Liver T2 Research Articles

Association between CMR derived hepatic T1 times, tricuspid regurgitation severity, and outcomes

Abstract Background Hepatic T1 times have been shown to predict adverse clinical outcomes. However, up to date, the various causes contributing to changes in hepatic T1 times are not fully understood. So far, strong correlations with liver congestion and hepatic fibrosis have been demonstrated. Valvular heart disease, especially tricuspid regurgitation (TR), can lead to congestive hepatopathy (CH) and might significantly increase liver T1 values. In contrast, hepatic steatosis – commonly present in patients with cardiovascular disease - would result in lower T1 values. Currently, no studies are investigating the relationship between hepatic T1 times and TR. Methods We retrospectively measured hepatic T1-times, displayed on standard cardiac T1-maps, in an all-comer CMR cohort. Only patients, who underwent a comprehensive transthoracic echocardiogram within three weeks of CMR were included. Results 1029 participants (67±17 y/o, 44% female) had mean hepatic T1-times of 605±79ms. Overall, 41% (417) presented with non/trace, 38% (391) mild, 13% (135) moderate, 8% (85) severe, massive, and torrential tricuspid regurgitation. Liver T1 times were significantly correlated with TR severity (no/trace: 586±72ms; mild: 601±74ms; moderate: 634±84ms; severe/massive/torrential: 665±83ms; r= 0.25, p<0.001). Additionally, when adjusted for higher NT-proBNP levels, and right ventricular function in a linear regression model, TR severity was associated with hepatic T1 times (p<0.001). During follow-up (mean 53±36months), a total of 326 (32%) events occurred. Patients with higher T1 times and more severe tricuspid regurgitation were more likely to suffer events (adj.HR 1.44 [95%CI:1.23-1.69] per 100ms increase, p<0.001). Conclusion Tricuspid regurgitation exerts a notable influence on hepatic T1 times which is likely attributable to hepatic congestion. Importantly, hepatic T1 times were associated with outcomes even after adjustment for NTproBNP, LVEF, and RVEF. This underscores the importance of hepatic T1 times as both a marker of tricuspid regurgitation and an independent predictor of clinical outcomes.

Organ-Specific Iron Overload in Non-Transfusion-Dependent Thalassemia Patients: Insights from Quantitative MRI Evaluation

ObjectiveTo elucidate the iron load in different organs of non-transfusion-dependent thalassemia (NTDT) patients using magnetic resonance imaging (MRI) T2* scan. MethodsThirty-four NTDT patients, including 28 NTDT iron chelation without and 6 NTDT with iron chelation, together with 15 normal controls, underwent MRI examination between December 2022 and July 2024 were enrolled in the study. Measured T2* of the pituitary gland, kidney cortex, heart, liver, pancreas, spleen. Liver and spleen volumes were evaluated. ResultsOf the 28 patients in NTDT without iron chelation group, 19 patients with iron overload in the liver, 9 patients with iron overload in the kidneys, and 4 patients with iron overload in the spleen. Most patients with abnormal kidney and spleen iron (76.9 %) had liver iron overload. Compared with the control group, NTDT without iron chelation patients had lower T2* in the liver, kidney, and spleen (p < 0.05). And heart T2* was correlated with kidney T2* (r = 0.480, p = 0.010) and pancreas (r = 0.411, p = 0.037). Liver T2* was correlated with spleen T2* (r = 0.479, p = 0.011). Pancreas T2* was correlated with pituitary T2* (r = -0.433, p = 0.031). ConclusionsNTDT patients exhibit significant organ-specific iron overload, particularly in the liver, kidneys, and spleen. The correlations between iron levels in different organs suggest interconnected mechanisms of iron accumulation. These findings highlight the importance of regular MRI screening to monitor and manage iron overload in NTDT patients.

Assessment of transfusion-induced iron overload with T2*MRI in survivors of childhood acute lymphoblastic leukemia: A case control study

IntroductionChildhood acute lymphoblastic leukemia survivors receiving multiple packed red blood transfusions may be at risk of vital organ iron deposition causing long-term complications. This study was undertaken to assess the prevalence and severity of iron overload in the liver and heart by magnetic resonance imaging. MethodsA case-control study was conducted on 60 acute lymphoblastic leukemia survivors aged from 6 to 18 years and 60 healthy, age- and sex-matched children as a control group. The hematological profile, and serum ferritin was assessed and the iron content of the liver and heart was measured by T2* magnetic resonance imaging. ResultsTwenty-six (43.3 %) and two (3.3 %) patients had elevated liver and myocardial iron concentrations, respectively. The statistics show a significantly positive correlation between liver T2* magnetic resonance and serum ferritin. The total volume of blood transfused and duration of follow up were associated with elevated liver iron concentrations (p-values = 0.036 and 0.028 respectively). Myocardial T2* magnetic resonance lacked correlation with serum ferritin and transfusion therapy ConclusionLiver iron overload was detected in children and adolescents after acute lymphoblastic leukemia therapy. The risk of iron overload was related mainly to the transfusion burden during therapy. These patients need monitoring after therapy to assess their need for future chelation therapy.

Magnetic resonance imaging T1 mapping of the liver, pancreas and spleen in children

PurposeTo characterize T1 relaxation times of the pancreas, liver, and spleen in children with and without abdominal pathology.MethodsThis retrospective study included pediatric patients (< 18-years-old). T1 mapping was performed with a Modified Look-Locker Inversion Recovery sequence. Patients were grouped based on review of imaging reports and electronic medical records. The Kruskal–Wallis test with Dunn’s multiple comparison was used to compare groups.Results220 participants were included (mean age: 11.4 ± 4.2 years (1.5 T); 10.9 ± 4.5 years (3 T)). Pancreas T1 (msec) was significantly different between subgroups at 1.5 T (p < 0.0001). Significant pairwise differences included: normal (median: 583; IQR: 561–654) vs. acute pancreatitis (731; 632–945; p = 0.0024), normal vs. chronic pancreatitis (700; 643–863; p = 0.0013), and normal vs. acute + chronic pancreatitis (1020; 897–1099; p < 0.0001). Pancreas T1 was also significantly different between subgroups at 3 T (p < 0.0001). Significant pairwise differences included: normal (779; 753–851) vs. acute pancreatitis (1087; 910–1259; p = 0.0012), and normal vs. acute + chronic pancreatitis (1226; 1025–1367; p < 0.0001).Liver T1 was significantly different between subgroups only at 3 T (p = 0.0011) with pairwise differences between normal (818, 788–819) vs. steatotic (959; 848–997; p = 0.0017) and normal vs. other liver disease (882; 831–904; p = 0.0455). Liver T1 was weakly correlated with liver fat fraction at 1.5 T (r = 0.39; 0.24–0.52; p < 0.0001) and moderately correlated at 3 T (r = 0.64; 0.49–0.76; p < 0.0001).There were no significant differences in splenic T1 relaxation times between subgroups.ConclusionPancreas T1 relaxation times are higher at 1.5 T and 3 T in children with pancreatitis and liver T1 relaxation times are higher in children with steatotic and non-steatotic chronic liver disease at 3 T.

Intravenous iron therapy results in rapid and sustained rise in myocardial iron content through a novel pathway.

Intravenous iron therapies contain iron-carbohydrate complexes, designed to ensure iron becomes bioavailable via the intermediary of spleen and liver reticuloendothelial macrophages. How other tissues obtain and handle this iron remains unknown. This study addresses this question in the context of the heart. A prospective observational study was conducted in 12 patients receiving ferric carboxymaltose (FCM) for iron deficiency. Myocardial, spleen, and liver magnetic resonance relaxation times and plasma iron markers were collected longitudinally. To examine the handling of iron taken up by the myocardium, intracellular labile iron pool (LIP) was imaged in FCM-treated mice and cells. In patients, myocardial relaxation time T1 dropped maximally 3 h post-FCM, remaining low 42 days later, while splenic T1 dropped maximally at 14 days, recovering by 42 days. In plasma, non-transferrin-bound iron (NTBI) peaked at 3 h, while ferritin peaked at 14 days. Changes in liver T1 diverged among patients. In mice, myocardial LIP rose 1 h and remained elevated 42 days after FCM. In cardiomyocytes, FCM exposure raised LIP rapidly. This was prevented by inhibitors of NTBI transporters T-type and L-type calcium channels and divalent metal transporter 1. Intravenous iron therapy with FCM delivers iron to the myocardium rapidly through NTBI transporters, independently of reticuloendothelial macrophages. This iron remains labile for weeks, reflecting the myocardium's limited iron storage capacity. These findings challenge current notions of how the heart obtains iron from these therapies and highlight the potential for long-term dosing to cause cumulative iron build-up in the heart.

DYNamic Assessment of Multi-Organ level dysfunction in patients recovering from COVID-19: DYNAMO COVID-19.

We evaluated the impacts of COVID-19 on multi-organ and metabolic function in patients following severe hospitalised infection compared to controls. Patients (n=21) without previous diabetes, cardiovascular or cerebrovascular disease were recruited 5-7months post-discharge alongside controls (n=10) with similar age, sex and body mass. Perceived fatigue was estimated (Fatigue Severity Scale) and the following were conducted: oral glucose tolerance (OGTT) alongside whole-body fuel oxidation, validated magnetic resonance imaging and spectroscopy during resting and supine controlled exercise, dual-energy X-ray absorptiometry, short physical performance battery (SPPB), intra-muscular electromyography, quadriceps strength and fatigability, and daily step-count. There was a greater insulin response (incremental area under the curve, median (inter-quartile range)) during the OGTT in patients [18,289 (12,497-27,448) mIU/min/L] versus controls [8655 (7948-11,040) mIU/min/L], P<0.001. Blood glucose response and fasting and post-prandial fuel oxidation rates were not different. This greater insulin resistance was not explained by differences in systemic inflammation or whole-body/regional adiposity, but step-count (P=0.07) and SPPB scores (P=0.004) were lower in patients. Liver volume was 28% greater in patients than controls, and fat fraction adjusted liver T1, a measure of inflammation, was raised in patients. Patients displayed greater perceived fatigue scores, though leg muscle volume, strength, force-loss, motor unit properties and post-exercise muscle phosphocreatine resynthesis were comparable. Further, cardiac and cerebral architecture and function (at rest and on exercise) were not different. In this cross-sectional study, individuals without known previous morbidity who survived severe COVID-19 exhibited greater insulin resistance, pointing to a need for physical function intervention in recovery.

Noninvasive assessment of organ-specific and shared pathways in multi-organ fibrosis using T1 mapping.

Fibrotic diseases affect multiple organs and are associated with morbidity and mortality. To examine organ-specific and shared biologic mechanisms that underlie fibrosis in different organs, we developed machine learning models to quantify T1 time, a marker of interstitial fibrosis, in the liver, pancreas, heart and kidney among 43,881 UK Biobank participants who underwent magnetic resonance imaging. In phenome-wide association analyses, we demonstrate the association of increased organ-specific T1 time, reflecting increased interstitial fibrosis, with prevalent diseases across multiple organ systems. In genome-wide association analyses, we identified 27, 18, 11 and 10 independent genetic loci associated with liver, pancreas, myocardial and renal cortex T1 time, respectively. There was a modest genetic correlation between the examined organs. Several loci overlapped across the examined organs implicating genes involved in a myriad of biologic pathways including metal ion transport (SLC39A8, HFE and TMPRSS6), glucose metabolism (PCK2), blood group antigens (ABO and FUT2), immune function (BANK1 and PPP3CA), inflammation (NFKB1) and mitosis (CENPE). Finally, we found that an increasing number of organs with T1 time falling in the top quintile was associated with increased mortality in the population. Individuals with a high burden of fibrosis in ≥3 organs had a 3-fold increase in mortality compared to those with a low burden of fibrosis across all examined organs in multivariable-adjusted analysis (hazard ratio = 3.31, 95% confidence interval 1.77-6.19; P = 1.78 × 10-4). By leveraging machine learning to quantify T1 time across multiple organs at scale, we uncovered new organ-specific and shared biologic pathways underlying fibrosis that may provide therapeutic targets.

Evaluation of iron overload in visceral organs in thalassemia patients by point shear-wave elastography.

The aim of this study was to investigate the value of point shear-wave elastography (pSWE) in the measurement of iron overload in the liver and other visceral organs in patients with beta thalassemia major (BTM). The study included 103 patients diagnosed with BTM who were referred to our clinic for cardiac and liver T2* measurement and a control group of 120 age- and gender-matched healthy volunteers. Cardiac and hepatic T2* measurements were performed in the patient group. Hepatic, pancreatic, splenic, and renal pSWE values were measured in both groups. The pSWE values were compared between the two groups. In the patient group, correlations between pSWE values, cardiac-hepatic T2* values and hepatic size, patient age, and serum ferritin levels were analyzed. Hepatic, pancreatic, splenic, and renal pSWE values were significantly higher in the patient group compared to the control group (p ≤ 0.001, < 0.001, 0.014, 0.026, respectively). In the patient group, hepatic pSWE values established a significant correlation with cardiac T2* values, liver size-T2*, pancreatic pSWE values, serum ferritin levels, and age (p = 0.006, < 0.001, 0.001, 0.042, 0.001, 0.032, respectively). In the ROC analysis, the area under the ROC curve was 0.807 for hepatic pSWE in the discrimination of thalassemia patients and healthy controls, and the cut-off value was 1.42, which gave a sensitivity and specificity of 75.7% and 75%, respectively. CONCLUSıON: Point shear-wave elastography can be a useful technique in the clinical measurement of iron overload in the liver, pancreas, spleen, and kidney.

Navigator-based motion compensation for liver BOLD measurement with five-echo SAGE EPI and breath-hold task.

The purpose of this work is to apply multi-echo spin- and gradient-echo (SAGE) echo-planar imaging (EPI) combined with a navigator-based (NAV) prospective motion compensation method for a quantitative liver blood oxygen level dependent (BOLD) measurement with a breath-hold (BH) task. A five-echo SAGE sequence was developed to quantitatively measure T2 and T2* to depict function with sufficient signal-to-noise ratio, spatial resolution and sensitivity to BOLD changes induced by the BH task. To account for respiratory motion, a navigator was employed in the form of a single gradient-echo projection readout, located at the diaphragm along the inferior-superior direction. Prior to each transverse imaging slice of the spin-echo EPI-based readouts, navigator acquisition and fat suppression were incorporated. Motion data was obtained from the navigator and transmitted back to the sequence, allowing real-time adjustments to slice positioning. Six healthy volunteers and three patients with liver carcinoma were included in this study. Quantitative T2 and T2* were calculated at each time point of the BH task. Parameters of t value from first-level analysis using a general linear model and hepatovascular reactivity (HVR) of Echo1, T2 and T2* were calculated. The motion caused by respiratory activity was successfully compensated using the navigator signal. The average changes of T2 and T2* during breath-hold were about 1% and 0.7%, respectively. With the help of NAV prospective motion compensation whole liver t values could be obtained without motion artifacts. The quantified liver T2 (34.7 ± 0.7 ms) and T2* (29 ± 1.2 ms) values agreed with values from literature. In healthy volunteers, the distribution of statistical t value and HVR was homogeneous throughout the whole liver. In patients with liver carcinoma, the distribution of t value and HVR was inhomogeneous due to metastases or therapy. This study demonstrates the feasibility of using a NAV prospective motion compensation technique in conjunction with five-echo SAGE EPI for the quantitative measurement of liver BOLD with a BH task.

Cardiac and Liver Fibrosis Assessed by Multiparametric MRI in Patients with Fontan Circulation.

The abnormal hemodynamics in Fontan circulation due to persistently increased systemic venous pressure results in hepatic venous congestion and Fontan-associated liver disease. Combined assessment of cardiac and liver fibrosis and cardiac remodeling using multiparametric MRI in this context have not been fully explored. To evaluate cardiac and liver fibrosis and cardiac remodeling using multiparametric MRI in patients who have undergone Fontan procedures. Thirty-eight patients and 23 controls underwent cardiac and liver MRI examinations in a 3.0-T scanner. Mann-Whitney, Fisher exact test, and Spearman's correlation were applied to evaluate myocardial volumes, function, native cardiac and liver T1 mapping, ECVs and liver stiffness. The mean native cardiac T1 value (p = 0.018), cardiac ECV (p < 0.001), liver native T1 (p < 0.001), liver ECV (p < 0.001), and liver stiffness (p < 0.001) were higher in patients than controls. The indexed end-diastolic volume (EDVi) correlated with the myocardial ECV (r = 0.356; p = 0.033), native liver T1 (r = 0.571; p < 0.001), and with liver stiffness (r = 0.391; p = 0.015). In addition, liver stiffness correlated with liver ECV (r = 0.361; p = 0.031) and native liver T1 (r = 0.458; p = 0.004). An association between cardiac remodeling and cardiac and liver fibrosis were found in this population. The usefulness of MRI to follow cardiac and liver involvement in these patients is critical to improve treatment strategies and to prevent the need for combined liver and heart transplantation.

MRI Dixon Fat-Corrected Look-Locker T1 Mapping for Quantification of Liver Fibrosis and Inflammation-A Comparison With the Non-Fat-Corrected Shortened Modified Look-Locker Inversion Recovery Technique.

This study evaluates the impact of liver steatosis on the discriminative ability for liver fibrosis and inflammation using a novel Dixon water-only fat-corrected Look-Locker T1 mapping sequence, compared with a standard shortened Modified Look-Locker Inversion Recovery (shMOLLI) sequence, with the aim of overcoming the limitation of steatosis-related confounding in liver T1 mapping. 3 T magnetic resonance imaging of the liver including the 2 T1 mapping sequences and proton density fat fraction (PDFF) was prospectively performed in 24 healthy volunteers and 38 patients with histologically proven liver fibrosis evaluated within 90 days of liver biopsy. Paired Mann-Whitney test compared sequences between participants with and without significant liver steatosis (PDFF cutoff 10%), and unpaired Kruskal-Wallis test compared healthy volunteers to patients with early (F0-2) and advanced (F3-4) liver fibrosis, as well as low (A0-1) and marked (A2-3) inflammatory activity. Univariate and multivariate logistic regression models assessed the impact of liver steatosis on both sequences. Dixon_W T1 was higher than shMOLLI T1 in participants without steatosis (median 896 ms vs 890 ms, P = 0.04), but lower in participants with liver steatosis (median 891 ms vs 973 ms, P < 0.001). Both methods accurately differentiated between volunteers and patients with early and advanced fibrosis (Dixon_W 849 ms, 910 ms, 947 ms, P = 0.011; shMOLLI 836 ms, 918 ms, 978 ms, P < 0.001), and those with mild and marked inflammation (Dixon_W 849 ms, 896 ms, 941 ms, P < 0.01; shMOLLI 836 ms, 885 ms, 978 ms, P < 0.001). Univariate logistic regression showed slightly lower performance of the Dixon_W sequence in differentiating fibrosis (0.69 vs 0.73, P < 0.01), compensated by adding liver PDFF in the multivariate model (0.77 vs 0.75, P < 0.01). Dixon water-only fat-corrected Look-Locker T1 mapping accurately identifies liver fibrosis and inflammation, with less dependency on liver steatosis than the widely adopted shMOLLI T1 mapping technique, which may improve its predictive value for these conditions.

Role of magnetic resonance imaging (MRI) in liver iron quantification in thalassemic (thalassemia major) patients

BackgroundIron overload is a major problem in beta thalassemia patients due to repeated blood transfusions. The liver is the first organ to be loaded with iron. An accurate assessment of iron overload is necessary for managing iron chelation therapy in such patients. Iron quantification by MRI scores over liver biopsy due to its non-invasive nature.MethodsFifty-one patients with thalassemia major were subjected to 3.0-T MRI. Multiecho T2* sequence was used to cover the entire liver. Region of interest (ROI) was placed in three areas with maximum signal change, and an average T2* value was obtained. Similarly, a single ROI was placed at the mid-interventricular septum in the heart, and T2* value was obtained. T2* values so obtained were converted to iron concentration with the help of a T2* iron concentration calculator. The liver iron values were correlated with serum ferritin value.ResultsThere was a significant negative correlation between liver iron concentration (LIC) and T2* value of the liver (r = − 0.895, p < 0.01) and between cardiac iron concentration (CIC) and T2* value of the heart (r = − 0.959, p < 0.01). There was a slight positive correlation between LIC and serum ferritin (r = 0.642, p < 0.01) and no correlation between CIC and serum ferritin (r = − 0.137, p = 0.354).ConclusionsMRI is a useful tool to titrate the doses of chelating agents as it is accurate and non-invasive, does not involve radiation hazards and hence can be repeated as and when needed. Simultaneous assessment of cardiac iron overload is an added advantage of MRI.

Can Automated 3-Dimensional Dixon-Based Methods Be Used in Patients With Liver Iron Overload?

Accurate quantification of liver iron concentration (LIC) can be achieved via magnetic resonance imaging (MRI). Maps of liver T2*/R2* are provided by commercially available, vendor-provided, 3-dimensional (3D) multiecho Dixon sequences and allow automated, inline postprocessing, which removes the need for manual curve fitting associated with conventional 2-dimensional (2D) gradient echo (GRE)-based postprocessing. The main goal of our study was to investigate the relationship among LIC estimates generated by 3D multiecho Dixon sequence to values generated by 2D GRE-based R2* relaxometry as the reference standard. A retrospective review of patients who had undergone MRI scans for estimation of LIC with conventional T2* relaxometry and 3D multiecho Dixon sequences was performed. A 1.5 T scanner was used to acquire the magnetic resonance studies. Acquisition of standard multislice multiecho T2*-based sequences was performed, and R2* values with corresponding LIC were estimated. The comparison between R2* and corresponding LIC estimates obtained by the 2 methods was analyzed via the correlation coefficients and Bland-Altman difference plots. This study included 104 patients (51 male and 53 female patients) with 158 MRI scans. The mean age of the patients at the time of scan was 15.2 (SD, 8.8) years. There was a very strong correlation between the 2 LIC estimation methods for LIC values up to 3.2 mg/g (LIC quantitative multiecho Dixon [qDixon; from region of interest R2*] vs LIC GRE [in-house]: r = 0.83, P < 0.01; LIC qDixon [from segmentation volume R2*] vs LIC GRE [in-house]: r = 0.92, P < 0.01); and very weak correlation between the 2 methods at liver iron levels >7 mg/g. Three-dimensional-based multiecho Dixon technique can accurately measure LIC up to 7 mg/g and has the potential to replace 2D GRE-based relaxometry methods.

Reconstruction of multi-phase parametric maps in 4D-magnetic resonance fingerprinting (4D-MRF) by optimization of local T1 and T2 sensitivities.

Time-resolved magnetic resonance fingerprinting (MRF), or 4D-MRF, has been demonstrated its feasibility in motion management in radiotherapy (RT). However, the prohibitive long acquisition time is one of challenges of the clinical implementation of 4D-MRF. The shortening of acquisition time causes data insufficiency in each respiratory phase, leading to poor accuracies and consistencies of the predicted tissues' properties of each phase. To develop a technique for the reconstruction of multi-phase parametric maps in four-dimensional magnetic resonance fingerprinting (4D-MRF) through the optimization of local T1 and T2 sensitivities. The proposed technique employed an iterative optimization to tailor the data arrangement of each phase by manipulation of inter-phase frames, such that the T1 and T2 sensitivities, which were quantified by the modified Minkowski distance, of the truncated signal evolution curve was maximized. The multi-phase signal evolution curves were modified by sliding window reconstruction and inter-phase frame sharing (SWIFS). Motion correction (MC) and dot product matching were sequentially performed on the modified signal evolution and dictionary to reconstruct the multi-parametric maps. The proposed technique was evaluated by numerical simulations using the extended cardiac-torso (XCAT) phantom with regular and irregular breathing patterns, and by in vivo MRF data of three health volunteers and six liver cancer patients acquired at a 3.0 T scanner. In simulation study, the proposed SWIFS approach achieved the overall mean absolute percentage error (MAPE) of 8.62%±1.59% and 16.2%±3.88% for the eight-phases T1 and T2 maps, respectively, in the sagittal view with irregular breathing patterns. In contrast, the overall MAPE of T1 and T2 maps generated by the conventional approach with multiple MRF repetitions were 22.1%±11.0% and 30.8%±14.9%, respectively. For in-vivo study, the predicted mean T1 and T2 of liver by the proposed SWIFS approach were 795ms±38.9ms and 58.3ms±11.7ms, respectively. Both simulation and in vivo results showed that the approach empowered by T1 and T2 sensitivities optimization and sliding window under the shortened acquisition of MRF had superior performance in the estimation of multi-phase T1 and T2 maps as compared to the conventional approach with oversampling of MRF data.

Erratum: Head-to-head comparison of magnetic resonance elastography-based liver stiffness, fat fraction, and T1 relaxation time in identifying at-risk NASH.

Erratum: Head-to-head comparison of magnetic resonance elastography-based liver stiffness, fat fraction, and T1 relaxation time in identifying at-risk NASH.

Accelerated liver water T1 mapping using single-shot continuous inversion-recovery spiral imaging.

Liver T1 mapping techniques typically require long breath holds or long scan time in free-breathing, need correction for inhomogeneities and process composite (water and fat) signals. The purpose of this work is to accelerate the multi-slice acquisition of liver water selective T1 (wT1) mapping in a single breath hold, improving the k-space sampling efficiency. The proposed continuous inversion-recovery (IR) Look-Locker methodology combines a single-shot gradient echo spiral readout, Dixon processing and a dictionary-based analysis for liver wT1 mapping at 3 T. The sequence parameters were adapted to obtain short scan times. The influence of fat, inhomogeneities and TE on the estimation of T1 was first assessed using simulations. The proposed method was then validated in a phantom and in 10 volunteers, comparing it with MRS and the modified Look-Locker inversion-recovery (MOLLI) method. Finally, the clinical feasibility was investigated by comparing wT1 maps with clinical scans in nine patients. The phantom results are in good agreement with MRS. The proposed method encodes the IR-curve for the liver wT1 estimation, is minimally sensitive to inhomogeneities and acquires one slice in 1.2 s. The volunteer results confirmed the multi-slice capability of the proposed method, acquiring nineslices in a breath hold of 11 s. The present work shows robustness to inhomogeneities ( , good repeatability ( and is in better agreement with MRS ( than is MOLLI ( . The wT1 maps in patients captured diverse lesions, thus showing their clinical feasibility. A single-shot spiral acquisition can be combined with a continuous IR Look-Locker method to perform rapid repeatable multi-slice liver water T1 mapping at a rate of 1.2 s per slice without a map. The proposed method is suitable for nine-slice liver clinical applications acquired in a single breath hold of 11 s.

Two risk factors for hypozincemia in diabetic β-thalassemia patients: Hepatitis C and deferasirox.

Hypozincemia is a prevalent adverse consequence in diabetes mellitus (DM) and β-Thalassemia patients. We aimed to evaluate the level of serum zinc in β-thalassemia patients with DM and a risk assessment for hypozincemia. The study population included transfusion-dependent thalassemia (TDT) and non-transfusion-dependent thalassemia (NTDT) with overt DM (fasting plasma glucose (FPG) ≥126 mg/dL, and/or 2-h plasma glucose≥200 mg/dL). Serum zinc concentration was measured by the colorimetric method, and the values below 70 μg/dL were defined as hypozincemia. Myocardial and liver T2*-weighted magnetic resonance imaging (MRI T2*, millisecond [ms]) were valued by a free contrast MRI. The demographic, clinical, paraclinical, and laboratory data were also recorded. The data belonged to the period from December 2018 until December 2020. Of 64 diabetic β-thalassemia patients, 41 cases had zinc data in their medical files (aged 38 ± 9 years, 48.8% female). 78.05% of patients (n = 32) were TDT, and 21.95% were NTDT (n = 9). The mean ± standard deviation of zinc level was 110.2 ± 127.6 μg/dL. The prevalence of hypozincemia was 9.76%, 95% confidence interval [CI] 0.27 to 19.24 (four cases). After controlling age, the odds of hypozincemia for using deferasirox (DFX) was 8.77, 95% CI 0.60 to 127.1. In β-thalassemia patients, the age-adjusted risk of hypozincemia was calculated at 15.85, 95% CI 0.47 to 529.3 for hepatitis C. The adjusted risk of hypozincemia based on age for antacid use was 6.34, 95% CI 0.39 to 102.7. In light of this study, as well as hepatitis C, using DFX and antacids is associated with a high risk of hypozincemia amid diabetic β-thalassemia cases. However, upward bias should be taken into consideration.

Liver T1 Mapping Derived From Cardiac Magnetic Resonance Imaging: A Potential Prognostic Marker in Idiopathic Dilated Cardiomyopathy.

Hepatic alterations are common aftereffects of heart failure (HF) and ventricular dysfunction. The prognostic value of liver injury markers derived from cardiac MRI studies in nonischemic dilated cardiomyopathy (DCM) patients is unclear. Evaluate the prognostic performance of liver injury markers derived from cardiac MRI studies in DCM patients. Prospective. Three hundred fifty-six consecutive DCM patients diagnosed according to ESC guidelines (age 48.7 ± 14.2 years, males 72.6%). Steady-state free precession, modified Look-Locker inversion recovery T1 mapping and phase sensitive inversion recovery late gadolinium enhancement (LGE) sequences at 3 T. Clinical characteristics, conventional MRI parameters (ventricular volumes, function, mass), native myocardial and liver T1, liver extracellular volume (ECV), and myocardial LGE presence were assessed. Patients were followed up for a median duration of 48.3 months (interquartile range 42.0-69.9 months). Primary endpoints included HF death, sudden cardiac death, heart transplantation, and HF readmission; secondary endpoints included HF death, sudden cardiac death, and heart transplantation. Models were developed to predict endpoints and the incremental value of including liver parameters assessed. Optimal cut-off value was determined using receiver operating characteristic curve and Youden method. Survival analysis was performed using Kaplan-Meier and Cox proportional hazard. Discriminative power of models was compared using net reclassification improvement and integrated discriminatory index. P value <0.05 was considered statistically significant. 47.2% patients reached primary endpoints; 25.8% patients reached secondary endpoints. Patients with elevated liver ECV (cut-off 34.4%) had significantly higher risk reaching primary and secondary endpoints. Cox regression showed liver ECV was an independent prognostic predictor, and showed independent prognostic value for primary endpoints and long-term HF readmission compared to conventional clinical and cardiac MRI parameters. Liver ECV is an independent prognostic predictor and may serve as an innovative approach for risk stratification for DCM. 1 TECHNICAL EFFICACY: Stage 2.

Beta-Thalassemia Major and Myocardial Iron Overload: A Longitudinal Study with Magnetic Resonance Imaging.

Patients with β-thalassemia major depend on lifelong transfusion, resulting in tissue iron overload. This longitudinal retrospective observational study aims to assess myocardial and liver iron overload using magnetic resonance imaging (MRI) and investigate the lag between myocardial and liver iron unloading in β-thalassemia patients undergoing chelation therapy. Beta-thalassemia major patients with at least two MRI studies between 2016 and 2020 were enrolled. Myocardial and liver iron overload were defined as T2 ∗ less than 20 and 2.1, respectively. Outcomes included mortality, myocardial and liver T2 ∗ changes, and systolic dysfunction assessed by cardiac MRI. Fifty-five patients with a mean age of 24.62 ± 7.94 years, a mean follow-up duration of 24.3 ± 12.9 months, and a mean ferritin level of 1475.75 ± 771.12 ng/mL were enrolled. All of the abovementioned patients only took deferoxamine as the iron-chelating medication. Mortality occurred in three patients (5.5%) during follow-up. Liver T2 ∗ significantly increased (p value <0.05), while myocardial T2 ∗ showed a nonsignificant increase. Iron unloading of the myocardium was not significantly different from that of the liver and did not result in a significant lag (56% vs. 44%; p value = 0.419). Baseline myocardial T2 ∗ correlated with extramedullary hematopoiesis, weekly number of deferoxamine injections (p value <0.01), timing between the transfusions, and serum ferritin (p value <0.05). Liver T2 ∗ reduced during deferoxamine chelation therapy, while myocardial T2 ∗ remained unchanged. No significant lag was observed between myocardial and liver iron unloading. Further studies are required to elucidate these findings.

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.