Liver iron content determination by magnetic resonance imaging

Revolutionizing disease diagnosis and management: Open-access magnetic resonance imaging datasets a challenge for artificial intelligence driven liver iron quantification

Artificial intelligence (AI), particularly machine learning (ML) and deep learning (DL) techniques, such as convolutional neural networks (CNNs), have emerged as transformative technologies with vast potential in healthcare. Body iron load is usually assessed using slightly invasive blood tests (serum ferritin, serum iron, and serum transferrin). Serum ferritin is widely used to assess body iron and drive medical management; however, it is an acute phase reactant protein offering wrong interpretation in the setting of inflammation and distressed patients. Magnetic resonance imaging is a non-invasive technique that can be used to assess liver iron. The ML and DL algorithms can be used to enhance the detection of minor changes. However, a lack of open-access datasets may delay the advancement of medical research in this field. In this letter, we highlight the importance of standardized datasets for advancing AI and CNNs in medical imaging. Despite the current limitations, embracing AI and CNNs holds promise in revolutionizing disease diagnosis and treatment.

Cardiac MR images of thalassemia major patients with myocardial iron overload: a data note

OBJECTIVE

Patients with thalassemia major (TM) have the highest mortality rate due to heart failure induced by myocardial iron overload. However, T2* weighted MR imaging is currently a gold standard approach for measuring iron overload. Examining ventricular volumes with magnetic resonance imaging (MR imaging) and measuring myocardial iron overload in TM patients allows for an early prediction of heart failure. This dataset includes cardiac MR images of TM patients and the control group with clinical and echocardiographic data. This dataset may be useful to researchers investigating myocardial iron overload. This dataset can also be used for medical image processing applications, such as ventricle segmentation.

DATA DESCRIPTION

This study provides open-source cardiac MR images of 50 subjects and clinical and echocardiographic data. From February 2016 to January 2019, all images and clinical data were obtained from the MRI department of a general hospital in Mashhad, Iran. All the images are 16-bit gray-scale and stored in DICOM format. All patient-specific information is removed from image headers to preserve patient privacy. In addition, all images associated with each subject are compressed and saved in the RAR format.

Cardiac T2* magnetic resonance analysis of membranous interventricular septum in assessment of cardiac iron overload in pediatric thalassemia patients: A pilot study

Background:

Cardiac iron deposition in transfusion-dependent thalassemia patients is patchy in distribution.

Purpose:

The purpose of this study is to assess the correlation between T2* matrices of membranous interventricular septum (MIVS) and T2* values of muscular interventricular septum (IVS) on magnetic resonance imaging (MRI) and to evaluate the relationship of myocardial T2* at these two locations with MRI-estimated liver iron concentrations (LIC) and electrocardiographic (ECG) parameters.

Material and Methods:

MRI of heart and liver was performed in 16 consecutive pediatric patients of transfusion-dependent thalassemia major to calculate liver iron concentration and T2* time of membranous and muscular IVS. ECG parameters of these patients were charted and correlated with MRI parameters.

Results:

No significant correlation between T2* values of muscular IVS and MIVS was observed. Mean T2* of MIVS (9.8 ms) was significantly lower than that of muscular IVS (26.9 ms). T2* of MIVS correlated strongly with LIC where as a weak correlation was observed between T2* of IVS and LIC. Significantly higher mean QTc (corrected QT interval) value (439.86 ms) was seen in patients with T2* IVS <20 ms.

Conclusion:

Addition of T2* analysis of MIVS to the existing MRI protocol, consisting of muscular IVS analysis, may offer a more sensitive estimation of cardiac iron overload.

Evaluation of liver iron overload with R2* relaxometry with versus without fat suppression: both are clinically accurate but there are differences

OBJECTIVES

To assess clinically relevant difference in hepatic iron quantification using R2* relaxometry with (FS) and without (non-FS) fat saturation for the evaluation of patients with suspected hepatic iron overload.

METHODS

We prospectively enrolled 134 patients who underwent 1.5-T MRI R2* relaxometry with FS and non-FS gradient echo sequences (12 echoes, initial TE = 0.99 ms). Proton density fat fraction for the quantification of steatosis was assessed. Linear regression analyses and Bland-Altman plots including Lin's concordance correlation coefficient were performed for correlation of FS R2* with non-FS R2*. Patients were grouped into 4 severity classes of iron overload (EASL based), and agreement was evaluated by contingency tables and the proportion of overall agreement.

RESULTS

A total of 41.8% of patients showed hepatic iron overload; 67.9% had concomitant steatosis; and 58.2% revealed no iron overload of whom 60.3% had steatosis. The mean R2* value for all FS data was 102.86 1/s, for non-FS 108.16 1/s. Linear regression resulted in an R-squared value of 0.99 (p < 0.001); Bland-Altman plot showed a mean R2* difference of 5.26 1/s (SD 17.82). The concordance correlation coefficient was only slightly lower for patients with steatosis compared with non-steatosis (0.988 vs. 0.993). The overall agreement between FS and non-FS R2* measurements was 94.8% using either method to classify patients according to severity of iron storage. No correlation between R2* and proton density fat fraction was found for both methods.

CONCLUSION

R2* relaxometry showed an excellent overall agreement between FS and non-FS acquisition. Both variants can therefore be used in daily routine. However, clinically relevant differences might result when switching between the two methods or during patient follow-up, when fat content changes over time. We therefore recommend choosing a method and keeping it straight in the context of follow-up examinations.

KEY POINTS

• Both variants of R2* relaxometry (FS and non-FS) may be used in daily routine. • Clinically relevant differences might result when switching between the two methods or during patient follow-up, when fat content changes over time. • It seems advisable choosing one method and keeping it straight in the context of follow-up examinations.

Cardiac T2* MR in patients with thalassemia major: a 10-year long-term follow-up

The consequence of regular blood transfusion in patients with thalassemia major (TM) is iron overload. Herein, we report the long-term impact of chelation on liver iron concentration (LIC) and cardiac T2* MR in patients with TM. This is a retrospective cohort study over 10 years of adolescents and adults with TM aged at least 10 years who had their first cardiac T2* MR between September 2006 and February 2007. One-year chelation therapy was considered the unit of analysis. A total of 99 patients were included in this study with a median age of 18 years. The median cardiac T2* MR and LIC at baseline were 19 ms and 11.6 mg/g dw, respectively. During follow-up, 18 patients died and six underwent successful bone marrow transplantation. Factors associated with decreased survival were older age (HR 1.12, p = 0.014) and high risk cardiac T2* (HR 8.04, p = 0.004). The median cardiac T2* and LIC significantly improved over the 10-year follow-up period (p = 0.000011 and 0.00072, respectively). In conclusion, this long-term "real-life" study confirms that low cardiac T2* adversely impacts the overall survival in patients with TM. Higher baseline LIC predicts a larger reduction in LIC, and lower baseline cardiac T2* predicts a larger improvement in T2*.

Transplantation in patients with iron overload: is there a place for magnetic resonance imaging? : Transplantation in iron overload

In iron overload diseases (thalassemia, sickle cell, and myelodysplastic syndrome), iron is deposited in all internal organs, leading to functional abnormalities. Hematopoietic stem cell transplantation (HSCT) is the only treatment offering a potential cure in these diseases. Our aim was to describe the experience in the field and the role of magnetic resonance imaging in the evaluation of iron overload before and after HSCT. Magnetic resonance imaging (MRI), using T2*, is the most commonly used tool to diagnose myocardial-liver iron overload and guide tailored treatment. Currently, HSCT offers complete cure in thalassemia major, after overcoming the immunologic barrier, and should be considered for all patients who have a suitable donor. The overall thalassemia-free survival of low-risk, HLA-matched sibling stem cell transplantation patients is 85-90%, with a 95% overall survival. The problems of rejection and engraftment are improving with the use of adequate immunosuppression. However, a detailed iron assessment of both heart and liver is necessary for pre- and post-transplant evaluation. In iron overload diseases, heart and liver iron evaluation is indispensable not only for the patients' survival, but also for evaluation before and after HSCT.

Disorders of metal metabolism

Trace elements are chemical elements needed in minute amounts for normal physiology. Some of the physiologically relevant trace elements include iodine, copper, iron, manganese, zinc, selenium, cobalt and molybdenum. Of these, some are metals, and in particular, transition metals. The different electron shells of an atom carry different energy levels, with those closest to the nucleus being lowest in energy. The number of electrons in the outermost shell determines the reactivity of such an atom. The electron shells are divided in sub-shells, and in particular the third shell has s, p and d sub-shells. Transition metals are strictly defined as elements whose atom has an incomplete d sub-shell. This incomplete d sub-shell makes them prone to chemical reactions, particularly redox reactions. Transition metals of biologic importance include copper, iron, manganese, cobalt and molybdenum. Zinc is not a transition metal, since it has a complete d sub-shell. Selenium, on the other hand, is strictly speaking a nonmetal, although given its chemical properties between those of metals and nonmetals, it is sometimes considered a metalloid. In this review, we summarize the current knowledge on the inborn errors of metal and metalloid metabolism.

Utility of Transient Elastography in Estimating Hepatic Iron Concentration in Comparison to Magnetic Resonance Imaging in Patients Who are Transfusion-Dependent: A Canadian Center Experience

Transfusion-dependent hereditary anemias such as β-thalassemia (β-thal), predispose patients to iron overload and its numerous clinical sequelae. Accurate assessment of overall iron status and prompt initiation of chelation therapy to prevent irreversible end-organ damage can be achieved using magnetic resonance imaging (MRI) to measure liver iron concentration (LIC) as a surrogate marker of total body iron; however, its access may be associated with long wait times and delay in treatment. We report an observational cohort study at a single tertiary care center assessing the theoretical role of transient elastography (TE), which measures liver stiffness, in estimating LIC compared to other established diagnostic measures. While regression analyses confirm a moderate correlation between LIC per R2 MRI and serum ferritin level (pooled estimate of correlation = 0.55), there was no significant correlation between TE reading and LIC based on R2 MRI (pooled estimate of correlation = -0.06), and only a weak correlation was observed with serum ferritin level (pooled estimate of correlation = 0.45). These results suggest TE may not be sensitive enough to detect subtle changes in the hepatic parenchymal stiffness associated with liver iron deposition.

Simultaneous liver iron and fat measures by magnetic resonance imaging in patients with hyperferritinemia

OBJECTIVE

Hyperferritinemia is frequent in chronic liver diseases of any cause, but the extent to which ferritin truly reflects iron stores is variable. In these patients, both liver iron and fat are found in variable amount and association. Liver biopsy is often required to quantify liver fat and iron, but sampling variability and invasiveness limit its use. We aimed to assess single breath-hold multiecho magnetic resonance imaging (MRI) for the simultaneous lipid and iron quantification in patients with hyperferritinemia.

MATERIAL AND METHODS

We compared MRI results for both iron and fat with their respective gold standards - liver iron concentration and computer-assisted image analysis for steatosis on biopsy. We prospectively studied 67 patients with hyperferritinemia and other 10 consecutive patients were used for validation. We estimated two linear calibration equations for the prediction of iron and fat based on MRI. The agreement between MRI and biopsy was evaluated.

RESULTS

MRI showed good performances in both the training and validation samples. MRI information was almost completely in line with that obtained from liver biopsy.

CONCLUSION

Single breath-hold multiecho MRI is an accurate method to obtain a valuable measure of both liver iron and steatosis in patients with hyperferritinemia.

Cardiac and Hepatic T2*-Weighted Magnetic Resonance Imaging in Transfusion Dependent Hemoglobinopathy in North West of Iran

BACKGROUND

Iron overload is the main transfusion related side effects in patients with transfusion dependent hemoglobinopathies. Severe iron deposition in tissues leads to organ dysfunction. Many organs can be affected such as heart, liver, and endocrine organs. Cardiac failure and liver fibrosis are the consequent of Iron overload in transfusion dependent hemoglobinopathy. Magnetic Resonance Imaging (MRI) is a safe, noninvasive, and accurate method for the assessment of iron deposition in different tissues. This study assessed iron levels in liver and heart of the patients with transfusion dependent hemoglobinopathies.

MATERIALS AND METHODS

The studied population consisted of 12 patients (7 male and 5 female) with transfusion dependent hemoglobinopathies, aged between 10-18 years old. Then, Cardiac and liver T2*- weighted magnetic resonance imaging (MRI) were obtained.

RESULTS

In current study, 1patient (8.33%) had severe, 2 patients (16.66%) had moderate and 2(16.66%) had mild cardiac iron deposition. Out of 12 patients, 1 had severe iron deposition in liver (8.33%), 5(41.66%) and 4(33.33%) had moderate and mild hepatic iron deposition, respectively. Differences between Hepatic and cardiac iron levels were not significant between males and females (p>0.05).

CONCLUSION

Since cardiac and liver iron levels were higher than normal in most of the study group, checking ferritin level and liver function test and also echocardiography in shorter intervals (each 3 months) in involved group is suggested instead of checking routinely in 6 month intervals in patients with transfusion dependent hemoglobinopathies.

Serum ferritin is an important inflammatory disease marker, as it is mainly a leakage product from damaged cells

"Serum ferritin" presents a paradox, as the iron storage protein ferritin is not synthesised in serum yet is to be found there. Serum ferritin is also a well known inflammatory marker, but it is unclear whether serum ferritin reflects or causes inflammation, or whether it is involved in an inflammatory cycle. We argue here that serum ferritin arises from damaged cells, and is thus a marker of cellular damage. The protein in serum ferritin is considered benign, but it has lost (i.e. dumped) most of its normal complement of iron which when unliganded is highly toxic. The facts that serum ferritin levels can correlate with both disease and with body iron stores are thus expected on simple chemical kinetic grounds. Serum ferritin levels also correlate with other phenotypic readouts such as erythrocyte morphology. Overall, this systems approach serves to explain a number of apparent paradoxes of serum ferritin, including (i) why it correlates with biomarkers of cell damage, (ii) why it correlates with biomarkers of hydroxyl radical formation (and oxidative stress) and (iii) therefore why it correlates with the presence and/or severity of numerous diseases. This leads to suggestions for how one might exploit the corollaries of the recognition that serum ferritin levels mainly represent a consequence of cell stress and damage.

The Role of Magnetic Resonance Imaging in the Evaluation of Thalassemic Syndromes: Current Practice and Future Perspectives

Iron can be deposited in all internal organs, leading to different types of functional abnormalities. However, myocardial iron overload that contributes to heart failure remains one of the main causes of death in thalassemia major. Using magnetic resonance imaging, tissue iron is detected indirectly by the effects on relaxation times of ferritin and hemosiderin iron interacting with hydrogen nuclei. The presence of iron in the human body results in marked alterations of tissue relaxation times. Currently, cardiovascular magnetic resonance using T2* is routinely used in many countries to identify patients with myocardial iron loading and guide chelation therapy, specifically tailored to the heart. Myocardial T2* is the only clinically validated non-invasive measure of myocardial iron loading and is superior to surrogates such as serum ferritin, liver iron, ventricular ejection fraction and tissue Doppler parameters. Finally, the substantial amelioration of patients’ survival, allows the detection of other organs’ abnormalities due to iron overload, apart from the heart, missed in the past. Recent studies revealed that iron deposition has a different pattern in various parenchymal organs, which is independent from serum ferritin and follows an individual way after chelation treatment application. This new upcoming reality orders a closer monitoring of all organs of the body in order to detect preclinical lesions and early apply adequate treatment.

Noninvasive measurement of liver fibrosis using transient elastography in pediatric patients with major thalassemia who are candidates for hematopoietic stem cell transplantation

Although liver biopsy is an invasive procedure, it remains the gold standard technique for the evaluation of hepatic fibrosis in different patients, including those with major thalassemia (MT). Recently, noninvasive imaging techniques, such as transient elastography, have emerged. We investigated the effectiveness of TE, in comparison to liver biopsy, for the evaluation of liver fibrosis in pediatric patients with MT who were candidates for hematopoietic stem cell transplantation (HSCT). Eighty-three pediatric MT patients (48 boys and 35 girls), who were candidates for HSCT, were included in this study. The median age was 8 years. Liver stiffness was assessed for all patients, before transplantation, using both TE, measured in kilopascals (kPa) and liver biopsy, based on the Metavir score. The diagnostic accuracy of TE and liver biopsy were estimated using linear discriminated analysis (the area under the receiver operating characteristic curves [AUROCs]). The median TE score was 4.3 kPa (range, 3.5 to 5.2). The TE value did not differ among patients with different ferritin levels (P = .53). TE increased proportionally to Metavir fibrosis stages (P < .001) and the necro-inflammatory grade (P < .001). The TE score also correlated to liver iron content (P < .001), liver size (P < .003), and Lucarelli risk classification (LRC) (P < .001). ROC curve analysis revealed moderate accuracy of the TE score for the diagnosis of fibrosis (AUROC = 73%) and for distinguishing individuals with a LRC III from those classified as I and II (AUROC = 82%). The TE score was also superior to Fibrosis-4 (AUROC = 61%) for the assessment of liver fibrosis and LRC differentiation. The results of this study demonstrated that TE can be a valuable method for assessing liver fibrosis and differentiating LRC III from the other 2 classes in pediatric patients with MT who have been selected for HSCT.

How early can myocardial iron overload occur in beta thalassemia major?

BACKGROUND

Myocardial siderosis is the most common cause of death in patients with beta thalassemia major(TM). This study aimed at investigating the occurrence, prevalence and severity of cardiac iron overload in a young Chinese population with beta TM.

METHODS AND RESULTS

We analyzed T2* cardiac magnetic resonance (CMR), left ventricular ejection fraction (LVEF) and serum ferritin (SF) in 201 beta TM patients. The median age was 9 years old. Patients received an average of 13 units of blood per year. The median SF level was 4536 ng/ml and 165 patients (82.1%) had SF>2500 ng/ml. Myocardial iron overload was detected in 68 patients (33.8%) and severe myocardial iron overload was detected in 26 patients (12.6%). Twenty-two patients ≤10 years old had myocardial iron overload, three of whom were only 6 years old. No myocardial iron overload was detected under the age of 6 years. Median LVEF was 64% (measured by CMR in 175 patients). Five of 6 patients with a LVEF<56% and 8 of 10 patients with cardiac disease had myocardial iron overload.

CONCLUSIONS

The TM patients under follow-up at this regional centre in China patients are younger than other reported cohorts, more poorly-chelated, and have a high burden of iron overload. Myocardial siderosis occurred in patients younger than previously reported, and was strongly associated with impaired LVEF and cardiac disease. For such poorly-chelated TM patients, our data shows that the first assessment of cardiac T2* should be performed as early as 6 years old.

Iron overload in children undergoing cancer treatments

BACKGROUND

Iron overload is responsible for severe morbidity and mortality in polytransfused patients. Although repeated blood transfusions are needed during the treatment of most cancers, pediatric patients are not routinely screened for subsequent iron overload.

PROCEDURE

Seventy-five patients were identified as candidates for cancer treatment and enrolled prospectively in a yearly protocol including a cardiac and liver magnetic resonance imaging coupled with ferritin level measurements. Patients were divided into four groups using the intensity of treatment rating (ITR-3).

RESULTS

Fifty-nine patients reached 1-year of follow-up and liver iron overload was found in up to 66% of them. Such overload correlated with the total volume of red blood cells transfused and persisted at least 2 years after the initiation of therapy. Moderate myocardial overload was also, but less frequently (14%), observed in these patients.

CONCLUSIONS

Our study demonstrated that severe liver iron overload as well as moderate myocardial iron overload can be found 1 year after cancer treatment and that this overload persists overtime. The patients with higher ITR and those who have received more than a liter of blood red cells per square meter, regardless of their diagnosis or ITR, are at risk of iron overload and should be screened carefully.

Effect of deferasirox chelation on liver iron and total body iron concentration

OBJECTIVE

To determine efficacy of Deferasirox (DFX) on total body iron and liver iron concentration (LIC) as estimated by serum ferritin (SF) and liver MRI T2.

METHODS

Thirty patients had baseline MRI T2 of the liver performed to determine LIC before starting DFX therapy and classified as normal >6.3 milliseconds (ms), mild 6.3-2.7 ms, moderate 2.7-1.4 ms and severe iron overload <1.4 ms. DFX was given 25-35 mg/kg/d. The serum ferritin (SF) level was estimated every 3 monthly. Liver iron is expressed as liver R2 = 1,000/T2. The primary end point of the study was to determine change in SF and liver MRI R2 values after 18 mo of therapy.

RESULTS

All 30 patients had some degree of liver iron overload; 11 (36.6 %) had severe, 15 (50 %) had moderate while 4 (13.3 %) had mild overload. The pre-DFX therapy median SF of all was 3604.5 ng/mL (IQR 2357.0-5056.0) and median liver R2 was 574.71 Hz (IQR 411.3-770.8). After 18 mo, SF dropped significantly to a median of 2036.5 ng/mL (IQR 1700.0-3162.0) (p = 0.0011), while median liver R2 decreased from 574.71 to 568.18 Hz (IQR 393.4-803.2) which was not significant (p = 0.986).

CONCLUSIONS

DFX monotherapy at the doses used decreases total body iron, but does not significantly decrease liver iron. It is well tolerated by Indian thalassemia patients, with observed side effects including rash, diarrhea, and transient albuminuria. MRI T2 (and derived R2) can serve as useful method in non invasive monitoring of LIC in thalassemia patient management.

Iron stores assessment in alcoholic liver disease

BACKGROUND

The relation between alcoholic liver disease (ALD) and iron overload is well known. Liver biopsy is the gold standard for assessing iron stores. MRI is also validated for liver iron concentration (LIC) assessment. We aimed to assess the effect of active drinking in liver iron stores and the practicability of measuring LIC by MRI in ALD patients.

MATERIALS AND METHODS

We measured LIC by MRI in 58 ALD patients. We divided patients into two groups - with and without active alcoholism - and we compared several variables between them. We evaluated MRI-LIC, liver iron stores grade, ferritin and necroinflammatory activity grade for significant correlations.

RESULTS

Significant necroinflammation (40.0% vs. 4.3%), LIC (40.1 vs. 24.3 µmol/g), and ferritin (1259.7 vs. 568.7 pmol/L) were significantly higher in drinkers. LIC values had a strong association with iron stores grade (r s = 0.706). Ferritin correlated with LIC (r s = 0.615), iron stores grade (r s = 0.546), and necroinflammation (r s = 0.313). The odds ratio for elevated serum ferritin when actively drinking was 7.32.

CONCLUSION

Active alcoholism is associated with increased ALD activity. It is also the key factor in iron overload. Scheuers' semiquantitative score with Perls' staining gives a fairly accurate picture of liver iron overload. Serum ferritin also shows a good correlation with LIC values and biopsy iron stores grade. As most patients present only with mild iron overload, serum ferritin measurement and semiquantitative evaluation of iron stores are adequate, considering MRI high cost. However, if MRI is required to evaluate liver structure, LIC assessment could be performed without added cost.

Assessment of hepatic and pancreatic iron overload in pediatric Beta-thalassemic major patients by t2* weighted gradient echo magnetic resonance imaging

Background. MRI has emerged for the noninvasive assessment of iron overload in various tissues. The aim of this paper is to evaluate hepatic and pancreatic iron overload by T2^∗ weighted gradient echo MRI in young beta-thalassemia major patients and to correlate it with glucose disturbance and postsplenectomy status. Subjects and Methods. 50 thalassemic patients, in addition to 15 healthy controls. All patients underwent clinical assessment and laboratory investigations. Out of 50 thalassemic patients, 37 patients were splenectomized. MRI was performed for all subjects. Results. All patients showed significant reduction in the signal intensity of the liver and the pancreas on T2^∗GRD compared to controls, thalassemic patients who had abnormal glucose tolerance; diabetic and impaired glucose tolerance patients displayed a higher degree of pancreatic and hepatic siderosis and more T2^∗ drop in their signal intensity than those with normal blood sugar level. Splenectomized thalassemic patients had significantly lower signal intensity of the liver and pancreas compared to nonsplenectomized patients. Conclusion. T2^∗ gradient echo MRI is noninvasive highly sensitive method in assessing hepatic and pancreatic iron overload in thalassemic patients, more evident in patients with abnormal glucose tolerance, and is accelerated in thalassemic splenectomized patients.

MRI evaluation of hepatic iron overload: Recent advances

Many studies show that hepatic iron overload has a close association with hepatitis, hepatic fibrosis, cirrhosis, and hepatic tumors. Methods currently used for detection of hepatic iron overload, such as plasma ferritin detection, liver biopsy, and superconducting quantum interface device, have some limitations. Improvement in software and hardware has enabled MRI to become a safe, noninvasive and accurate method for detecting hepatic iron overload. This article aims to summarize the performance and application of MRI in the evaluation of hepatic iron overload.

Cross-sectional investigation of correlation between hepatic steatosis and IVIM perfusion on MR imaging

The purpose of this study was to investigate the relationship between liver fat fraction (FF) and diffusion parameters derived from the intravoxel incoherent motion (IVIM) model. Thirty-six subjects with suspected nonalcoholic fatty liver disease underwent diffusion-weighted magnetic resonance imaging with 10 b-values and spoiled gradient recalled echo imaging with six echoes for fat quantification. Correlations were measured between FF, transverse relaxivity (R2), diffusivity (D) and perfusion fraction (f). The primary finding was that no significant correlation was obtained for D vs. FF or f vs. FF. Significant correlations were obtained for D vs. R2 (r=-0.490, P=.002) and f vs. D (r=-0.458, P=.005). The conclusion is that hepatic steatosis does not affect measurement of perfusion or diffusion and therefore is unlikely to confound the use of apparent diffusivity to evaluate hepatic fibrosis.

Room-temperature susceptometry predicts biopsy-determined hepatic iron in patients with elevated serum ferritin

BACKGROUND

There is an ongoing clinical need for novel methods to measure hepatic iron content (HIC) noninvasively. Both magnetic resonance imaging (MRI) and superconducting quantum interference device (SQUID) methods have previously shown promise for estimation of HIC, but these methods can be expensive and are not widely available. Room-temperature susceptometry (RTS) represents an inexpensive alternative and was previously found to be strongly correlated with HIC estimated by SQUID measurements among patients with transfusional iron overload related to thalassemia.

AIM

The goal of the current study was to examine the relationship between RTS and biochemical HIC measured in liver biopsy specimens in a more varied patient cohort.

MATERIAL AND METHODS

Susceptometry was performed in a diverse group of patients with hyperferritinemia due to hereditary hemochromatosis (HHC) (n = 2), secondary iron overload (n = 3), nonalcoholic fatty liver disease (NAFLD) (n = 2), and chronic viral hepatitis (n = 3) within one month of liver biopsy in the absence of iron depletion therapy.

RESULTS

The correlation coefficient between HIC estimated by susceptometry and by biochemical iron measurement in liver tissue was 0.71 (p = 0.022). Variance between liver iron measurement and susceptometry measurement was primarily related to reliance on the patient's body-mass index (BMI) to estimate the magnetic susceptibility of tissue overlying the liver.

CONCLUSIONS

We believe RTS holds promise for noninvasive measurement of HIC. Improved measurement techniques, including more accurate overlayer correction, may further improve the accuracy of liver susceptometry in patients with liver disease.

Non-invasive methods for liver fibrosis prediction in hemochromatosis: One step beyond

Advances in recent years in the understanding of, and the genetic diagnosis of hereditary hemochromatosis (HH) have changed the approach to iron overload hereditary diseases. The ability to use a radiologic tool (MRI) that accurately provides liver iron concentration determination, and the presence of non-invasive serologic markers for fibrosis prediction (serum ferritin, platelet count, transaminases, etc), have diminished the need for liver biopsy for diagnosis and prognosis of this disease. Consequently, the role of liver biopsy in iron metabolism disorders is changing. Furthermore, the irruption of transient elastography to assess liver stiffness, and, more recently, the ability to determine liver fibrosis by means of MRI elastography will change this role even more, with a potential drastic decline in hepatic biopsies in years to come. This review will provide a brief summary of the different non-invasive methods available nowadays for diagnosis and prognosis in HH, and point out potential new techniques that could come about in the next years for fibrosis prediction, thus avoiding the need for liver biopsy in a greater number of patients. It is possible that liver biopsy will remain useful for the diagnosis of associated diseases, where other non-invasive means are not possible, or for those rare cases displaying discrepancies between radiological and biochemical markers.

Liver magnetic resonance imaging: State of the art

Magnetic resonance imaging (MRI) has now been used for about three decades to characterize the human liver in a non-invasive way, that is without the need of using ionizing radiation or removing tissue samples. During the past few years, technical progress has been considerable and novel applications of MRI have been implemented in the clinic. The beginning of a new decade offers an excellent opportunity for having five experts to present their view on the current status of MRI (and magnetic resonance spectroscopy) in the study of perfusion, fat and iron contents, diffusion and the metabolism of diffuse liver diseases. This topic highlight series thus provides an update of current knowledge in the field of liver MRI.