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Oduor H, Minniti CP, Brofferio A, Gharib AM, Abd-Elmoniem KZ, Hsieh MM, Tisdale JF, Fitzhugh CD. Severe cardiac iron toxicity in two adults with sickle cell disease. Transfusion 2016; 57:700-704. [PMID: 28019032 DOI: 10.1111/trf.13961] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/21/2016] [Accepted: 10/26/2016] [Indexed: 12/23/2022]
Abstract
BACKGROUND Use of chronic blood transfusions as a treatment modality in patients with blood disorders places them at risk for iron overload. Since patients with β-thalassemia major (TM) are transfusion-dependent, most studies on iron overload and chelation have been conducted in this population. While available data suggest that compared to TM, patients with sickle cell disease (SCD) have a lower risk of extrahepatic iron overload, significant iron overload can develop. Further, previous studies have demonstrated a direct relationship between iron overload and morbidity and mortality rates in SCD. However, reports describing the outcome for patients with SCD and cardiac iron overload are rare. STUDY DESIGN AND METHODS We performed a retrospective analysis and identified two SCD patients with cardiac iron overload. We provide detailed descriptions of both cases and their outcomes. RESULTS Serum ferritin levels ranged between 17,000 and 19,000 μg/L. Both had liver iron concentrations in excess of 35 mg of iron per gram of dried tissue as well as evidence of cardiac iron deposition on magnetic resonance imaging. One patient died of an arrhythmia and had evidence of severe multiorgan iron overload via autopsy. On the other hand, after appropriate therapy, a second patient had improvement in cardiac function. CONCLUSION Improper treatment of iron overload in SCD can lead to a fatal outcome. Alternatively, iron overload may potentially be prevented or reversed with judicious use of blood transfusions and early use of chelation therapy, respectively.
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Affiliation(s)
- Hellen Oduor
- Hematology Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Caterina P Minniti
- Division of Hematology, Department of Medicine, Einstein College of Medicine, Bronx, New York
| | - Alessandra Brofferio
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Ahmed M Gharib
- Biomedical and Metabolic Imaging Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Khaled Z Abd-Elmoniem
- Biomedical and Metabolic Imaging Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Matthew M Hsieh
- Molecular and Clinical Hematology Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - John F Tisdale
- Molecular and Clinical Hematology Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Courtney D Fitzhugh
- Hematology Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland.,Molecular and Clinical Hematology Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
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Ibrahim ESH, Khalifa AM, Eldaly AK. MRI T2* imaging for assessment of liver iron overload: study of different data analysis approaches. Acta Radiol 2016; 57:1453-1459. [PMID: 26861202 DOI: 10.1177/0284185116628337] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Background Recently, magnetic resonance imaging (MRI) has been established as an effective technique for evaluating iron overload by measuring T2* in the liver. Purpose To investigate the effects of various factors associated with T2* calculation on the resulting measurement and to determine the analysis criterion that provides the most accurate T2* measurements. Material and Methods Both phantom and in vivo MRI experiments were conducted to study the effects of the selected region of interest (ROI) location and size, signal-averaging method, exponential-fitting model, echo truncation, iron-overload severity, and inter-/intra-observer variabilities on T2* measurements. The results were compared to reference values from the scanner processing software. Results The pixel-by-pixel calculation method provided results in better agreement with the reference values from the MRI scanner than the average or median methods. The choice of the exponential fitting model affected the results, depending on signal-to-noise ratio, number of echoes, minimum and maximum echo times, and tissue composition inside the selected ROI. The single-exponential model resulted in smaller error than the bi-exponential or exponential-plus-constant models, where the latter two models showed similar results. The relative performance of the different models and methods was not affected by the degree of iron-overload. Conclusion Various factors associated with the adopted T2* calculation method affect the resulting measurement. In this study, the pixel-by-pixel calculation method and single-exponential model provided the most accurate results based on the conducted phantom and in vivo MRI experiments.
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Ibrahim ESH, Cernigliaro JG, Pooley RA, Williams JC, Haley WE. Motion artifacts in kidney stone imaging using single-source and dual-source dual-energy CT scanners: a phantom study. ACTA ACUST UNITED AC 2016; 40:3161-7. [PMID: 26318750 DOI: 10.1007/s00261-015-0530-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE Dual-energy computed tomography (DECT) has shown the capability of differentiating uric acid (UA) from non-UA stones with 90-100% accuracy. With the invention of dual-source (DS) scanners, both low- and high-energy images are acquired simultaneously. However, DECT can also be performed by sequential acquisition of both images on single-source (SS) scanners. The objective of this study is to investigate the effects of motion artifacts on stone classification using both SS-DECT and DS-DECT. METHODS 114 kidney stones of different types and sizes were imaged on both DS-DECT and SS-DECT scanners with tube voltages of 80 and 140 kVp with and without induced motion. Postprocessing was conducted to create material-specific images from corresponding low- and high-energy images. The dual-energy ratio (DER) and stone material were determined and compared among different scans. RESULTS For the motionless scans, all stones were correctly classified with SS-DECT, while two cystine stones were misclassified with DS-DECT. When motion was induced, 94% of the stones were misclassified with SS-DECT versus 11% with DS-DECT (P < 0.0001). Stone size was not a factor in stone misclassification under motion. Stone type was not a factor in stone misclassification under motion with SS-DECT, although with DS-DECT, cystine showed higher number of stone misclassification. CONCLUSIONS Motion artifacts could result in stone misclassification in DECT. This effect is more pronounced in SS-DECT versus DS-DECT, especially if stones of different types lie in close proximity to each other. Further, possible misinterpretation of the number of stones (i.e., missing one, or thinking that there are two) in DS-DECT could be a potentially significant problem.
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Affiliation(s)
- El-Sayed H Ibrahim
- Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL, 32224, USA. .,University of Michigan, 1500 E. Medical Center Dr., Ann Arbor, MI, 48109, USA.
| | | | - Robert A Pooley
- Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL, 32224, USA
| | | | - William E Haley
- Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL, 32224, USA
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Ibrahim ESH, Bowman AW. Characterization of myocardial iron overload by dual-energy computed tomography compared to T2∗ MRI. A phantom study. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2014:5133-6. [PMID: 25571148 DOI: 10.1109/embc.2014.6944780] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Iron toxicity plays a key role in tissue damage in patients with iron overload, with induced heart failure being the main cause of death. T2*-weighted magnetic resonance imaging (MRI) has been established for evaluating myocardial iron overload with strong correlation with biopsy. The recently introduced dual-energy computed tomography (DECT) has the potential for evaluating iron overload without energy-dependent CT attenuation or tissue fat effects. This study investigates the performance of DECT for evaluating myocardial iron overload (based on images acquired at four different diagnostic imaging energies of 80, 100, 120, and 140 kVp) and compare the results to MRI T2* measurements based on DECT and MRI experiments on phantoms with calibrated iron concentrations. DECT showed high accuracy for evaluating iron overload compared to MRI T2* imaging, which might help in patient staging based on the degree of iron overload and independent of the implemented imaging energy.
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Alam MH, Auger D, McGill LA, Smith GC, He T, Izgi C, Baksi AJ, Wage R, Drivas P, Firmin DN, Pennell DJ. Comparison of 3 T and 1.5 T for T2* magnetic resonance of tissue iron. J Cardiovasc Magn Reson 2016; 18:40. [PMID: 27391316 PMCID: PMC4938967 DOI: 10.1186/s12968-016-0259-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 06/22/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND T2* magnetic resonance of tissue iron concentration has improved the outcome of transfusion dependant anaemia patients. Clinical evaluation is performed at 1.5 T but scanners operating at 3 T are increasing in numbers. There is a paucity of data on the relative merits of iron quantification at 3 T vs 1.5 T. METHODS A total of 104 transfusion dependent anaemia patients and 20 normal volunteers were prospectively recruited to undergo cardiac and liver T2* assessment at both 1.5 T and 3 T. Intra-observer, inter-observer and inter-study reproducibility analysis were performed on 20 randomly selected patients for cardiac and liver T2*. RESULTS Association between heart and liver T2* at 1.5 T and 3 T was non-linear with good fit (R (2) = 0.954, p < 0.001 for heart white-blood (WB) imaging; R (2) = 0.931, p < 0.001 for heart black-blood (BB) imaging; R (2) = 0.993, p < 0.001 for liver imaging). R2* approximately doubled between 1.5 T and 3 T with linear fits for both heart and liver (94, 94 and 105 % respectively). Coefficients of variation for intra- and inter-observer reproducibility, as well as inter-study reproducibility trended to be less good at 3 T (3.5 to 6.5 %) than at 1.5 T (1.4 to 5.7 %) for both heart and liver T2*. Artefact scores for the heart were significantly worse with the 3 T BB sequence (median 4, IQR 2-5) compared with the 1.5 T BB sequence (4 [3-5], p = 0.007). CONCLUSION Heart and liver T2* and R2* at 3 T show close association with 1.5 T values, but there were more artefacts at 3 T and trends to lower reproducibility causing difficulty in quantifying low T2* values with high tissue iron. Therefore T2* imaging at 1.5 T remains the gold standard for clinical practice. However, in centres where only 3 T is available, equivalent values at 1.5 T may be approximated by halving the 3 T tissue R2* with subsequent conversion to T2*.
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Affiliation(s)
- Mohammed H. Alam
- />NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
- />Imperial College, London, UK
| | - Dominique Auger
- />NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
| | - Laura-Ann McGill
- />NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
- />Imperial College, London, UK
| | - Gillian C. Smith
- />NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
- />Imperial College, London, UK
| | | | - Cemil Izgi
- />NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
| | - A. John Baksi
- />NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
| | - Rick Wage
- />NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
| | - Peter Drivas
- />NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
| | - David N. Firmin
- />NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
- />Imperial College, London, UK
| | - Dudley J. Pennell
- />NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
- />Imperial College, London, UK
- />Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
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Ibrahim ESH, Khalifa AM, Eldaly AK. Influence of the analysis technique on estimating hepatic iron content using MRI. J Magn Reson Imaging 2016; 44:1448-1455. [PMID: 27240936 DOI: 10.1002/jmri.25317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Accepted: 05/05/2016] [Indexed: 12/17/2022] Open
Abstract
PURPOSE To investigate the effect of the analysis technique on estimating hepatic iron content using MRI. MATERIALS AND METHODS We evaluated the influences of single-exponential (EXP), bi-exponential (BEXP), and exponential-plus-constant (CEXP) models; and pixel-wise (MAP), average (AVG), and median (MED) signal calculation methods on T2* measurement using numerical simulations, calibrated phantoms, and nine patients scanned on 3 Tesla MRI, based on regression, correlation, and t-test statistical analysis. RESULTS The T2* measurement error varied from 9 to 51% in the numerical simulations (T2*: 5-20 ms), depending on signal-to-noise ratio (SNR; range: 8-233) with significant (P < 0.05) difference between actual and predicted values. The MAP method performed well (error < 10%) at high SNR (>100), but resulted in severe estimation errors at low SNR (<50). The EXP model resulted in significant measurement differences (P < 0.05) compared with all other methods, irrespective of SNR. In vivo T2* values ranged from 3.1 to 53.6 ms, depending on the amount of iron overload and implemented analysis method. The BEXP (range: 3.7-50 ms) and CEXP (range: 3.8-53.6 ms) models, and the AVG (range: 3.2-38.8 ms) and MED (range: 3.1-38.5 ms) methods provided more accurate measurements than the EXP model (range: 3.1-18.3 ms) and MAP (range: 3.8-53.6 ms) method, respectively (P < 0.05). The BEXP and CEXP models provided very similar measurements (P > 0.87). Similarly, the AVG and MED methods provided very similar results (P > 0.97), with slightly better performance of the AVG method. CONCLUSION Different analysis techniques show different performances based on the fitting model and signal calculation method. Based on this study, the CEXP model and AVG method are recommended due to simpler implementation and less influence by the selected analysis region. J. Magn. Reson. Imaging 2016;44:1448-1455.
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Affiliation(s)
- El-Sayed H Ibrahim
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Ayman M Khalifa
- Department of Biomedical Engineering, Helwan University, Cairo, Egypt
| | - Ahmed K Eldaly
- Department of Biomedical Engineering, Helwan University, Cairo, Egypt
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Comparison of myocardial T1 and T2 values in 3 T with T2* in 1.5 T in patients with iron overload and controls. Int J Hematol 2016; 103:530-6. [PMID: 26872908 DOI: 10.1007/s12185-016-1950-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 01/26/2016] [Accepted: 01/26/2016] [Indexed: 12/31/2022]
Abstract
Myocardial iron quantification remains limited to 1.5 T systems with T2* measurement. The present study aimed at comparing myocardial T2* values at 1.5 T to T1 and T2 mapping at 3.0 T in patients with iron overload and healthy controls. A total of 17 normal volunteers and seven patients with a history of myocardial iron overload were prospectively enrolled. Mid-interventricular septum T2*, native T1 and T2 times were quantified on the same day, using a multi-echo gradient-echo sequence at 1.5 T and T1 and T2 mapping sequences at 3.0 T, respectively. Subjects with myocardial iron overload (T2* < 20 ms) in comparison with those without had significantly lower mean myocardial T1 times (868.9 ± 120.2 vs. 1170.3 ± 25.0 ms P = 0.005 respectively) and T2 times (34.9 ± 4.7 vs. 45.1 ± 2.0 ms P = 0.007 respectively). 3 T T1 and T2 times strongly correlated with 1.5 T, T2* times (Pearson's r = 0.95 and 0.91 respectively). T1 and T2 measures presented less variability than T2* in inter- and intra-observer analysis. Native myocardial T1 and T2 times at 3 T correlate closely with T2* times at 1.5 T and may be useful for myocardial iron overload quantification.
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Ibrahim ESH, Cernigliaro JG, Pooley RA, Bridges MD, Giesbrandt JG, Williams JC, Haley WE. Detection of different kidney stone types: an ex vivo comparison of ultrashort echo time MRI to reference standard CT. Clin Imaging 2015; 40:90-5. [PMID: 26526527 DOI: 10.1016/j.clinimag.2015.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 08/24/2015] [Accepted: 09/04/2015] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND PURPOSE With the development of ultrashort echo time (UTE) sequences, it may now be possible to detect kidney stones by using magnetic resonance imaging (MRI). In this study, kidney stones of varying composition and sizes were imaged using both UTE MRI as well as the reference standard of computed tomography (CT), with different surrounding materials and scan setups. METHODS One hundred and fourteen kidney stones were inserted into agarose and urine phantoms and imaged both on a dual-energy CT (DECT) scanner using a standard renal stone imaging protocol and on an MRI scanner using the UTE sequence with both head and body surface coils. A subset of the stones representing all composition types and sizes was then inserted into the collecting system of porcine kidneys and imaged in vitro with both CT and MRI. RESULTS All of the stones were visible on both CT and MRI imaging. DECT was capable of differentiating between uric acid and nonuric acid stones. In MRI imaging, the choice of coil and large field of view (FOV) did not affect stone detection or image quality. The MRI images showed good visualization of the stones' shapes, and the stones' dimensions measured from MRI were in good agreement with the actual values (R(2)=0.886, 0.895, and 0.81 in the agarose phantom, urine phantom, and pig kidneys, respectively). The measured T2 relaxation times ranged from 4.2 to 7.5ms, but did not show significant differences among different stone composition types. CONCLUSIONS UTE MRI compared favorably with the reference standard CT for imaging stones of different composition types and sizes using body surface coil and large FOV, which suggests potential usefulness of UTE MRI in imaging kidney stones in vivo.
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Affiliation(s)
- El-Sayed H Ibrahim
- Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA; University of Michigan, 1500 East Medical Center Drive, Ann Arbor, MI 48109, USA.
| | | | - Robert A Pooley
- Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | | | | | - James C Williams
- Indiana University, 340 West 10th Street, Indianapolis, IN 46202, USA
| | - William E Haley
- Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA
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Ibrahim ESH, Pooley RA, Bridges MD, Cernigliaro JG, Haley WE. Kidney stone imaging with 3D ultra-short echo time (UTE) magnetic resonance imaging. A phantom study. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2014:2356-9. [PMID: 25570462 DOI: 10.1109/embc.2014.6944094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Computed tomography (CT) is the current gold standard for imaging kidney stones, albeit at the cost of radiation exposure. Conventional magnetic resonance imaging (MRI) sequences are insensitive to detecting the stones because of their appearance as a signal void. With the development of 2D ultra-short echo-time (UTE) MRI sequences, it becomes possible to image kidney stones in vitro. In this work, we optimize and implement a modified 3D UTE MRI sequence for imaging kidney stones embedded in agarose phantoms mimicking the kidney tissue and in urine phantoms at 3.0T. The proposed technique is capable of imaging the stones with high spatial resolution in a short scan time.
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Ibrahim ESH, Khalifa AM, Eldaly AK. The influence of the analysis technique on estimating liver iron overload using magnetic resonance imaging T2* quantification. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2014:4639-42. [PMID: 25571026 DOI: 10.1109/embc.2014.6944658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Iron toxicity is the major cause of tissue damage in patients with iron overload. Iron deposits mainly in the liver, where its concentration closely correlates with whole body iron overload. Different techniques have been proposed for estimating iron content, with liver biopsy being the gold standard despite its invasiveness and influence by sampling error. Recently, magnetic resonance imaging (MRI) has been established as an effective technique for evaluating iron overload by measuring T2(*) in the liver. However, various factors associated with the adopted analysis technique, mainly the exponential fitting model and signal averaging method, affect the resulting measurements. In this study, we evaluate the influences of these factors on T2(*) measurement in numerical phantom, calibrated phantoms, and nine patients with different degrees of iron overload. The results show different performances among the fitting models and signal averaging methods, which are affected by SNR, image quality and signal homogeneity inside the selected ROI for analysis.
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