Background: Accurate measurement of the liver iron concentration (LIC) is needed to guide iron-chelating therapy for patients with transfusional iron overload. In this work, we investigate the feasibility of automated quantitative susceptibility mapping (QSM) to measure the LIC. Purpose: To develop a rapid, robust and automated liver QSM for clinical practice. Study Type: Prospective Population: 13 healthy subjects and 22 patients. Field strength/Sequences 1.5T and 3T / 3D multi-echo gradient-recalled echo (GRE) sequence. Assessment: Data were acquired using a 3D GRE sequence with an out-of-phase echo spacing with respect to each other. All odd echoes that were in-phase (IP) were used to initialize the fat-water separation and field estimation (T2*-IDEAL) before performing QSM. Liver QSM was generated through an automated pipeline without manual intervention. This IP echo-based initialization method was compared with an existing graph cuts initialization method (SPURS) in healthy subjects (n=5). Reproducibility was assessed over 4 scanners at 2 field strengths from 2 manufacturers using healthy subjects (n=8). Clinical feasibility was evaluated in patients (n=22). Statistical Tests: IP and SPURS initialization methods in both healthy subjects and patients were compared using paired t-test and linear regression analysis to assess processing time and ROI measurements. Reproducibility of QSM, R2*, and proton density fat fraction (PDFF) among the four different scanners was assessed using linear regression, Bland-Altman analysis, and the intraclass correlation coefficient (ICC). Results: Liver QSM using the IP method was found to be approximately 5.5 times faster than SPURS (P< 0.05) in initializing T2*-IDEAL with similar outputs. Liver QSM using the IP method were reproducibly generated in all four scanners (average coefficient of determination 0.95, average slope 0.90, average bias 0.002 ppm, 95% limits of agreement between −0.06 to 0.07 ppm, ICC 0.97). Conclusion: Use of IP echo-based initialization, enables robust water/fat separation and field estimation for automated, rapid and reproducible liver QSM for clinical applications.

In vivo cardiac QSM is feasible and can be used to measure SvO , but improvements in data acquisition are needed. Magn Reson Med 79:1545-1552, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Purpose The Sophisticated Harmonic Artifact Reduction for Phase data (SHARP) method has been proposed for the removal of background field in MRI phase data. It relies on the spherical mean value (SMV) property of harmonic functions, and its accuracy depends on the radius of the sphere used for computing the SMV and truncation threshold needed for deconvolution. The goal of this work is to develop an alternative SMV based background field removal method with reduced dependences on these parameters. Methods The proposed background field removal method (termed iterative SMV or iSMV) consists of applying the SMV operation repeatedly on the field map and it was validated in a phantom and in vivo brain data of five healthy volunteers. Results The iSMV method demonstrates accurate background field removal in the phantom. Compared to SHARP, the iSMV method shows a significantly reduced dependence on the SMV radius both in phantom and in human data. Because a smaller radius can be chosen, the iSMV method allows retaining a larger part of the region of interest, compared to SHARP. Conclusion The iSMV method is an effective background field removal method with a reduced dependence on method parameters.

The purpose of this study was to explore the application value of lncRNA MEG3 in lung cancer. From March 2017 to March 2019, 119 asthma patients and 125 healthy people undergoing physical examination in the same period were selected as the research objects. The levels of lncRNA MEG3 in the peripheral blood of the two groups were compared, and the predictive value of MEG3 for asthma as well as the differences in different inflammatory phenotypes were analyzed. The expression of MEG3 was low in asthma patients (P<0.050), the diagnostic sensitivity and specificity for asthma were 79.83 and 66.40%, respectively (P<0.001), it was the lowest in mixed granulocytic asthma (P<0.050) and was negatively correlated with the course of disease (r=-0.666, P<0.001). Logistic regression analysis showed that course of disease, inflammatory phenotype and MEG3 were independent factors affecting recurrence of asthma (P<0.050). MEG3 was low expressed in asthma and had good predictive value for it; in mixed granulocytic asthma, its expression was the lowest and the course of disease was closely related. It might be the key to the diagnosis and treatment of asthma in the future.

Purpose:To develop a nonlinear preconditioned total field-inversion algorithm using the MEDI toolbox (MEDInpt) for robust QSM of carotid plaques and evaluate its performance in comparison with a local field-inversion algorithm (STI Suite) previously applied to carotid QSM. Methods: Numerical simulation and in vivo carotid QSM were performed to compare the MEDInpt and STI Suite algorithms. Multicontrast MRI was used as the reference standard for detecting calcified plaque and intraplaque hemorrhage (IPH).A total of 5 healthy volunteers and 11 patients with at least one significant carotid artery stenosis were enrolled in this study. Results: In the numerical carotid phantom, the relative susceptibility errors for calcified plaque and IPH were reduced from −63.2% and −56.5% with STI Suite to −13.0% and −24.2% with MEDInpt, respectively. In humans, MEDInpt provided a higher QSM quality score and better detection of calcification and IPH than STI Suite. Although all calcifications and IPHs detected on multicontrast MRI could be seen on QSM obtained with MEDInpt, only 50% of calcified plaques and 83% of IPHs could be captured on QSM obtained with STI Suite. Conclusion: MEDInpt can resolve calcification and IPH in advanced atherosclerotic carotid plaques. Compared with STI Suite, MEDInpt provided better QSM quality and has the potential to improve the detection of these plaque components. K E Y W O R D S atherosclerosis, calcification, carotid plaques, intraplaque hemorrhage, quantitative susceptibility mapping (QSM) 1502 | NGUYEN Et al.

Purpose To develop an automated adaptive preconditioner for QSM reconstruction with improved susceptibility quantification accuracy and increased image quality. Theory and Methods The total field was used to rapidly produce an approximate susceptibility map, which was then averaged and trended over R2∗ binning to generate a spatially varying distribution of preconditioning values. This automated adaptive preconditioner was used to reconstruct QSM via total field inversion and was compared with its empirical counterparts in a numerical simulation, a brain experiment with 5 healthy subjects and 5 patients with intracerebral hemorrhage, and a cardiac experiment with 3 healthy subjects. Results Among evaluated preconditioners, the automated adaptive preconditioner achieved the fastest convergence in reducing the RMSE of the QSM in the simulation, suppressed hemorrhage‐associated artifacts while preserving surrounding brain tissue contrasts, and provided cardiac chamber oxygenation values consistent with those reported in the literature. Conclusion An automated adaptive preconditioner allows high‐quality QSM from the total field in imaging various anatomies with dynamic susceptibility ranges.

Purpose: Typical quantitative susceptibility mapping (QSM) reconstruction steps consist of first estimating the magnetization field from the gradient-echo images, and then reconstructing the susceptibility map from the estimated field. The errors from the field-estimation steps may propagate into the final QSM map, and the noise in the estimated field map may no longer be zero-mean Gaussian noise, thus, causing streaking artifacts in the resulting QSM. A multiecho complex total field inversion (mcTFI) method was developed to compute the susceptibility map directly from the multiecho gradient echo images using an improved signal model that retains the Gaussian noise property in the complex domain. It showed improvements in QSM reconstruction over the conventional field-to-source inversion. Methods: The proposed mcTFI method was compared with the nonlinear total field inversion (nTFI) method in a numerical brain with hemorrhage and calcification, the numerical brains provided by the QSM Challenge 2.0, 18 brains with intracerebral hemorrhage scanned at 3T, and 6 healthy brains scanned at 7T. Results: Compared with nTFI, the proposed mcTFI showed more accurate QSM reconstruction around the lesions in the numerical simulations. The mcTFI reconstructed QSM also showed the best image quality with the least artifacts in the brains with intracerebral hemorrhage scanned at 3T and healthy brains scanned at 7T. Conclusion:The proposed multiecho complex total field inversion improved QSM reconstruction over traditional field-to-source inversion through better signal modeling. K E Y W O R D Sbrain imaging, nonlinear total field inversion, quantitative susceptibility mapping

BackgroundDifferential blood oxygenation between left (LV) and right ventricles (RV; ΔSaO2) is a key index of cardiac performance; LV dysfunction yields increased RV blood pool deoxygenation. Deoxyhemoglobin increases blood magnetic susceptibility, which can be measured using an emerging cardiovascular magnetic resonance (CMR) technique, Quantitative Susceptibility Mapping (QSM) – a concept previously demonstrated in healthy subjects using a breath-hold 2D imaging approach (2DBHQSM). This study tested utility of a novel 3D free-breathing QSM approach (3DNAVQSM) in normative controls, and validated 3DNAVQSM for non-invasive ΔSaO2 quantification in patients undergoing invasive cardiac catheterization (cath).MethodsInitial control (n = 10) testing compared 2DBHQSM (ECG-triggered 2D gradient echo acquired at end-expiration) and 3DNAVQSM (ECG-triggered navigator gated gradient echo acquired in free breathing using a phase-ordered automatic window selection algorithm to partition data based on diaphragm position). Clinical testing was subsequently performed in patients being considered for cath, including 3DNAVQSM comparison to cine-CMR quantified LV function (n = 39), and invasive-cath quantified ΔSaO2 (n = 15). QSM was acquired using 3 T scanners; analysis was blinded to comparator tests (cine-CMR, cath).Results3DNAVQSM generated interpretable QSM in all controls; 2DBHQSM was successful in 6/10. Among controls in whom both pulse sequences were successful, RV/LV susceptibility difference (and ΔSaO2) were not significantly different between 3DNAVQSM and 2DBHQSM (252 ± 39 ppb [17.5 ± 3.1%] vs. 211 ± 29 ppb [14.7 ± 2.0%]; p = 0.39). Acquisition times were 30% lower with 3DNAVQSM (4.7 ± 0.9 vs. 6.7 ± 0.5 min, p = 0.002), paralleling a trend towards lower LV mis-registration on 3DNAVQSM (p = 0.14). Among cardiac patients (63 ± 10y, 56% CAD) 3DNAVQSM was successful in 87% (34/39) and yielded higher ΔSaO2 (24.9 ± 6.1%) than in controls (p < 0.001). QSM-calculated ΔSaO2 was higher among patients with LV dysfunction as measured on cine-CMR based on left ventricular ejection fraction (29.4 ± 5.9% vs. 20.9 ± 5.7%, p < 0.001) or stroke volume (27.9 ± 7.5% vs. 22.4 ± 5.5%, p = 0.013). Cath measurements (n = 15) obtained within a mean interval of 4 ± 3 days from CMR demonstrated 3DNAVQSM to yield high correlation (r = 0.87, p < 0.001), small bias (− 0.1%), and good limits of agreement (±8.6%) with invasively measured ΔSaO2.Conclusion3DNAVQSM provides a novel means of assessing cardiac performance. Differential susceptibility between the LV and RV is increased in patients with cine-CMR evidence of LV systolic dysfunction; QSM-quantified ΔSaO2 yields high correlation and good agreement with the reference of invasively-quantified ΔSaO2.