T2* cardiovascular magnetic resonance in the management of thalassemia patients in Oman

MRI Deep Learning-Based Automatic Segmentation of Interventricular Septum for Black-Blood Myocardial T2* Measurement in Thalassemia

BACKGROUND

The T2* value of interventricular septum is routinely reported for grading myocardial iron load in thalassemia major, and automatic segmentation of septum could shorten analysis time and reduce interobserver variability.

PURPOSE

To develop a deep learning-based method for automatic septum segmentation from black-blood MR images for the myocardial T2* measurement of thalassemia patients.

STUDY TYPE

Retrospective.

POPULATION/SUBJECTS

One hundred forty-six transfusion-dependent thalassemia patients with cardiac MR examinations from two centers. Data from Center 1 (1.5 T) were assigned to the training (100 examinations) and internal testing (20 examinations) sets; data from Center 2 were assigned to the external testing set (26 examinations; 10 at 1.5 T and 16 at 3.0 T).

FIELD STRENGTH/SEQUENCE

1.5 T and 3.0 T, multiecho gradient-echo sequence.

ASSESSMENT

A modified attention U-Net for septum segmentation was constructed and trained, and its performance evaluated on unseen internal and external datasets. T2* was measured by fitting the average septum signal, separately segmented by automatic and manual methods.

STATISTICAL TESTS

Agreement between manual and automatic septum segmentations was assessed with the Dice coefficient, and T2* agreement was assessed using the Bland-Altman plot and the coefficient of variation (CoV).

RESULTS

The median Dice coefficient of deep network-based septum segmentation was 0.90 [0.05] on the internal dataset, 0.82 [0.10] on the external 1.5 T dataset, and 0.86 [0.14] on the external 3.0 T dataset. T2* measurements using automatic segmentation corresponded with those from manual segmentation, with a mean difference of 0.02 (95% LoA: -0.74 to 0.79) msec, 0.43 (95% LoA: -2.1 to 3.0) msec, and 0.36 (95% LoA: -0.72 to 1.4) msec on the three datasets. The CoVs between the two methods were 3.1%, 7.0%, and 6.1% on the internal and two external datasets, respectively.

DATA CONCLUSIONS

The proposed septum segmentation yielded myocardial T2* measurements which were highly consistent with those obtained by manual segmentation. This automatic approach may facilitate data processing and avoid operator-dependent variability in practice.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 1.

The Importance of Cardiac T2* Magnetic Resonance Imaging for Monitoring Cardiac Siderosis in Thalassemia Major Patients

Objective: Cardiac T2* magnetic resonance imaging (MRI) has recently attracted considerable attention as a non-invasive method for detecting iron overload in various organs in thalassemia major patients. This study aimed to identify the prevalence of cardiac siderosis in thalassemia major patients and evaluate cardiac T2* MRI for monitoring cardiac siderosis before and after patients receive iron chelation therapy and its relation to serum ferritin, left ventricular ejection fraction, and liver iron concentration. The information gathered would be used for the direct monitoring, detection, and treatment of complications early on. Methods: A total of 119 thalassemia major patients were recruited in the present study. The cardiac T2* MRI was compared to serum ferritin levels, liver iron concentration (LIC), and left ventricular ejection fraction. All patients were classified into four groups based on their cardiac siderosis as having normal, marginal, mild to moderate, or severe cardiac iron overload. At the follow-up at years one, three, and five, the cardiac T2* MRI, LIC, serum ferritin, and left ventricular ejection fraction (LVEF) were determined. Results: The prevalence of cardiac siderosis with cardiac T2* MRI ≤ 25 ms was 17.6% (n = 21). There was no correlation between cardiac T2* MRI and serum ferritin, liver iron concentration, and LVEF (p = 0.39, 0.54, and 0.09, respectively). During one year to five years’ follow-up periods, cardiac T2* MRI (ms) in patients with severe cardiac siderosis had significantly improved from 8.5 ± 1.49 at baseline to 33.9 ± 1.9 at five years (p < 0.0001). Patients with severe, mild-moderate, marginal, and no cardiac siderosis had median LIC (mg/g dw) of 23.9 ± 6.5, 21.6 ± 13.3, 25.3 ± 7.7, and 19.9 ± 5.5 at baseline, respectively. Conclusions: This study supports the use of cardiac T2* MRI to monitor cardiac iron overload in patients who have had multiple blood transfusions. Early diagnosis and treatment of patients at risk of cardiac siderosis is a reasonable method of reducing the substantial cardiac mortality burden associated with myocardial siderosis. Cardiac T2* MRI is the best test that can identify at-risk patients who can be managed with optimization of their chelation therapy.

Cardiac T2* MR in patients with thalassemia major: a 10-year long-term follow-up

The consequence of regular blood transfusion in patients with thalassemia major (TM) is iron overload. Herein, we report the long-term impact of chelation on liver iron concentration (LIC) and cardiac T2* MR in patients with TM. This is a retrospective cohort study over 10 years of adolescents and adults with TM aged at least 10 years who had their first cardiac T2* MR between September 2006 and February 2007. One-year chelation therapy was considered the unit of analysis. A total of 99 patients were included in this study with a median age of 18 years. The median cardiac T2* MR and LIC at baseline were 19 ms and 11.6 mg/g dw, respectively. During follow-up, 18 patients died and six underwent successful bone marrow transplantation. Factors associated with decreased survival were older age (HR 1.12, p = 0.014) and high risk cardiac T2* (HR 8.04, p = 0.004). The median cardiac T2* and LIC significantly improved over the 10-year follow-up period (p = 0.000011 and 0.00072, respectively). In conclusion, this long-term "real-life" study confirms that low cardiac T2* adversely impacts the overall survival in patients with TM. Higher baseline LIC predicts a larger reduction in LIC, and lower baseline cardiac T2* predicts a larger improvement in T2*.

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.

Evaluation of Glutathione-S-Transferase P1 Polymorphism and its Relation to Bone Mineral Density in Egyptian Children and Adolescents with Beta-Thalassemia Major

BACKGROUND

Osteoporosis is a major complication of beta thalassemia major (TM). Increased oxidative stress and its controlling genes were linked to osteoporosis. Ile105 Val variant is a functional polymorphism of Glutathione S-transferase P1 (GSTP1), with reduced anti-oxidative property. No data are available about this variant or its association with osteoporosis among thalassemia patients yet.

OBJECTIVES

To investigate Ile105Val polymorphism and its possible association with bone mineral density (BMD) values in a group of TM children.

METHODS

Thirty five TM children and 30 age and sex matched healthy controls were included. Liver and renal functions, serum ferritin, calcium, phosphorous, alkaline phosphatase and osteocalcin were assayed. BMD was determined by DXA with calculation of Z-scores at lumbar spine (LS) and femoral neck (FN). Height for age Z- score (HAZ) adjusted BMD Z-scores were calculated. GSTP1 Ile105Val polymorphism was studied by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

The relative frequency of 105 Val allele was significantly higher in TM patients than the controls (p<0.0001). Significant association between genotype subgroups and BMD parameters was detected. Compared to wild homozygotes, polymorphic homozygotes had lower LS-BMD (p =0.029), LS-BMD Z -score (p=0.008 ), LS- BMD haz - Z-score (p=0.011), FN- BMD (p= 0.001), FN- BMD Z -score (p=0.02) and FN-BMD haz - Z-score (p=0.001). They exhibited higher osteocalcin levels compared to heterozygotes and wild homozygotes (p=0.012, p=0.013, respectively).

CONCLUSION

Ile105Val polymorphism was frequent among TM patients and could increase their susceptibility to reduced BMD. Large sample studies are required to confirm these findings.

Glutathione S-transferase gene polymorphism: Relation to cardiac iron overload in Egyptian patients with Beta Thalassemia Major

OBJECTIVES

Estimating the prevalence of glutathione S-transferase gene polymorphism (GSTM1) null genotype among patients with beta thalassemia major (β-TM) in relation to myocardial status assessed by tissue Doppler and cardiac siderosis assessed by cardiac magnetic resonance imaging (MRI) T2*.

METHODS

Hundred patients with β-TM and 100 healthy controls were enrolled. Complete blood count (CBC), mean serum ferritin and GSTM1 genotyping, echocardiography, tissue Doppler, and cardiac MRI T2* were done.

RESULTS

Serum ferritin ranged from 1200 to 8000 ng/ml, and mean T2* value was 27.10 ± 11.20 ms. Of patients, 68 (68%) had no cardiac siderosis, while 24 (24%) with mild to moderate, and 8 (8%) with sever cardiac siderosis. T2* values were not correlated with serum ferritin (r = -0.09, P = 0.50). GSTM1 null genotype was prevalent in 46% of patients and 40% of controls (P = 0.69). Patients with null genotype had significantly shorter T2* (P = 0.001), higher left ventricular end-diastolic diameter (P = 0.002), and shorter ejection time (P = 0.005) with no significant relation to serum ferritin (P = 0.122). GSTM1 null genotype was the only predictor for cardiac iron overload (P = 0.002).

DISCUSSION

Serum ferritin concentrations have been shown to correlate poorly with all stages of cardiac dysfunction. Low cardiac MRI T2* values occur in patients with β-TM despite good chelation therapy, suggesting a possible role of genetic factors in cardiac siderosis.

CONCLUSION

GSTM1 null genotype is significantly associated with cardiac iron overload independent of serum ferritin in Egyptian patients with β-TM.

Prevalence and distribution of iron overload in patients with transfusion-dependent anemias differs across geographic regions: results from the CORDELIA study

OBJECTIVES

The randomized comparison of deferasirox to deferoxamine for myocardial iron removal in patients with transfusion-dependent anemias (CORDELIA) gave the opportunity to assess relative prevalence and body distribution of iron overload in screened patients.

METHODS

Patients aged ≥ 10 yr with transfusion-dependent anemias from 11 countries were screened. Data were summarized descriptively, overall and across regions.

RESULTS

Among 925 patients (99.1% with β-thalassemia major; 98.5% receiving prior chelation; mean age 19.2 yr), 36.7% had myocardial iron overload (myocardial T2* ≤ 20 ms), 12.1% had low left ventricular ejection fraction. Liver iron concentration (LIC) (mean 25.8 mg Fe/g dw) and serum ferritin (median 3702 ng/mL) were high. Fewer patients in the Middle East (ME; 28.5%) had myocardial T2* ≤ 20 ms vs. patients in the West (45.9%) and Far East (FE, 40.9%). Patients in the West had highest myocardial iron burden, but lowest LIC (26.9% with LIC < 7 mg Fe/g dw) and serum ferritin. Among patients with normal myocardial iron, a higher proportion of patients from the ME and FE had LIC ≥ 15 than < 7 mg Fe/g dw (ME, 56.7% vs. 17.2%; FE, 78.6% vs. 7.8%, respectively), a trend which was less evident in the West (44.6% vs. 33.9%, respectively). Transfusion and chelation practices differed between regions.

CONCLUSIONS

Evidence of substantial myocardial and liver iron burden across regions revealed a need for optimization of effective, convenient iron chelation regimens. Significant regional variation exists in myocardial and liver iron loading that are not well explained; improved understanding of factors contributing to differences in body iron distribution may be of clinical benefit.

Automated interventricular septum segmentation for black-blood myocardial T2* measurement in thalassemia

PURPOSE

To develop and validate an automated segmentation method that extracts the interventricular septum (IS) from myocardial black-blood images for the T2* measurement in thalassemia patients.

MATERIALS AND METHODS

A total of 144 thalassemia major patients (age range, 11-51 years; 73 males) were scanned with a black-blood multi-echo gradient-echo sequence using a 1.5 Tesla Siemens Sonata system (flip angle 20°, sampling bandwidth 810 Hz/pixel, voxel size 1.56 × 1.56 × 10 mm(3) and variable fields of view (20-30) × 40 cm(2) depending on patient size). The improved Chan-Vese model with an automated initialization by the circular Hough transformation was implemented to segment the endocardial and epicardial margins of the left ventricle (LV). Consequently, the IS was extracted by analyzing the anatomical relation between the LV and the blood pool of the right ventricle, identified by intensity thresholding. The proposed automated IS segmentation (AISS) method was compared with the conventional manual method by using the Bland-Altman analysis and the coefficient of variation (CoV).

RESULTS

The T2* measurements using the AISS method were in good agreement with those manually measured by experienced observers with a mean difference of 1.71% and a CoV of 4.15% (P < 0.001).

CONCLUSION

Black-blood myocardial T2* measurement can be fully automated with the proposed AISS method.

Efficacy and safety of deferasirox in β-thalassemia major patients in Iran: a prospective study from a single referral center in Iran

INTRODUCTION

Herein, the results of a prospective study evaluating the efficacy and safety of treatment with deferasirox are studied in iron-overloaded patients with β-thalassemia major during an 18-month trial.

METHODS

Thirty patients who were previously chelated with deferoxamine with/without deferiprone, and fulfilled the inclusion criteria were recruited. Patients received an initial dose of 10-30 mg/kg/day. Liver and cardiac MRI T2* were evaluated before and after the trial. In addition, serum ferritin level was assessed every 3 months. Primary endpoint was regarded as significant improvement in the severity of liver and cardiac iron overload in severe and moderate cases, in addition to improvement or maintenance of the grade of severity in patients with mild iron overload or normal iron accumulation. Therapy was considered effective if primary endpoint was met in >50%.

RESULTS

Liver MRI values improved significantly (P = .002), achieving a 73.33% success rate. A successful outcome regarding myocardial iron overload was observed in 80%. Finally, an overall of 66.66% of patients met the success criteria. Secondary endpoint, regarded as safety and tolerability was reached by 93.33%. The most common adverse events were skin rash and gastrointestinal disturbance. A dose between 30 and 40 mg/kg/day, tailored to each patient was considered the optimal dose.

CONCLUSION

Deferasirox proved as an efficient and safe chelating agent in our patients, specifically in mild to moderate iron overloaded patients.

Low prevalence of cardiac siderosis in heavily iron loaded Egyptian thalassemia major patients

Myocardial siderosis in thalassemia major remains the leading cause of death in developing countries. Once heart failure develops, the outlook is usually poor with precipitous deterioration and death. Cardiovascular magnetic resonance (CMR) can measure cardiac iron deposition directly using the magnetic relaxation time T2*. This allows earlier diagnosis and treatment and helps to reduce mortality from this cardiac affection. This study aims to determine the prevalence of cardiac siderosis in Egyptian patients who are heavily iron loaded and its relation to liver iron concentration, serum ferritin, and left ventricular ejection fraction. Eighty-nine β-thalassemia patients receiving chelation therapy (mean age of 20.8 ± 6.4 years) were recruited in this study. Tissue iron levels were determined by CMR with cardiac T2* and liver R2*. The mean ± standard deviation (range) of cardiac T2* was 28.5 ± 11.7 ms (4.3 to 53.8 ms), the left ventricular ejection fraction (LVEF) was 67.7 ± 4.7 % (55 to 78 %), and the liver iron concentration (LIC) was 26.1 ± 13.4 mg Fe/g dry weight (dw) (1.5 to 56 mg Fe/g dw). The mean serum ferritin was 4,510 ± 2,847 ng/ml (533 to 22,360 ng/ml), and in 83.2 %, the serum ferritin was >2,500 ng/ml. The prevalence of myocardial siderosis (T2* of <20 ms) was 24.7 % (mean age 20.9 ± 7.5 years), with mean T2* of 12.7 ± 4.4 ms, mean LVEF of 68.6 ±5.8 %, mean LIC of 30.9 ± 13 mg Fe/g dw, and median serum ferritin of 4,996 ng/ml. There was no correlation between T2* and age, LVEF, LIC, and serum ferritin (P = 0.65, P = 0.085, P = 0.99, and P = 0.63, respectively). Severe cardiac siderosis (T2* of <10 ms) was present in 7.9 %, with a mean age of 18.4 ± 4.4 years. Although these patients had a mean T2* of 7.8 ± 1.7 ms, the LVEF was 65.1 ± 6.2 %, and only one patient had heart failure (T2* of 4.3 ms and LVEF of 55 %). LIC and serum ferritin results were 29.8 ± 17.0 mg/g and 7,200 ± 6,950 ng/ml, respectively. In this group of severe cardiac siderosis, T2* was also not correlated to age (P = 0.5), LVEF (P = 0.14), LIC (P = 0.97), or serum ferritin (P = 0.82). There was a low prevalence of myocardial siderosis in the Egyptian thalassemia patients in spite of very high serum ferritin and high LIC. T2* is the best test that can identify at-risk patients who can be managed with optimization of their chelation therapy. The possibility of a genetic component for the resistance to cardiac iron loading in our population should be considered.

Cardiovascular function and treatment in β-thalassemia major: a consensus statement from the American Heart Association

This aim of this statement is to report an expert consensus on the diagnosis and treatment of cardiac dysfunction in β-thalassemia major (TM). This consensus statement does not cover other hemoglobinopathies, including thalassemia intermedia and sickle cell anemia, in which a different spectrum of cardiovascular complications is typical. There are considerable uncertainties in this field, with a few randomized controlled trials relating to treatment of chronic myocardial siderosis but none relating to treatment of acute heart failure. The principles of diagnosis and treatment of cardiac iron loading in TM are directly relevant to other iron-overload conditions, including in particular Diamond-Blackfan anemia, sideroblastic anemia, and hereditary hemochromatosis. Heart failure is the most common cause of death in TM and primarily results from cardiac iron accumulation. The diagnosis of ventricular dysfunction in TM patients differs from that in nonanemic patients because of the cardiovascular adaptation to chronic anemia in non-cardiac-loaded TM patients, which includes resting tachycardia, low blood pressure, enlarged end-diastolic volume, high ejection fraction, and high cardiac output. Chronic anemia also leads to background symptomatology such as dyspnea, which can mask the clinical diagnosis of cardiac dysfunction. Central to early identification of cardiac iron overload in TM is the estimation of cardiac iron by cardiac T2* magnetic resonance. Cardiac T2* <10 ms is the most important predictor of development of heart failure. Serum ferritin and liver iron concentration are not adequate surrogates for cardiac iron measurement. Assessment of cardiac function by noninvasive techniques can also be valuable clinically, but serial measurements to establish trends are usually required because interpretation of single absolute values is complicated by the abnormal cardiovascular hemodynamics in TM and measurement imprecision. Acute decompensated heart failure is a medical emergency and requires urgent consultation with a center with expertise in its management. The first principle of management of acute heart failure is control of cardiac toxicity related to free iron by urgent commencement of a continuous, uninterrupted infusion of high-dose intravenous deferoxamine, augmented by oral deferiprone. Considerable care is required to not exacerbate cardiovascular problems from overuse of diuretics or inotropes because of the unusual loading conditions in TM. The current knowledge on the efficacy of removal of cardiac iron by the 3 commercially available iron chelators is summarized for cardiac iron overload without overt cardiac dysfunction. Evidence from well-conducted randomized controlled trials shows superior efficacy of deferiprone versus deferoxamine, the superiority of combined deferiprone with deferoxamine versus deferoxamine alone, and the equivalence of deferasirox versus deferoxamine.

Magnetic resonance imaging in the evaluation of iron overload: a comparison of MRI, echocardiography and serum ferritin level in patients with β-thalassemia major

PURPOSE

This study aimed to evaluate iron levels in cardiac and hepatic tissues using magnetic resonance imaging (MRI) T2*.

METHODS

Cardiac and hepatic MRI was performed for 93 patients with β-thalassemia major.

RESULTS

Cardiac T2* was in the range of 2.9-56.6 ms. Myocardial siderosis was detected in 44% of patients; 25 patients had moderate and severe siderosis with serum ferritin level (SFL) of 576-10,284 ng/ml. There was a significant correlation between SFL and cardiac T2* (p<.001).

CONCLUSIONS

The effective role of MRI as a noninvasive producible method in measurement of iron concentration in tissues is not accessible with conventional techniques.

On improvement in ejection fraction with iron chelation in thalassemia major and the risk of future heart failure

BACKGROUND

Trials of iron chelator regimens have increased the treatment options for cardiac siderosis in beta-thalassemia major (TM) patients. Treatment effects with improved left ventricular (LV) ejection fraction (EF) have been observed in patients without overt heart failure, but it is unclear whether these changes are clinically meaningful.

METHODS

This retrospective study of a UK database of TM patients modelled the change in EF between serial scans measured by cardiovascular magnetic resonance (CMR) to the relative risk (RR) of future development of heart failure over 1 year. Patients were divided into 2 strata by baseline LVEF of 56-62% (below normal for TM) and 63-70% (lower half of the normal range for TM).

RESULTS

A total of 315 patients with 754 CMR scans were analyzed. A 1% absolute increase in EF from baseline was associated with a statistically significant reduction in the risk of future development of heart failure for both the lower EF stratum (EF 56-62%, RR 0.818, p < 0.001) and the higher EF stratum (EF 63-70%, RR 0.893 p = 0.001).

CONCLUSION

These data show that during treatment with iron chelators for cardiac siderosis, small increases in LVEF in TM patients are associated with a significantly reduced risk of the development of heart failure. Thus the iron chelator induced improvements in LVEF of 2.6% to 3.1% that have been observed in randomized controlled trials, are associated with risk reductions of 25.5% to 46.4% for the development of heart failure over 12 months, which is clinically meaningful. In cardiac iron overload, heart mitochondrial dysfunction and its relief by iron chelation may underlie the changes in LV function.

Rapid iron loading in heart and liver in a patient with transfusion dependent thalassaemia after brief poor compliance with iron chelation therapy

Iron loading in patients with transfusion dependent thalassaemia is considered to occur primarily in the liver and, once the liver becomes saturated, other organs begin loading. We report here a splenectomised male patient who was treated for hepatitis C virus infection. Prior to starting antiviral therapy, his serum ferritin was maintained below 500 ng/ml with deferiprone monotherapy; cardiac T2* by magnetic resonance imaging was 48.8ms and hepatic T2* was 19.5ms. After twelve months of antiviral treatment during which time he was very poorly compliant with his deferoxamine chelation therapy, his ferritin had risen to 3820 ng/ml and cardiac and hepatic T2* findings were 12.7 ms and 14.5 ms respectively, indicating increased iron loading in both organs, but particularly in the heart. Fifteen months after recommencing combination chelation, his ferritin was 95 ng/ml and cardiac and hepatic T2* were 27.5 and 28.4ms respectively, indicating complete clearance of iron load in both organs. This case demonstrates that iron overload can develop rapidly and in some cases there is relatively rapid iron loading in the heart as compared to the liver.

Evaluation of cardiac iron load by cardiac magnetic resonance in thalassemia

OBJECTIVE

To quantify myocardial iron stores by Cardiac Magnetic Resonance (CMR).

DESIGN

Prospective cohort study.

SETTING

Thalassemia center in a teaching hospital.

PARTICIPANTS

60 transfusion dependant thalassemia major patients and 10 controls during 2008-2009.

METHODS

MRI T2* for cardiac iron load and cardiac functions was performed on a 1.5 Tesla Siemens Sonata machine using the thalassemia tools software. Ejection fraction (EF) was measured using standard CMR sequence and EF <56% considered as cardiac dysfunction. Quantification of iron deposition was categorized as T2* <10 milliseconds (ms) as high risk, 10-20 ms as intermediate risk and >20 ms as low risk. Simultaneous liver iron T2* values were categorized into normal i.e. >6.3 ms, mild iron overload 6.3-2.7 ms , moderate iron overload 2.7- 1.4 ms and severe iron overload <1.4 ms. Pretransfusion serum ferritin levels were simultaneously determined. Data was analyzed by paired and unpaired t test of mean.

RESULTS

Of 60 patients, 50% had no cardiac siderosis; 33.3% had mild to moderate and while 16.7% had severe cardiac siderosis . In contrast, only 8.3% had normal liver iron values, 55.7% had mild to moderate and 36% had severe iron stores. The mean serum ferritin of all 60 cases was 3528.6 ± 1958.6 ng/mL. There was a statistically significant difference in the mean cardiac T2* of patients (23.45 ± 13.4 ms) as compared to controls (32.67 ± 2.68 ms) (P<0.01).

CONCLUSIONS

Thalassemia patients had significantly higher cardiac iron stores as compared to controls. Serum ferritin and liver iron values did not correlate with cardiac iron values. Three of 10 patients <10 years showed evidence of myocardial siderosis.

Deferasirox (Exjade) significantly improves cardiac T2* in heavily iron-overloaded patients with beta-thalassemia major

Noninvasive measurement of tissue iron levels can be assessed using T2* magnetic resonance imaging (MRI) to identify and monitor patients with iron overload. This study monitored cardiac siderosis using T2* MRI in a cohort of 19 heavily iron-overloaded patients with β-thalassemia major receiving iron chelation therapy with deferasirox over an 18-month period. Overall, deferasirox therapy significantly improved mean ± standard deviation cardiac T2* from a baseline of 17.2 ± 10.8 to 21.5 ± 12.8 ms (+25.0%; P = 0.02). A concomitant reduction in median serum ferritin from a baseline of 5,497 to 4,235 ng/mL (−23.0%; P = 0.001), and mean liver iron concentration from 24.2 ± 9.0 to 17.6 ± 12.9 mg Fe/g dry weight (−27.1%; P = 0.01) was also seen. Improvements were seen in patients with various degrees of cardiac siderosis, including those patients with a baseline cardiac T2* of <10 ms, indicative of high cardiac iron burden. These findings therefore support previous observations that deferasirox is effective in the removal of myocardial iron with concomitant reduction in total body iron.