Liver Iron Overload In Patients Research Articles

Assessing the accuracy of CMRtools software for diagnosing liver iron overload in thalassemia patients: influencing factors and optimisation strategies.

CMRtools is a software package that can be used to measure T2* values to diagnose liver iron overload, however, its accuracy in terms is affected by multiple factors, including goodness-of-fit (R2 value), the number of echo time (TE) images, and the liver iron concentration (LIC). To investigate the effects of the R2 value, the number of TE images, and the LIC on the accuracy of CMRtools software for measuring T2* values to diagnose liver iron overload (LIO). CMRtools software was used to measure liver T2* values among 108 thalassemia patients via the truncation method, and the R2 values, the number of TE images, and T2* values were recorded. These values were subsequently converted into liver iron concentration (LICT) values. The LICF (derived from MRI-R2/FerriScan) was used as a reference, and the diagnostic accordance rate (DAR) was compared between R2 value subgroups, between TE image number subgroups, and between LIC subgroups. The greater the R2 value was, the greater the standardized DAR (SDAR) was (p < 0.05). The SDAR are not identical between each TE image number subgroup (p > 0.05). However, the relationship between TE image number subgroups and SDAR was analysed using Spearman's correlation, and it was found to be positively correlated (rs = 0.729, p = 0.017). The SDAR are not identical between each LIC subgroup (p > 0.05), furthermore, the relationship between LIC subgroup and SDAR was found irrelevant (p = 0.747). The accuracy of CMRtools software for diagnosing LIO in patients with thalassemia can be improved by artificially controlling the number of TE images to be fitted and selecting higher R2 values.

Prediction of Heart and Liver Iron Overload in β-Thalassemia Major Patients Using Machine Learning Methods

Patients with β-thalassemia major (β-TM) face a wide range of complications as a result of excess iron in vital organs, including the heart and liver. Our aim was to find the best predictive machine learning (ML) model for assessing heart and liver iron overload in patients with β-TM. Data from 624 β-TM patients were entered into three ML models using random forest (RF), gradient boost model (GBM), and logistic regression (LR). The data were classified and analyzed by R software. Four evaluation metrics of predictive performance were measured: sensitivity, specificity, accuracy, and area under the curve (AUC), operating characteristic curve. For heart iron overload, the LR had the highest predictive performance based on AUC: 0.68 [95% CI (95% confidence interval): 0.60, 0.75]. The GBM also had the highest specificity (69.0%) and accuracy (67.0%). Most sensitivity is also acquired with LR (75.0%). For liver iron overload, the highest performance based on AUC was observed with RF, AUC: 0.68 (95% CI: 0.59, 0.76). The RF showed the highest accuracy (66.0%) and specificity (66.0%), while the LR had the highest sensitivity (84.0%). Ferritin, duration of transfusion, and age were determined as the most effective predictors of iron overload in both heart and liver. Logistic regression LR was determined to be the strongest method to predict cardiac and RF values for liver iron overload in patients with β-TM. Older thalassemia patients with a high serum ferritin (SF) level and a longer duration of transfusion therapy were more prone to heart and liver iron overload.

Evaluation of Hepatic Iron Overload Using a Contemporary 0.55 T MRI System.

MRI T2* and R2* mapping have gained clinical acceptance for noninvasive assessment of iron overload. Lower field MRI may offer increased measurement dynamic range in patients with high iron concentration and may potentially increase MRI accessibility, but it is compromised by lower signal-to-noise ratio that reduces measurement precision. To characterize a high-performance 0.55 T MRI system for evaluating patients with liver iron overload. Prospective. Forty patients with known or suspected iron overload (sickle cell anemia [n=5], ß-thalassemia [n=3], and hereditary spherocytosis [n=2]) and a liver iron phantom. A breath-held multiecho gradient echo sequence at 0.55 T and 1.5 T. Patients were imaged with T2*/R2* mapping 0.55 T and 1.5 T within 24 hours, and 16 patients returned for follow-up exams within 6-16 months, resulting in 56 paired studies. Liver T2* and R2* measurements and standard deviations were compared between 0.55 T and 1.5 T and used to validate a predictive model between field strengths. The model was then used to classify iron overload at 0.55 T. Linear regression and Bland-Altman analysis were used for comparisons, and measurement precision was assessed using the coefficient of variation. A P-value < 0.05 was considered statistically significant. R2* was significantly lower at 0.55 T in our cohort (488 ± 449 s-1 at 1.5 T vs. 178 ± 155 s-1 at 0.55 T, n=56 studies) and in the patients with severe iron overload (937 ± 369 s-1 at 1.5 T vs. 339 ± 127 s-1 at 0.55 T, n=23 studies). The coefficient of variation indicated reduced precision at 0.55 T (3.5 ± 2.2% at 1.5 T vs 6.9 ± 3.9% at 0.55 T). The predictive model accurately predicted 1.5 T R2* from 0.55 T R2* (Bland Altman bias=-6.6 ± 20.5%). Using this model, iron overload at 0.55 T was classified as: severe R2* > 185 s-1 , moderate 81 s-1 < R2* < 185 s-1 , and mild 45 s-1 < R2* < 91 s-1 . We demonstrated that 0.55 T provides T2* and R2* maps that can be used for the assessment of liver iron overload in patients. 2 TECHNICAL EFFICACY: Stage 2.

Prevalence and predictors of cardiac and liver iron overload in patients with thalassemia: A multicenter study based on real-world data

Prevalence of cardiac and liver iron overload in patients with thalassemia in real-world practice may vary among different regions especially in the era of widely-used iron chelation therapy. The aim of this study was to determine the prevalence of cardiac and liver iron overload in and the management patterns of patients with thalassemia in real-world practice in Thailand. We established a multicenter registry for patients with thalassemia who underwent magnetic resonance imaging (MRI) as part of their clinical evaluation. All enrolled patients underwent cardiac and liver MRI for assessment of iron overload. There were a total of 405 patients enrolled in this study. The mean age of patients was 18.8±12.5years and 46.7% were male. Two hundred ninety-six (73.1%) of patients received regular blood transfusion. Prevalence of cardiac iron overload (CIO) and liver iron overload (LIO) was 5.2% and 56.8%, respectively. Independent predictors for iron overload from laboratory information were serum ferritin and transaminase for both CIO and LIO. Serum ferritin can be used as a screening tool to rule-out CIO and to diagnose LIO. Iron chelation therapy was given in 74.6%; 15.3% as a combination therapy.

Accuracy of Magnetic Resonance Imaging in Diagnosis of Liver Iron Overload: A Systematic Review and Meta-analysis

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. 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. 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). 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.

Sobrecarga de ferro transfusional em portadores de anemia falciforme: comparação entre ressonância magnética e ferritina sérica

OBJETIVO: Identificar variáveis preditoras de sobrecarga de ferro em portadores de anemia falciforme e correlacionar indicadores bioquímicos e imaginológicos. MATERIAiS E MÉTODOS: Foi realizado estudo transversal envolvendo 32 portadores de anemia falciforme, que foram submetidos a dosagem sérica de ferro, ferritina e a ressonância magnética do fígado. Foram realizadas cinco sequências gradiente-eco e uma spin-eco. A intensidade de sinal foi obtida em cada sequência pelas médias das regiões de interesse no fígado e musculatura paravertebral para obter a razão da intensidade de sinal (RIS) fígado/músculo. A partir da RIS foi obtida a concentração hepática estimada de ferro (CHEF) pela fórmula: e[5,808 - (0,877 × T2*) - (1,518 × PI)], onde T2* é a RIS na sequência com TE de 13 ms e PI é a RIS da sequência com ponderação intermediária. Os pacientes foram agrupados segundo o regime de transfusão de hemácias (regulares mensais versus esporádicas). RESULTADOS: Os grupos transfusionais foram comparados pelas variáveis clínico-laboratoriais, sendo significativas as diferenças entre RIS, CHEF e ferritina sérica: o grupo que recebeu transfusões regulares apresentou sobrecarga de ferro hepático mais intensa. CONCLUSÃO: A ressonância magnética foi ferramenta eficiente para avaliação de sobrecarga hepática de ferro em portadores de anemia falciforme.

The role of MR imaging in detection of hepatic iron overload in patients with cirrhosis of different origins

BackgroundThere are many pathological conditions with hepatic iron overload. Classical definite diagnostic methods of these disorders are invasive and based on a direct tissue biopsy material. For the last years the role of MR imaging in liver diagnostics has been increasing. MRI shows changes of liver intensity in patients with hepatic iron overload. Changes in MR signal are an indirect consequence of change of relaxation times T2 and T2*, that can be directly measured.The purpose of the study was to evaluate usefulness of MR imaging in the detection of hepatic iron overload in patients with cirrhosis of different origins.MethodsMR imaging at 1.5T was prospectively performed in 44 patients with liver cirrhosis who had undergone liver biopsy with histopathological assessment of hepatic iron deposits. In all patients the following sequences were used: SE, Express, GRE in T2 and T1-weighted images. Signal intensity (SI) was measured on images obtained with each T2 weighted sequence by means of regions of interest, placed in the liver and paraspinal muscles. The correlation between iron overload, histopathological score, serum ferritin and SI ratio was analyzed.ResultsIn 20 patients with iron overload confirmed by the biopsy, the liver parenchyma demonstrated lower signal intensity than that of paraspinal muscles. This effect was visible only in 8 patients with hepatic iron overload in Express T2-weighted images. Higher signal intensity of liver than that of skeletal muscles on GRE - T2 weighted images was noted in 24 patients with cirrhosis and without elevated hepatic iron concentration. We observed a correlation between low and high iron concentration and liver to muscle SI ratio.ConclusionMR imaging is a useful and fast noninvasive diagnostic tool for the detection of liver iron overload in patients with cirrhosis of different origins.Liver to muscle SI ratio in GRE-T2-weighted sequence facilitates to differentiate patients with low and high degree of hepatic iron overload, which correlates with the origin of liver cirrhosis.

Transient Elastography May Predict Liver Iron Overload in Adult Thalassaemia Patients

Although it is life saving, transfusion therapy has resulted in the majority of thalassemia patients being at risk for hemosiderosis-induced organ damage. Liver Iron Concentration (LIC) assessed by liver biopsy is considered the most accurate and sensitive method for determining body iron burden in patients with iron overload. The development of liver fibrosis is more closely related to liver iron concentration. Transient elastography (FibroScan, FS), which measures liver stiffness (LS), is a novel, noninvasive method to assess liver fibrosis. Whether FS is useful in the detection of preexisting liver iron overload in patients presenting with thalassaemia major without chronic viral hepatitis, is unclear. On the other hand, Magnetic Resonance Imaging (MRI) is a relatively inexpensive, widely available but more time consuming method that has long been considered as a useful tool for the non-invasive estimation of tissue iron content in multiple transfused patients with thalassemia.Aim: To study the prevalence and severity of liver fibrosis of transfusion dependent thalassaemia major patients, and correlate the MRI.LIC with the measurements of FS.Methods-Patients: The applicability for FS (Echosens, Paris, France) was defined as at least 10 valid measures and a success rate (number of valid measures/total number of LS Measures, LSM) ≥60% and a ratio of interquartile range/stiffness ≤0,2. Most subjects with FS scores below 5.1 kilopascals (kPa) are considered to have minimal fibrosis (grade F0 or F1, METAVIR score) according to the literature. The cut off FS values for diagnosing different stages of hepatic fibrosis were defined as > 7.9kPa for F≥2, > 10.3kPa for F≥3 and > 11.9kPa for F=4. A total of 43 thalassaemic patients 23 males/20 females, median age 26,8±4,9 years, regularly transfused (pre-transfusion haemoglobin 9,7g/dl) were included in the study. All patients were hepatitis C virus (HCV) negative and chelated with different drugs (13 on deferasirox, 12 on deferiprone, 5 on desferrioxamine and 13 on combined therapy). Median ferritin levels were 1552±1576ng/ml. Liver tests (AST, ALT, γGT and Alkaline Phosphatase) were done simultaneously to all patients. Twenty-two of the 43 patients underwent liver iron determination (LIC) simultaneously by two methods: T2* Magnetic Imaging (T2*MRI) assessment and by calculation of MR-Hepatic Iron Concentration (MR.HIC) values (based on an algorithm developed by Gandon et al (Lancet 2004), using liver to muscle ratios in five axial gradient-echo sequences). T-test was used in statistical analysis to compare means.Results: Applicability of LSM was 100%. Overall median LSM was 8,25±6,05kPa (range 4–40,3kPa). Nineteen (44,1%) patients had FS<6,1kPa (notably 8/19 patients below 5,1kPa), 13 (30,2%) had <7,9kPa, 4 (9,3%) had <10,3kPa, 2 (4,7%) had <11,9kPa and 5 (11,7%) above 11,9kPa. Total FS correlated with Ferritin (r=0,39, p=0,008). Using the cutt-off value of 6,1 kPa for FS measurements, patients were divided in two groups with different ferritin levels: A (<6,1kPa) 1039±758ng/ml vs B (>6,1kPa) 1833±1742ng/ml, p<0,03. FS values of the three different major therapy groups did not differ significantly. FS (22pts) correlated negatively with T2*MRI results (r=−0,39, p=0,07) and positively with MR.HIC results (r=0,49, p=0,02). There was no correlation with liver function tests.Conclusions: Severe haemosiderosis and hepatic fibrosis are common in patients with thalassaemia major despite the use of chelation therapy and the absence of HCV. Elastography has several characteristics that make it a desirable method for assessing hepatic fibrosis. In addition to being noninvasive and painless, it is also quick, inexpensive, and produces consistent results. It can also be useful as an alternative to check for liver iron overload, as abnormal results predict heavy liver iron overload. Further longitudinal and prospective studies are necessary to confirm these preliminary data.

Liver iron overload in patients with chronic active hepatitis C. Prevalence, role of the hemochromatosis gene and relation with hepatic histological lesions

Liver iron overload in patients with chronic active hepatitis C. Prevalence, role of the hemochromatosis gene and relation with hepatic histological lesions