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Evidence Level: 1 Technical Efficacy Stage: 3 [ABSTRACT FROM AUTHOR]

This article discusses the importance of studying the placenta and the potential of non-invasive techniques to measure placental function. The authors focus on the use of diffusion MRI and the intravoxel incoherent motion (IVIM) model to evaluate placental blood flow and microstructures. They propose a new model that includes two perfusion compartments in addition to the diffusion compartment in the placenta. The study includes patients with normal pregnancies, Small for Gestational Age (SGA), Fetal Growth Restriction (FGR), and placenta accreta spectrum (PAS) disorders. The results show differences in perfusion fractions between these groups, but further validation and testing with more cases are needed. [Extracted from the article]

Purpose: To evaluate the feasibility of T1 rho mapping in myocardium at 3T and to determine whether T1 rho mapping could better characterize myocardial injury in end-stage renal disease (ESRD) patients compared to T1 and T2 mapping.Materials and Methods: T1 rho mapping, T1 mapping, and T2 mapping were performed at 3T on 35 healthy volunteers (15 males, 20 females, 40.7 ± 13.6 years) and 32 ESRD patients (16 males, 16 females, 48.6 ± 11.9 years). The mean T1 rho, T1 , and T2 values were compared using Student's t-test and correlated with cardiac function parameters, including peak ejection rate (PER), short-axis percent thickening (SAPT), peak filling rate (PFR), and time to peak filling (TTPF).Results: The mean T1 rho values (49.4 ± 2.6 msec vs. 52.2 ± 4.0 msec, P = 0.001) and T2 values (50.5 ± 2.5 msec vs. 54.1 ± 4.0 msec, P < 0.001) were significantly different between the volunteers and patients, but there were no significant differences between the two groups in the T1 values (1253.1 ± 71.6 msec vs. 1273.4 ± 41.7 msec, P = 0.157). The mean T1 rho values were negatively correlated with the PER (r = -0.397; P = 0.03), SAPT (r = -0.688; P < 0.001), and PFR (r = -0.537; P = 0.002), whereas positively correlated with the TTPF (r = 0.677; P < 0.001). The mean T2 values were negatively correlated only with the SAPT (r = -0.427; P = 0.019) in the ESRD patients.Conclusion: T1 rho mapping of the myocardium is feasible at 3T. T1 rho values are higher in ESRD patients and relate to cardiac function, which may better characterize myocardial injury than can T1 and T2 . J. Magn. Reson. Imaging 2016;44:723-731. [ABSTRACT FROM AUTHOR]

Purpose To design a multislice double inversion-recovery fast spin-echo (FSE) sequence, with k-space reordered by inversion time at slice position (KRISP) technique, to produce black-blood vessel wall magnetic resonance imaging (MRI). Materials and Methods In this sequence, central k-space sampling for each slice is required at inversion time (TI) of the blood signal. To fill the entire k-space, the peripheral lines are obtained less or greater the TI and using a rotating slice order. Blood flow signal suppression was first evaluated using a phantom. Simulation studies were used to investigate FSE image quality. The final sequence was then applied to the rabbit abdominal aorta MRI at 4.7 T. Results In the flow phantom study, artifacts from slow-flowing water were substantially reduced by the KRISP technique; residual water spins were dephased by the strong phase-encoding gradient required for peripheral k-space. These dephased spins flowed into the slice plane where the center of k-space was being acquired at the TI of the flowing water signal. Multislice black-blood MR images were successfully obtained in the rabbit abdomen using the sequence with the k-trajectory optimized by the simulation study. Conclusion The KRISP technique was effective both in multislice double inversion-recovery FSE and in blood signal suppression. J. Magn. Reson. Imaging 2004;20:881-888. © 2004 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]