Mohammed H Alam

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

To compare myocardial T1 against T2 and T2* in patients with thalassemia major (TM) for myocardial iron 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. Magn Reson Med 70:1765–1774, 2013.

Value of black blood T2* cardiovascular magnetic resonance.

PurposeTo 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 methodsWe 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.ResultsCardiac 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).ConclusionsBlack 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.

Effect of deferiprone or deferoxamine on right ventricular function in thalassemia major patients with myocardial iron overload

BackgroundThalassaemia major (TM) patients need regular blood transfusions that lead to accumulation of iron and death from heart failure. Deferiprone has been reported to be superior to deferoxamine for the removal of cardiac iron and improvement in left ventricular (LV) function but little is known of their relative effects on the right ventricle (RV), which is being increasingly recognised as an important prognostic factor in cardiomyopathy. Therefore data from a prospective randomised controlled trial (RCT) comparing these chelators was retrospectively analysed to assess the RV responses to these drugs.MethodsIn the RCT, 61 TM patients were randomised to receive either deferiprone or deferoxamine monotherapy, and CMR scans for T2* and cardiac function were obtained. Data were re-analysed for RV volumes and function at baseline, and after 6 and 12 months of treatment.ResultsFrom baseline to 12 months, deferiprone reduced RV end systolic volume (ESV) from 37.7 to 34.2 mL (p = 0.008), whilst RV ejection fraction (EF) increased from 69.6 to 72.2% (p = 0.001). This was associated with a 27% increase in T2* (p < 0.001) and 3.1% increase in LVEF (p < 0.001). By contrast, deferoxamine showed no change in RVESV (38.1 to 39.1 mL, p = 0.38), or RVEF (70.0 to 69.9%, p = 0.93) whereas the T2* increased by 13% (p < 0.001), but with no change in LVEF (0.32%; p = 0.66). Analysis of between drugs treatment effects, showed significant improvements favouring deferiprone with a mean effect on RVESV of -1.82 mL (p = 0.014) and 1.16% for RVEF (p = 0.009). Using regression analysis the improvement in RVEF at 12 months was shown to be greater in patients with lower baseline EF values (p < 0.001), with a significant difference in RVEF of 3.5% favouring deferiprone over deferoxamine (p = 0.012).ConclusionIn this retrospective analysis of a prospective RCT, deferiprone monotherapy was superior to deferoxamine for improvement in RVEF and end-systolic volume. This improvement in the RV volumes and function may contribute to the improved cardiac outcomes seen with deferiprone.

An unexpected finding in an asymptomatic patient with atrial fibrillation: cardiac angiosarcoma

A 70-year-old asymptomatic man was found to have atrial fi brillation during a routine check-up by his family doctor. He was referred to hospital for further investigation, where transthoracic echocardiography showed a large echogenic intra-atrial mass that almost obliterated the left atrium (fi gure, videos). Transoesophageal echocardio graphy showed a spaceoccupying lesion 9·5 × 7·2 cm arising from the interatrial septum, fi lling the left atrium, bulging into the right atrium and close to the mitral-aortic continuity. Cardiac MRI showed that the mass was encapsulated, with mixed fi brous and cystic components (video). Coronary angiography was normal, and fl uorine-33-labelled fl uorodeoxyglucose (33FDG) PET-CT showed no FDG accumulation. Histology of the mass after complete surgical excision confi rmed an angiosarcoma. 1 year later he remained in atrial fi brillation but had no cardiac or systemic tumour recurrence and was otherwise well. Primary cardiac tumours are rare (0·0017–0·02% of all cardiac tumours), of which sarcomas account for about a third. 30–45% of malignant sarcomas are angiosarcomas, which usually arise in the right atrium near the atrioventricular groove (unlike myxomas, they rarely arise from the interatrial septum). Patients usually present with symptoms related to the tumour size, such as rightsided heart failure, compression syndrome, chest pain, or haemopericardium. Intracardiac angiosarcomas have an especially poor prognosis because they tend to present with metastatic disease, most frequently pulmonary and hepatic metastases. Incidental fi nding of angiosarcoma is rare. Evaluation of intracardiac tumours can be complex and should include a variety of diagnostic techniques. Diagnosis relies on non-invasive imaging techniques and tissue histology. Echocardiography is best for assessment of the tumour’s eff ect on fl ow dynamics, and cardiac MRI is useful for detection of tumour infi ltration and tissue characterisation.

Atrial septal defect infective endocarditis: a direct pathway from left atrium to the lung

A 19-year-old female was admitted with refractory pyrexia, dyspnoea, and hypoxia. She undergone cardiac surgery, aged 2, including arterial switch procedure with Lecompte manoeuvre, ventricular septal defect patch closure, and native pulmonary valve resection with direct anastomosis of the pulmonary artery bifurcation to the right ventricle (RV) infundibulum. Chest …

Validation of Siemens T2* inline WIP package for quantification of cardiac and hepatic iron loading at 1.5T and 3T

Background The ability of T2* cardiovascular magnetic resonance (CMR) to identify cardiac iron loading has facilitated a dramatic reduction in mortality in patients with iron overload. There remains a worldwide need for improved access to iron evaluation. One route to achieving this would be simple in-line T2* analysis. We compared our validated T2* methods which use Royal Brompton Hospital (RBH) T2* sequences with analysis by CMRtools against a novel work-in-progress (WIP) sequence and inline T2* analysis. Methods 22 healthy volunteers and 78 patients were recruited (thalassaemia major 39, sickle cell disease 15, hereditary hemochromatosis 10, other iron overload conditions 14) who were referred for routine iron assessment (53 male, aged 13 to 81 years). A 1.5T study (MAGNETOM Avanto, Siemens AG Healthcare Sector, Erlangen, Germany) was performed on all subjects, from whom a subset of 50 underwent an additional 3T study (MAGNETOM Skyra). The same mid-ventricular short axis cardiac slice and transaxial slice through the liver were used to acquire both RBH T2* images and WIP T2* maps for each scan. Cardiac white blood (WB) and black blood (BB) sequences were acquired. All data acquisition and ROI based analysis was performed by a single observer. Results

Comparison of white blood and black blood T2* cardiovascular magnetic resonance at 3 Tesla

Background T2* relaxometry offers a non-invasive method to accurately quantify myocardial iron levels, thus aiding the diagnosis and assessment of prognosis of patients. Two T2* sequences are used clinically: the single breathhold multi-echo gradient echo white blood (WB) and black blood (BB) techniques. At 1.5T, BB T2* has superior reproducibility and fewer artefacts than WB T2*. We compared BB and WB T2* iron measurement at 3T and compared results with corresponding 1.5T measurements.

Myocardial iron assessment by T1 cardiovascular magnetic resonance at 3 Tesla

Background Myocardial T2* relaxometry at 1.5T provides reliable non-invasive assessment of cardiac iron burden and is commonly used for the diagnosis and monitoring of patients at risk. 3T CMR offers some advantages over 1.5T but iron assessment has not been routinely performed at 3T due to technical concerns regarding artefacts and rapid signal loss, as well as a lack of tissue calibration. In vitro data has shown that like T2*, T1 shortens with increasing tissue iron. At 1.5T, T1 correlates reasonably with T2* in cases of iron overload ( < 20 ms). We compared myocardial T1 measurement at 3T with measurements made at 1.5T of T1 and the established black blood (BB) T2* technique. Methods

Myocardial iron assessment by T1 cardiovascular magnetic resonance at 1.5 Tesla

Background Heart failure secondary to cardiac siderosis is the prevalent cause of mortality in patients with primary or secondary iron overload. Myocardial iron assessment using T2* has been successfully calibrated against myocardial iron at 1.5T and the black blood (BB) technique has demonstrated high reproducibility such that it has become the clinical gold standard. T1 appears to correlate with T2* in cases of significant iron loading (T2* < 20 ms) but this relationship weakens when T2* is in the normal range. We evaluated this further. Methods