Measurement Of Liver Iron Concentration Research Articles

Improvement in Iron Burden in Patients with Transfusion-Dependent β-Thalassemia (TDT) Treated with Betibeglogene Autotemcel (Beti-cel) Gene Therapy: Up to 9 Years of Follow-up

Introduction: Beti-cel is an approved, one-time gene therapy treatment for adult and pediatric patients with TDT. Beti-cel consists of autologous hematopoietic stem and progenitor cells transduced with the BB305 lentiviral vector encoding a modified β-globin gene (β A-T87Q), which produces functional hemoglobin (Hb) and addresses the underlying genetic cause of TDT. While transfusion independence (TI) remains a critical component for assessing patient response to gene therapy, other measures, including markers of iron overload, are important for evaluating the impact of therapy and management of disease burden over time. Previously, we demonstrated that iron markers stabilized in patients who achieved TI and stopped chelation therapy. Here, we report iron management outcomes in patients who completed either a phase 1/2 or phase 3 beti-cel parent study and subsequently enrolled in the long-term follow-up study. Methods: Patients with TDT who completed a parent beti-cel study (phase 1/2 studies: HGB-204 [NCT01745120]; HGB-205 [NCT02151526]; phase 3 studies: HGB-207 [NCT02906202]; HGB-212 [NCT03207009]) could enroll in a long-term study (LTF-303 [NCT02633943]) for up to an additional 13 years of follow-up. In these studies, TI was defined as a weighted average Hb ≥9 g/dL without packed red blood cell transfusions for ≥12 months. Iron removal therapy was at the discretion of the treating physician. Liver and cardiac magnetic resonance imaging evaluated liver iron concentration (LIC) and cardiac T2*; serum ferritin and transferrin receptor (TfR) were assessed at regular intervals according to protocol. Results:As of January 30, 2023, 63 patients received beti-cel; median (range) follow-up was 60.1 (23.8-109.5) months. In phase 3 studies, 37/41 (90%) patients achieved TI and maintained TI through the last follow-up, which was 5+ years for 10 patients ( Figure 1). In phase 1/2 studies, 15/22 (68%) patients achieved TI; 14 of these patients maintained TI through the last follow-up, which was up to 9 years. One patient no longer meets protocol-defined TI as a result of Hb level <9g/dL at year 6 due to acute health events unrelated to β-thalassemia, which were not attributed to loss of beti-cel treatment effect. In total, 51 patients across phase 1/2 and 3 studies achieved and maintained TI through last follow-up with 35/51 (69%) patients off chelation. Thirty of 51 patients had an LIC measurement at month 48. Of these 30 patients, 21 had an LIC <5 mg/g at month 48 post infusion. Among these 21 patients, 5 never restarted chelation after infusion (2 received phlebotomy only), 11 restarted chelation and then were able to discontinue after iron stores normalized (1 also received phlebotomy), and 5 continue to receive chelation (none had phlebotomy). The other 9 patients who had an LIC measurement at month 48 had an iron burden ≥5 mg/g. All 9 of these patients restarted chelation; 4 were able to discontinue (2 had phlebotomy) and 5 continue to receive chelation (1 had phlebotomy). Analysis of iron marker stabilization after discontinuation of chelation will be presented. The median (range) change from baseline in LIC levels at month 48 was -3.9 (-22.3 to 10.5) mg Fe/g dry weight; the median (range) change from baseline in serum ferritin was -2119.0 (-7211 to 3889) pmoL/L. Reductions from baseline in serum TfR were observed at month 36; cardiac T2* remained stable at month 48 ( Table 1). Safety of beti-cel treatment largely reflected the known side effects of hematopoietic stem cell collection and the busulfan conditioning regimen. Conclusion: In this analysis with up to 9 years of follow up, patients treated with beti-cel who achieved TI also demonstrated sustained improvements in iron burden, and the majority of patients were able to stop chelation. Collectively, these results demonstrate the long-term durability and stability of response after beti-cel gene therapy in patients with TDT.

Iron Overload in Dialysis Patients: Serum Ferritin Underestimates Liver Iron Measured By MRI

Background: Parenteral iron supplementation and erythropoietin-stimulating agents are the mainstay management for anemia in patients requiring dialysis. Traditionally, iron status in this patient population is determined by monitoring of widely available and inexpensive serum ferritin level. However, serum ferritin is an acute phase reactant and its usefulness is disease specific. Therefore, several non-invasive methods to evaluate body iron storage have been studied, with measurement of liver iron concentration (LIC) by MRI FDA approved. In this retrospective chart review, we explored the utility of serum ferritin for predicting LIC in a convenience sample of adults on dialysis who had LIC measured by MRI. Methods: Seven adults on dialysis who had been referred to an academic hematology clinic between July 2020 to June 2023 for elevated ferritin and subsequently had completed LIC by MRI were included in this chart review. Liver iron was quantified by T2* Relaxometry in a 1.5 Tesla MRI . Patients age, gender, etiology of end stage renal disease, duration on dialysis, initial LIC, and the ferritin and hemoglobin levels within three month of LIC were collected from patient medical records. Clinical recommendation for holding parenteral iron or starting chelation and patient-follow through were also recorded. In 2 patients, repeat LIC was available. The clinical recommendation for all patients with elevated LICs was to hold parenteral iron and not to start chelation but repeat LIC in 6 month intervals. Result: The median age was 56 years (min 26 years - max 73 years) and 4 of 7 patients were female. The median time of first LIC from initiation of dialysis was 88.5 months (min 19 months - max 130 months). The median of initial LIC was 6.6 mg/g (min 4.6 mg/g - max 12.5 mg/g). The median ferritin was 1120 ng/mL (min 736 ng/mL - max 2650 ng/mL). The median hemoglobin was 10.8 g/dL (min 8.4 g/dL - max 13.7 g/dL). Figure 1A demonstrates that despite similar ferritin levels (bolded group or underlined group), LICs were very variable. Additionally, it is visible in figure 1A that serum ferritin underestimates the LIC (italicized) in this patient population. Holding iron infusion for 2 years in patient 4, resulted in LIC trending down from 6.3 mg/g to 3.2 mg/g (Figure 1B) with minimal impact on hemoglobin. Despite clinical recommendation to hold iron infusion in patient 5 with an initial LIC of 6.8 mg/g, iron infusion was continued. Repeat LIC for this patient 6 months later remained unchanged at 7.0 mg/g, while serum ferritin trended down from 1084 to 843. Conclusion: Ferritin underestimates liver iron concentration in dialysis patients. More investigation is required to determine if liver iron assessment by MRI improves iron management in dialysis patients and optimize serum ferritin utility. This data also suggests that, chelation is not required in iron overloaded dialysis patients, and holding IV iron can result in decline in liver iron concentration.

Diagnostic Accuracy of a Fully Automated Method of Analysing MR Images for Evaluation of Liver Iron Concentration in a Population of Thalassemia Major Patients Following Curative Stem Cell Transplantation in Lebanon

Background Measurement of liver iron concentration (LIC) by MRI is recommended in several guidelines on the management of iron overload in patients with thalassemia. However, a key barrier to adoption of such methods in resource poor countries is access to expertise and training in the associated image data analysis [Padeniya, et al. (2020) Orphanet Journal of Rare Diseases, 15: 26]. A new software system, DLA R2-MRI, based on deep-learning trained neural networks, (FerriSmart®, Resonance Health Analysis Services Pty Ltd, Australia) has become available that automatically carries out both input data quality assurance and data analysis of suitable MR images, increasing the possibility of more widespread adoption of reliable MRI based LIC measurement. Aims The aim of this study was to assess the diagnostic accuracy of the index DLA R2-MRI method on MR images acquired as part of a previous study comparing phlebotomy with deferasirox for the treatment of iron overload in pediatric patients with thalassemia major following curative stem cell transplantation [Inati, et al. (2017) Pediatric Blood & Cancer, 64: 188]. LIC values from MR scans obtained with the spin-density-projection-assisted R2 MRI method (FerriScan®) were to be used as the reference values for the diagnostic accuracy study. Methods Archived MR data from the previous study were retrieved and analysed using the fully automated DLA R2-MRI software to generate LIC values. No human input was required in the analysis process and results were generated in seconds. The methods of Bland and Altman were used to determine the bias and 95% limits of agreement between the index and reference method. None of the image datasets in the study had been used to train the DLA R2-MRI neural networks. The sensitivities and specificities (with 95% CIs) of the index method for predicting LIC values by the reference method above the clinically relevant thresholds of 3, 5, 7, and 15 mg Fe/g dw were calculated using the Wilson-Brown method. Results Sixty nine (69) evaluations of LIC were carried out in the original study using the reference method. Sixty eight (68) datasets were retrieved from archives with one dataset missing. The 68 datasets were analysed by the DLA R2-MRI software. Six were rejected by the input quality control module owing to an absent date of birth in the DICOM images. The remaining 62 datasets yielded an LIC value. The 62 successful analyses represented evaluations on 32 patients with 8 patients being scanned 3 times, 14 patients being scanned twice, and 10 patients being scanned once. Patients (18 male, 14 female) ranged in age from 3.2 to 19.7 years at first scan (mean 13.1 SD 4.1 years). Twenty six (26) patients underwent iron reduction therapy during the study (14 phlebotomy and 12 chelation); 5 patients did not receive iron reduction therapy (4 not meeting eligibility criteria, and one was not treated due to parental refusal); one patient withdrew from the study after only 2 months of iron reduction therapy. A plot of the 62 LIC values by the index method plotted against the values from the reference method is shown in Figure 1. The bias between the index and reference results represented as the geometric mean ratio of the index LIC to the reference LIC was statistically insignificant being 1.00 [95% CI 0.96 - 1.05]. The sensitivities and specificities of the index method for predicting reference LIC values above clinically relevant thresholds are shown in Table 1. Conclusions The data show a negligible bias between the fully automated index DLA R2-MRI method and the manual expert-dependent reference SDPA R2-MRI method. The diagnostic accuracy is sufficient to guide iron reduction therapy in thalassemia major patients. The ability of the software both to provide input data quality assessment and LIC results within seconds without the need for data analyst training or outsourced analysis offers the opportunity for lower cost and more widespread availability of reliable LIC measurement by MRI for thalassemia major patients in Lebanon and beyond.

Hyperferritinemia and liver iron content determined with MRI: Reintroduction of the liver iron index

BackgroundHyperferritinemia is found in around 12 % of the general population. Analyzing the cause can be difficult. In case of doubt about the presence of major iron overload most guidelines advice to perform a MRI as a reliable non-invasive marker to measure liver iron concentration (LIC). In general, a LIC of ≥ 36 µmol/g dw is considered the be elevated however in hyperferritinemia associated with, for example, obesity or alcohol (over)consumption the LIC can be ≥ 36 µmol/g dw in abscence of major iron overload. So, unfortunately a clear cut-off value to differentiate iron overload from normal iron content is lacking. Previously the liver iron index (LII) (LIC measured in liver biopsy (LIC-b)/age (years)), was introduced to differentiate between patients with major (LII ≥ 2) and minor or no iron overload (LII < 2). Based on the good correlation between the LIC-b and LIC determined with MRI (LIC-MRI), our goal was to investigate whether a LII_MRI ≥ 2 is a good indicator of major iron overload, reflected by a significantly higher amount of iron needed to be mobilized to reach iron depletion. MethodsWe compared the amount of mobilized iron to reach depletion and inflammation-related characteristics in two groups: LII-MRI ≥ 2 versus LII-MRI <2 in 92 hyperferritinemia patients who underwent HFE genotyping and MRI-LIC determination. ResultsSignificantly more iron needed to be mobilized to reach iron depletion in the LII ≥ 2 group (mean 4741, SD ± 4135 mg) versus the LII-MRI <2 group (mean 1340, SD ± 533 mg), P < 0.001. Furthermore, hyperferritinemia in LII-MRI < 2 patients was more often related to components of the metabolic syndrome while hyperferritinemia in LII-MRI ≥ 2 patients was more often related to HFE mutations. ROC curve analysis showed good performance of LII =2 as cut-off value. However the calculations showed that the optimal cut-off for the LII = 3.4. ConclusionThe LII-MRI with a cut-off value of 2 is an effective method to differentiate major from minor iron overload in patients with hyperferritinemia. But the LII-MRI = 3.4 seems a more promising diagnostic test for major iron overload.

5613049 THE DIAGNOSTIC ACCURACY AND REPEATABILITY OF AN ARTIFICIAL INTELLIGENCE BASED SYSTEM TO OBTAIN AUTOMATED LIVER IRON CONCENTRATION MEASUREMENTS USING MAGNETIC RESONANCE IMAGING.

Background: Magnetic resonance imaging (MRI) methods have become routine for measuring liver iron concentration (LIC) for hemoglobinopathy patients in high income countries but require specialised training to analyse the image data1. While the cost of outsourcing data analysis is acceptable to many patients or providers in high income countries, the majority of hemoglobinopathy patients reside in low-income countries. Automated LIC measurements using artificial intelligence (AI) or deep-learning-assessed (DLA) algorithms could provide the solution for globally affordable and reliable patient monitoring of LIC. Here we update information presented at the EHA Annual Congress 2022. Aims: The aim of this study was to evaluate the diagnostic performance and repeatability of an automated deep-learning-based medical device (DLA R2-MRI) for measuring LIC from MRI. Methods: The DLA R2-MRI device was assessed prospectively on 1395 eligible consecutive MRI datasets from 63 different scanners submitted for expert manual analysis using spin-density projection assisted (SDPA) R2-MRI (the reference standard) between August 2017 and July 2020. Informed consent was waived by the Human Research Ethics Committee. The aetiologies for iron overload reported by the radiologists submitting the image data were thalassemias (477), hereditary hemochromatosis (168), sickle cell disease (152), MDS (11), other (316), unknown (271). The bias and limits of agreement between the automated and manual measurements of LIC were assessed. In addition, the diagnostic performance was assessed using sensitivity and specificity analysis. The repeatability of the DLA R2-MRI device was assessed by recruiting 60 participants with informed consent (50 patients and 10 healthy controls) each being measured twice with DLA R2-MRI (time between visits: min:1 hour max:7 days). Limits of agreement, bias, and repeatability coefficients were determined using Bland Altman statistics2. Results: The distribution of LIC values measured by the reference method was 31.6% (LIC<3 mg Fe/g); 17.3% (3≤ LIC <5 mg Fe/g); 11.4% (5≤ LIC <7 mg Fe/g); 18.7% (7≤ LIC <15 mg Fe/g); 21.0% (LIC > 15 mg Fe/g). The automated LIC results from the DLA R2-MRI are plotted against the results from the reference standard in the Figure where the solid line is the line of equivalence.The geometric mean ratios of the automated LIC results from the DLA R2-MRI to the manually derived results from SDPA R2-MRI were 0.98 (95% CI 0.94 - 1.01) below 3 mg Fe/g dry tissue and 0.93 (95% CI 0.92 - 0.95) above 3 mg Fe/g dry tissue. The sensitivities and specificities of the automated DLA R2-MRI system for predicting LIC values by the SDPA R2-MRI method above clinically relevant thresholds3 of 3.0, 5.0, 7.0, and 15.0 mg Fe/g dry tissue are shown in the Table. 95% of the repeat measures of LIC by DLA R2-MRI had ratios that fall between 0.79 and 1.26 above 3 mg Fe/g dw and between 0.64 and 1.57 below 3 mg Fe/g dry tissue. - Clinically relevant threshold3(mg Fe/g dry tissue) Sensitivity [95% CI](%) Specificity [95% CI](%) 3.0 96 [94-97] 95 [92-98] 5.0 91 [89-94] 97 [95-99] 7.0 92 [90-95] 97 [95-98] 15.0 89 [85-93] 98 [98-99] Summary/Conclusion: The repeatability of the DLA R2-MRI method for LIC measurement is significantly better than that for liver biopsy methods4-6. While there is an overall bias between DLA R2-MRI and SDPA R2-MRI, the bias does not result in unacceptable sensitivities and specificities of DLA R2-MRI for predicting SDPA R2-MRI results above the clinically relevant LIC thresholds. However, the bias between the automated and manual methods indicates that the two techniques should not be used interchangeably.

Multi-Center, Multi-Vendor Reproducibility and Calibration of MRI-Based R2* for Liver Iron Quantification

Introduction: Excessive accumulation of iron is caused by a variety of conditions, including hereditary hemochromatosis and transfusional hemosiderosis. If untreated, iron overload can lead to damage in those organs where iron accumulates. Therefore, accurate and reproducible evaluation of body iron stores is needed to guide diagnosis, grading, and treatment monitoring of iron overload. While serum ferritin is the simplest means to assess body iron, it is also an acute phase reactant and therefore is not a reliable biomarker of body iron. Liver iron concentration (LIC) is directly and linearly related to total body iron stores. As such, LIC is widely recognized as a useful surrogate biomarker for the evaluation of iron overload. Liver biopsy is limited by its invasive nature and is contraindicated in many patients (eg. thrombocytopenia) due to bleeding risk. Magnetic resonance imaging (MRI) is a standard of care tool to measure LIC. Arguably the most practical method is R2* MRI due to its speed and ease of use, but the cross-vendor reproducibility of R2*-based LIC estimation remains unknown. Therefore, we evaluated the reproducibility and calibration of R2*-based LIC measurement via a single-breath-hold, confounder-corrected R2*-MRI at both 1.5T and 3T, through a multi-center, multi-vendor study.Methods: Four centers (University of Wisconsin-Madison, University of Texas-Southwestern, Johns Hopkins University, and Stanford University) using MRI scanners of different vendors (GE, Philips, and Siemens) participated in this HIPAA-compliant IRB-approved prospective cross-sectional study. This study recruited subjects with known or suspected iron overload from a variety of etiologies, including hereditary hemochromatosis, transfusional hemosiderosis (due to non-malignant or malignant conditions), and chronic liver disease. Subjects with were recruited for same day multiecho gradient-echo MRI for R2* mapping at both 1.5T and 3T (UW, UTSW, Stanford: 3.0T; JHU: 2.89T). R2* maps were reconstructed from the raw multiecho images and analyzed at a single center. Spin-echo MRI were also performed at 1.5T according to a standardized protocol (FerriScan, Resonance Health, Australia) and processed by a commercial algorithm to obtain FDA-approved reference standard LIC estimates. R2*-vs.-LIC calibrations were generated across centers and field strengths using linear regression and compared using F-tests. A predicted 2.89T calibration was interpolated from the 1.5T and 3.0T calibrations, and compared to the measured (JHU) calibration. Receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic accuracy of R2* MRI for detection of clinically relevant LIC thresholds.Results: A total of 200 subjects were recruited and successfully scanned for this study. We confirmed a linear relationship between R2* and LIC. All calibrations within the same field strength (see Figure 1) were highly reproducible showing no statistically significant center-specific differences (F > 3.0461). Pooled calibrations for 1.5T, 2.89T, and 3.0T were generated. At either field strength and for each of the LIC thresholds under consideration (1.8, 3.2, 7.0, 15.0 mg/g), estimated areas under the ROC curve (AUCs) of 0.98 or higher were observed.Discussion and Conclusions: In conclusion, confounder-corrected R2* MRI enables accurate and reproducible quantification of liver iron overload, over clinically relevant ranges of LIC. The data generated in this study provide the necessary calibrations for broad dissemination of R2*-based LIC quantification. [Display omitted] DisclosuresHernando: Calimetrix: Current holder of individual stocks in a privately-held company. Pedrosa: Merck: Honoraria; Bayer Healthcare: Honoraria; Health Tech International: Current holder of stock options in a privately-held company. Vasanawala: HeartVista: Current holder of individual stocks in a privately-held company; InkSpace: Current holder of individual stocks in a privately-held company; Arterys: Current holder of individual stocks in a privately-held company. Reeder: Bayer: Research Funding; Pfizer: Research Funding; Calimetrix, LLC: Current holder of individual stocks in a privately-held company; Reveal Pharmaceuticals: Current holder of individual stocks in a privately-held company; Elucent Medical: Current holder of individual stocks in a privately-held company; Cellectar Biosciences: Current holder of individual stocks in a privately-held company; HeartVista: Current holder of individual stocks in a privately-held company.

Guidelines for the monitoring and management of iron overload in patients with haemoglobinopathies and rare anaemias.

Guidelines for the monitoring and management of iron overload in patients with haemoglobinopathies and rare anaemias.

Effects of B1+ Heterogeneity on Spin Echo-Based Liver Iron Estimates.

Liver iron concentration (LIC) measured by MRI has become the clinical reference standard for managing iron overload in chronically transfused patients. Transverse relaxivity (R2 or R2* ) measurements are converted to LIC units using empirically derived calibration curves. That flip angle (FA) error due to B1+ spatial heterogeneity causes significant LIC quantitation error. B1+ scale (b1 , [FAactual /FAspecified ]) variation is a major problem at 3 T which could reduce the accuracy of transverse relaxivity measurements. Prospective. Forty-seven subjects with chronic transfusional iron overload undergoing clinically indicated LIC assessment. 5 T/3 T dual-repetition time B1+ mapping sequence ASSESSMENT: We quantified the average/standard deviation b1 in the right and left lobes of the liver from B1+ maps acquired at 1.5 T and 3 T. The impact of b1 variation on spin echo LIC estimates was determined using a Monte Carlo model. Mean, median, and standard deviation in whole liver and right and left lobes; two-sided t-test between whole-liver b1 means. Average b1 within the liver was 99.3% ± 12.3% at 1.5 T versus 69.6% ± 14.6% at 3 T and was independent of iron burden (P< 0.05). Monte Carlo simulations demonstrated that b1 systematically increased R2 estimates at lower LIC (<~25 mg/g at 1.5 T, <~15 mg/g at 3 T) but flattened or even inverted the R2 -LIC relationship at higher LIC (≥~25 mg/g to 1.5 T, ≥~15 mg/g to 3 T); changes in the R2 -LIC relationship were symmetric with respect to over and under excitation and were similar at 1.5 T and 3 T (for the same R2 value). The R2* -LIC relationship was independent of b1 . Spin echo R2 measurement of LIC at 3 T is error-prone without correction for b1 errors. The impact of b1 error on current 1.5 T spin echo-based techniques for LIC quantification is large enough to introduce measurable intersubject variability but the in vivo effect size needs a dedicated validation study. 2.

Measurement of Liver Iron Concentration in a Population of Non-Transfusion Dependent Thalassemia Patients Using a Trained Artificial Neural Network to Analyse Magnetic Resonance Images

Background: Measurements of liver iron concentration (LIC) by magnetic resonance imaging (MRI) have become established and validated in several research intensive centers. However, challenges remain with translating these measurement methodologies for routine clinical use. Current methods involve many steps presenting multiple opportunities for human error and can lead to systematic severe measurement error. Artificial neural networks (ANNs) can be trained to replace human input into image processing and may have a role in providing a simple, robust, and low cost solution for LIC measurement.Aims: The aim of the study wasto determine the limits of agreement between measurements of LIC by a reference standard spin-density-projection-assisted (SDPA) R2-MRI method (FerriScan) and a method using trained ANNs to analyse image data. MR image datasets (400) previously acquired from Siemens scanners were pre-processed and then, together with their corresponding SDPA R2-MRI LIC values, were filtered through publically available ANNs. The ANNs had been pre-trained on large image sets (ImageNet). Relevant features were extracted and then used to train a machine learning (gradient boosting) algorithm to predict LIC values from previously unseen MR image datasets.Methods: Thalassemia patients (N=100) referred by the National Institute of Haematology and Blood Transfusion, Hanoi, Vietnam for routine LIC measurement by MRI were prospectively recruited with informed consent. Patients were randomised to be scanned in either a Philips Ingenia or a Siemens Avanto 1.5T scanner. Image data were acquired using the FerriScan protocol. Images were then processed (1) using a quality controlled core laboratory data analysis service using the SDPA R2-MRI method and (2) by a non-radiologically-trained technician using the trained artificial neural network to generate LIC values. The technician was required to trace the outline of the torso and then click a mouse button. The technician using the ANN was blinded from the SDPA R2-MRI results and the analysts generating the SDPA R2-MRI results were blinded from the ANN results. Reported data were analysed using the statistical methods of Bland and Altman.Results: A plot of the ANN-predicted LIC values against the SDPA R2-MRI LIC values (Figure) shows the data scattered about the line of equivalence indicating that the ANN method is generating results that correlate with the validated SDPA R2-MRI reference standard. The geometric mean ratio of ANN LIC to SDPA R2-MRI LIC was 0.93 (95% CI 0.91 -0.96) indicating a small but statistically significant systematic underestimation of LIC by the ANN. The geometric mean ratios of the two LIC measurements were significantly different for the two scanners (0.98 for Philips and 0.90 for Siemens, p = 0.006) indicating that the bias of the ANN method against the reference standard is not universal but is dependent on scanner. Bland Altman analysis indicates that 95% of pairs of measurements are predicted to have ratios between 1.23 and 0.69 indicating a modest random variability between the ANN method and the reference standard that is better than that between biopsy and the reference standard. The performance of the ANN method in predicting SDPA R2-MRI LIC values above the clinically relevant thresholds of 7 and 15 mg Fe/g dw is characterized in Table 1 showing positive predictive values (PPVs) and negative predictive values (NPVs) together with their 95% CIs.Conclusion: The data indicate that the ANN method of measurement of LIC has potential to be used as a fast and robust method of analysing MR image data to generate LIC values. Further testing is required on a wider range of scanner types and with more patients with lower LICs. The performance of the ANN will also likely be improved through training on a larger number of datasets. [Display omitted] DisclosuresSt Pierre:Resonance Health Ltd: Consultancy, Equity Ownership, Speakers Bureau. Cooper:Resonance Health Ltd: Consultancy. Boulos:Resonance Health Ltd: Employment. House:Resonance Health Ltd: Employment. Pang:Resonance Health Ltd: Employment. Bangma:Resonance Health Ltd: Employment. Taher:Novartis Pharmaceuticals: Honoraria, Research Funding; Celgene: Research Funding.

Surrogate Thresholds for Iron Chelation in Patients with Hematological Malignancies

Background: The reference standard for evaluating the magnitude of body iron overload is measurement of the liver iron concentration (LIC). Until recently, the conventional clinical method for measuring LIC was through analysis of biopsy specimens considered the “gold standard” of LIC measurement. To counter the shortcomings of liver biopsy, several noninvasive techniques have been applied to estimate LIC. The spin-density projection-assisted (SDPA) R2-MRI (FerriScan) technique has been recently validated to estimate LIC. There are reports in the literature that ferritin levels in patients with hematological malignancies (HM) may not correlate sufficiently with LIC. We conducted R2-MRI Ferriscan sequencing in consecutive patients with HM followed in our center to better evaluate the diagnostic value of ferritin levels and packed red blood cell (pRBC) transfusions for iron overload.Methods: HM patients with a history of transfusion requirement were evaluated for inclusion in the study within the Liver Iron Cutino Network (Licnet) project. Patients were excluded if they had contraindications to MRI assessment (heart pacemaker, metallic foreign body or devices, and claustrophobia). Demographics and HM disease data were collected, together with ferritin levels and transfusion requirement. R2 LIC measures by FerriScan were defined as indicating normal/marginally high iron load for values 0 to <3, mild liver iron overload for values 3 to < 7, moderate between 7 and 15 and severe if >15. Correlations and the generation of receiver operating characteristic (ROC) curves were performed to test the diagnostic power of ferritin levels and volume of transfused blood (ml/kg in the preceeding 12 months) to indicate moderate-severe iron overload.Results: 28 patients (20 males) of mean age 62, SD 17 years with HM (myelodysplastic syndromes N=14; acute myeloid leukemia N=7, of which 5 post-transplant; acute lymphoblastic leukemia post-transplant N=2; aplastic anemia N=2; non Hodgkin lymphoma N=1; chronic lymphocytic leukemia N=1; erythroblastopenia N=1) were evaluated. Median baseline ferritin levels were 1617 (interquartile range 1185-2360). Mean R2 values were 10.9, SD 10.1 mg/kg. Three patients had normal or marginally high LIC, 12 patients had mild overload, 6 patients moderate and 7 patients severe overload. Both ferritin levels and amount of blood volume transfused in the preceding 12 months correlated well with R2 measures (Spearman rho=0.478, p=0.10 and r=0.509, p=0.006, respectively). However, neither ferritin levels nor transfusions correlated with R2 MRI in patients with normal-mild iron overload while the correlations were confirmed and highly significant in patients with moderate-severe iron overload (r=0.692, p=0.009 and r= 0.754, p=0.003, respectively). ROC curves denied the diagnostic power of ferritin levels and confirmed transfusions to indicate moderate to severe liver iron overload (Figure 1), indicating that 37 ml/kg/year (about 14 units of pRBC) has a sensitivity of 77% and a specificity of 80% to predict moderate-severe iron overloadConclusions: We confirm that, though ferritin levels do generally correlate with LIC, they are not to be considered an appropriate surrogate marker for iron overload in HM. R2 MRI sequencing is valuable to diagnose the state of LIC. The results of this study indicate that as soon as an HM patient begins to receive regular transfusions, since the probability of developing moderate-severe iron overload is high, it is warranted not to await high ferritin levels, nor a large number of pRBC units, to initiate iron chelation. [Display omitted] DisclosuresOliva:Celgene: Consultancy; La Jolla: Consultancy; Amgen Inc.: Consultancy; Novartis: Consultancy; Janssen: Consultancy.

Correlation Between Serum Ferritin and Viral Hepatitis in Thalassemia Patients

Serum ferritin is an acute phase protein; importantly, its level is noticeably increased in response to iron overload and systemic inflammation. The iron overload status in thalassemia patients has been recognized as a potential way to measure liver iron concentration (LIC) levels using magnetic resonance imaging (MRI). The aim of this study was to investigate the effect of chronic viral hepatitis on the level of serum ferritin in patients with thalassemia. A cross-sectional study was conducted involving chronic viral hepatitis infection. Mean serum ferritin and LIC levels were recorded. The LIC values were used to divide the patients into two groups; a higher LIC group (>5 mg Fe/g) and a lower LIC group (<5 mg Fe/g). Mean serum ferritin levels were then compared between the two LIC groups. We identified 32 thalassemia patients comprising of 13 chronic viral hepatitis patients, seven patients with hepatitis B virus (HBV), and six patients with hepatitis C virus (HCV). With regard to the group with higher LIC values, the mean serum ferritin levels in the hepatitis group were significantly higher than for those in the non hepatitis group (1776 ± 488 vs. 967 ± 860 ng/mL, p = 0.03). Furthermore, the linear correlation between the mean serum ferritin levels and the viral load in the non transfusion-dependent thalassemia (NTDT) group were found to be significantly correlated (r = 0.7, p = 0.04). Chronic viral hepatitis was determined to be a possible casualty of disproportionately high ferritin levels in the NTDT group.

Non-invasive measurement of liver iron concentration by magnetic resonance imaging and its clinical usefulness.

Determination of liver iron concentration by magnetic resonance imaging (MRI) is becoming the new technique of choice for the diagnosis of iron overload in hereditary haemochromatosis and other liver iron surcharge diseases. Determination of hepatic iron concentration obtained by liver biopsy has been the gold standard for years. The development of MRI techniques, via signal intensity ratio methods or relaxometry, has provided a non-invasive and more accurate approach to the diagnosis of liver iron overload. This article reviews the available MRI methods for the determination of liver iron concentration and also evaluates the technique for the diagnosis and quantification of iron overload in different clinical practice scenarios.

Real-World Experience Measurement of Liver Iron Concentration by R2 vs. R2 Star MRI in Hemoglobinopathies.

Background: Non-invasive determination of liver iron concentration (LIC) is a valuable tool that guides iron chelation therapy in transfusion-dependent patients. Multiple methods have been utilized to measure LIC by MRI. The purpose of this study was to compare free breathing R2* (1/T2*) to whole-liver Ferriscan R2 method for estimation of LIC in a pediatric and young adult population who predominantly have hemoglobinopathies. Methods: Clinical liver and cardiac MRI scans from April 2016 to May 2018 on a Phillips 1.5 T scanner were reviewed. Free breathing T2 and T2* weighted images were acquired on each patient. For T2, multi-slice spin echo sequences were obtained. For T2*, a single mid-liver slice fast gradient echo was performed starting at 0.6 ms with 1.2 ms increments with signal averaging. R2 measurements were performed by Ferriscan analysis. R2* measurements were performed by quantitative T2* map analysis. Results: 107 patients underwent liver scans with the following diagnoses: 76 sickle cell anemia, 20 Thalassemia, 9 malignancies and 2 Blackfan Diamond anemia. Mean age was 12.5 ± 4.5 years. Average scan time for R2 sequences was 10 min, while R2* sequence time was 20 s. R2* estimation of LIC correlated closely with R2 with a correlation coefficient of 0.94. Agreement was strongest for LIC < 15 mg Fe/g dry weight. Overall bias from Bland–Altman plot was 0.66 with a standard deviation of 2.8 and 95% limits of agreement −4.8 to 6.1. Conclusion: LIC estimation by R2* correlates well with R2-Ferriscan in the pediatric age group. Due to the very short scan time of R2*, it allows imaging without sedation or anesthesia. Cardiac involvement was uncommon in this cohort.

Room temperature magnetoelectric sensor arrays for application of detecting iron profiles in organs

Noninvasive measurement of liver iron concentration (LIC) is clinically important. Yet, at the present time, it can only be achieved with SQUID technology. However, SQUID based BLS suffers high costs and cumbersome cryogenic requirements that prevent SQUID BLS from being adopted by clinical applications. Recently, we demonstrated that a single channel ME sensor with piezo-single crystals could detect LIC from only 3 ml of mouse liver tissue without any magnetic field shielding. The results demonstrated not only the sensitivity of ME sensor system for LIC but also the feasibility for mapping LIC profiles spatially. This investigation further developed ME sensor arrays, exploiting the compact size and room temperature operation. A Dual-channel 1-D ME sensor array along the vertical, Z-direction, was developed and shown to be sensitive to the skin-liver distance change which can be utilized to calibrate and eliminate the inter-subject variability of the LIC measurement due to skin-liver distance. With phantom having spatially dependent iron concentrations, the 1-D ME sensor array was capable of mapping the one-dimensional profile of the iron concentration in the horizontal X- and Y-directions. The results of the prototype sensor devices show the feasibility of an array ME-sensors for imaging iron profile.

Quantification of Liver Iron Overload: Correlation of MRI and Liver Tissue Biopsy in Pediatric Thalassemia Major Patients Undergoing Bone Marrow Transplant.

Determination of the magnitude of body iron stores helps to identify individuals at risk of iron-induced organ damage in Thalassemia patients. The most direct clinical method of measuring liver iron concentration (LIC) is through chemical analysis of needle biopsy specimens. Here we present a noninvasive method for the measurement of LIC in vivo using magnetic resonance imaging (MRI). Twenty-three pediatric Thalassemia major patients undergoing bone marrow transplantation at our centre were studied. All 23 patients had MRI T2* and R2* decay time for evaluation of LIC on a 1.5Tesla MRI system followed by liver tissue biopsy for the assessment of iron concentration using an atomic absorption spectrometry. Simultaneously, serum ferritin levels were measured by enzymatic assay. We have correlated biopsy LIC with liver T2* and serum ferritin values with liver R2*. Of the 23 patients 11 were males, the mean age was 8.3 ± 3.7years. The study results showed a significant correlation between biopsy LIC and liver T2* MRI (r = 0.768; p < 0.001). Also, there was a significant correlation between serum ferritin levels and liver R2* MRI (r = 0.5647; p < 0.01). Two patients had high variance in serum ferritin levels (2100 and 4100mg/g) while their LIC was around 24mg/g, whereas the difference was not seen in T2* MRI. Hence, the liver T2* MRI is a better modality for assessing LIC. Serum ferritin is less reliable than quantitative MRI. The liver T2* MRI is a safe, reliable, feasible and cost-effective method compared to liver tissue biopsy for LIC assessment.

Histological Scores Validate the Accuracy of Hepatic Iron Load Measured by Signal Intensity Ratio and R2* Relaxometry MRI in Dialysis Patients.

Almost all haemodialysis patients are treated with parenteral iron to compensate for blood loss and to allow the full therapeutic effect of erythropoiesis-stimulating agents. Iron overload is an increasingly recognised clinical situation diagnosed by quantitative magnetic resonance imaging (MRI). MRI methods have not been fully validated in dialysis patients. We compared Deugnier’s and Turlin’s histological scoring of iron overload and Scheuer’s classification (with Perls’ stain) with three quantitative MRI methods for measuring liver iron concentration (LIC)—signal intensity ratio (SIR), R2* relaxometry, and R2* multi-peak spectral modelling (Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation (IDEAL-IQ®)) relaxometry—in 16 haemodialysis patients in whom a liver biopsy was formally indicated for medical follow-up. LIC MRI with these three different methods was highly correlated with Deugnier’s and Turlin’s histological scoring (SIR: r = 0.8329, p = 0.0002; R2* relaxometry: r = −0.9099, p < 0.0001; R2* relaxometry (IDEAL-IQ®): r = −0.872, p = 0.0018). Scheuer’s classification was also significantly correlated with these three MRI techniques. The positive likelihood ratio for the diagnosis of abnormal LIC by Deugnier’s histological scoring was > 62 for the three MRI methods. This study supports the accuracy of quantitative MRI methods for the non-invasive diagnosis and follow-up of iron overload in haemodialysis patients.

The Effect of Chronic Viral Hepatitis on Serum Ferritin Level in Thalassemia Patients

Background: Serum ferritin is widely used as a marker of iron overload in thalassemia patients. However, the ferritin level is affected by active infections or inflammation. The association between viral hepatitis and serum ferritin level in thalassemia patients is still unclear. This study aimed to determine the effect of chronic viral hepatitis on serum ferritin level in thalassemia patients. Methods: This was a cross-sectional study in thalassemia patients aged ≥15 years-old at Chiang Mai University hospital. We expected that thalassemic patients in our clinic have a mean serum ferritin of 767 ng/mL with a standard deviation of 210 ng/mL. As a result, we have to enroll a total of 28 patients to demonstrate 30% difference of mean serum ferritin when the power was set at 80% with alpha level of 0.05. Information on chronic viral hepatitis, mean serum ferritin and liver iron concentration (LIC) as measured by T2* MRI were collected. Chronic viral hepatitis status was confirmed by either HBV DNA or HCV RNA testing. Patients were categorized to hepatitis and non-hepatitis group. Serum ferritin levels were compared between two groups. LIC measurement was used as a gold standard for iron overload. Subgroup analysis was performed according to iron overload and transfusion requirement status. Categorical and continuous variables were compared using the Chi-squared test and T-test, respectively. The correlation between viral loads and mean serum ferritin levels was analyzed by Pearson's correlation. Result: Of 32 thalassemia patients (25 non-transfusion dependent [NTDT] and 7 transfusion dependents [TDT]), 13 patients had chronic viral hepatitis (7 with hepatitis B and 6 with hepatitis C infections). The LIC between hepatitis and non-hepatitis groups were not significantly different (7.28 [SD 4.7] vs 9.08 [SD 5.2] mg Fe/g, p=0.19). In the higher LIC group (≥ 5 mg Fe/g), the mean serum ferritin level was higher in the hepatitis group than non-hepatitis group (1,776 [SD 488] vs 967 [SD 860] ng/mL, p=0.03). For the lower LIC group (&lt;5 mg Fe/g), the mean ferritin levels were not significantly different between the hepatitis and non-hepatitis groups (646 [SD 224] vs 459 [SD 205] ng/mL, p=0.22). The correlation between the viral load and mean ferritin level in NTDT group showed a significant linear correlation with R=0.7 (p=0.04). Conclusions: We observe a higher serum ferritin level among thalassemia patients who concurrently have chronic viral hepatitis. Chronic viral hepatitis is a possible cause of a falsely high ferritin level in these patient population. Furthermore, the viral load is positively correlated with serum ferritin level. Disclosures No relevant conflicts of interest to declare.

Measurement of liver iron by magnetic resonance imaging in the UK Biobank population.

The burden of liver disease continues to increase in the UK, with liver cirrhosis reported to be the third most common cause of premature death. Iron overload, a condition that impacts liver health, was traditionally associated with genetic disorders such as hereditary haemochromatosis, however, it is now increasingly associated with obesity, type-2 diabetes and non-alcoholic fatty liver disease. The aim of this study was to assess the prevalence of elevated levels of liver iron within the UK Biobank imaging study in a cohort of 9108 individuals. Magnetic resonance imaging (MRI) was undertaken at the UK Biobank imaging centre, acquiring a multi-echo spoiled gradient-echo single-breath-hold MRI sequence from the liver. All images were analysed for liver iron and fat (expressed as proton density fat fraction or PDFF) content using LiverMultiScan. Liver iron was measured in 97.3% of the cohort. The mean liver iron content was 1.32 ± 0.32 mg/g while the median was 1.25 mg/g (min: 0.85 max: 6.44 mg/g). Overall 4.82% of the population were defined as having elevated liver iron, above commonly accepted 1.8 mg/g threshold based on biochemical iron measurements in liver specimens obtained by biopsy. Further analysis using univariate models showed elevated liver iron to be related to male sex (p<10−16, r2 = 0.008), increasing age (p<10−16, r2 = 0.013), and red meat intake (p<10−16, r2 = 0.008). Elevated liver fat (>5.6% PDFF) was associated with a slight increase in prevalence of elevated liver iron (4.4% vs 6.3%, p = 0.0007). This study shows that population studies including measurement of liver iron concentration are feasible, which may in future be used to better inform patient stratification and treatment.

Advances in Biomagnetic Liver Susceptometry Allow the Measurement of Liver Iron Concentration with a Room Temperature Sensor

Introduction: Iron overload is frequently observed in diverse states ranging from thalassemia, sickle cell disease, hereditary hemochromatosis, transfusion-dependent anemias, cancer chemotherapy and chronic liver disease. Management of iron overload depends on the ability to quantify and monitor the patient's iron stores with precision. Organ iron measurement by relaxometry-based MRI techniques has become the current standard. MRI is expensive and has the added limitations of multiple existing methods and reduced dynamic range with 3 Tesla scanners. Liver iron measurements by magnetic susceptometers using superconductive quantum interference device (SQUID) technology are expensive and have limited availability. In this study an improved low-cost device, the room-temperature susceptometer (RTS, Insight Magnetics, San Diego, CA), was tested against the Model 5700 Ferritometer ® 3-Channel SQUID BioSusceptometer System (Tristan Technologies, Inc. San Diego, CA). Both systems quantify liver iron concentration (LIC) using bulk magnetic susceptibility.Where the SQUID uses an ultra-stable sensing system immersed in liquid helium, the RTS cancels the temperature and magnetic-field fluctuations inherent in an apparatus that works at room temperature. The RTS uses three main techniques to sense the very weak magnetic field produced by liver iron: (a) oscillatory magnetic fields that can be detected with high sensitivity using coils of ordinary copper wire, (b) field-producing and field-sensing coils to cancel the signal due to the applied magnetic field, and (c) movement of the sensing unit periodically toward and away from the patient so as to distinguish the patient's magnetic field response from the interfering signal caused by temperature fluctuations in the sensing system.Methods: This study compared measurements of LIC from RTS to those by the SQUID. The RTS in this study was modified from an earlier model to make the baseline reading more stable, and to increase the accuracy of the water reference measurement to which the patient's magnetic response is compared. The magnetic-field source and sensing coils were enlarged to increase the signal of the liver compared with that of the overlying tissue.LIC was measured once on the SQUID and once on the RTS at a single visit. Using ultrasound imaging, optimum liver measurement position was determined and marked with an x-y-positioning and z-distance sensing Locator Loop (Positronic Systemtechnik GmbH, Germany). The locator loop remained attached to the patient for measurements with both devices to preserve measurement location. LIC calculation was corrected for the susceptibility and geometry of the overlying tissue. Measurement results from SQUID and RTS were analyzed independently by two investigators.Results: Thirteen adults (10 with transfusion-dependent thalassemia and 3 controls) with body mass index (BMI) <25 were enrolled. All measurements were completed at a single visit with no failures. LIC values (µg/g wet-liver weight), ranged from -33 to 6493 with SQUID, and -305 to 7237 with RTS. In the three controls, the LIC was -33, 144 and 427 µg/g with SQUID, and -305, 451 and 230 µg/g with RTS. The overall correlation between the two methods was excellent, yielding an r2 = 0.976 and slope = 1.037 ± 0.068 (p<0.001, Fig 1). Bland-Altman analysis of percent-difference versus the average of the two methods showed bias -2.72 (95% limits of agreement -149.1 to 143.6) for all subjects, which improved to 1.94 (95% limits of agreement -41.1 to 45.3) when the average values below 350 µg/g (n=4) were excluded (Fig 2). The percent difference between the two methods was influenced by the subject's BMI (p=0.050 for all subjects; p=0.031 after excluding average LIC <350 µg/g), with the least difference observed in the BMI range of 20-23 Kg/m2.Conclusion: This study shows that, with the recent improvements in the RTS technology, LIC measurements now closely align with those using SQUID. The remaining difference between the two methods likely results from the models used to compensate for the overlying tissue. Further comparison of RTS to SQUID and MRI-based methods in diverse iron overload states is warranted in a larger study. This work may ultimately make low-cost noninvasive measurement of iron overload accessible to the large number of patients in the US, and to resource-limited countries around the world. DisclosuresLal:Bluebird Bio: Research Funding; Insight Magnetics: Research Funding; Terumo Corporation: Research Funding; Novartis: Research Funding; Celgene Corporation: Research Funding; La Jolla Pharmaceutical Company: Consultancy, Research Funding. Avrin:Insight Magnetics: Employment, Other: Proprietor of company developing the study device, Patents & Royalties: Own rights to patents on the study device. Weyhmiller:Insight Magnetics: Research Funding.

SEVERE LIVER IRON CONCENTRATIONS (LIC) IN 24 PATIENTS WITH Β-THALASSEMIA MAJOR: CORRELATIONS WITH SERUM FERRITIN, LIVER ENZYMES AND ENDOCRINE COMPLICATIONS

IntroductionChronic blood transfusion is the mainstay of care for individuals with β-thalassemia major (BTM). However, it causes iron-overload that requires monitoring and management by long-term iron chelation therapy to prevent endocrinopathies and cardiomyopathies, which can be fatal. Hepatic R2 MRI method (FerriScan®) has been validated as the gold standard for evaluation and monitoring liver iron concentration (LIC) that reflects the total body iron-overload. Although adequate oral iron chelation therapy (OIC) is promising for the treatment of transfusional iron-overload, some patients are less compliant with it, and others suffer from long-term effects of iron overload.ObjectiveThe aim of our study was to evaluate the prevalence of endocrinopathies and liver dysfunction, in relation to LIC and serum ferritin level, in a selected group of adolescents and young adult BTM patients with severe hepatic iron overload (LIC from 15 to 43 mg Fe/g dry weight).Patients and MethodsTwenty-four selected BTM patients with severe LIC, due to transfusion-related iron-overload, followed at the Haematology Section, National Centre for Cancer Care and Research, Hamad Medical Corporation of Doha (Qatar), from April 2015 to July 2017, were retrospectively evaluated. The prevalence of short stature, hypogonadism, hypothyroidism, hypoparathyroidism, impaired fasting glucose (IFG), diabetes, and adrenal insufficiency was defined and assessed according to the International Network of Clinicians for Endocrinopathies in Thalassemia (ICET) and American Diabetes Association criteria.ResultsPatients’ most common transfusion frequency was every three weeks (70.8%). At the time of LIC measurements, their median age was 21.5 years with a mean age of 21.7 ± 8.0 years. Mean LIC was 32.05 ± 10.53 mg Fe/g dry weight (range: 15 to 43 mg Fe/g dry weight), and mean serum ferritin level was 4,488.6 ± 2,779 μg/L. LIC was correlated significantly with serum ferritin levels (r = 0.512; p = 0.011). The overall prevalence of short stature was 26.1% (6/23), IFG was 16.7% (4/24), sub-clinical hypothyroidism was 14.3% (3/21), hypogonadotropic hypogonadism was 14.3% (2/14), diabetes mellitus was 12.5% (3/24), and biochemical adrenal insufficiency was 6.7% (1/15). The prevalence of hepatitis C positivity was 20.8% (5/24). No case of clinical hypothyroidism, adrenal insufficiency or hypoparathyroidism was detected in this cohort of patients. The prevalence of IFG impaired fasting glucose was significantly higher in BTM patients with very high LIC (>30 mg Fe/g dry liver) versus those with lower LIC (p = 0.044). The prevalence of endocrinopathies was not significantly different between the two groups of patients with LIC above and below 15 mg Fe/g dry weight.ConclusionsA significant number of BTM patients, with high LIC and endocrine disorders, still exist despite the recent developments of new oral iron chelating agents. Therefore, physicians’ strategies shall optimize early identification of those patients to optimise their chelation therapy and to avoid iron-induced organ damage. We believe that further studies are needed to evaluate if serial measurements of quantitative LIC may predict the risk for endocrine complications. Until these data are available, we recommend a close monitoring of endocrine and other complications, according to the international guidelines.