Pancreatic iron stores assessed by magnetic resonance imaging (MRI) in beta thalassemic patients

Quantitative Magnetic Resonance Imaging for the Pancreas: Current Status

ABSTRACT

Magnetic resonance imaging (MRI) is important for evaluating pancreatic disorders, and anatomical landmarks play a major role in the interpretation of results. Quantitative MRI is an effective diagnostic modality for various pathologic conditions, as it allows the investigation of various physical parameters. Recent advancements in quantitative MRI techniques have significantly improved the accuracy of pancreatic MRI. Consequently, this method has become an essential tool for the diagnosis, treatment, and monitoring of pancreatic diseases. This comprehensive review article presents the currently available evidence on the clinical utility of quantitative MRI of the pancreas.

Serum Ferritin Levels and Other Associated Parameters with Diabetes Mellitus in Adult Patients Suffering from Beta Thalassemia Major

Background

Although beta thalassemia major (BTM) patients are properly treated with blood transfusions in accompany with iron chelation therapy, they suffer from complications, such as diabetes mellitus (DM).

Purpose

The purpose was to detect the critical serum ferritin level and other parameters correlated with DM among adult BTM patients. Also, it was to study whether each of these parameters is associated with a certain period of age.

Patients and Methods

This study included 200 adult BTM patients. A cross-sectional study was carried out. Patients clinical and laboratory variables, such as ferritin levels, and fasting blood glucose (FBS) were extracted from medical records at Zagazig University Hospital, Egypt. Liver and cardiac iron contents were assessed using MRI T2* methods. Statistical analysis was performed using IBM SPSS V26.0 software package.

Results

The overall frequency of DM over the total sample equals 6.5%. There were no impaired fasting glucose (IFG) in the medical records. Statistical significance between serum ferritin and DM was (P = 0.014). The serum ferritin 2500 ng/mL with age group (27-<32) years-old were risk factors. The distributions of DM according to BMI were (3.5%) of class overweight. Significant association between DM and BMI was (r = 0.357, P < 0.001). Liver MRI T2* has significant correlation with serum ferritin, but cardiac MRI T2* was poorly correlated. Association between liver and cardiac MRI T2* was not found.

Conclusion

Age group (27-<32) years-old and ferritin >2500 ng/mL should be properly treated immediately. The serum ferritin and BMI of class "overweight" were risk factors for DM. Factors such as diet should be followed. Serum ferritin can be used for estimating liver iron content for economic factors. But cardiac MRI T2* must be performed for evaluating cardiac iron accurately.

Cardiac iron overload evaluation in thalassaemic patients using T2* magnetic resonance imaging following chelation therapy: a multicentre cross-sectional study

INTRODUCTION

Magnetic resonance imaging (MRI) T2* technique is used to assess iron overload in the heart, liver and pancreas of thalassaemic patients. Optimal iron chelation and expected tissue iron response rates remain under investigation. The objective of this study was to analyse serum ferritin and the iron concentration in the heart, liver and pancreas measured by MRI T2*/R2* during regular chelation therapy in a real-world cohort of patients with thalassemia.

METHODS

We evaluated thalassaemic patients ≥ 7 years old undergoing chelation/transfusion therapy by MRI and assessed serum ferritin at baseline and follow-up from 2004-2011.

RESULTS

We evaluated 136 patients, 92% major thalassaemic, with a median age of 18 years, and median baseline ferritin 2.033ng/ml (range: 59-14,123). Iron overload distribution was: liver (99%), pancreas (74%) and heart (36%). After a median of 1.2 years of follow-up, the iron overload in the myocardium reduced from 2,63 Fe mg/g to 2,05 (p 0.003). The optimal R2* pancreas cut-off was 148 Hertz, achieving 78% sensitivity and 73% specificity. However, when combining the R2* pancreas cut off ≤ 50 Hertz and a ferritin ≤ 1222 ng/ml, we could reach a negative predictive value (NPV) of 98% for cardiac siderosis. Only 28% were undergoing combined chelation at baseline assessment, which increased up to 50% on follow up evaluation.

CONCLUSIONS

Chelation therapy significantly reduced cardiac siderosis in thalassaemic patients. In patients with moderate/severe liver iron concentration undergoing chelation therapy, ferritin levels and myocardium iron improved earlier than the liver siderosis.

Quantitative abdominal magnetic resonance imaging in children-special considerations

The use of quantitative MRI methods for assessment of the abdomen in children has become commonplace over the past decade. Increasingly employed methods include MR elastography, chemical shift encoded (CSE) MR imaging for determination of proton density fat fraction, diffusion-weighted imaging, and a variety of relaxometry techniques, such as T1 and T2* mapping. These techniques can be used in a variety of settings to distinguish normal from abnormal tissue as well as determine the severity of disease. The performance of quantitative MRI methods in the pediatric population presents unique challenges as compared to adult populations. These challenges relate to multiple factors, including patient size, pediatric physiology, inability to breath hold, and greater physical motion during the examination. The purpose of this review article is to review quantitative MRI methods that may be used in clinical practice to assess the pediatric abdomen and to discuss special considerations when performing these techniques in children.

Indicators of glucose dysregulation and the relationship with iron overload in Chinese children with beta thalassemia major

INTRODUCTION

Patients with beta thalassemia major (TM) have a higher risk of diabetes and an abnormal oral glucose tolerance test (OGTT), but there is no single agree monitoring parameter that reflects glycemic status. The possible mechanisms include iron overload and blood transfusion, but they require further investigation.

PURPOSE

This study explored the role of glycated hemoglobin A1c (HbA1c), fructosamine, and glycated albumin (GA) in evaluating the glucose dysregulation and to determine the potential relationship between iron deposition and glucose metabolism disorder in beta TM.

METHODS

A cross-sectional study was performed on 118 patients with beta TM and the control group consisted of 33 healthy children with no statistical differences in age, sex, and body mass index (BMI). Fast plasma glucose (FPG), fast insulin (FINS), insulin resistance index (HOMA-IRI), and insulin sensitivity index (HOMA-ISI) were compared between the patient and control groups. HbA1c, GA, fructosamine, and serum ferritin (SF) were measured in the patient group. OGTT, as well as heart and liver magnetic resonance imaging (MRI) T2*, was performed. For all statistical analyses, SPSS 21.0 was used and p < 0.05 was accepted as statistically significant.

RESULTS

FPG, FINS, and HOMA-IRI were significantly increased while HOMA-ISI decreased in the beta TM patients when compared with those in the control group. In patients with beta TM, 17 (14.41%) of patients had been diagnosed with diabetes, while 48 (40.68%) had both impaired fasting glucose and impaired glucose tolerance. HbA1c, GA, and fructosamine were increased according to the degree of abnormal glucose metabolism. Statistically significant differences were found in age, SF, and cardiac T2* between the abnormal and normal OGTT groups.

CONCLUSION

HbA1c may be used as a significant measure for monitoring glycemic levels in patients with beta TM. Furthermore, GA and fructosamine were alternative indicators of glucose status. Patients with heart iron deposition or an SF > 4000 μg/L were prone to abnormal glucose metabolism, so chelation therapy should be reinforced.

Pancreatic iron quantification with MR imaging: a practical guide

Accurate determination of pancreatic iron status is crucial for preventing impairment of the exocrine and endocrine function of the pancreas and for prospectively stratifying the cardiac iron risk. The following article should be a sort of practical guide for radiologists interested in quantifying pancreatic iron overload by Magnetic Resonance Imaging (MRI). After a brief background on iron-deposition diseases, we will describe basic principles and relative advantages and disadvantages of the more widely used and clinically feasible MRI-based techniques for pancreatic iron assessment. These methods can be classified into signal intensity ratio (SIR) and relaxometry methods. We will examine different technical aspects representing the key for accurate and precise relaxation time measurement.

Pancreatic MR imaging and endocrine complications in patients with beta-thalassemia: a single-center experience

Iron deposition in various organs can cause endocrine complications in patients with transfusion-dependent beta-thalassemia. The aim was to investigate the relationship between endocrine complications and pancreatic iron overload using magnetic resonance imaging (MRI). Forty patients with transfusion-dependent thalassemia (TDT) were enrolled in the study. The magnetic resonance imagings of the patients were performed using a 1.5 Tesla Philips MRI scanner. Two out of three patients had at least one clinical endocrine complication. The rate of iron deposition was 62.5% in liver, and 45% in pancreas tissue, and was 12.5% in heart tissue. Pancreatic T2* and hepatic T2* values were significantly positively correlated (p = 0.006). Pancreatic T2* and ferritin were significantly negatively correlated (p = 0.03). Cardiac T2* values were negatively correlated with fasting blood glucose (p = 0.03). Patients with short stature had significantly higher cardiac iron burden (22.3 vs. 36.6 T2*ms; p 0.01), and patients with hypothyroidism had higher liver iron concentrations (9.9 vs. 6.4 LIC mg/g; p = 0.05). The ferritin level of 841 ng/mL and liver iron concentration (LIC) value of 8.7 mg/g were detected as the threshold level for severe pancreatic iron burden (AUC 70%, p:0.04, AUC 80%, p = 0.002, respectively). Moreover, males were found to have decreased pancreas T2* values compared with the values in females (T2* 19.3 vs. 29.9, p = 0.05). Patients with higher ferritin levels over than 840 ng/mL should be closely monitored for pancreatic iron deposition, and patients with endocrine complications should be assessed in terms of cardiac iron burden.

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.

Endocrinopathies complicating transfusion-dependent hemoglobinopathy

OBJECTIVES

To investigate the prevalence and significance of different endocrinopathies in children and adolescents with transfusion-dependent thalassemia and sickle-cell anemia.

METHODS

This is a descriptive, retrospective study between January 2010 and July 2018 in King Abdulaziz University Hospital, Jeddah, Saudi Arabia. Data was collected through reviewing electronic hospital medical records then filling out data collection sheets and was interpreted through the IBM SPSS Statistics for Windows version 20.0 (IBM Corp, Armonk, NY, USA). Results: The total sample size was 119 patients, gender equality was almost achieved with 55.5% being male and 45.5% being female. The most common endocrinopathies were identified in the following order of short stature (39.5%), diabetes mellitus (29.4%), hypogonadism (12.6%), osteopenia (12.6%), osteoporosis (9.2%), hypothyroidism (9.2%), hypocortisolism (3.4%), and hypoparathyroidism (2.5%). All of which were statistically significant in their relationship to hemoglobinopathies with the exception of osteopenia and osteoporosis. Hypogonadism and hypocortisolism were found to be statistically significant in their relationship to a positive history of splenectomy at p=0.026 and p=0.012. Short stature was found to be statistically significant in its relationship to the male gender with a p=0.001. Conclusion: Endocrinopathy is a frequent complication of hemoglobinopathies, for which the most common were found to be short stature, diabetes mellitus,  and low bone mineral density.

Insulin secretion-sensitivity index-2 could be a novel marker in the identification of the role of pancreatic iron deposition on beta-cell function in thalassemia major

The purpose of this study is to evaluate the impact of insulin secretion-sensitivity index-2 (ISSI-2) in the identification of the role of pancreatic iron deposition on beta-cell function in thalassemia major. Tissue iron stores were measured with magnetic resonance imaging (MRI) in the liver (R2), pancreas (R2*), and heart (T2*). ISSI-2 was assessed as a novel oral glucose tolerance test-based measure of beta-cell function. Also, the Stumvoll index showing the insulin sensitivity and Stumvoll index estimating first and second phase insulin secretion were calculated. Fourteen of the 51 Thalassemia Major patients, aged 8-34 (mean 21.1 ± 7.2) years-old, had either an impaired glucose tolerance test (n = 9, 17.6%) or diabetes mellitus (n = 5, 9.8%)-referred to as the glucose dysregulation (GD) group. The median serum ferritin and the mean liver R2 and cardiac T2* values were not significantly different between the GD and normal glucose tolerance (NGT, n = 37) groups whereas pancreas R2* was significantly higher in the GD group compared to the NGT group (p = 0.004). Patients with GD showed significantly lower ISSI-2 index (p < 0.001) as well as the Stumvoll index and Stumvoll first and second phase indices compared to those with NGT (p < 0.001). All patients with GD displayed a pancreas R2* >50 Hz and ISSI-2 <2. In conclusion, Pancreas R2* MRI combined with ISSI-2 index may be valuable parameters to identify patients at the highest risk for developing glucose dysregulation.

Glucose dysregulation in patients with iron overload: is there a relationship with quantitative pancreas and liver iron and fat content measured by MRI?

OBJECTIVES

The aim was to investigate the relationship between pancreatic and hepatic iron and fat to glucose metabolism in patients with iron overload and address conflicting results in literature as regards the relationship between pancreas iron and glucose dysregulation.

METHODS

We retrospectively evaluated pancreatic and hepatic R2*, fat fraction (FF), liver iron concentration (LIC), and glucose metabolism in 105 patients with iron overload obtained with a multi-echo gradient echo R2* technique and assessed the correlation between pancreatic R2* and FF to glucose dysregulation.

RESULTS

There were no significant differences in pancreatic R2*, liver R2*, and FF in patients with iron overload and glucose dysregulation compared to those with normoglycemia (p = 0.435, p = 0.674, and p = 0.976), whereas pancreatic FF was significantly higher, 23.5% vs 16.7% respectively (p = 0.011). Pancreatic FF and R2* demonstrated an area under the curve of 0.666 and 0.571 for discriminating glucose dysregulation. Pancreatic FF of 26.2% yielded specificity and sensitivity of 80% and 45% for prediction of glucose dysregulation. Pancreatic R2* weakly correlated with pancreatic FF, r = 0.388 (p < 0.001), and liver R2*, r = 0.201 (p = 0.033), and showed no correlation with hepatic FF r = -0.013 (p = 0.892) or LIC categories (p = 0.493).

CONCLUSION

Pancreatic FF but not pancreatic R2* was associated with glucose dysregulation in patients with iron overload. Prior studies reporting correlation of pancreatic R2* to glucose dysregulation likely relate from inadequate MRI technique or analysis employed, which unlike our study did not perform simultaneous measurements of fat and iron essential to avoid their confounding effects during quantitative analysis.

KEY POINTS

• Pancreatic fat fraction, unlike iron, is associated with glucose dysregulation in iron overload. • Simultaneous measurement of pancreatic iron and fat content with MRI is essential to avoid confounding effects of one another during quantitative analysis. • Pancreatic fat fraction could be utilized to predict glucose dysregulation in iron overload states.

Quantitative pancreatic MRI: a pathology-based review

MRI plays an important role in the clinical management of pancreatic disorders and interpretation is reliant on qualitative assessment of anatomy. Conventional sequences capturing pancreatic structure can however be adapted to yield quantitative measures which provide more diagnostic information, with a view to increasing diagnostic accuracy, improving patient stratification, providing robust non-invasive outcome measures for therapeutic trials and ultimately personalizing patient care. In this review, we evaluate the use of established techniques such as secretin-enhanced MR cholangiopancreatography, diffusion-weighted imaging, T ₁, T ₂* and fat fraction mapping, but also more experimental methods such as MR elastography and arterial spin labelling, and their application to the assessment of diffuse pancreatic disease (including chronic, acute and autoimmune pancreatitis/IgG4 disease, metabolic disease and iron deposition disorders) and cystic/solid focal pancreatic masses. Finally, we explore some of the broader challenges to their implementation and future directions in this promising area.

Characterization of thalassemia major and diabetes mellitus patients at a reference center in Brazil

OBJECTIVE

This is a quantitative transversal study that aimed to analyze the sociodemographic and clinical characteristics of thalassemia major patients with and without diabetes mellitus.

METHOD

The cohort consisted of 31 thalassemia major patients from a reference center of treatment in Brazil in 2016. The data were obtained from an interview using a questionnaire containing demographic and clinical variables. The results show that 16.1% of the participants with thalassemia major had diabetes mellitus. The participants' ages ranged from 20 to 48 years, with an average of 35 years, mostly students and starting in the formal job market. The most commonly used treatment was the oral desferasirox and the transfusion treatment interval was 15-22 days.

RESULTS

Patients with thalassemia major and diabetes mellitus presented altered values of fasting glycemia, serum alanine transaminase, magnetic resonance imaging and bone densitometry.

CONCLUSION

It was concluded that knowledge of the characteristics of this population contributes in the proposal of effective educational strategies in light of the complexity of care and the progression of the disease.

Prevalence of abnormal glucose homeostasis in Chinese patients with non-transfusion-dependent thalassemia

Purpose: To determine the prevalence and underlying pathology of abnormal glucose homeostasis in Chinese patients with non-transfusion-dependent thalassemia (NTDT). Patients and methods: In this study, we enrolled 211 patients aged 4-63 years with NTDT, including 79 β thalassemia intermedia patients, 114 Hb H disease patients and 18 Hb E/β thalassemia patients. All had oral glucose tolerance test, serum ferritin (SF), homeostasis model assessment (HOMA) and liver iron concentration (LIC) measurement. One hundred and twenty healthy age-matched controls were also used for the comparative purpose. Iron load was assessed by using SF and hepatic load by LIC using validated MRI techniques. Results: The 211 patients were divided into three groups according to their fasting and 2 hrs postprandial blood glucose levels: hypoglycemic, normal glucose tolerance (NGT) and hyperglycemic groups. In this study, 149 patients had NGT, 33 had hypoglycemia, 4 had diabetes and 25 had impaired glucose tolerance (IGT). None had impaired fasting glucose. There was a significant correlation between 2 hrs postprandial blood glucose levels and age, PINS120, HOMA-IR, alanine aminotransferase and LIC (P<0.05). Risk factors for IGT in NTDT patients were older age (≥24 years) and SF concentration of ≥2,500 ng/mL. Conclusion: Age ≥24 years and SF ≥2,500 ng/mL of NTDT patients were at a greater risk for impaired glucose tolerance.

Decrement in Cellular Iron and Reactive Oxygen Species, and Improvement of Insulin Secretion in a Pancreatic Cell Line Using Green Tea Extract

OBJECTIVES

We have investigated the efficacy of mono- and combined therapy with green tea extract (GTE) in mobilizing redox iron, scavenging reactive oxygen species (ROS), and improving insulin production in iron-loaded pancreatic cells.

METHODS

Rat insulinoma pancreatic β-cells were iron-loaded using culture medium supplemented with either fetal bovine serum or ferric ammonium citrate and treated with various doses of GTE for epigallocatechin-3-gallate (EGCG) equivalence and in combination with iron chelators. Cellular iron, ROS, and secretory insulin were measured.

RESULTS

The rat insulinoma pancreatic cells took up iron from fetal bovine serum more rapidly than ferric ammonium citrate. After treatment with GTE (0.23-2.29 μg EGCG equivalent), cellular levels of iron and ROS were dose dependently decreased. Importantly, secretory insulin levels were increased nearly 2.5-fold with 2.29 μg of EGCG equivalent GTE, indicating a recovery in insulin production.

CONCLUSIONS

Green tea EGCG ameliorated oxidative damage of iron-loaded β-cells by removing redox iron and free radicals and attenuating insulin production. The impact can result in the restoration of pancreatic functions and an increase in insulin production. Green tea extract exerts iron-chelating, free-radical scavenging, and pancreato-protective effects in the restoration of β-cell functions, all of which we believe can increase insulin production in diabetic β-thalassemia patients.

Multicenter validation of the magnetic resonance T2* technique for quantification of pancreatic iron

OBJECTIVES

To assess the transferability of the magnetic resonance imaging (MRI) multislice multiecho T2* technique for pancreatic iron overload assessment.

METHODS

Multiecho T2* sequences were installed on ten 1.5-T MRI scanners of the three main vendors. Five healthy subjects (n = 50) were scanned at each site. Five patients with thalassemia (n = 45) were scanned locally at each site and were rescanned at the reference site within 1 month. T2* images were analyzed using a previously validated software and the global pancreatic T2* value was calculated as the mean of T2* values over the head, body, and tail.

RESULTS

T2* values of healthy subjects were above 26 ms and showed inter-site homogeneity. The T2* values measured in the MRI sites were comparable to the correspondent values observed in the reference site (12.02 ± 10.20 ms vs 11.98 ± 10.47 ms; p = 0.808), and the correlation coefficient was 0.978 (p < 0.0001). Coefficients of variation (CoVs) ranged from 4.22 to 9.77%, and the CoV for all the T2* values independently from the sites was 8.55%. The intraclass correlation coefficient (ICC) for each MRI site was always excellent and the global ICC was 0.995, independently from the sites. The mean absolute difference in patients with pancreatic iron (n = 39) was -0.15 ± 1.38 ms.

CONCLUSION

The gradient-echo T2* MRI technique is an accurate and reproducible means for the quantification of pancreatic iron and may be transferred among MRI scanners by different vendors in several centers.

KEY POINTS

• The gradient-echo T2* MRI technique is an accurate and reproducible means for the quantification of pancreatic iron. • The gradient-echo T2* MRI technique for the quantification of pancreatic iron may be transferred among MRI scanners by different vendors in several centers. • Pancreatic iron might serve as an early predictor of cardiac siderosis and is the strongest overall predictor of glucose dysregulation.

Green tea extract modulates oxidative tissue injury in beta-thalassemic mice by chelation of redox iron and inhibition of lipid peroxidation

Iron overload in patients with β-thalassemia can cause oxidative organ dysfunction. Iron chelation along with antioxidant supplementation can ameliorate such complications and prolong lives. Green tea extract (GTE) rich in epigallocatechin-3-gallate (EGCG) exhibits anti-oxidation and iron chelation properties in β-knockout thalassemic (BKO) mice diagnosed with iron overload. We investigated the effects of GTE and deferiprone (DFP) alone in combination with one another, and upon the levels of redox-active iron, lipid-peroxidation product, insulin and hepcidin in BKO mice. A state of iron overload was induced in the mice via a trimethylhexanoyl-ferrocene supplemented (Fe) diet for 3 months, and the mice were treated daily with either: DFP (50 mg/kg), DFP (50 mg/kg) plus GTE (50 mg EGCG equivalent/kg), or GTE alone for 2 months. Plasma non-transferrin bound iron (NTBI), malondialdehyde (MDA), alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepcidin and insulin; tissue iron and MDA were measured. DFP, GTE and GTE + DFP effectively decreased plasma MDA (p < 0.05), NTBI and ALT, and increased plasma hepcidin and insulin. All the treatments also reduced iron accumulation and MDA production in both the pancreas and liver in the mice. However, the combination therapy demonstrated no advantages over monotherapy. The findings suggest GTE improved liver and pancreatic β-cell functions in iron-overloaded β-thalassemia mice by diminishing redox iron and free radicals, while inhibiting lipid peroxidation. Consequently, there are indications that GTE holds significant potential for clinical use.

Estimation of pancreatic R2* for iron overload assessment in the presence of fat: a comparison of different approaches

OBJECTIVES

To propose a method for estimating pancreatic relaxation rate, R2*, from conventional multi-echo MRI, based on the nonlinear fitting of the acquired magnitude signal decay to MR signal models that take into account both the signal oscillations induced by fat and the different R2* values of pancreatic parenchyma and fat.

MATERIALS AND METHODS

Single-peak fat (SPF) and multi-peak fat (MPF) models were introduced. Single-R2* and dual-R2* assumptions were considered as well. Analyses were conducted on simulated data and 20 thalassemia major patients.

RESULTS

Simulations revealed the ability of the MPF model to correctly estimate the R2* value in a large range of fat fractions and R2* values. From the comparison between the results obtained with a single R2* value for water and fat and the dual-R2* approach, the latter is more accurate in both water R2* and fat fraction estimation. In patient's data analysis, a strong concordance was found between SPF and MPF estimated data with measurements done with manual signal correction and from fat-saturated images. The MPF method showed better reproducibility.

CONCLUSION

The MPF dual-R2* approach improves reproducibility and reduces image analysis time in the assessment of pancreatic R2* value in patients with iron overload.

MRI for the measurement of liver iron content, and for the diagnosis and follow-up of iron overload disorders

MRI is now the reference method for detecting and quantifying hepatic and extrahepatic iron overload, regardless of its cause. The decrease of the hepatic signal is proportional to the amount of iron in the tissues. It is more pronounced with T2*-weighted gradient echo sequences. It increases proportionally with the strength of the magnetic field. Thus a 3-T MRI is be more sensitive and probably more accurate to detect a slight iron overload, as seen in dysmetabolic hepatosiderosis. Conversely, a 1.5-T MRI better estimates a high overload. Quantification can be done with the calculation of T2* (or R2*) or by using the liver to muscle signal intensity ratio (SIR). Today with a single multi-echo gradient-echo sequence, obtained in a unique apnea, the two methods can be used simultaneously. An associated quantification of steatosis is also obtained. This same type of sequence is proposed for quantification of iron in other tissues and in particular for the myocardium.

Correlation of Pancreatic Iron Overload Measured by T2*-Weighted Magnetic Resonance Imaging in Diabetic Patients with β-Thalassemia Major

Diabetes mellitus (DM) is one of the potential complications in patients with transfusion-dependent β-thalassemia major (β-TM). In this case-controlled study, we examined the pancreatic iron levels in outpatients with β-TM. In this study, cases of patients with β-TM and DM were gender- and age-matched with control subjects, who were non-diabetic and had normal blood glucose on standard oral glucose tolerance (OGTT) tests. One of four diagnoses [normal, pre-diabetes, impaired glucose tolerance (IGT), DM] was made according to the American Diabetes Association (ADA) criteria. The T2*-weighted magnetic resonance imaging (T2*-weighted MRI) of the heart, liver, and pancreas was performed using a 1.5 Tesla scanner. The study enrolled 26 diabetic cases, 17 non-diabetic cases, and eight cases of IGT or pre-diabetes cases. The severity of pancreatic and cardiac iron siderosis was significantly different between the groups. We found a statistically significant difference at 5.6 ms in the T2*-weighted MRI values for the pancreas between patients with normal vs. abnormal glucose metabolism [p < 0.009; odds ratio (OR): 11.2; 95% confidence interval (95% CI): 1.32-94.4)]. The receiver operating characteristic (ROC) curve for the 5.6 ms cutoff led to an area under the curve (AUC) of 0.69 (95% CI: 55.0-84.0; p < 0.02), with sensitivity and specificity of 94.0 and 42.0%, respectively. There was a moderate positive correlation between pancreatic and cardiac T2*-weighted MRI (r = 0.4; p < 0.001), and a weak correlation between the pancreas and the liver (r = 0.38; p < 0.005). To conclude, we have introduced a cutoff of 5.6 ms on T2*-weighted MRI of the pancreas for prediction of abnormal glucose metabolism in β-TM patients.

Diabetes Mellitus in Thalassaemia Major Patients: A Report from the Southeast of Iran

INTRODUCTION

Diabetes Mellitus (DM) represents a major concern in Thalassaemia Major (TM) patients.

AIM

The present study was conducted to evaluate the frequency of Impaired Fasting Glucose (IFG) and DM in TM patients in Southeast of Iran.

MATERIALS AND METHODS

Fasting Blood Glucose (FBS) was determined using fasting blood samples in 148 TM patients. Demographical data was collected by a questionnaire. Clinical and laboratory variables including cell blood counts, pre-transfusion Haemoglobin (Hb) level, and five-year ferritin were extracted from medical records. Statistical analysis was performed in SPSS19.0 software using chi-square, student t-test and logistic regression.

RESULTS

Females and males comprised 83 (56.1%) and 65 (43.9%) subjects respectively. The mean age and mean five-year ferritin were 17.3±6.1 year-old and 5060.6±2395 ng/ml respectively. Overall, 39 (26.4%) patients had IFG, while 13 (8.8%) were diagnosed with DM. Significant differences were identified in the mean age, volume of transfused blood per occasion, and mean five-years ferritin between the patients with IFG or DM and the patients with normal fasting glucose level. Patients with age >25-year-old had an increased risk of both IFG (OR=4.7,95% CI: 1.3-17, p=0.01) and DM (OR= 7.1, 95% CI: 1-49.2, p=0.04). In addition, splenectomized patients showed a higher risk for IFG (OR=4.3, 95% CI: 1.5-12.1, p=0.005), and ferritin value >6000 ng/ml were associated with an elevated risk of DM (OR=7, 95% CI: 0.8-60.1, p=0.07).

CONCLUSION

Our results indicated that higher age, mean five-years ferritin, volume of blood transfused per occasion, as well as splenectomy were risk factors of IFG and DM in TM patients.

T2* Magnetic Resonance Imaging Study of Pancreatic Iron Overload and its Relation With the Diabetic State in Thalassemic Patients

The present study was performed to evaluate pancreatic hemosiderosis by means of magnetic resonance imaging (MRI) T2* and its relation to the diabetic state in thalassemic patients. One hundred thirty transfusion-dependent thalassemic patients from Zafar adult thalassemia clinic, Tehran, Iran, were enrolled in the study. Data such as age, type of thalassemia, age at diagnosis, transfusion duration, ferritin level, and fasting blood sugar results were gathered. Pancreatic MRI T2* was performed for all patients. One hundred four thalassemic patients with no sign of diabetes mellitus and 26 thalassemic patients with diabetes mellitus entered the study. Out of a total of 130 patients, 102 had pancreatic hemosiderosis. Among them, 23 of 26 diabetic patients (88.5%) and 79 of 104 nondiabetic patients (76%) showed pancreatic hemosiderosis, indicating no statistically significant difference between the 2 groups. The mean pancreatic MRI T2* relaxation time for all patients was 13.99±12.43 ms. The mean relaxation was 13.62±8.38 and 14.08±13.28 ms for diabetic and nondiabetic patients, respectively, showing no statistical difference (P=0.202). In conclusion, we did not find a significant difference between diabetic and nondiabetic thalassemic patients regarding the MRI T2* relaxation time readings or the rate of pancreatic hemosiderosis. We recommend performing studies with a higher sample size and including patients from different age groups to further evaluate the role of T2* MRI of pancreatic iron overload and its relation with the diabetic state in thalassemic patients.

R2*-relaxometry of the pancreas in patients with human hemochromatosis protein associated hereditary hemochromatosis

PURPOSE

To evaluate pancreatic iron in patients with human hemochromatosis protein associated hereditary hemochromatosis (HHC) using R2* relaxometry.

MATERIALS AND METHODS

81 patients (58 male, 23 female; median age 49.5, range 10-81 years) with HHC were retrospectively studied. All underwent 1.5T magnetic resonance imaging (MRI) of the abdomen. A fat-saturated multi-gradient echo sequence with 12 echoes (TR=200ms; TE-initial 0.99ms; Delta-TE 1.41ms; 12 echoes; flip-angle: 20°) was used for the R2* quantification of the liver and the pancreas. Parameter maps were analyzed using regions of interest (3 in the liver and 2 in the pancreas) and R2* values were correlated.

RESULTS

59/81 patients had a liver R2*≥70 1/s of which 10/59 patients had a pancreas R2*≥50 1/s. No patient presented with a liver R2*<70 1/s and pancreas R2*≥50 1/s. All patients with pancreas R2* values≥50 1/s had liver R2* values≥70 1/s. ROC analysis resulted in a threshold of 209.4 1/s for liver R2* values to identify HFE positive patients with pancreas R2* values≥50 1/s with a median specificity of 78.87% and a median sensitivity of 90%.

CONCLUSION

In patients with HHC R2* relaxometry of the pancreas should be performed when liver iron overload is present and can be omitted in cases with no sign of hepatic iron.

The ICET-A Recommendations for the Diagnosis and Management of Disturbances of Glucose Homeostasis in Thalassemia Major Patients

Iron overload in patients with thalassemia major (TM) affects glucose regulation and is mediated by several mechanisms. The pathogenesis of glycaemic abnormalities in TM is complex and multifactorial. It has been predominantly attributed to a combination of reduced insulin secretory capacity and insulin resistance. The exact mechanisms responsible for progression from norm glycaemia to overt diabetes in these patients are still poorly understood but are attributed mainly to insulin deficiency resulting from the toxic effects of iron deposited in the pancreas and insulin resistance. A group of endocrinologists, haematologists and paediatricians, members of the International Network of Clinicians for Endocrinopathies in Thalassemia and Adolescence Medicine (ICET-A) convened to formulate recommendations for the diagnosis and management of abnormalities of glucose homeostasis in thalassemia major patients on the basis of available evidence from clinical and laboratory data and consensus practice. The results of their work and discussions are described in this article.

Pregnancy in women with thalassemia: challenges and solutions

Advances in treatment of thalassemia have led to the aging of thalassemic patients, and consequently concern about successful reproductive outcome is augmented. Although women with thalassemia intermedia only were considered competent of achieving pregnancy, case series reveal the willingness of both thalassemia major and thalassemia intermedia women to have a family. Pregnancy in general is characterized by dynamic multiple-system changes and increased susceptibility to oxidative stress, while homozygous, transfusion-dependent, β-thalassemia patients manifest cardiac, hepatic, endocrine, and metabolic disorders attributable to chronic anoxia and iron overload and thalassemia intermedia, usually nontransfused, is associated with augmented risk of thromboembolic events. Pregnancy in thalassemia should be considered a high risk for both mother and fetus, and favorable outcomes are the result of continuous preconception, antenatal, and postpartum assessment and management by a team of thalassemia experts.

Accurate estimate of pancreatic T2* values: how to deal with fat infiltration

PURPOSE

We examined different approaches aimed to deal with the signal fluctuation of pancreatic T2* values due to fat infiltration in order to obtain accurate estimates of iron overload.

METHODS

Pancreatic T2* values were assessed in 20 patients (13 females, 37.24 ± 9.12 years) enrolled in the Myocardial Iron Overload in Thalassemia network without and with the application of fat suppression-FS (T2*-NoFS and T2*-FS). T2* values were assessed in three different ways: (1) from the immediate fit (original T2*); (2) discarding the echoes until the achievement of a good visual concordance between the signal and the model (final_vis T2*); (3) eliminating the echoes until the achievement of a fitting error (known) <5% (final_thres T2*).

RESULTS

For the T2*-NoFS sequence the original T2* values were significantly higher than the final_vis T2* values (difference:4.8 ± 6.1 ms; P < 0.0001) and the final_thres T2* values (difference:4.3 ± 6.1 ms; P = 0.006). For the T2*-FS sequence the original T2* values were comparable to final_vis and final_thres T2* values. The original T2*-FS values were significantly different from the original T2*-NoFS values. The final_vis T2*-FS values were comparable to the final_vis T2*-NoFS values and the final_thresh T2*-FS values were comparable to the final_thresh T2*-NoFS values. For both T2*-FS and T2*-NoFS sequences, the final_thres T2* values were not significantly different from the final_vis T2* values and no bias was present.

CONCLUSIONS

In the clinical practice, an accurate pancreatic iron overload assessment should be done by applying FS and, when needed, by discarding the TEs until the fitting error goes below 5%.

Zinc status affects glucose homeostasis and insulin secretion in patients with thalassemia

Up to 20% of adult patients with Thalassemia major (Thal) live with diabetes, while 30% may be zinc deficient. The objective of this study was to explore the relationship between zinc status, impaired glucose tolerance and insulin sensitivity in Thal patients. Charts from thirty subjects (16 male, 27.8 ± 9.1 years) with Thal were reviewed. Patients with low serum zinc had significantly lower fasting insulin, insulinogenic and oral disposition indexes (all p < 0.05) and elevated glucose response curve, following a standard 75 g oral load of glucose compared to those with normal serum zinc after controlling for baseline (group × time interaction p = 0.048). Longitudinal data in five patients with a decline in serum zinc over a two year follow up period (−19.0 ± 9.6 μg/dL), showed consistent increases in fasting glucose (3.6 ± 3.2 mg/dL) and insulin to glucose ratios at 120 min post glucose dose (p = 0.05). Taken together, these data suggest that the frequently present zinc deficiency in Thal patients is associated with decreased insulin secretion and reduced glucose disposal. Future zinc trials will require modeling of oral glucose tolerance test data and not simply measurement of static indices in order to understand the complexities of pancreatic function in the Thal patient.

Endocrine and bone complications in β-thalassemia intermedia: current understanding and treatment

Thalassemia intermedia (TI), also known as nontransfusion dependent thalassemia (NTDT), is a type of thalassemia where affected patients do not require lifelong regular transfusions for survival but may require occasional or even frequent transfusions in certain clinical settings and for defined periods of time. NTDT encompasses three distinct clinical forms: β-thalassemia intermedia (β-TI), Hb E/β-thalassemia, and α-thalassemia intermedia (Hb H disease). Over the past decade, our understanding of the molecular features, pathophysiology, and complications of NTDT particularly β-TI has increased tremendously but data on optimal treatment of disease and its various complications are still lacking. In this paper, we shall review a group of commonly encountered complications in β-TI, mainly endocrine and bone complications.

Accuracy of magnetic resonance imaging in diagnosis of liver iron overload: a systematic review and meta-analysis

BACKGROUND & AIMS

Guidelines advocate use of magnetic resonance imaging (MRI) to estimate concentrations of iron in liver, to identify patients with iron overload, and to guide titration of chelation therapy. However, this recommendation was not based on a systematic synthesis and analysis of the evidence for MRI's diagnostic accuracy.

METHODS

We conducted a systematic review and meta-analysis to investigate the diagnostic accuracy of MRI in identifying liver iron overload in patients with hereditary hemochromatosis, hemoglobinopathy, or myelodysplastic syndrome; liver biopsy analysis was used as the reference standard. We searched MEDLINE and EMBASE databases, the Cochrane Library, and gray literature, and computed summary receiver operating curves by fitting hierarchical models. We assessed methodologic quality using the Quality Assessment of Diagnostic Accuracy Studies 2 tool.

RESULTS

Our final analysis included 20 studies (819 patients, total). Sensitivity and specificity values varied greatly, ranging from 0.00 to 1.00 and from 0.50 to 1.00, respectively. Because of substantial heterogeneity and variable positivity thresholds, we calculated only summary receiver operating curves (and summary estimate points for studies that used the same MRI sequences). T2 spin echo and T2* gradient-recalled echo MRI sequences accurately identified patients without liver iron overload (liver iron concentration > 7 mg Fe/g dry liver weight) (negative likelihood ratios, 0.10 and 0.05 respectively). However, these MRI sequences are less accurate in establishing a definite diagnosis of liver iron overload (positive likelihood ratio, 8.85 and 4.86, respectively).

CONCLUSIONS

Based on a meta-analysis, measurements of liver iron concentration by MRI may be accurate enough to rule out iron overload, but not to definitely identify patients with this condition. Most studies did not use explicit and prespecified MRI thresholds for iron overload, therefore some patients may have been diagnosed inaccurately with this condition. More studies are needed of standardized MRI protocols and to determine the effects of MRI surveillance on the development of chronic liver disease and patient survival.

The Role of Magnetic Resonance Imaging in the Evaluation of Thalassemic Syndromes: Current Practice and Future Perspectives

Iron can be deposited in all internal organs, leading to different types of functional abnormalities. However, myocardial iron overload that contributes to heart failure remains one of the main causes of death in thalassemia major. Using magnetic resonance imaging, tissue iron is detected indirectly by the effects on relaxation times of ferritin and hemosiderin iron interacting with hydrogen nuclei. The presence of iron in the human body results in marked alterations of tissue relaxation times. Currently, cardiovascular magnetic resonance using T2* is routinely used in many countries to identify patients with myocardial iron loading and guide chelation therapy, specifically tailored to the heart. Myocardial T2* is the only clinically validated non-invasive measure of myocardial iron loading and is superior to surrogates such as serum ferritin, liver iron, ventricular ejection fraction and tissue Doppler parameters. Finally, the substantial amelioration of patients’ survival, allows the detection of other organs’ abnormalities due to iron overload, apart from the heart, missed in the past. Recent studies revealed that iron deposition has a different pattern in various parenchymal organs, which is independent from serum ferritin and follows an individual way after chelation treatment application. This new upcoming reality orders a closer monitoring of all organs of the body in order to detect preclinical lesions and early apply adequate treatment.

Pancreatic iron and fat assessment by MRI-R2* in patients with iron overload diseases

BACKGROUND

To determine the pancreatic iron (R2*) and fat content (FC) in comparison to hepatic and cardiac R2* in patients with iron overload disorders like β-thalassemia major (TM), Diamond-Blackfan anemia (DBA) or hereditary hemochromatosis.

METHODS

R2* rates were assessed in the liver, heart and pancreas of 42 patients with TM, 29 subjects with other iron overload diseases, and 10 controls using an ECG-gated breathhold sequence (12 echo time [TE] = 1.3-25.7 ms, readout repetition time [TR] = 244 ms). Pancreatic R2* and FC were assessed from TE dependent region of interest based signal intensities performing water-fat chemical shift relaxometry and were compared with laboratory parameters (glucose, HbA1c, amylase and lipase).

RESULTS

A pancreatic iron gradient from tail (R2* = 122 s(-1) ) to head (R2* = 114 s(-1) , P < 10(-4) ) was found. The close association between cardiac and pancreatic R2* was also confirmed in patients with TM and other iron overload diseases (rs  = 0.64, P < 10(-4) ). Receiver operator characteristic analysis (area: 0.89, P < 10(-4) ) identified patients with elevated cardiac iron at a pancreatic R2* cut-off level of 131s(-1) (sensitivity = specificity at 81%). Highest pancreatic R2* (211s(-1) ) and FC (36%) were found in the tail region of diabetic patients with TM.

CONCLUSION

Pancreatic tail showed highest R2* rates and fat contents, especially in patients with thalassemia. Besides iron accumulation fatty degeneration might be an additional risk factor for the development of diabetes in β-thalassemia major, but this hypothesis needs further studies in prediabetic patients.

Brazilian Thalassemia Association protocol for iron chelation therapy in patients under regular transfusion

In the absence of an iron chelating agent, patients with beta-thalassemia on regular transfusions present complications of transfusion-related iron overload. Without iron chelation therapy, heart disease is the major cause of death; however, hepatic and endocrine complications also occur. Currently there are three iron chelating agents available for continuous use in patients with thalassemia on regular transfusions (desferrioxamine, deferiprone, and deferasirox) providing good results in reducing cardiac, hepatic and endocrine toxicity. These practice guidelines, prepared by the Scientific Committee of Associação Brasileira de Thalassemia (ABRASTA), presents a review of the literature regarding iron overload assessment (by imaging and laboratory exams) and the role of T2* magnetic resonance imaging (MRI) to control iron overload and iron chelation therapy, with evidence-based recommendations for each clinical situation. Based on this review, the authors propose an iron chelation protocol for patients with thalassemia under regular transfusions.

Diabetes mellitus in patients with thalassemia major

BACKGROUND

Diabetes mellitus is a major endocrinopathy for patients with thalassemia major. Although diabetes mellitus is multifactorial, iron loading is its primary cause and its management poses a clinical challenge. Detecting the pre-diabetes stage is critical because clinical diabetes can potentially be reversed or prevented.

PROCEDURE

Patients with thalassemia major who received regular blood transfusion therapy from 1994 to 2010 were evaluated for the incidence of diabetes mellitus and glucose dysregulation. The association between patients' clinical, biochemical, and image parameters was also evaluated.

RESULTS

The patients with diabetes were significantly older, had higher ferritin levels, a smaller pancreas volume, and lower cardiac T2* magnetic resonance imaging (MRI) values than the patients without diabetes. The pancreas T2* MRI values were higher in the patients without diabetes, but the difference was not statistically significant. The liver iron concentration did not differ between the patients with and without diabetes. The prevalence of hepatitis C infection and hypogonadism was also higher in the patients with diabetes. In the patients without diabetes, the cardiac T2* MRI values were higher in patients with normal fasting glucose levels (P = 0.03), and the homeostasis model assessment of insulin resistance level was associated with hepatitis C infection (P = 0.024, r = 0.32) and hypogonadism (P = 0.034, r = 0.301).

CONCLUSIONS

Fasting glucose and insulin levels were appropriate screening tools for evaluating glucose dysregulation and complemented the MRI findings. The cardiac T2* and pancreas volumes were significant predictors of diabetes.

Iron deposits in the knee joints of a thalassemic patient

The overall prognosis for patients with β-thalassemia has improved considerably during the past decades mainly due to regular blood transfusions, improvements in chelation therapy, and enhanced surveillance with imaging studies examining iron overload and other clinical complications. However, the prolonged survival of these patients leads to the development of other health problems including degenerative diseases such as arthropathies, which require further attention since they have a significant impact on the quality of life. In the current case report, we present a 45-year-old white man with β-thalassemia complaining of non-traumatic pain and restriction in the range of motion of both knees. Magnetic resonance imaging (MRI) revealed a tear in the medial meniscus of the left knee as well as iron deposits in both knees. Histological findings confirmed the presence of hemosiderin in both joints. To our knowledge, this is the first reported case of macroscopically documented iron deposits in the knee joints of a patient with β-thalassemia using MRI.