International reproducibility of single breathhold T2* MR for cardiac and liver iron assessment among five thalassemia centers

Assessment and management of iron overload in β-thalassaemia major patients during the 21st century: a real-life experience from the Italian WEBTHAL project

We conducted a cross-sectional study on 924 β-thalassaemia major patients (mean age 30·1 years) treated at nine Italian centres using the WEBTHAL software, to evaluate real-life application of iron overload assessment and management standards. Serum ferritin <2500 ng/ml was a risk factor for never having liver iron concentration (LIC) measurement, while absence of cardiac disease and siderosis were risk factors for a delay in LIC measurement >2 years. Patients who never had a cardiac MRI (CMR) T2* measurement were <18 years, had iron intake ≤0·4 mg/kg per day, or a serum ferritin <2500 ng/ml. A history of normal CMR T2* was the main risk factor for a delay in subsequent assessment of >2 years. Deferoxamine (22·8%) was more commonly used in patients with Hepatitis C Virus or high serum creatinine. Deferiprone (20·6%) was less commonly prescribed in patients with elevated alanine aminotransferase; while a deferoxamine + deferiprone combination (17·9%) was more commonly used in patients with serum ferritin >2500 ng/ml or CMR T2* <20 ms. Deferasirox (38·3%) was more commonly prescribed in patients <18 years, but less commonly used in those with heart disease or high iron intake. These observations largely echoed guidelines at the time, although some practices are expected to change in light of evolving evidence.

Deferiprone (GPO-L-ONE(®) ) monotherapy reduces iron overload in transfusion-dependent thalassemias: 1-year results from a multicenter prospective, single arm, open label, dose escalating phase III pediatric study (GPO-L-ONE; A001) from Thailand

Accessibility to iron chelators including deferoxamine and deferasirox remains obscured in many developing countries. To provide an alternative, the government pharmaceutical organization of Thailand (GPO) manufactured deferiprone which has similar bioequivalent to the standard product. Seventy-three pediatric patients with severe β thalassemias, age range 3.2-19 years, were recruited to a 1-year multicenter prospective, single arm, open label, dose escalating Phase III study of deferiprone to determine its clinical efficacy and safety. Sixty-four patients (87.6%) completed the study with good compliance (>94%). Average deferiprone dose was 79.1±4.3 mg/kg/day. Overall, mean serum ferritin (SF) levels at 1 year were not significantly changed from baseline. However, 45% of patients (response group) had SF reduced >15% from baseline at 1 year with a median reduction of 1,065 ng ml(-1) . Baseline SF was the major factor that predicts clinical efficacy; patients with baseline SF>3,500 ng ml(-1) had the most significant fall of SF at 1 year. A subgroup analysis by MRI-T2* confirmed that the response group had higher baseline liver iron and deferiprone could significantly reduce liver iron overload and normalize levels of ALT at 1 year. Although, gastrointestinal irritation (20.5%) was the most common drug-related adverse events (AEs) followed by transaminitis (16.4%) and neutropenia (6.8%), all patients were well tolerated. There was no mortality and agranulocytosis found in this trial. Monotherapy of deferiprone with appropriate dose adjustment and monitoring for adverse events appeared to be an effective chelation therapy in some patients with good compliance and acceptable safety profiles.

Cross-talk between available guidelines for the management of patients with beta-thalassemia major

Efforts to optimize the management of patients with β-thalassemia major (TM) continue to expand. Evidence from biomedical research evaluating safe and careful processing measures of blood products, the efficacy and safety of oral iron chelators, and noninvasive techniques for the assessment of iron overload are translated into better patient outcomes. The construction of TM management guidelines facilitated the incorporation of such evidence into practice. However, as several aspects of the management of TM remain controversial or governed by resource availability, a concern regarding potential variations in recommendations made by the different guidelines becomes rational, especially for physicians treating TM patients outside countries where the guidelines were constructed. In this work, we overview currently available guidelines for the management of TM and explore apparent similarities and differences between them. The evaluated guidelines included the Thalassaemia International Federation, US, Canadian, UK, Italian and Australian guidelines. We noted a general consensus for most aspects of management, although some guidelines provided more comprehensive and contemporary recommendations than others. We did not identify differences warranting concern, although minor differences in iron overload assessment strategy and more notable variations in the recommendations for iron chelation therapy were observed.

Automated truncation method for myocardial T2* measurement in thalassemia

PURPOSE

To propose an automated truncation method for myocardial T2* measurement and evaluate this method on a large population of patients with iron loading in the heart and scanned at multiple magnetic resonance imaging (MRI) centers.

MATERIALS AND METHODS

A total of 550 thalassemia patients were scanned at 20 international centers using a variety of MR scanners (Siemens, Philips, or GE). A single mid-ventricular short axis slice was imaged. All patient data were anonymized before the T2* were measured by expert observers using standard techniques. These same datasets were then retrospectively processed using the proposed automated truncation method by another independent observer and the resulting T2* measurements were compared with those of expert readings.

RESULTS

The T2* measurements using the automated method showed good agreement with those measured by expert observers using standard techniques (P = 0.95) with a low coefficient of variation (1.6%).

CONCLUSION

This study demonstrates feasibility and good reproducibility of a new automated truncation method for myocardial T2* measurement. This approach simplifies the overall analysis and can be easily incorporated into T2* analysis software to facilitate further development of a fully automated myocardial tissue iron quantification.

In vivo comparison of myocardial T1 with T2 and T2* in thalassaemia major

PURPOSE

To compare myocardial T1 against T2 and T2* in patients with thalassemia major (TM) for myocardial iron characterization.

MATERIALS AND METHODS

A total of 106 TM patients (29 ± 10 years; 58 males) were studied on a 1.5 Tesla scanner using dedicated T1, T2*, and T2 relaxometry sequences. A single mid-ventricular short axis slice was acquired within a breath-hold.

RESULTS

In patients with myocardial iron overload (T2* < 20 ms; n = 52), there were linear correlations between T2 and T2* (r = 0.82; P = 0.0), and between T1 and T2* (r = 0.83; P = 0.0). In patients with no myocardial iron (n = 54), T2* values were scattered with no significant correlation against T2 or T1. For all patients (n = 106) there was a strong linear correlation (r = 0.93; P = 0.0) between myocardial T1 and T2.

CONCLUSION

In patients with iron overload, myocardial T2 and T1 are correlated with T2*. In patients with low or normal myocardial iron concentration, other factors become dominant in affecting T2* values as shown by scattered T2* data. Myocardial T1 correlates linearly with T2 measurements in all patients suggesting that these two relaxation parameters avoid extrinsic magnetic field inhomogeneity effects and may potentially provide improved myocardial tissue characterization.

Improved MRI R2 * relaxometry of iron-loaded liver with noise correction

Accurate and reproducible MRI R2 * relaxometry for tissue iron quantification is important in managing transfusion-dependent patients. MRI data are often acquired using array coils and reconstructed by the root-sum-square algorithm, and as such, measured signals follow the noncentral chi distribution. In this study, two noise-corrected models were proposed for the liver R2 * quantification: fitting the signal to the first moment and fitting the squared signal to the second moment in the presence of the noncentral chi noise. These two models were compared with the widely implemented offset and truncation models on both simulation and in vivo data. The results demonstrated that the "slow decay component" of the liver R2 * was mainly caused by the noise. The offset model considerably overestimated R2 * values by incorrectly adding a constant to account for the slow decay component. The truncation model generally produced accurate R2 * measurements by only fitting the initial data well above the noise level to remove the major source of errors, but underestimated very high R2 * values due to the sequence limit of obtaining very short echo time images. Both the first and second-moment noise-corrected models constantly produced accurate and precise R2 * measurements by correctly addressing the noise problem.

Molecular diagnosis of hemochromatosis

INTRODUCTION

The discovery of hemochromatosis genes and the availability of molecular-genetic tests considerably modified the knowledge of the disease relative to physiopathology, penetrance, and expression, and had major impact in the diagnostic settings.

AREAS COVERED

Hemochromatosis is a heterogenous disorder at both genetic and phenotypic level. The review discusses criteria to define patients' iron phenotype and to use molecular tests to diagnose HFE-related and non-HFE hemochromatosis. The material examined includes articles published in the journals covered by PubMed US National Library of Medicine. The author has been working in the field of iron overload diseases for several years and has contributed 18 of the papers cited in the references.

EXPERT OPINION

Hemochromatosis genotyping is inseparable from phenotype characterization. A full clinical assessment is needed and DNA test performed when data suggest a clear indication of suspicion of being at risk for HH. HFE testing for p.Cys282Tyr mutation and p.His63Asp variant is the first molecular diagnostic step. Genotyping for rare mutations can be offered to patients with negative first-level HFE testing who have iron overload with no other explanation and should be performed in referral centers for iron overload disorders that can provide genetic advice and in-house genotyping services.

High spatial resolution and temporally resolved T2* mapping of normal human myocardium at 7.0 Tesla: an ultrahigh field magnetic resonance feasibility study

Myocardial tissue characterization using T(2)(*) relaxation mapping techniques is an emerging application of (pre)clinical cardiovascular magnetic resonance imaging. The increase in microscopic susceptibility at higher magnetic field strengths renders myocardial T(2)(*) mapping at ultrahigh magnetic fields conceptually appealing. This work demonstrates the feasibility of myocardial T(2)(*) imaging at 7.0 T and examines the applicability of temporally-resolved and high spatial resolution myocardial T(2)(*) mapping. In phantom experiments single cardiac phase and dynamic (CINE) gradient echo imaging techniques provided similar T(2)(*) maps. In vivo studies showed that the peak-to-peak B(0) difference following volume selective shimming was reduced to approximately 80 Hz for the four chamber view and mid-ventricular short axis view of the heart and to 65 Hz for the left ventricle. No severe susceptibility artifacts were detected in the septum and in the lateral wall for T(2)(*) weighting ranging from TE = 2.04 ms to TE = 10.2 ms. For TE >7 ms, a susceptibility weighting induced signal void was observed within the anterior and inferior myocardial segments. The longest T(2)(*) values were found for anterior (T(2)(*) = 14.0 ms), anteroseptal (T(2)(*) = 17.2 ms) and inferoseptal (T(2)(*) = 16.5 ms) myocardial segments. Shorter T(2)(*) values were observed for inferior (T(2)(*) = 10.6 ms) and inferolateral (T(2)(*) = 11.4 ms) segments. A significant difference (p = 0.002) in T(2)(*) values was observed between end-diastole and end-systole with T(2)(*) changes of up to approximately 27% over the cardiac cycle which were pronounced in the septum. To conclude, these results underscore the challenges of myocardial T(2)(*) mapping at 7.0 T but demonstrate that these issues can be offset by using tailored shimming techniques and dedicated acquisition schemes.

How I treat transfusional iron overload

Patients with β-thalassemia major (TM) and other refractory anemias requiring regular blood transfusions accumulate iron that damages the liver, endocrine system, and most importantly the heart. The prognosis in TM has improved remarkably over the past 10 years. This improvement has resulted from the development of magnetic resonance imaging (MRI) techniques, especially T2*, to accurately measure cardiac and liver iron, and from the availability of 3 iron-chelating drugs. In this article we describe the use of MRI to determine which adult and pediatric patients need to begin iron chelation therapy and to monitor their progress. We summarize the properties of each of the 3 drugs, deferoxamine (DFO), deferiprone (DFP), and deferasirox (DFX), including their efficacy, patient acceptability, and side effects. We describe when to initiate or intensify therapy, switch to another drug, or use combined therapy. We also discuss the management of refractory anemias other than TM that may require multiple blood transfusions, including sickle cell anemia and myelodysplasia. The development of a potential fourth chelator FBS 0701 and the combined use of oral chelators may further improve the quality of life and survival in patients with TM and other transfusion-dependent patients.

New updating into hemoglobinopathies

Thalassemia and abnormal hemoglobin are the most common genetic disorders and are considered health problems in many developing countries. In the last few years, there has been much progress in laboratory diagnosis, treatment and control of thalassemia. The variation in the clinical severity in both α- and β-thalassemia reflects a genotype-phenotype interaction. This is important for future therapeutic intervention and should be well characterized in each population. The quality of life of the patients is much improved with regular blood transfusion and novel iron chelators. The cure for thalassemia is possible by stem cell transplantation and future gene therapy. It is expected that under multinational collaboration the prevention of thalassemia will happen worldwide.

The role of cardiac magnetic resonance imaging in the assessment of non-ischemic cardiomyopathy

Cardiovascular magnetic resonance imaging (CMR) plays an increasing role in the assessment of patients with various cardiovascular disorders. Given its enhanced spatial resolution, improved tissue characterization, and lack of ionizing radiation, it has become the test of choice in the evaluation of patients with new-onset cardiomyopathy of unknown etiology. In this paper, we will review the role of CMR in the evaluation of patients with various types of non-ischemic cardiomyopathy.

On T2* magnetic resonance and cardiac iron

BACKGROUND

Measurement of myocardial iron is key to the clinical management of patients at risk of siderotic cardiomyopathy. The cardiovascular magnetic resonance relaxation parameter R2* (assessed clinically via its reciprocal, T2*) measured in the ventricular septum is used to assess cardiac iron, but iron calibration and distribution data in humans are limited.

METHODS AND RESULTS

Twelve human hearts were studied from transfusion-dependent patients after either death (heart failure, n=7; stroke, n=1) or transplantation for end-stage heart failure (n=4). After cardiovascular magnetic resonance R2* measurement, tissue iron concentration was measured in multiple samples of each heart with inductively coupled plasma atomic emission spectroscopy. Iron distribution throughout the heart showed no systematic variation between segments, but epicardial iron concentration was higher than in the endocardium. The mean ± SD global myocardial iron causing severe heart failure in 10 patients was 5.98 ± 2.42 mg/g dry weight (range, 3.19 to 9.50 mg/g), but in 1 outlier case of heart failure was 25.9 mg/g dry weight. Myocardial ln[R2*] was strongly linearly correlated with ln[Fe] (R²=0.910, P<0.001), leading to [Fe]=45.0×(T2*)⁻¹·²² for the clinical calibration equation with [Fe] in milligrams per gram dry weight and T2* in milliseconds. Midventricular septal iron concentration and R2* were both highly representative of mean global myocardial iron.

CONCLUSIONS

These data detail the iron distribution throughout the heart in iron overload and provide calibration in humans for cardiovascular magnetic resonance R2* against myocardial iron concentration. The iron values are of considerable interest in terms of the level of cardiac iron associated with iron-related death and indicate that the heart is more sensitive to iron loading than the liver. The results also validate the current clinical practice of monitoring cardiac iron in vivo by cardiovascular magnetic resonance of the midseptum.

Value of black blood T2* cardiovascular magnetic resonance

PURPOSE

To assess whether black blood T2* cardiovascular magnetic resonance is superior to conventional white blood imaging of cardiac iron in patients with thalassaemia major (TM).

MATERIALS AND METHODS

We performed both conventional white blood and black blood T2* CMR sequences in 100 TM patients to determine intra and inter-observer variability and presence of artefacts. In 23 patients, 2 separate studies of both techniques were performed to assess interstudy reproducibility.

RESULTS

Cardiac T2* values ranged from 4.5 to 43.8 ms. The mean T2* values were not different between black blood and white blood acquisitions (20.5 vs 21.6 ms, p=0.26). Compared with the conventional white blood diastolic acquisition, the coefficient of variance of the black blood CMR technique was superior for intra-observer reproducibility (1.47% vs 4.23%, p<0.001), inter-observer reproducibility (2.54% vs 4.50%, p<0.001) and inter-study reproducibility (4.07% vs 8.42%, p=0.001). Assessment of artefacts showed a superior score for black blood vs white blood scans (4.57 vs 4.25; p<0.001).

CONCLUSIONS

Black blood T2* CMR has superior reproducibility and reduced imaging artefacts for the assessment of cardiac iron, in comparison with the conventional white blood technique, which make it the preferred technique for clinical practice.

Low prevalence of fibrosis in thalassemia major assessed by late gadolinium enhancement cardiovascular magnetic resonance

BACKGROUND

Heart failure remains a major cause of mortality in thalassaemia major. The possible role of cardiac fibrosis in thalassemia major in the genesis of heart failure is not clear. It is also unclear whether cardiac fibrosis might arise as a result of heart failure.

METHODS

We studied 45 patients with thalassaemia major who had a wide range of current cardiac iron loading and included patients with prior and current heart failure. Myocardial iron was measured using T2* cardiovascular magnetic resonance (CMR), and following this, late gadolinium enhancement (LGE) was used to determine the presence of macroscopic myocardial fibrosis.

RESULTS

The median myocardial T2* in all patients was 22.6 ms (range 5.3-58.8 ms). Fibrosis was detected in only one patient, whose myocardial T2* was 20.1 ms and left ventricular ejection fraction 57%. No fibrosis was identified in 5 patients with a history of heart failure with full recovery, in 3 patients with current left ventricular dysfunction undergoing treatment, or in 18 patients with myocardial iron loading with cardiacT2* < 20 ms at the time of scan.

CONCLUSION

This study shows that macroscopic myocardial fibrosis is uncommon in thalassemia major across a broad spectrum of myocardial iron loading. Importantly, there was no macroscopic fibrosis in patients with current or prior heart failure, or in patients with myocardial iron loading without heart failure. Therefore if myocardial fibrosis indeed contributes to myocardial dysfunction in thalassemia, our data combined with the knowledge that the myocardial dysfunction of iron overload can be reversed, indicates that any such fibrosis would need to be both microscopic and reversible.

Impact of volume and specialization for cancer surgery

BACKGROUND/AIMS

The so-called volume/outcome relationship postulates that a higher caseload and specialization results in an improved outcome. The existence of such a relationship, however, is still debated in the literature. The objective of this review is to discuss the available data on this relationship in surgical oncology.

METHODS

A Medline analysis was performed using the following terms: volume, outcome, cancer, and surgery. The bibliography of each relevant article was screened for further studies.

RESULTS

For most malignancies a volume/outcome relationship was demonstrated in recent years. Components of this improved outcome are decreased perioperative morbidity and mortality, higher quality of life after surgery, improved economic outcome, and a better long-term prognosis for patients with cancer. The magnitude of this relationship, however, varies greatly among different malignancies. The exact reason for the volume/outcome relationship is still unknown.

CONCLUSION

Concentrating high-risk procedures in high-volume hospitals might prevent thousands of perioperative deaths per year. This concept seems feasible for rare and high-risk diseases; however, it is unclear what threshold should be used for the definition of a high-volume provider. For common and low-risk diagnoses, it seems more realistic to educate the medical community in order to improve the outcome for the patients.