MRI detects myocardial iron in the human heart

Circulation, 2011

Background— Measurement of myocardial iron is key to the clinical management of patients at risk of siderotic cardiomyopathy. The cardiovascular magnetic resonance relaxation parameter R2* (assessed clinically via its reciprocal, T2*) measured in the ventricular septum is used to assess cardiac iron, but iron calibration and distribution data in humans are limited. Methods and Results— Twelve human hearts were studied from transfusion-dependent patients after either death (heart failure, n=7; stroke, n=1) or transplantation for end-stage heart failure (n=4). After cardiovascular magnetic resonance R2* measurement, tissue iron concentration was measured in multiple samples of each heart with inductively coupled plasma atomic emission spectroscopy. Iron distribution throughout the heart showed no systematic variation between segments, but epicardial iron concentration was higher than in the endocardium. The mean±SD global myocardial iron causing severe heart failure in 10 patients was...

Magma: Magnetic Resonance Materials in Physics, Biology, and Medicine, 2001

The purpose of this study was to evaluate the potential ability of magnetic resonance imaging (MRI) for evaluation of myocardial iron deposits. The applied MRI technique has earlier been validated for quantitative determination of the liver iron concentration. The method involves cardiac gating and may, therefore, also be used for simultaneous evaluation of myocardial iron. The tissue signal intensities were measured from spin echo images and the myocardium/muscle signal intensity ratio was determined. The SI ratio was converted to tissue iron concentration values based on a modified calibration curve from the liver model. The crucial steps of the method were optimized: i.e. recognition and selection of the myocardial slice for analysis and positioning of the regions of interest (ROIs) within the myocardium and the skeletal muscle. This made the myocardial MRI measurements sufficiently reproducible. We applied this method in 41 multiply transfused patients. Our data demonstrate significant positive linear relationships between different iron store parameters and the MRt-derived myocardial iron concentration, which was significantly related to the serum ferritin concentration (p = 0.62, P <0.0001) and to the MRI-determined liver iron concentration (p =0.36, P =0.02). The myocardial MRI iron concentrations demonstrated also a significant positive correlation with the number of blood units given (p = 0.45, P = 0.005) and the aminotransferase serum concentration (/)= 0.54, P = 0.0008). Our data represents indirect evidence for the ability of MRI techniques based on myocardium/muscle signal intensity ratio measurements to evaluate myocardial iron overload. ( 9

Journal of Cardiovascular Magnetic Resonance, 2021

Background Non-invasive estimation of the cardiac iron concentration (CIC) by T2* cardiovascular magnetic resonance (CMR) has been validated repeatedly and is in widespread clinical use. However, calibration data are limited, and mostly from post-mortem studies. In the present study, we performed an in vivo calibration in a dextran-iron loaded minipig model. Methods R2* (= 1/T2*) was assessed in vivo by 1.5 T CMR in the cardiac septum. Chemical CIC was assessed by inductively coupled plasma-optical emission spectroscopy in endomyocardial catheter biopsies (EMBs) from cardiac septum taken during follow up of 11 minipigs on dextran-iron loading, and also in full-wall biopsies from cardiac septum, taken post-mortem in another 16 minipigs, after completed iron loading. Results A strong correlation could be demonstrated between chemical CIC in 55 EMBs and parallel cardiac T2* (Spearman rank correlation coefficient 0.72, P

Journal of Magnetic Resonance Imaging, 2006

To assess the tissue iron concentration of the left ventricle (LV) using a multislice, multiecho T2* MR technique and a segmental analysis.

Journal of Magnetic Resonance Imaging, 2009

To assess the transferability of the magnetic resonance imaging (MRI) multislice multiecho T2* technique for global and segmental measurement of iron overload in thalassemia patients.

Magnetic Resonance in Medicine, 2007

This work demonstrates the use of a fast and precise methodology for evaluating myocardial and liver iron status in multitransfused thalassemic patients by means of a fast T quantitative MRI (TqMRI) technique. Myocardial and liver T values were calculated in 48 thalassemic patients and 21 normal subjects on a 1.5T MRI system using a breath-hold 2D single-slice multiecho gradient-echo (MEGRE) sequence (16 echoes, TR/TE1/TE16/FA = 160/2.7/37.65 ms/25°). No ECG gating was used. Myocardial T, liver T, and myocardial to muscle (CR/MS) and liver to muscle (LV/MS) T ratios were correlated with serum ferritin concentration (SFC) levels for all patients. Significant differences in myocardial and liver mean T, CR/MS, and LV/MS T values between patients and normal subjects were found (P < 0.0005). Differences in paraspinous muscle mean T values between patients and normal subjects were not significant. Myocardial T and CR/MS T values were not correlated with SFC levels. Liver T and LV/MS T values were significantly correlated with SFC (r = 0.540, P < 0.0005). Myocardial T and CR/MS T values were not correlated with either liver T or LV/MS T values, respectively. We conclude that myocardial and liver iron deposition can be evaluated using the fast non-ECG-gated TqMRI technique. Magn Reson Med 57:742–753, 2007. © 2007 Wiley-Liss, Inc.

Magnetic resonance imaging, 2010

A magnetic resonance imaging cardiac magnetic susceptometry (MRI-CS) technique for assessing cardiac tissue iron concentration based on phase mapping was developed. Normal control subjects (n=9) and thalassemia patients (n=13) receiving long-term blood transfusion therapy underwent MRI-CS and MRI measurements of the cardiac relaxation rate R2*. Using MRI-CS, subepicardium and subendocardium iron concentrations were quantified exploiting the hemosiderin/ferritin iron specific magnetic susceptibility. The average of subepicardium and subendocardium iron concentrations and R2* of the septum were found to be strongly correlated (r=0.96, P&lt;.0001), and linear regression analysis yielded CIC (microg Fe/g(wet tissue))=(6.4+/-0.4).R2* (septum) (s(-1)) - (120+/-40). The results demonstrated that septal R2* indeed measures cardiac iron level.

Acta Radiologica, 2017

Background Cardiac and liver iron assessment using magnetic resonance imaging (MRI) is non-invasive and used as a preclinical “endpoint” in asymptomatic patients and for serial iron measurements in iron-overloaded patients. Purpose To compare iron measurements between hepatic and myocardial T2* and T2 at 1.5T and 3T MRI in normal and iron-overloaded patients. Material and Methods The T2 and T2* values from the regions of interest (ROIs) at mid-left ventricle and mid-hepatic slices were evaluated by 1.5T and 3T MRI scans for healthy and iron-overloaded patients. Results For iron-overloaded patients, the myocardial T2 (1.5T) and myocardial T2 (3T) values were 60.3 ms (range = 56.2–64.8 ms) and 55 ms (range = 51.6–60.1 ms) (ρ = 0.3679) while the myocardial T2* (3T) 20.5 ms (range = 18.4–25.9 ms) was shorter than the myocardial T2* (1.5T) 35.9 ms (range = 31.4–39.5 ms) (ρ = 0.6454). The hepatic T2 at 1.5T and 3T were 19.1 ms (range = 14.8–27.9 ms) and 15.5 ms (14.6–20.4 ms) (ρ = 0.9444)...

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature, 2011

Background-Measurement of myocardial iron is key to the clinical management of patients at risk of siderotic cardiomyopathy. The cardiovascular magnetic resonance (CMR) relaxation parameter R2* (assessed clinically via its reciprocal T2*) measured in the ventricular septum is used to assess cardiac iron, but iron calibration and distribution data in humans is limited. Methods and Results-Twelve human hearts were studied from transfusion dependent patients following either death (heart failure n=7, stroke n=1) or transplantation for end-stage heart failure (n=4). After CMR R2* measurement, tissue iron concentration was measured in multiple samples of each heart using inductively coupled plasma atomic emission spectroscopy. Iron distribution throughout the heart showed no systematic variation between segments, but epicardial iron concentration was higher than in the endocardium. The mean (±SD) global myocardial iron causing severe heart failure in 10 patients was 5.98 ±2.42mg/g dw (range 3.19-9.50), but in 1 outlier case of heart failure was 25.9mg/g dw. Myocardial ln[R2*] was strongly linearly correlated with ln[Fe] (R 2 =0.910, p<0.001) leading to [Fe]=45.0•(T2*) −1.22 for the clinical calibration equation with [Fe] in mg/g dw and T2* in ms. Mid-ventricular septal iron concentration and R2* were both highly representative of mean global myocardial iron.