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Background: Quantitative susceptibility mapping (QSM) uses prior information to reconstruct maps, but prior information may not show pathology and introduce inconsistencies with susceptibility maps, degrade image quality and inadvertently smoothing image features., Purpose: To develop a local field data-driven QSM reconstruction that does not depend on spatial edge prior information., Study Type: Retrospective., Subjects, Animal Models: A dataset from 2016 ISMRM QSM Challenge, 11 patients with glioblastoma, a patient with microbleeds and porcine heart., Sequence/field Strength: 3D gradient echo sequence on 3T and 7T scanners., Assessment: Accuracy was compared to Calculation of Susceptibility through Multiple Orientation Sampling (COSMOS), and several published techniques using region of interest (ROI) measurements, root-mean-squared error (RMSE), structural similarity index metric (SSIM), and high-frequency error norm (HFEN). Numerical ranking and semiquantitative image grading was performed by three expert observers to assess overall image quality (IQ) and image sharpness (IS)., Statistical Tests: Bland-Altman, Friedman test, and Conover multiple comparisons., Results: Loss adaptive dipole inversion (LADI) (β = 0.82, R 2 = 0.96), morphology-enabled dipole inversion (MEDI) (β = 0.91, R 2 = 0.97), and fast nonlinear susceptibility inversion (FANSI) (β = 0.81, R 2 = 0.98) had excellent correlation with COSMOS and no bias was detected (bias = 0.006 ± 0.014, P < 0.05). In glioblastoma patients, LADI showed consistently better performance (IQ Grade = 2.6 ± 0.4, IS Grade = 2.6 ± 0.3, IQ Rank = 3.5 ± 0.4, IS Rank = 3.9 ± 0.2) compared with MEDI (IQ Grade = 2.1 ± 0.3, IS Grade = 2 ± 0.5, IQ Rank = 2.4 ± 0.5, IS Rank = 2.8 ± 0.2) and FANSI (IQ Grade = 2.2 ± 0.5, IS Grade = 2 ± 0.4, IQ Rank = 2.8 ± 0.3, IS Rank = 2.1 ± 0.2). Dark artifact visible near the infarcted region in MEDI (Inf MEDI = -0.27 ± 0.06 ppm) was better mitigated by FANSI (Inf FANSI-TGV = -0.17 ± 0.05 ppm) and LADI (Inf LADI = -0.18 ± 0.05 ppm)., Conclusion: For neuroimaging applications, LADI preserved image sharpness and fine features in glioblastoma and microbleed patients. LADI performed better at mitigating artifacts in cardiac QSM., Evidence Level: 4 TECHNICAL EFFICACY STAGE: 1 J. Magn. Reson. Imaging 2020;52:823-835., (© 2020 International Society for Magnetic Resonance in Medicine.)

Background: Uterine artery (UtA) hemodynamics might be used to predict risk of hypertensive pregnancy disorders, including preeclampsia and intrauterine growth restriction., Purpose or Hypothesis: To determine the feasibility of 4D flow MRI in pregnant subjects by characterizing UtA anatomy, computing UtA flow, and comparing UtA velocity, and pulsatility and resistivity indices (PI, RI) with transabdominal Doppler ultrasound (US)., Study Type: Prospective cross-sectional study from June 6, 2016, to May 2, 2018., Population or Subjects or Phantom or Specimen or Animal Model: Forty-one singleton pregnant subjects (age [range] = 27.0 ± 5.9 [18-41] years) in their second or third trimester. We additionally scanned three subjects who had prepregnancy diabetes or chronic hypertension., Field Strength/sequence: The subjects underwent UtA and placenta MRI using noncontrast angiography and 4D flow at 1.5T., Assessment: UtA anatomy was described based on 4D flow-derived noncontrast angiography, while UtA flow properties were characterized by net flow, systolic/mean/diastolic velocity, PI and RI through examination of 4D flow data. PI and RI are standard hemodynamic parameters routinely reported on Doppler US., Statistical Tests: Spearman's rank correlation, Wilcoxon signed rank tests, and Bland-Altman plots were used to preliminarily investigate the relationships between flow parameters, gestational age, and Doppler US. or RESULTS: 4D flow MRI and UtA flow quantification was feasible in all subjects. There was considerable heterogeneity in UtA geometry in each subject between left and right UtAs and between subjects. Mean 4D flow-based parameters were: mean bilateral flow rate = 605.6 ± 220.5 mL/min, PI = 0.72 ± 0.2, and RI = 0.47 ± 0.1. Bilateral flow did not change with gestational age. We found that MRI differed from US in terms of lower PI (mean difference -0.1) and RI (mean difference < -0.1) with Wilcoxon signed rank test P = 0.05 and P = 0.13, respectively., Data Conclusion: 4D flow MRI is a feasible approach for describing UtA anatomy and flow in pregnant subjects., Level of Evidence: Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:59-68., (© 2018 International Society for Magnetic Resonance in Medicine.)