Myocardial iron overload assessed by magnetic resonance imaging (MRI)T2* in multi-transfused patients with thalassemia and acquired anemias

Complications in patients with transfusion dependent thalassemia: A descriptive cross-sectional study

Background and Aims

One of the most common hemoglobinopathies globally related to blood transfusion and iron overload in the body is thalassemia syndrome. Increasing ferritin levels can cause severe damage to the patient's body organs. This study aims to evaluate the complications of iron overload on vital body organs in patients with transfusion-dependent beta-thalassemia.

Methods

This descriptive cross-sectional study was performed in Iran University of Medical Sciences Hospitals on patients with a beta-thalassemia major with frequent blood transfusions. To evaluate the effect of iron overload on vital body organs, hematologic and blood analysis, echocardiography with measurement of pulmonary artery pressure (PAP) and ejection fraction (EF) tests, bone densitometry, and audiometric tests were performed for all patients.

Results

Of the 1010 patients participating in this study, 497 (49%) were males, 513 were (51%) females aged 5-74 years, and the majority of participants (85%) were over 20 years old. This study demonstrated that increasing ferritin levels had no notable correlation with sex, cholesterol, low-density lipoprotein, parathyroid hormone, T4, and aspartate aminotransferase. However, elevating ferritin levels had significant correlations with increasing triglyceride, phosphorus, thyroid stimulating hormone, alkaline phosphatase, alanine transaminase, and PAP levels, age, hearing disorders, splenectomy, osteoporosis, and decreasing high-density lipoprotein, body mass index, calcium, and EF levels.

Conclusion

Improvement in beta-thalassemia patients' survival and quality of life can be due to multidisciplinary care in a comprehensive unit through regular follow-up and early complication detection.

Optimized serum ferritin prediction of iron overload in transfusion-dependent thalassemia: likelihood ratio and age-adjustment approach

BACKGROUND

Early detection of iron overload in transfusion-dependent thalassemia (TDT) patients is critical to prevent complications and improve survival.

OBJECTIVES

Evaluate the utility of serum ferritin (SF) in the prediction of hepatic and myocardial iron overload (HIO and MIO) compared to T2*-MRI.

DESIGN

Retrospective SETTINGS: Governmental hospitals.

PATIENTS AND METHODS

Patients with TDT who had T2*-MRI examinations between January 2016 to October 2019 were included. The predictive value of SF for detection of HIO and MIO was assessed by measuring area under the curve (AUC). A sample size of 123 cases was calculated to detect a correlation of 0.25 with 90% power and a two-sided type I error of 0.05.

MAIN OUTCOME MEASURES

The correlation between SF and estimated hepatic iron concentration.

SAMPLE SIZE

137 TDT patients who required regular blood transfusions.

RESULTS

The predictive value of SF was excellent for detection of HIO (AUC=0.83-0.87) but fair for detection of MIO (AUC=0.67). The two independent predictors of MIO were age and SF. The log of (age × SF) enhanced the SF predictive value for MIO (AUC=0.78). SF values of 700 and 1250 mg/L effectively excluded mild and moderate HIO with a sensitivity of 97.8% and 94.2%, respectively (LR-=0.1). While SF values of 1640 and 2150 mg/L accurately diagnosed mild and moderate HIO with a specificity of 95.55% and 96.4%, respectively (LR+>10). A log of (age × SF) cut-off value of 4.15 effectively excluded MIO (LR-=0.1), while a value of 4.65 moderately confirmed MIO (LR+=3.2).

CONCLUSIONS

SF is an excellent predictor of hepatic IO in TDT. Age adjustment enhanced its myocardial IO predictive accuracy. Likelihood ratio-based SF cut-off values may help clinicians in risk stratification and treatment decision-making.

LIMITATIONS

The laboratory data were gathered retrospectively and although the risk of selection bias for T2*-MRI examination is thought to be low, it cannot be ignored.

CONFLICT OF INTEREST

None.

Cardiac Magnetic Resonance Strain in Beta Thalassemia Major Correlates with Cardiac Iron Overload

BACKGROUND

Beta thalassemia major (Beta-TM) is an inherited condition which presents at around two years of life. Patients with Beta-;TM may develop cardiac iron toxicity secondary to transfusion dependence. Cardiovascular magnetic resonance (CMR) T2*, a technique designed to quantify myocardial iron deposition, is a driving component of disease management. A decreased T2* value represents increasing cardiac iron overload. The clinical manifestation is a decline in ejection fraction (EF). However, there may be early subclinical changes in cardiac function that are not detected by changes in EF. CMR-derived strain assesses myocardial dysfunction prior to decline in EF. Our primary aim was to assess the correlation between CMR strain and T2* in the Beta-TM population.

METHODS

Circumferential and longitudinal strain was analyzed. Pearson's correlation was calculated for T2* values and strain in the Beta-TM population.

RESULTS

We identified 49 patients and 18 controls. Patients with severe disease (low T2*) were found to have decreased global circumferential strain (GCS) in comparison to other T2* groups. A correlation was identified between GCS and T2* (r = 0.5; p < 0.01).

CONCLUSION

CMR-derived strain can be a clinically useful tool to predict early myocardial dysfunction in Beta-TM.

Ferritin thresholds for cardiac and liver hemosiderosis in β-thalassemia patients: a diagnostic accuracy study

Ferritin is frequently used to screen some dire consequences of iron overload in β-thalassemia patients. The study aimed to define the best cutoff point of ferritin to screen for cardiac and liver hemosiderosis in these cases. This was a registry-based study on β-thalassemia patients living throughout Mazandaran province, Iran (n = 1959). In this diagnostic research, the index test was ferritin levels measured by a chemiluminescent immunoassay. As a reference test, T2*-weighted magnetic resonance imaging (T2*-weighted MRI) was applied to determine cardiac and liver hemosiderosis. A cutoff point of 2027 ng/mL for ferritin showed a sensitivity of 50%, specificity 77.4%, PPV 42.1%, and NPV 82.5% for cardiac hemosiderosis (area under curve [AUC] 0.66, 95% CI 0.60-0.71, adjusted odds ratio [OR] 2.05, 95% CI 1.05-4.01). At an optimum cutoff point of 1090 ng/mL, sensitivity 66.7%, specificity 68%, PPV 82.9%, and NPV 46.8% for liver hemosiderosis were estimated (AUC 0.68, 95% CI 0.63-0.73, adjusted OR 3.93, 95% CI 2.02-7.64. The likelihood of cardiac hemosiderosis serum ferritin levels below 2027 ng/mL is 17.5%. Moreover, 82.9% of β-thalassemia patients with serum ferritin levels above 1090 ng/mL may suffer from liver hemosiderosis, regardless of the grades.

Magnetic resonance imaging T2* of the pancreas value using an online software tool and correlate with T2* value of myocardium and liver among patients with transfusion-dependent thalassemia major

Objective

Patients with thalassemia major do require lifetime blood transfusions that eventually result in iron accumulation in different organs. We described the usefulness of using magnetic resonance imaging (MRI) T2^*imaging values for the evaluation of pancreatic iron load in these patients, and we correlated it with MRI T2^* haemosiderosis of the myocardium and liver that has been recognized as a non-invasive assessment of iron overload among patients with thalassemia major.

Materials and methods

We conducted a cross-sectional study on 39 patients with thalassemia major in one of the tertiary university hospitals for a 1-year period. Demographic data were collected from the patient's history. MRI T2^* of the pancreas, liver, and heart were executed on all patients in the same setting. Objective values of iron overload in these organs were obtained using the MRI post-processing software from online software.

Results

A total of 32 (82.1%) patients had pancreatic iron overload including 2 patients (5.1%) with severe iron overload and 15 patients (38.5%) with moderate and mild iron overload, respectively. Nine patients (23.1%) had myocardial iron overload, which included 3 patients (7.7%) who had severe cardiac haemosiderosis. Notably, 37 patients (94.9%) had liver iron overload, which included 15 patients (38.5%) who had severe liver haemosiderosis. There was a moderate positive correlation between the relaxation time of the pancreas and heart haemosiderosis (r = 0.504, P < 0.001). No significant correlation was found between the relaxation time of the pancreas with the liver and the heart with the liver.

Conclusion

Pancreatic haemosiderosis precedes cardiac haemosiderosis, which establishes a basis for initiating earlier iron chelation therapy to patients with thalassemia major.

Assessment of Cardiac Functions and Arrhythmia in Children with Beta-Thalassemia Major and Beta-Thalassemia Intermedia

BACKGROUND: Heart disease is a major complication in thalassemic patients. Heart injuries in iron overload cases include arrhythmia, pulmonary hypertension, systolic/diastolic dysfunction, and heart failure. AIM: This study aimed to assess cardiac functions and arrhythmia in children with β-thalassemia major (TM) and β-thalassemia intermedia (TI) and its relation to cardiac iron overload. METHODS: Thirty β-TM patients and 30 β-TI patients were evaluated using echocardiography and 24-h ambulatory electrocardiogram monitoring (Holter). Among these patients, 15 β-TM and 15 β-TI patients were evaluated using cardiac magnetic resonance imaging T2* by single breath-hold multi-echo technique. RESULTS: Arrhythmia was detected significantly more in β-TM patients than β-TI (p = 0.049). Nine (30%) β-TM and five (16.6%) β-TI patients had Sinus tachycardia. Two (6.7%) β-TM patients compared to one (3.33%) β-TI patient had supraventricular tachycardia runs. Three (10%) β-TM and one (3.33%) β-TI patient had extreme sinus tachycardia. Two (3.3%) β-TI patients had sinus bradycardia, while two (3.3%) β-TM patients had incomplete Right bundle branch block. Regarding echo parameters: Isovolumic relaxation time (IVRT), Left ventricle myocardial performance index (MPI LV), Right ventricle myocardial performance index (MPI RV) and end systolic pulmonary artery pressure, were significantly higher in β-TM than TI group (p < 0.05). Fractional shortening, Ejection fraction were significantly lower in β-TM than TI group (p < 0.001). A statistically significant negative correlation was found between cardiac T2* and each of (IVRT, MPI LV, MPI RV) (p ˂ 0.05). CONCLUSION: Arrhythmias are more common in the β-TM group. Systolic, diastolic dysfunction and high pulmonary pressure are more prevalent in TM than in TI. Global myocardial performance is more impaired in TM than in TI patients. Iron overload has a deleterious effect on cardiac function.

The impact of magnetic resonance imaging in the assessment of iron overload in heart and liver in transfusion-dependent thalassemic children: Minia experience

Background

Thalassemia is the most prevalent single-gene disorder. Myocardial and hepatic iron depositions lead to complications and eventually death. We aimed to assess the diagnostic efficacy of magnetic resonance imaging T2* (MRI T2*) in quantifying iron overload in liver and heart in transfusion-dependent B-thalassemia major (TDT) children.

Methods

Prospective clinical study was carried on sixty children diagnosed with TDT. All of them underwent laboratory investigations, including CBC, serum iron, and ferritin levels. MRI T2* of the heart and liver was carried out to measure the iron overload and estimate the left ventricular ejection fraction (LVEF).

Results

Thirty-eight males and 22 females with TDT with a mean age of 13.23 years were included. Twenty cases (33.3%) had severe liver iron overload, while 36 (60%) had normal cardiac iron. There was a moderate significant negative association between hepatic and cardiac iron deposition (P = 0.03). All cases with severe cardiac iron overload had impaired LVEF below 56%. A non-significant positive association was noticed between cardiac iron deposition and LVEF in T2* (P = 0.08). A moderate negative significant association was detected between hepatic iron deposition and serum ferritin, while a fair negative significant association was found between serum ferritin and cardiac iron deposition with P values of 0.04 and 0.02, respectively.

Conclusion

MRI T2* is the gold standard for monitoring and follow-up of iron overload in the heart and liver. It should be routinely performed in all TDT children as liver iron, and serum ferritin do not reflect cardiac iron overload.

Analysis of the influencing factors related to liver and cardiac iron overload in MDS patients detected by MRI in the real world

OBJECTIVES

We aim to explore and analyze the related influencing factors of liver and cardiac iron overload in MDS patients detected by magnetic resonance imaging (MRI).

METHODS

We have detected cardiac T2* and liver T2* by MRI in 105 MDS patients. Among them, 20 patients accepted MRI examination before and after iron chelation therapy (ICT). Results: We found that adjusted ferritin (ASF) was significantly correlated with liver T2* and cardiac T2*. RBC transfusion volume, brain natriuretic peptide (BNP) and age were the related factors of cardiac T2*, while RBC transfusion volume and erythropoietin (EPO) were related factors of liver T2*. After ICT, the changes of ASF and liver T2* were earlier than cardiac T2*. Chronic hepatitis but virus copy normal's has no significant effect on liver iron deposition.

CONCLUSION

These results showed special attention should be paid to these related influencing factors of liver and cardiac T2* expression when we evaluated iron overload and detected the efficacy of ICT in MDS patients.

Cardiovascular magnetic resonance native T2 and T2* quantitative values for cardiomyopathies and heart transplantations: a systematic review and meta-analysis

BACKGROUND

The clinical application of cardiovascular magnetic resonance (CMR) T2 and T2* mapping is currently limited as ranges for healthy and cardiac diseases are poorly defined. In this meta-analysis we aimed to determine the weighted mean of T2 and T2* mapping values in patients with myocardial infarction (MI), heart transplantation, non-ischemic cardiomyopathies (NICM) and hypertension, and the standardized mean difference (SMD) of each population with healthy controls. Additionally, the variation of mapping outcomes between studies was investigated.

METHODS

The PRISMA guidelines were followed after literature searches on PubMed and Embase. Studies reporting CMR T2 or T2* values measured in patients were included. The SMD was calculated using a random effects model and a meta-regression analysis was performed for populations with sufficient published data.

RESULTS

One hundred fifty-four studies, including 13,804 patient and 4392 control measurements, were included. T2 values were higher in patients with MI, heart transplantation, sarcoidosis, systemic lupus erythematosus, amyloidosis, hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) and myocarditis (SMD of 2.17, 1.05, 0.87, 1.39, 1.62, 1.95, 1.90 and 1.33, respectively, P <  0.01) compared with controls. T2 values in iron overload patients (SMD = - 0.54, P = 0.30) and Anderson-Fabry disease patients (SMD = 0.52, P = 0.17) did both not differ from controls. T2* values were lower in patients with MI and iron overload (SMD of - 1.99 and - 2.39, respectively, P <  0.01) compared with controls. T2* values in HCM patients (SMD = - 0.61, P = 0.22), DCM patients (SMD = - 0.54, P = 0.06) and hypertension patients (SMD = - 1.46, P = 0.10) did not differ from controls. Multiple CMR acquisition and patient demographic factors were assessed as significant covariates, thereby influencing the mapping outcomes and causing variation between studies.

CONCLUSIONS

The clinical utility of T2 and T2* mapping to distinguish affected myocardium in patients with cardiomyopathies or heart transplantation from healthy myocardium seemed to be confirmed based on this meta-analysis. Nevertheless, variation of mapping values between studies complicates comparison with external values and therefore require local healthy reference values to clinically interpret quantitative values. Furthermore, disease differentiation seems limited, since changes in T2 and T2* values of most cardiomyopathies are similar.

[Study of iron overload assessment by T2* magnetic resonance imaging in patients with myelodysplastic syndromes]

Objectives: To analyze the cardiac T2* value, liver iron concentration (LIC) , and related laboratory parameters in myelodysplastic syndrome (MDS) with iron overload and evaluate the changes of organ functions after iron chelation therapy. To explore the value of magnetic resonance imaging (MRI) T2* in making early diagnosis and assessing organs iron overload. Methods: Retrospective investigation was used to observe the cardiac T2* value, LIC, iron metabolism parameters and related laboratory parameters of 85 MDS patients from Nov 2014 to Jan 2018. Among them, 7 MDS patients with Low/Int-1 have received iron chelation therapy for 6 months during two MRI examinations. The above parameters were collected before and after iron chelation therapy for comparison. Results: Correlations were found between heart T2* value and age (rs=-0.290, P=0.007) and left ventricular ejection fraction (LVEF) (rs=0.265, P=0.009) . There was a significant negative correlation between heart T2* value and blood transfusion units (rs=-0.701, P<0.001) . There was a significant positive correlation between LIC and serum ferritin (SF) (rs=0.577, P<0.001) . There was also a correlation between LIC and ALT (rs=0.268, P=0.014) and blood transfusion units (rs=0.244, P=0.034) . There was no correlation between heart T2* and pro-BNP, SF (all P>0.05) , and no correlation between LIC and age (P>0.05) . The increase of heart T2* between the normal and abnormal groups was statistically significant (P=0.005) , but the iron overload ratio of the heart T2*<20 ms was not significant between the two groups. There was statistical significance in the proportion of severe liver iron overload (LIC>15 mg/g DW) (P=0.045) . After iron chelation therapy, the values of SF, transferrin saturation, ALT, AST, pro-BNP and LIC of 7 patients were decreased compared with values before iron chelation therapy, and the peripheral blood cell level was increased. However, the changes of LVEF and T2* values after iron chelation were not obvious. Conclusion: MRI T2* may be a predictor of iron overload in patients with MDS in early stage, and may be more valuable compare with LVEF, SF and other laboratory indicators. The safety and repeatability of MRI cardiac T2* examination are recognized, and it can be used as an ideal detection for patients with iron overload.

Association between genotype and disease complications in Egyptian patients with beta thalassemia: A Cross-sectional study

In beta thalassemia, the degree of globin chain imbalance is determined by the nature of the mutation of the β-gene. β° refers to the complete absence of production of β-globin on the affected allele. β⁺ refers to alleles with some residual production of β-globin. The homozygous state results in severe anemia that necessitates regular blood transfusion. On the other hand, frequent blood transfusion can lead to iron overload resulting in progressive dysfunction of the heart, Liver as well as multiple endocrinopathies. We studied the impact of genotype on the development of disease complications in patients with β thalassemia. A Cross sectional study was carried on 73 patients with beta thalassemia. Genotyping was determined by DNA sequencing technique. Routine investigations as well as MRI liver and heart were performed to assess iron overload. We found that β⁺β⁺ was the most common genotype in our patients followed by β°β° and β°β⁺. Mean Liver iron content (LIC) was significantly higher in β°β° compared to β°β⁺ and β⁺β⁺ genotypes and mean cardiac T2* was significantly lower in β°β° compared to β°β⁺ and β⁺β⁺ genotypes. Hepatic complications, hepatitis C, cardiac complications and some endocrinopathies were significantly higher in patients with β°β° genotype compared to other genotypes which explain the role of the underlying genetic defect in thalassemia patients in development of disease complications.

Impact of Genotype of Beta Globin Gene on Hepatic and Myocardial Iron Content in Egyptian Patients with Beta Thalassemia

Iron overload causes most of the mortality and morbidity associated with thalassemia. Excess iron deposits primarily in the liver, but once a threshold level is reached, iron loading may occur in other tissues such as the heart. Magnetic resonance imaging is a well established technique to noninvasively quantify myocardial and liver iron content. More than 300 disease-causing mutations have been identified. We aimed to determine the impact of genotype on liver iron content in patients with beta thalassemia. Cross sectional study was carried on 73 patients with beta thalassemia. MRI liver and heart was performed to determine hepatic and myocardial iron overload. Genotyping was determined by DNA sequencing technique. The mean liver iron content was 17.4 mg/g dw and mean cardiac T2* was 25.5 ms in our patients. Patients with β⁰β⁰ were associated with significantly higher liver and myocardial iron content compared to those with β⁰β⁺ and β⁺β⁺ genotypes. There was a clear association between genotype and both hepatic and myocardial iron overload. Patients with β⁰β⁰ had significantly higher liver and heart iron content compared to those with β⁰β⁺ and β⁺β⁺ genotypes. Liver iron content was strongly correlated to serum ferritin levels and myocardial iron overload.

Quantifying iron content in magnetic resonance imaging

Measuring iron content has practical clinical indications in the study of diseases such as Parkinson's disease, Huntington's disease, ferritinopathies and multiple sclerosis as well as in the quantification of iron content in microbleeds and oxygen saturation in veins. In this work, we review the basic concepts behind imaging iron using T2, T2*, T2', phase and quantitative susceptibility mapping in the human brain, liver and heart, followed by the applications of in vivo iron quantification in neurodegenerative diseases, iron tagged cells and ultra-small superparamagnetic iron oxide (USPIO) nanoparticles.

Magnetic resonance imaging during management of patients with transfusion-dependent thalassemia: a single-center experience

BACKGROUND

Cardiac and hepatic magnetic resonance imaging evaluation during treatment can tailor physicians' chelation therapy titrations.

AIM

The aim of the study was to assess the relationship of cardiac and hepatic T2* values with chelation therapy in patients with transfusion-dependent thalassemia (TDT).

METHODS

A total of 106 patients with TDT who were followed up in Istanbul Medical Faculty Thalassemia Center were evaluated for the study. Forty-eight (45%) patients with TDT had more than one consecutive MRI examination. The patients were divided into three subgroups according to the cardiac T2* values as the high-risk group (T2* MRI < 10 ms), medium-risk group (T2* MRI 10-20 ms), and the low-risk group (T2* MRI > 20 ms).

RESULTS

The majority of patients used DFX (deferasirox) (79%) and deferiprone (DFP) (17%). Approximately 80% of patients according to cardiac T2* value and 40% of patients according to hepatic T2* value were initially in the low-risk group. Patients with follow-up MRI examinations exhibited significant improvement in liver iron concentration, which correlated with an increase in hepatic T2* values. The decrease of liver iron concentration was prominent in the DFX group (p < 0.01). The serum ferritin level was significantly correlated with liver iron concentrations (rs = 0.65, p < 0.001), hepatic T2* value (rs = - 0.62, p < 0.001), but not with cardiac T2* value (rs = - 0.20, p = 0.07).

CONCLUSION

Cardiovascular and hepatic MRI is a useful follow-up tool during the assessment of risk groups and chelation therapy of patients with TDT. Consecutive MRI tests showed good monitoring of cardiac and liver iron overload.

Relationship between T2* magnetic resonance imaging-derived liver and heart iron content and serum ferritin levels in transfusion-dependent thalassemic children

CONTEXT:

T2* magnetic resonance imaging (MRI) is being increasingly used for the assessment of organ iron content in thalassemics, but cost is a major prohibitive factor for repeated measurements. If serum ferritin correlates well with the T2* MRI liver and heart, it will be economical and more simple tool to assess organ iron deposition.

AIMS:

The aim of this study was to find out the relationship between serum ferritin level and T2* MRI-derived liver and heart iron content in transfusion-dependent thalassemic children

SETTINGS:

Thalassemia day-care center of a teaching hospital

DESIGN:

This was a cross-sectional study

SUBJECTS AND METHODS:

Seventy-three transfusion-dependent beta thalassemic children belonging to 2–18 years of age were subjected to T2* MRI of heart and liver to assess their iron content. Values obtained here were related to serum ferritin.

STATISTICAL ANALYSIS USED:

Keeping the correlation between serum ferritin and T2* MRI as primary outcome, spearman's correlation coefficient was calculated.

RESULTS:

We found poor (negative) correlation between serum ferritin level and T2* MRI liver (r = -0.448, P = 0.000) but no correlation between serum ferritin and T2*MRI heart (r = -0.221, P = 0.060).

Conclusions:

Serum ferritin cannot reliably predict the liver and heart iron content in Indian children with β thalassemia.

Heart Rate Recovery as a Novel Test for Predicting Cardiac Involvement in Beta-Thalassemia Major

BACKGROUND

Abnormal heart rate recovery (HRR) is predictive of cardiac mortality. Autonomic abnormalities in beta-thalassemia major (TM) patients have been reported in previous studies. However, the importance of low HRR in exercise stress test in TM patients has not yet been ascertained. Therefore, this study will be the first of its kind in the literature.

METHODS

Exercise stress test was performed on 56 TM patients who were being treated at the Thalassemia Center of our hospital, along with 46 non-TM iron deficiency anemia (IDA) patients as a control group. Values for HHR were recorded at 1, 2, 3, 4 and 5 min, and HRR was calculated by the difference of heart rate at peak exercise and at a specific time interval following the onset of recovery.

RESULTS

All HRR values were found to be lower in TM patients compared to those in the IDA group. Exercise capacity [metabolic equivalents (METs)] was also found to be low in these patients (p < 0.001) as well. Total exercise time was significantly lower in the TM group compared to the IDA group (8.40 ± 1.7 min vs. 11.17 ± 1.51 min, p < 0.001). Exercise capacity (METs) was also lower in the TM group compared to the IDA group. Mean T2* value was 28.3 ± 13.7 ms in TM patients on magnetic resonance imaging (MRI). In addition, there are 18 TM patients with T2* value was < 20 ms.

CONCLUSIONS

This study found that TM was independently associated with low HRR. Such a condition is an indicator of autonomic dysfunction in TM patients, since abnormal HRR is related to impaired autonomic response. In addition, impaired HRR may be a marker of early cardiac involvement in patients, whose T2* value is high on MRI. Modifying HRR with a cardiac rehabilitation program in TM patients with impaired HRR is a field open for further investigation.

Myocardial and liver iron overload, assessed using T2* magnetic resonance imaging with an excel spreadsheet for post processing in Tunisian thalassemia major patients

Thalassemia is a common genetic disorder in Tunisia. Early iron concentration assessment is a crucial and challenging issue. Most of annual deaths due to iron overload occurred in underdeveloped regions of the world. Limited access to liver and heart MRI monitoring might partially explain these poor prognostic results. Standard software programs are not available in Tunisia. This study is the first to evaluate iron overload in heart and liver using the MRI T2* with excel spreadsheet for post processing. Association of this MRI tool results to serum ferritin level, and echocardiography was also investigated. One hundred Tunisian-transfused thalassemia patients older than 10 years (16.1 ± 5.2) were enrolled in the study. The mean myocardial iron concentration (MIC) was 1.26 ± 1.65 mg/g dw (0.06-8.32). Cardiac T2* (CT2*) was under 20 ms in 30 % of patients and under 10 ms in 21 % of patients. Left ventricular ejection function was significantly lower in patients with CT2* <10 ms. Abnormal liver iron concentration (LIC >3 mg/g dw) was found in 95 % of patients. LIC was over 15 mg/g dw in 25 % of patients. MIC was more correlated than CT2* to LIC and serum ferritin. Among patients with SF <1000 μg/l, 13 % had CT2* <20 ms. Our data showed that 30 % of the Tunisian thalassemia major patients enrolled in this cohort had myocardial iron overload despite being treated by iron chelators. SF could not reliably predict iron overload in all thalassemia patients. MRI T2* using excel spreadsheet for routine follow-up of iron overload might improve the prognosis of thalassemia major patients in developing countries, such as Tunisia, where standard MRI tools are not available or expensive.

Labile plasma iron, more practical and more sensitive to iron overload in myelodysplastic syndromes

OBJECTIVES

In order to gain an insight into labile plasma iron (LPI) in iron metabolism microenvironment in MDS.

METHODS

We performed ELISA, quantitative real-time polymerase chain reaction, flow cytometry, MRI T2* assays to test LPI, iron biochemical parameters, and liver iron concentration (LIC) among 22 MDS patients.

RESULTS

LPI has a statistical difference (P < 0.001 by analysis of variance (ANOVA)), which decreased gradually, among three groups, while no difference was found in adjusted serum ferritin (ASF) (P = 0.086 by ANOVA). After DFO treatment, serum hepcidin expression increased from 301.26 ± 59.78 to 340.33 ± 49.78 µg/l (P = 0.032), while hepcidin/ASF was upregulated gradually from 0.16 ± 0.08 to 0.22 ± 0.03 (P = 0.045). APAF-1 expression (P = 0.047) and erythroid apoptosis rate (P = 0.009) decreased significantly, respectively. No statistical difference was found in EPO (P = 0.247) and GDF15 expression (P = 0.172). LIC dropped from 9.83 ± 4.84 to 6.28 ± 4.01 mg/g dry weight (P < 0.001). No significant difference was found in cardiac T2* (P = 0.594). LPI has a closer connection to LIC than ASF (r = 0.739, P < 0.001 vs. r = 0.321, P = 0.034).

DISCUSSION

LPI seems to be a real-time indicator which reflects body iron loading status instantaneously. Despite the limited knowledge available on LPI speciation in different types and degrees of IO, LPI measurements can be and are in fact used for identifying systemic IO and for initiating/adjusting chelation regimens.

Burden of Cardiac Siderosis in a Thalassemia-Major Endemic Population: A Preliminary Report From Pakistan

OBJECTIVE

To describe the initial experience and demographics of T2* cardiac magnetic resonance-based myocardial-iron quantification of transfusion-dependent thalassemia-major (TM) patients from Pakistan and the correlation with serum ferritin.

METHODS

Eligible TM patients presenting between April 2014 and April 2015 to Aga Khan University Hospital, Pakistan, for T2*CMR were included. The severity of myocardial-iron deposition was defined as follows: normal T2*>20 ms, mild-moderate T2*10 to 20 ms, and severe T2*<10 ms. Cardiac symptoms were classified using the NYHA functional classification. Echocardiographic systolic and diastolic functions were performed. Continuous variables were presented as the median (minimum-maximum value). Correlation was measured using the Spearman rank correlation. Multivariate logistic regression was used to determine factors associated with the NYHA functional class.

RESULTS

A total of 83 patients (49 male and 34 female) with TM, age 19 (5 to 45) years at presentation for T2*CMR, were reviewed. At presentation, 70% of the patients were classified as NYHA class II or worse. T2*<20 ms was observed in 62.6% of the patients, with 47% showing severe iron deposition (T2<10 ms). No correlation of T2*<20 ms (r=-0.157, P=0.302) and T2*<10 ms (r=-0.128, P=0.464) was observed with serum ferritin. On multivariate analysis, lower T2* values correlated with a worsening NYHA functional class.

CONCLUSIONS

There is a high prevalence of severe myocardial iron load in Pakistani TM patients. Serum ferritin did not correlate with T2* values. Lower T2* was the only clinical factor associated with the NYHA functional class.

Assessment of Heart and Liver Iron Overload in Thalassemia Major Patients Using T2* Magnetic Resonance Imaging

Accumulation of excess iron in heart can lead to cardiac dysfunction, which is the most common cause of death in thalassemia major patients. Biopsy is an invasive procedure and therefore not an ideal option to assess iron load. However, standard/usual non-invasive methods, such as ferritin measurement, have some limitations and the results show poor correlations with iron load. Magnetic Response Imaging (MRI-T2*), as a non-invasive and reliable method for iron load assessment in organs such as liver and heart, can be suggested as a favorable alternative. This cross-sectional study was implemented in Thalassemia and Hemophilia Clinic Center (Sarvar) affiliated with Mashhad University of Medical Sciences, Mashhad, Iran, from 2012 to 2013. After the approval of the research protocol by the local ethic committee, laboratory tests, including CBC and serum ferritin, were carried out, and echocardiography and heart and liver MRI-T2* were performed. All statistical analysis was done through SPSS software (version 11.5), using independent sample t test and Pearson's correlation coefficient test. A P value ≤0.05 was considered to be significant. 88 patients with the mean (±SD) age of 21.2 (±5.6) years, (range 11-37 years) were observed. Iron load was assessed using MRI-T2* with the following results: Out of 88 patients, 48.9 % had mild to severe cardiac siderosis, and 75.2 % had mild to severe liver siderosis. We demonstrated a correlation between liver MRI-T2* and serum ferritin, and heart MRI-T2* and ejection fraction. However, no correlation between liver and heart MRI-T2* was observed. Heart and liver siderosis is a common and serious problem in thalassemia major patients, and MRI-T2* as a sensitive and non-invasive technique can be used for early/timely detection of siderosis and good therapeutic monitoring in these patients.

Guidelines for quantifying iron overload

Both primary and secondary iron overload are increasingly prevalent in the United States because of immigration from the Far East, increasing transfusion therapy in sickle cell disease, and improved survivorship of hematologic malignancies. This chapter describes the use of historical data, serological measures, and MRI to estimate somatic iron burden. Before chelation therapy, transfusional volume is an accurate method for estimating liver iron burden, whereas transferrin saturation reflects the risk of extrahepatic iron deposition. In chronically transfused patients, trends in serum ferritin are helpful, inexpensive guides to relative changes in somatic iron stores. However, intersubject variability is quite high and ferritin values may change disparately from trends in total body iron load over periods of several years. Liver biopsy was once used to anchor trends in serum ferritin, but it is invasive and plagued by sampling variability. As a result, we recommend annual liver iron concentration measurements by MRI for all patients on chronic transfusion therapy. Furthermore, it is important to measure cardiac T2* by MRI every 6-24 months depending on the clinical risk of cardiac iron deposition. Recent validation data for pancreas and pituitary iron assessments are also presented, but further confirmatory data are suggested before these techniques can be recommended for routine clinical use.

Optimal method for early detection of cardiac disorders in thalassemia major patients: magnetic resonance imaging or echocardiography?

Background

Heart failure resulting from myocardial iron deposition is the most important cause of death in β-thalassemia major (TM) patients. Cardiac T2*magnetic resonance imaging (MRI), echocardiography, and serum ferritin level serve as diagnostic methods for detecting myocardial iron overload. In this study, we aimed to evaluate the relationship between the above-mentioned methods.

Methods

T2*MRI and echocardiographic measurement of left ventricular (LV) systolic and diastolic function were performed in 63 patients. Serum ferritin level was measured. The relationships between all assessments were evaluated.

Results

There were 40 women and 23 men with a mean age of 23.7±5.1 years (range, 15-35 years). There was no statistically significant correlation between serum ferritin level and LV systolic and diastolic function (P=0.994 and P=0.475, respectively). T2*MRI results had a significant correlation with ferritin level; 63.6% of patients with serum ferritin level >2,000 ng/mL had abnormal cardiac MRI, while none of the patients with ferritin level <1,000 ng/mL had abnormal cardiac MRI (P=0.001). There was no significant correlation between MRI findings and LV systolic function (P=1.00). However, we detected a significant difference between LV diastolic function and cardiac siderosis (P=0.03)

Conclusion

MRI findings are a good predictor of future cardiac dysfunction, even in asymptomatic TM patients; however, diastolic dysfunction may happen prior to cardiac siderosis in some patients, and echocardiography is able to diagnose this diastolic dysfunction while T2*MRI shows normal findings.

Role of non-invasive assessment in prediction of preclinical cardiac affection in multi-transfused thalassaemia major patients

BACKGROUND

The principal cause of mortality and morbidity in β-thalassemia major (β-TM) is the iron overload as these patients receive about 20 times the normal intake of iron, which leads to iron accumulation and damage in the liver, heart, and endocrine organs. Chronically transfused patients used to die from cardiac iron overload in their teens and twenties. Monitoring of iron status through cardiac magnetic resonance imaging (CMRI) has replaced the conventional methods of assessment, yet this modality is not readily available in centers where the disease distribution is maximal. Objectives The aim of this work is to study some simple non-invasive tools and their abilities to predict preclinical cardiac affection reflecting cardiac iron deposition (CID) in multi-transfused β-TM patients taking the T2* CMRI as a gold standard reference test.

METHODS

One hundred consecutive multi-transfused, clinically stable β-TM patients with age ranging from 16 to 30 years (mean ± SD, 21.1 ± 3.9) were included in this study. Assessment of serum ferritin, serum hepcidin, and high-sensitivity C-reactive protein as well as cardiac assessment by echo-doppler and 24-hour Holter were used to predict CID, and consequently predict preclinical cardiac affection, in reference to CMRI results as the standard method of cardiac iron assessment.

RESULTS

According to CMRI results, patients were subdivided into a group of 42 patients with detectable myocardial iron (T*≤ 20 ms) and a group of 58 patients with no detectable myocardial iron (T* > 20 ms). No differences in age, gender, or distribution of splenectomized patients were observed between both groups. Patients with detectable myocardial iron received significantly higher number of transfusions per year than those with no detectable myocardial iron (mean ± SD, 14.6 ± 1.7 vs. 12.5 ± 1.7; P < 0.001) yet comparable levels of serum ferritin, serum hepcidin, and hepcidin/ferritin ratio (P > 0.05) were noted. Cardiac iron detection was associated with significantly lower heart rate (mean ± SD, 75 ± 6.1 vs. 80 ± 6.9; P < 0.001), lower left ventricular ejection fraction (LVEF) (mean ± SD 60.1 ± 3.2 vs. 70.1 ± 2.8; P < 0.001), and higher total number of premature ventricular contractions (PVCs) (median 78 vs. 14; P < 0.001). The group with CID comprised significantly more patients with left ventricular diastolic dysfunction (15/42, 35.7% vs. 3/58, 5.2%; P < 0.001); PVCs ≥10/hour (13/42, 31% vs. 2/58, 3.4%; P < 0.001); episodes of sinus pauses (6/42, 14.3% vs. 1/58, 1.7%; P < 0.05); episodes of high-grade atrio-ventricular block (5/42, 11.9% vs. 1/58, 1.7%; P < 0.05) compared to the group with no (CID). In presence of normal LVEF, detection of 10 or more PVCs per hour was the most predictive of cardiac iron loading with a positive predictive value of 86.7% and specificity of 96.6%, and the highest likelihood ratio (9.09). Detection of more than 22 PVCs/24 hours had the best sensitivity (81%) and the best negative predictive value (84%). The positive likelihood ratio of the studied parameters was highest in case of presence of PVCs ≥10/hour and lowest in case of average heart rate with a cut-off level of ≤77.5 bpm (9.09 and 1.46, respectively).

CONCLUSION

Our results support our hypothesis that monitoring β-TM patients with echo and Holter electrocardiogram can help in the detection of preclinical cardiac affection in centers lacking cardiac MRI; however, due to relatively low sensitivity they can not fully replace CMRI. Further work is needed to identify additional simple parameters that can form a diagnostic model with adequate sensitivity.

Dark blood versus bright blood T2 acquisition in cardiovascular magnetic resonance (CMR) for thalassaemia major (TM) patients: evaluation of feasibility, reproducibility and image quality

OBJECTIVES

To compare the effectiveness of dark blood (DB) versus bright blood (BB) sequences. To assess the intra and inter-observer variability and inter-study reproducibility between BB versus DB. To evaluate image quality level in the two sequences.

METHODS

In a setting of 138 patients we performed CMR using cardiac gated Gradient-multiecho single breath-hold BB and DB sequences in the middle ventricular septum. Each acquisition was repeated during the same exam. Truncation method was used to account for background noise. Image quality (IQ) was assessed using a 5 point grading scale and image analysis was conducted by 2 experienced observers.

RESULTS

Compared with the conventional BB acquisition, the coefficient of correlation and significance of the DB technique was superior for intra-observer reproducibility (p<0.001), inter-observer reproducibility (p<0.001) and inter-study reproducibility (p<0.001). The variability is also lower for DB sequences for T2* values <14 ms. Assessment of artifacts showed a superior score for DB versus BB scans (4 versus 3, p<0.001).

CONCLUSIONS

Improvement in terms of inter observer and inter study variability using DB sequences was obtained. The greatest disparity between them was seen in inter-study reproducibility and higher IQ in DB was seen. Study demonstrates better performance of DB imaging compared to BB in presence of comparable effectiveness.

The evaluation of iron overload through hepcidin level and its related factors in myelodysplastic syndromes

We chose hepcidin and its related factors as evaluating indicators to determine the degrees of iron overload in myelodysplastic syndromes (MDS) patients. A total of 73 patients and 28 healthy volunteers were enrolled in this study. We performed enzyme-linked immunosorbent assay to measure both bone marrow and peripheral blood serum hepcidin. Real-time quantitative polymerase chain reaction was used to determine the gene expression of growth differentiation factor 15 and twisted gastrulation 1. Serum ferritin (SF), C-reactive protein (CRP), and erythropoietin were measured by routine standard laboratory assays. CD4(+) and CD19(+) lymphocytes and Th polarization were detected by flow cytometry. Twenty-four MDS patients were measured their cardiac and liver iron deposition levels through magnetic resonance imaging (MRI) T2* examination. No significant difference was found between the bone marrow hepcidin levels and peripheral blood hepcidin levels (P = 0.134). Stratified according to different World Health Organization subtypes, refractory anemia with ringed sideroblasts patients had the lowest hepcidin levels (105.40 ± 5.13 ng/ml), while refractory anemia with excess blasts-1 had the highest levels (335.71 ± 25.16 ng/ml). Stratified according to International Prognostic Scoring System and WHO Classification-based Prognostic Scoring System, there was a significant difference of hepcidin levels between low-risk group and high-risk group in two systems, respectively (P = 0.033 and 0.009). The hepcidin levels of CD4(+) high-expression group were demonstrated higher than the normal expression groups (P = 0.02), but the CD19(+) high-expression group did not show the same result (P = 0.206). Meanwhile, patients with a Th1 polarization trend had a high level of hepcidin versus normal group (P < 0.001). Liver iron concentration (LIC) measured by MRI T2* had a closer correlation (r = 0.582, P < 0.001) to hepcidin than serum ferritin, by stepwise regression. C-reactive protein and LIC seemed to be the key determinants of hepcidin, by multivariate regression. Inflammation plays an important role in the regulation of hepcidin expression. T-lymphocyte activation and Th polarization trend might participate in the regulatory mechanism partly. The capability of organ iron load assessment of MRI T2* seems better than that of SF. It seems that hepcidin with CRP and LIC measured by MRI T2* are potential indicators of iron overload in MDS patients.

Assessment of cardiac iron deposition in sickle cell disease using 3.0 Tesla cardiovascular magnetic resonance

Many patients with sickle cell disease receive blood transfusions as a life-saving treatment. However, excess transfusions may lead to increased body iron burden. Specifically, heart failure due to cardiac iron overload is the leading cause of death in these patients. The purpose of this study was to investigate the potential role of high-field 3.0-Tesla (T) cardiovascular magnetic resonance (CMR) for assessment of cardiac iron content by measuring the transverse relaxivity rate R2*. The R2* was measured in calibrated phantoms with different iron concentrations at 3.0T and 1.5T using optimized pulse sequences. Myocardial R2* was measured at 3.0T in a group of sickle cell disease patients with different disease stages, and the results were compared to the serum ferritin levels and hepatic R2*. The phantom R2* measurements at 3.0T were double those at 1.5T, and the measurements of both systems showed linear relationships with iron concentration. The 3.0T R2* was more sensitive than 1.5T in detecting low iron concentration. In patients, myocardial R2* had weak and good correlations with hepatic R2* and serum ferritin levels, respectively. Bland-Altman analysis showed low inter- and intra-observer variabilities. In conclusion, measuring myocardial R2* at 3.0T is a promising technique with high sensitivity and reproducibility for evaluating cardiac iron overload in sickle cell disease patients.

R*(2) mapping in the presence of macroscopic B₀ field variations

R₂ mapping has important applications in MRI, including functional imaging, tracking of super-paramagnetic particles, and measurement of tissue iron levels. However, R₂ measurements can be confounded by several effects, particularly the presence of fat and macroscopic B₀ field variations. Fat introduces additional modulations in the signal. Macroscopic field variations introduce additional dephasing that results in accelerated signal decay. These effects produce systematic errors in the resulting R₂ maps and make the estimated R₂ values dependent on the acquisition parameters. In this study, we develop a complex-reconstruction, confounder-corrected R₂ mapping technique, which addresses the presence of fat and macroscopic field variations for both 2D and 3D acquisitions. This technique extends previous chemical shift-encoded methods for R₂, fat and water mapping by measuring and correcting for the effect of macroscopic field variations in the acquired signal. The proposed method is tested on several 2D and 3D phantom and in vivo liver, cardiac, and brain datasets.

Impact of iron assessment by MRI

The use of magnetic resonance imaging (MRI) to estimate tissue iron was conceived in the 1980s, but has only become a practical reality in the last decade. The technique is most often used to estimate hepatic and cardiac iron in patients with transfusional siderosis and has largely replaced liver biopsy for liver iron quantification. However, the ability of MRI to quantify extrahepatic iron has had a greater impact on patient care and on our understanding of iron overload pathophysiology. Iron cardiomyopathy used to be the leading cause of death in thalassemia major, but is now relatively rare in centers with regular MRI screening of cardiac iron, through earlier recognition of cardiac iron loading. Longitudinal MRI studies have demonstrated differential kinetics of uptake and clearance among the difference organs of the body. Although elevated serum ferritin and liver iron concentration (LIC) increase the risk of cardiac and endocrine toxicities, some patients unequivocally develop extrahepatic iron deposition and toxicity despite having low total body iron stores. These observations, coupled with the advent of increasing options for iron chelation therapy, are allowing clinicians to more appropriately tailor chelation therapy to individual patient needs, producing greater efficacy with fewer toxicities. Future frontiers in MRI monitoring include improved prevention of endocrine toxicities, particularly hypogonadotropic hypogonadism and diabetes.