Precision of Multi-Echo CMR for Myocardial Iron Overload Evaluation Is Dependent From MR Sequence Design

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 5169-5169
Author(s):  
Antonella Meloni ◽  
incenzo Positano ◽  
Alessia Pepe ◽  
Dell'Amico Maria Chiara ◽  
Luca Menichetti ◽  
...  
Keyword(s):  
Iron Overload ◽  
Conflicts Of Interest ◽  
Iron Concentration ◽  
Breath Hold ◽  
Myocardial Iron ◽  
Single Breath ◽  
Single Breath Hold ◽  
Values Assessment ◽  
Value Determination ◽  
Almost All

Abstract Abstract 5169 Introduction. T2* multiecho cardiovascular magnetic resonance (CMR) is largely used to assess iron overload in heart because of the established inverse relationship between the T2* value and the iron concentration in tissues (Wood JC et al, Hemoglobin 2008). The decay of CMR signal is sampled at several echo times (TEs) and the T2* is inferred by fitting the decay curve to an appropriate model (Positano V et al, NMR in Biomed 2007). Our aim was to quantify the reliance on TEs of the expected error in T2* value determination. Methods. The Cramer-Rao lower bounds theory (CRLB) was used. CRLB provide a fundamental limit to the accuracy in determination of the T2* value from experimental data in dependence of SNR at signal samples. CRLB were evaluated for a commonly used multi-echo sequence with the first TE equal to the minimum achievable (1.4-2 ms), ΔTE of about 2.3 ms to minimize the fat-water interface artifacts, 10 echoes to assure acquisition in a single breath-hold. Results. Percent error in T2* values assessment was lower than 10% in the range of clinical interest, with the exception of very low T2* values. Precision in measurement of low T2* values is strongly dependent on the value of the first TE, that is limited by the used scanner. T2* values greater than 1.8 ms and 1.5 ms can be assessed with an error below 20% using a first TE of 2 ms and 1.5 ms, respectively (see Figure). Conclusions. T2* multiecho sequences used in clinical practice assure an acceptable precision for T2* values ≥ 2 ms, depending from the used hardware. This limit includes almost all patients with hemochromatosis or hemosiderosis in country where the patients can be well managed. For patients with very high myocardial iron overload sequences with lower minimum echo time and/or lower echoes interval may be useful. Disclosures: No relevant conflicts of interest to declare.

Myocardial iron overload

2018 ◽  
pp. 364-374
Author(s):  
John P Carpenter ◽  
John C Wood ◽  
Dudley J Pennell
Keyword(s):  
Heart Failure ◽  
Iron Overload ◽  
Iron Concentration ◽  
Left Ventricular ◽  
Breath Hold ◽  
Liver Iron ◽  
Cardiac Iron ◽  
Single Breath ◽  
Developing Heart ◽  
Cost Efficient

The heart is the target lethal organ in thalassaemia major. Cardiovascular magnetic resonance (CMR) measures iron using the magnetic relaxation time T2*. This allows comparison with the left ventricular function and conventional iron measurements such as liver iron and serum ferritin. The single breath-hold cardiac-gated CMR acquisition takes only 15 seconds, making it cost-efficient and relevant to developing countries. Myocardial T2* of <20 ms (increased iron) correlates with reduced left ventricular ejection fraction, but poor correlation exists with ferritin and liver iron, indicating poor capability to assess future risk. Myocardial T2* of <10 ms is present in >90% of thalassaemia patients developing heart failure, and approximately 50% of patients with T2* of <6 ms will develop heart failure within 1 year without intensified treatment. The technique is validated and calibrated against human heart iron concentration. The treatment for iron overload is iron chelation, and three major trials have been performed for the heart. The first trial showed deferiprone was superior to deferoxamine in removing cardiac iron. The second trial showed a combination therapy of deferiprone with deferoxamine was more effective than deferoxamine monotherapy. The third trial showed that deferasirox was non-inferior to deferoxamine in removing cardiac iron. Each drug in suitable doses can be used to remove cardiac iron, but their use depends on clinical circumstances. Other combination regimes are also being evaluated. Use of T2*, intensification of chelation treatment, and use of deferiprone are associated with reduced mortality (a reduction in deaths by 71% has been shown in the United Kingdom). The use of T2* and iron chelators in the heart has been summarized in recent American Heart Association guidelines.

Inter-Site Validation of a Single Breath Hold T2* MR Technique for Heart and Liver Iron Measurement.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3830-3830 ◽  
Author(s):  
Paul Kirk ◽  
Lisa J. Anderson ◽  
Mark A. Tanner ◽  
Renzo Galanello ◽  
Gildo Matta ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Breath Hold ◽  
Iron Loading ◽  
Myocardial Iron ◽  
Thalassaemia Major ◽  
Liver Iron ◽  
Single Breath ◽  
Single Breath Hold ◽  
Average Coefficient ◽  
Siemens Sonata

Abstract Background Approximately 60,000 people are born with thalassaemia major every year. The average life expectancy of thalassaemia major patients is 35 years due to iron overload Cardiomyopathy. The cardiomyopathy is reversible when treated early, but once heart failure is established it is often rapidly progressive, and unresponsive to treatment. The single breath hold (SBH) T2* technique has been validated as the most robust and reproducible non-invasive measurement of myocardial and iron load. Our aim in this study was to validate the transferability and reproducibility of this technique in different scanners worldwide. Methods We aim to compare the reproducibility in six different sites worldwide as part of an NIH funded grant (R01-DK66084-01). So far, two of these sites have been validated: Singapore (Siemens Sonata, 1.5T scanner) and Cagliari, Italy (GE Signa, 1.5 T scanner). At both validation sites, 10 patients were scanned for heart and liver T2*, and scans were repeated for interstudy reproducibility. All patients then flew to London to be rescanned on our reference Siemens Sonata scanner. Results Of the 20 patients scanned, 70% had myocardial iron loading (T2* <20ms) and in 10% the myocardial iron loading was severe. Liver iron loading was present in 65% of patients and in 30% this was severe. The coefficient of variation (COV) for the heart T2* measurements between the local sites and London was 5.9% and 4.9% yielding an average coefficient of variation across both sites of 5.4% (figure 1). The coefficient of variation (COV) for the liver T2* measurements between the local sites and London was 11.3% and 3.9% yielding an average coefficient of variation across both sites of 7.6% (figure 2). There was no significant correlation between liver and myocardial loading. Conclusion These are the first data demonstrating the transferability of the SBH T2* technique and the clinical validation from the 2 collaborating centers were excellent for both heart and liver measurements. Further MR sites confirmed for validation include Children’s Hospital of Philadelphia (USA); Ramathibodi Hospital, Bangkok (Thailand); and Chinese University Hong Kong. Figure 1 Figure 1. Figure 2 Figure 2.

A Cross-Sectional MRI T2* Study of Pancreatic and Pituitary Hemosiderosis in 180 Thalassemia Major Patients in Hong Kong.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2771-2771
Author(s):  
Wing Y. Au ◽  
Wynnie Lam ◽  
Winnie Chu ◽  
Hui-leung Yuen ◽  
S.C. Ling ◽  
...  
Keyword(s):  
Multivariate Analysis ◽  
Iron Overload ◽  
Thalassemia Major ◽  
Carrier State ◽  
Breath Hold ◽  
Cross Sectional ◽  
Single Breath ◽  
Single Breath Hold ◽  
Organ Specific ◽  
Magnetic Resonance Imaging Mri

Abstract Background: The use of magnetic resonance imaging (MRI) for organ specific iron assessment has allowed better tailoring of chelation therapy. Since endocrine failure is common in thalassemia major (TM) patients, we explored the utility of rapid T2* MRI assessment of hemosiderosis in the pancreas and pituitary. The results were correlated with standard T2* heart and liver MRI assessments and clinical data. Material and methods: A total of 180 TM patients (M:F = 91:89, median age, range 12–48) were scanned on a 1.5 T scanner. (Sonata, Siemens Medical, Erlanger, Germany). T2* myocardium was assessed by a cardiac gated single breath hold 8-echo sequence (CMRtools; London, UK). The T2* liver, pancreas and pituitary were performed by a breath hold 20-echo sequence. Subcutaneous deferoxamine was used for chelation, except for addition of deferiprone in 24 cases for 1 year. Results: There was a high incidence of hemosiderosis of heart (severe T2*<12ms: 34%, mild-moderate <20ms, 15%) and liver (severe T2*<1.4ms, 14% mild-moderate <6.3ms, 63%). Iron overload above normal control was commonly found in the pancreas (T2*<23ms, 84%) and pituitary (T2*<5.9ms, 24%). Pancreatic T2* correlated with pituitary T2* (p=0.007, r=0.2), cardiac T2*(p<0.001, r=0.33), liver T2* (p<0.001, r=0.35), ferritin (p=0.004, r=−0.19) and age (p=0.033, r=0.16). Similarly pituitary T2* related to cardiac T2* (p<0.001, r=0.36) and liver T2* (p=0.026, r=0.17). On multivariate analysis, however, pancreatic T2* related to both heart T2* (p<0.001) and liver T2* (p=0.001), while pituitary T2* only related to heart T2* (p<0.001). Documented complications amongst the cases included heart failure (ejection fraction EF<55%, n=28, 16%), hypogonadism (n=84,47%), diabetes mellitus (n=44, 25%), hypoparathyroidism (n=16, 9%) and hypothyroidism (n=36, 20%), with hepatitis B and C carrier state in 2% and 25% respectively. On univariate and multivariate analysis, all 4 endocrine failures correlated with only cardiac T2* results (all p<0.001) and age (all p<0.001), but not with pituitary or pancreatic T2* results. The EF correlated with T2* of pituitary, pancreas and heart, but only MRI heart T2* correlation remained significant on multivariate analysis. Conclusions: MRI pituitary and pancreatic evaluation is viable in a cohort of poorly chelated Chinese thalassemia major patients on subcutaneous deferoxamine treatment. However, an abnormal cardiac T2* result is a good surrogate for endocrine iron overload and appeared more relevant in predicting endocrine complications.

scholarly journals Come eseguire lo studio cardiaco T2 star pesata di risonanza magnetica per gli accumuli di ferro nella talassemia

2020 ◽  
pp. 36-39
Author(s):  
Martini Alberto ◽  
Morelli Giovanni ◽  
Nappa Elena ◽  
Notorio Maurizio
Keyword(s):  
Iron Overload ◽  
Risk Group ◽  
Risonanza Magnetica ◽  
Middle Part ◽  
Mediterranean Coast ◽  
High Risk Group ◽  
Breath Hold ◽  
Single Breath ◽  
Single Breath Hold ◽  
T2 Mri

The aim of the study is to show how to execute a cardiac T2* MRI assessment correctly in patients who suffer from iron overload in vital organs, particularly in the heart. The main cause of iron overload is Thalassemia, the disease which is widely spread in the Southern and Middle part of Italy, as well as the Mediterranean coast. Researchers have demonstrated that patients who suffer from thalassemia might have an excessive and toxic iron overload which could lead to heart failure and death. Thanks to the T2*single breath-hold multi-echoes sequence, using a dedicated software, the patients’ myocardial iron deposition can be classified into three groups: T2* MRI < 10 ms ( high risk group) T2* MRI =10-20 ms ( medium-risk group) T2* MRI > 20 ms (low-risk group) This measure called “saturation time”(expressed in 1/1000 sec.), also allows physicians to customize medical treatment for every patient, same as a good tailor does to make a new dress fits well on every single client. However, to obtain precise and reliable results, radiographers first and radiologists afterwards, must respect every single technical parameter in MR techniques

Calibration of Improved T2* Method for the Estimation of Liver Iron Concentration in Transfusional Iron Overload.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2004-2004 ◽  
Author(s):  
Maciej W Garbowski ◽  
John-Paul Carpenter ◽  
Gillian Smith ◽  
Dudley J Pennell ◽  
John B Porter
Keyword(s):  
Liver Biopsy ◽  
Iron Concentration ◽  
Cardiovascular Imaging ◽  
Breath Hold ◽  
Liver Iron Concentration ◽  
Liver Iron ◽  
Single Breath ◽  
Single Breath Hold ◽  
Tissue Iron ◽  
The Relationship

Abstract Abstract 2004 Poster Board I-1026 Background and rationale Non-invasive estimation of tissue iron concentration is being used increasingly to follow responses to chelation therapy. Magnetic resonance (MR) T2* was originally developed to estimate myocardial iron but the first description of the myocardial T2* method also demonstrated a clear relationship between liver T2* and liver iron concentration (LIC) measured by biopsy (Anderson, Eur Heart J 2001). The inclusion of liver analysis at this time was intended mainly to show the relationship of T2* to tissue iron rather than as a standard method for LIC measurement, particularly as the echo times used were too long to measure the high iron levels commonly found in the liver. Since this work, other MR methods such as the R2 technique (St. Pierre, Blood 2004) have been specifically validated to measure LIC. However, if T2* could be validated and calibrated appropriately for LIC, it may be convenient to measure liver and heart iron at the same time using this rapid technique. Since the initial calibration of the T2* method, there have been major improvements in scanner technology and hardware. In the original paper, eight different echo times were acquired (TE 2.2- 20.1ms), each of which required a separate breath-hold with important implications for image registration regarding the measurement of T2*. Much shorter, more closely spaced echo times are now possible in a single breath-hold which makes the calculation of T2* more accurate, especially at higher liver iron concentrations where T2* is short. Methods: A large cohort of patients at UCLH have had liver biopsies as part of iron chelation studies on Deferasirox, while continuing to be monitored by T2* of both heart and liver. Data pairs for LIC calibration curve plots were chosen as nested values by shortest biopsy-to-MR time lapse criterion (±75 days) from all biopsy and hepatic T2* results. Liver biopsy iron was measured in a single central laboratory in Rennes, France (Clinique des Maladies du Foie [Clinic for Hepatic Illnesses], Center Hospitalier Universitaire) on paraffin embedded sections as previously described (Soriano-Cubells MJ, Atomic Spectrosc. 1984). All MR scans were performed on a 1.5T Sonata MR scanner (Siemens, Germany) using a 4-channel anterior phased array coil at Royal Brompton Hospital, London. A transverse slice through the centre of the liver was imaged using a multi-echo single breath-hold gradient echo T2* sequence with a range of echo times (TE 0.93-16.0ms). T2* decay was measured using Thalassaemia tools (Cardiovascular Imaging Solutions, London, UK) from a region of interest (ROI) in an area of homogeneous liver tissue, avoiding blood vessels and other sources of artefact. To account for background noise, a truncation method was used for curve-fitting (He, Magn Reson Med 2008). All T2* measurements were performed in triplicate by 2 independent observers choosing three separate ROIs to analyse. The ROIs were chosen to be as large as possible in three separate areas of the liver (anterior, mid/lateral and posterior). Spearman correlation method was used to estimate the degree of relationship between biopsy LIC and hepatic R2* (1/T2*) values, both of which showed positive skew. Results and conclusions: 61 patients had both liver biopsy and liver MR measurements undertaken. However, only 18 had biopsies within 75 days of MR T2* measurement and these are the patients included in the following analysis. There is a linear relationship between biopsy LIC and the reciprocal of T2* (R2*), given by: LIC = 0.03 x R2* + 0.74 (R2=0.96 p<0.0001, slope 95% CI 0.027-0.033, with y intercept CI -0.73 to 2.2). The 95% confidence intervals for the linear regression line were calculated from the SEM and are shown as the broken lines (Figure 1). Staging of fibrosis/cirrhosis provided in biopsy reports was not found to significantly affect regression analysis contrary to previous studies. The inset shows the relationship between T2* and biopsy LIC. The new calibration shows acceptable linearity and reproducibility over an LIC range up to 30mg/g dry weight and gives LIC values approximately 1.94 times higher than the original method reported by Anderson. Comparison of these values with those obtained by SQUID and Ferriscan would also be of interest. Disclosures: Pennell: Cardiovascular Imaging SOlutions, London, UK: Director.

Interpretation of CT Scan Findings During the COVID-19 Pandemic

2020 ◽  
Vol 24 (4) ◽  
Author(s):  
Ebrahim Nouri ◽  
Omolbanin Delashoub ◽  
Mohammad Ali Shahabi-Rabori ◽  
Reza Afzalipour ◽  
Salman Jafari
Keyword(s):  
Ct Scan ◽  
High Speed ◽  
Ground Glass Opacity ◽  
First Trimester ◽  
Breath Hold ◽  
Respiratory Problems ◽  
Single Breath ◽  
Single Breath Hold ◽  
First Trimester Of Pregnancy ◽  
Almost All

: Studies have documented criteria for the prevention, diagnosis, and treatment of COVID-19 pneumonia as more information has become available about its symptoms and complications. Similar to other coronavirus-induced cases of pneumonia, COVID-19 pneumonia causes acute respiratory problems. The chest CT scan, which is easily available in almost all areas, is a common imaging technique for diagnosing pneumonia. Its findings, which are accompanied by high speed, quality, and accuracy, allow the radiologist to easily identify affected areas of the lungs and to determine typical radiological features of patients with pneumonia caused by COVID-19. These features include ground-glass opacity, multifocal patchy consolidation, and interstitial changes with the peripheral distribution. The highest incidence occurs in the 4th and 5th lobes, where about 50% to 75% of the lesions observed. For infected patients, the CT scan protocol includes administration of HRCT technique in the inspiration phase with spiral 4-slice devices and higher. Scan parameters also include KV: 100 - 120, and mAs: 20 - 30, thickness = 1 - 2 mm, spiral, single breath-hold, and Pitch = 0.8 - 1.5, which are determined for all patients. Since there are restrictions on using ionizing radiation for pregnant women, it is recommended to initially conduct PCR tests. If necessary, typical radiography with an abdominal shield can be used for women in the first trimester of pregnancy, and the HRCT technique in low doses can be used for those in the second and third trimesters.

MRI Survey In Transfusion-Dependent and Non-Transfusion-Dependent MDS Patients

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2819-2819
Author(s):  
Alessia Pepe ◽  
Antonella Meloni ◽  
Giancarlo Carulli ◽  
Esther Natalie Oliva ◽  
Francesco Arcioni ◽  
...  
Keyword(s):  
Iron Overload ◽  
Serum Ferritin ◽  
Conflicts Of Interest ◽  
Iron Concentration ◽  
Left Ventricular ◽  
Volume Index ◽  
Hepatic Iron ◽  
Myocardial Iron ◽  
Hepatic Iron Overload ◽  
The Mean

Abstract Introduction Several studies have shown cardiac diseases as causes of death in myelodisplastic (MDS) patients receiving transfusions. So iron overload may be considered an independent negative prognostic factor. There are few and rather contradictory studies using Magnetic Resonance Imaging (MRI) in the evaluation of myelodysplastic syndromes. We report the baseline MRI findings at the end of the recruitment in the MIOMED (Myocardial Iron Overload in MyElodysplastic Diseases) study. In particular, we investigated myocardial iron overload (MIO), hepatic iron overload and biventricular functional parameters in MDS patients, outlying the differences between transfusion dependent and non transfusion dependent patients. Methods MIOMED is an observational, MRI multicentre study in low and intermediate-1 risk MDS patients who have not received regular iron chelation therapy. Out of the 51 MDS patients enrolled, 48 underwent the baseline MRI exam. Mean age was 71.7±8.5 years and 17 patients were females. Hepatic T2* values were assessed in a homogeneous tissue area and converted into liver iron concentration (LIC). MIO was assessed using a multislice multiecho T2* approach. Biventricular function parameters were quantified by cine sequences. Results The mean global heart T2* was 38.7±8.3 ms while the mean LIC was 7.6±8.8 mg/g/dw. Global heart T2* values were not significantly correlated with LIC or serum ferritin levels while a significant association between LIC and serum ferritin was detected (R=0.689; P<0.0001). Thirty-two (66.6%) patients were non-transfusion dependent while 16 patients were transfusion-dependent. The two groups were homogeneous for age, sex and hemoglobin levels but transfusion-dependent patients had significantly higher serum ferritin levels (1612±864 vs 711±430; P<0.0001). The percentage of patients with detectable hepatic iron (LIC≥3 mg/g/dw) was significantly higher in the transfusion-dependent group (Figure 1, left). Mean LIC was 14.4±11.1 mg/g/dw in the transfusion-dependent group and 4.2±4.6 mg/g/dw in the non-transfusion-dependent group (P<0.0001). A significant heart iron (global heart T2* value <20 ms) was found in two patients, in both patients an heterogeneous pattern (some segments with T2* values >20 ms and other segments with T2* values <20 ms) was detected. Out of two patients with significant heart iron one patient was not transfused and he did not show significant hepatic iron (LIC=2.12 mg/g/dw). The other one patient was regularly transfused and he received sporadically (less than two weeks/month) chelation treatment with deferoxamine in the 2 years before the MRI. The global heart T2* (Figure 1, right), the pattern of iron burden and the number of segments with T2*<20 ms were comparable between the two groups. Biventricular end-diastolic volume index, biventricular ejection fraction and left ventricular (LV) mass index were comparable between the two groups. Conclusions As expected, regularly transfused MDS patients showed significantly higher levels of hepatic iron overload, that, however, was present in almost the 30% of non-transfusion-dependent patients, mainly due to increased intestinal iron and augmented erythropoiesis. MIO is not frequent in MDS patients and it is not correlated with LIC and serum ferritin levels. Conversely, MIO can be present also in non-transfusion dependent patients and in absence of detectable hepatic iron. These data remark the importance to check directly for heart iron with a more sensitive segmental approach avoiding to estimate heart iron burden from indirect indicators such as LIC, serum ferritin or transfusion state. Disclosures: No relevant conflicts of interest to declare.

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