central Greece where the prevalence of RLS in the general population is 4% while in renal failure patients is 27%. To our surprise, there was no presence of RLS among this sample of beta thalassemia patients. The adequate levels of iron and ferritin often seen in these patients could be the reason of the absence of RLS symptoms.

Quantitative T1, T2, and T2* Mapping and Semi-Quantitative Neuromelanin-Sensitive Magnetic Resonance Imaging of the Human Midbrain

Purpose

Neuromelanin is a dark pigment granule present within certain catecholamine neurons of the human brain. Here, we aimed to clarify the relationship between contrast of neuromelanin-sensitive magnetic resonance imaging (MRI) and MR relaxation times using T₁, T₂, and T₂* mapping of the lower midbrain.

Methods

The subjects were 14 healthy volunteers (11 men and 3 women, mean age 29.9 ± 6.9 years). Neuromelanin-sensitive MRI was acquired using an optimized T₁-weighted two-dimensional (2D)-turbo spin-echo sequence. To quantitatively evaluate the relaxation time, 2D-image data for the T₁, T₂, and T₂* maps were also acquired. The regions of interest (substantia nigra pars compacta [SNc], superior cerebellar peduncles [SCP], cerebral peduncles [CP], and midbrain tegmentum [MT]) were manually drawn on neuromelanin-sensitive MRI to measure the contrast ratio (CR) and on relaxation maps to measure the relaxation times.

Results

The CR in the SNc was significantly higher than the CRs in the SCP and CP. Compared to the SCP and CP, the SNc had significantly higher T₁ relaxation times. Moreover, the SNc had significantly lower T₂ and T₂* relaxation times than the other three regions (SCP, CP, and MT). Correlation analyses showed no significant correlations between the CRs in the SNc, SCP, and CP and each relaxation time.

Conclusions

We demonstrated the relationship between the CR of neuromelanin-sensitive MRI and the relaxation times of quantitative maps of the human midbrain.

Investigation of cerebral iron deposition in aged patients with ischemic cerebrovascular disease using susceptibility-weighted imaging

OBJECTIVE

The aim of this study was to investigate focal iron deposition level in the brain in patients with ischemic cerebrovascular disease and its correlation with cerebral small vessel disease imaging markers.

PATIENTS AND METHODS

Seventy-four patients with first-ever transient ischemic attack (median age: 69 years; 30 males and 44 females) and 77 patients with positive ischemic stroke history (median age: 72 years; 43 males and 34 females) were studied retrospectively. On phase image of susceptibility-weighted imaging and regions of interest were manually drawn at the bilateral head of the caudate nucleus, lenticular nucleus (LN), thalamus (TH), frontal white matter, and occipital white matter. The correlation between iron deposition level and the clinical and imaging variables was also investigated.

RESULTS

Iron deposition level at LN was significantly higher in patients with previous stroke history. It linearly correlated with the presence and number of cerebral microbleeds (CMBs) but not with white matter hyperintensity and lacunar infarct. Multiple linear regression analysis showed that deep structure CMBs were the most relevant in terms of iron deposition at LN.

CONCLUSION

Iron deposition at LN may increase in cases of more severe ischemia in aged patients with transient ischemic attack, and it may be an imaging marker for CMB of ischemic origin.

Age-related iron deposition in the basal ganglia of controls and Alzheimer disease patients quantified using susceptibility weighted imaging

This study aimed to investigate age-related iron deposition changes in healthy subjects and Alzheimer disease patients using susceptibility weighted imaging. The study recruited 182 people, including 143 healthy volunteers and 39 Alzheimer disease patients. All underwent conventional magnetic resonance imaging and susceptibility weighted imaging sequences. The groups were divided according to age. Phase images were used to investigate iron deposition in the bilateral head of the caudate nucleus, globus pallidus and putamen, and the angle radian value was calculated. We hypothesized that age-related iron deposition changes may be different between Alzheimer disease patients and controls of the same age, and that susceptibility weighted imaging would be a more sensitive method of iron deposition quantification. The results revealed that iron deposition in the globus pallidus increased with age, up to 40 years. In the head of the caudate nucleus, iron deposition peaked at 60 years. There was a general increasing trend with age in the putamen, up to 50-70 years old. There was significant difference between the control and Alzheimer disease groups in the bilateral globus pallidus in both the 60-70 and 70-80 year old group comparisons. In conclusion, iron deposition increased with age in the globus pallidus, the head of the caudate nucleus and putamen, reaching a plateau at different ages. Furthermore, comparisons between the control and Alzheimer disease group revealed that iron deposition changes were more easily detected in the globus pallidus.

An investigation of age-related iron deposition using susceptibility weighted imaging

Aim

To quantify age-dependent iron deposition changes in healthy subjects using Susceptibility Weighted Imaging (SWI).

Materials and Methods

In total, 143 healthy volunteers were enrolled. All underwent conventional MR and SWI sequences. Subjects were divided into eight groups according to age. Using phase images to quantify iron deposition in the head of the caudate nucleus and the lenticular nucleus, the angle radian value was calculated and compared between groups. ANOVA/Pearson correlation coefficient linear regression analysis and polynomial fitting were performed to analyze the relationship between iron deposition in the head of the caudate nucleus and lenticular nucleus with age.

Results

Iron deposition in the lenticular nucleus increased in individuals aged up to 40 years, but did not change in those aged over 40 years once a peak had been reached. In the head of the caudate nucleus, iron deposition peaked at 60 years (p<0.05). The correlation coefficients for iron deposition in the L-head of the caudate nucleus, R-head of the caudate nucleus, L-lenticular nucleus and R-lenticular nucleus with age were 0.67691, 0.48585, 0.5228 and 0.5228 (p<0.001, respectively). Linear regression analyses showed a significant correlation between iron deposition levels in with age groups.

Conclusions

Iron deposition in the lenticular nucleus was found to increase with age, reaching a plateau at 40 years. Iron deposition in the head of the caudate nucleus also increased with age, reaching a plateau at 60 years.