This paper proposes an image reconstruction method for simultaneous multi-slice imaging (SMS) by combining the virtual conjugate coil (VCC) technology and robust artificial-neural-networks for k-space interpolation (RAKI). This method can effectively improve the reconstruction quality, and is named VIRGINIA (VIRtual conjuGate coIls Neural-networks InterpolAtion). VIRGINIA utilizes the complex conjugate symmetry property of the virtual coil concept to generate virtual coil data for training, and obtains better image quality by applying the trained network to the original aliased SMS data. With experimental data, the VIRGINIA method was compared to other reconstruction methods (i.e., RAKI only and slice-GRAPPA) in terms of quantitative indices such as structural similarity index (SSIM), peak signal-to-noise ratio (PSNR) and root mean square error (RMSE). The results demonstrated that, under some certain slice-acceleration factors, VIRGINIA produced better reconstruction quality than those obtainable by Slice-GRAPPA and RAKI.

Fiber tracking with diffusion magnetic resonance imaging provides a powerful tool for non-invasive observation of white matter in the brain. Constrained spherical deconvolution (CSD) is a multi-fiber tracking model, which can model the orientation of fibers in the voxel and achieve brain fiber reconstruction. This paper proposes a deterministic fiber tracking algorithm based on a non-local CSD model that combines neighborhood information and fractional regularization. The algorithm aimed to solve the ill-posed problem and loss detailed information in the conventional CSD model. The nonlocality of fractional order reduced the errors of fiber orientation distribution estimation, and the neighborhood information was used to ensure spatial consistency, reducing the effects of random noise. Simulation data and experimental human brain data were used to compare the performance of the proposed algorithm and the conventional CSD deterministic tracking algorithm. The results demonstrated that the proposed algorithm produced not only better overall visual effect, but also more complete and accurate reconstruction of the crossing fibers.

Developmental dysplasia of the hip (DDH) is a common hip disease that seriously affects children's growth, impairing limb development and quality of life. Early diagnosis and treatment of DDH are crucial. Magnetic resonance imaging provides rich morphological information of the hip during development. Clinically DDH is usually diagnosed by visual inspection of the medical images, thus requiring high professional expertise of the doctors. In this work, a quantitative morphological evaluation method for examining the hip images and diagnosing DDH in children is proposed. This method evaluates morphological parameters of the hip quantitatively by automatically measuring the morphological parameters relevant to DDH pathological changes. The magnetic resonance images were first preprocessed, followed by segmentation of the femur and pelvis. A three-dimensional (3D) model of the hip joint was then reconstructed, which was then used to measure the center-edge angle (CEA), acetabular index (AI) and femoral neck anteversion (FNA)'s automatically with algorithms such as thickness search, 3D Hough transform, and least squares fitting. The quantitative morphological evaluation method developed may have great value in preliminary screening of DDH in children, formulation of surgical plans, and longitudinal follow-ups after DDH surgery.

Segmentation of prostate magnetic resonance images is of great significance in the interventional diagnosis and treatment of prostate diseases. In this work, the conventional distance regularized level set evolution (DRLSE) model is improved and applied to prostate segmentation. In magnetic resonance image, the prostate boundary near the bladder is often blurred, while that near the urethra is clear, resulting in a poor performance for the traditional gradient information indicator function. In this study, two indicator functions were used to control the evolution of boundary in the clear segment and blurred segment, respectively, to achieve better segmentation. In addition, an energy check term was added to the external energy function to prevent evolution from stopping at a false boundary. This modification could drive the level set to move to regions with large gray level fluctuation and stop evolution at a blurred boundary. Experimental results demonstrated that the performance of prostate segmentation was satisfactory, judging from the Dice similarity coefficient (DSC) which reached an average of 96%.

Evaluating cardiac function from magnetic resonance images requires segmentation of the right ventricle (RV). The traditional segmentation methods, however, are often ineffective due to the complex structure of RV. Herein, a dense and multi-scale U-net (DMU-net) method is proposed to segment RV. Fifty six datasets were preprocessed, and the steps included normalization, enhancement and region of interest (ROI) extraction. Then a DMU-net was constructed by combining multi-scale aggregation with nested dense connection. The preprocessed datasets were then used to train and verify the DMU-net for predicting the results in 15 datasets with ROI extraction only. The mean of Dice index and Hausdorff distance obtained with the proposed method were 0.862 and 4.44 mm, respectively, which were better than those obtained with the conventional methods. Correlation coefficients of the endo-diastolic volume, endo-systolic volume, ejection fraction and stroke volume estimated were 0.992, 0.960, 0.987 and 0.982, respectively. The results demonstrated that the segmentation method based on the DMU-net has better relevance and consistency compared to manual segmentation, providing a promising tool the diagnosis of cardiac diseases.

The host-guest complex of water-soluble phosphate salt pillar[5]arene (PP5A) and cationic fluorescent dye acridine orange (AO) was constructed, and studied with ultraviolet spectrum (UV), infrared absorption spectrum (IR), molecular fluorescence spectroscopy (MFS), and nuclear magnetic resonance (NMR) spectra (¹H NMR and NOESY). And then, the effect of pH and two surfactants, including sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) on the fluorescence intensity of AO/PP5A complex system were investigated. Finally, the complexation mode and energy of PP5A with AO and CTAB were calculated by molecular docking. The results showed that AO and PP5A formed a 1:1 host-guest complex. PP5A reduced or quenched the fluorescence intensity of AO in the pH range of 3~11. The addition of SDS and CTAB did not affect the fluorescence intensity of AO/PP5A complex significantly. The fluorescence changes generated by AO and PP5A complexation can provide a theoretical basis for the design of fluorescence sensors.

Sample pretreatment is essential for metabonomic analysis. Lyophilization (freeze-drying) is widely used for sample pretreatment to remove solvent, especially water, prior to nuclear magnetic resonance (NMR) and/or mass spectrum (MS) analysis. However, the effects of lyophilization on metabonomic phenotypes remain to be fully investigated. In this study, NMR analysis was carried out to reveal the lyophilization-induced changes in metabonomic phenotypes of human urinary and serum samples. It was found that lyophilization resulted in large changes in the levels of some carboxylic acids and amino acids. Such effects were different between the urine and serum samples, perhaps indicating a biological matrix-dependent effect. The results of this study suggest that extra care and considerations should be taken when lyophilization is used for sample pretreatment and normalization in metabonomic analysis.

5G is on the way. This state-of-the-art communication technology has many advantages and potentials to solve an abundance of problems and make our lives easier, more comfortable and convenient. 5G communication also makes it possible to change the structure and communication in MRI scanners. Based on Ultra-Reliable and Low Latency Communication (uRRLC) provided by the 5G technology, a new MRI system architecture was proposed to achieve remote wireless control and successful processing. In addition, several distributed MRI scanners were enabled to share one common control center to process and reconstruct MR signal data. This sharing control strategy can be utilized to reduce the average cost of each individual MRI scanner.

N-acylhydrazone compounds have two isomers, E/cis and E/trans, in polar solvents. In this work, ¹H and ¹³C nuclear magnetic resonance (NMR) signals, coupling constants (J), and the spatial structures of the two isomers (E/cis and E/trans) of a novel carbazole-triazinoindole based N-acylhydrazone derivative 3, 2-(5H-[1,2,4] triazine[5,6-b]indol-3-ylthio)-N'-(9-ethylcarbazol-3-ylmethylene)acetylhydrazine, were obtained by one-dimensional and two-dimensional NMR techniques, infrared spectroscopy (IR) and elemental analysis. The ratios of the two isomers were determined.

A new air-stable and easy-to-handle 1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-3-butyl-imidazol-2-ylidene] Pd(pyridine)Br₂ (complex 2) was synthesized from the imidazolium halide salts 1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-3-butyl-midazolium bromide (compound 1) by reaction with Pd(OAc)₂ in pyridine. Complex 2 contains multiple chiral centers on the sugar ring. The molecular structures of complex 2 were determined with elemental analysis and liquid-state nuclear magnetic resonance (NMR) spectra. ¹H and ¹³C chemical shifts of complex 2 were fully assigned. It was found that the effects of the carbon and proton chemical environment on the sugar ring is more obvious than that on the butyl chain after formation of N-heterocyclic carbene-palladium(II)-pyridine (NHCs-Pd(II)-Py)-metal bond in the presence of multiple weakly coordinated oxygen.

The quality of the radio frequency (RF) excitation pulse signal has important effects on nuclear quadrupole resonance (NQR) response signal. In this work, a phase-controllable excitation pulse generator was designed based on the 32-bit flash microcontroller STM32 and the direct digital frequency synthesis (DDS) chip AD9910. STM32 is used to control the AD9910 to generate RF excitation pulses with controllable carrier phase. The LabVIEW software platform was used to design the pulse parameter setting interface, and the computer and microcontroller were established to communicate. This design achieved precise and optimized control of the waveform parameters (i.e., pulse width, pulse interval, number of pulses and resonance frequency) for the RF pulse. Experimental results demonstrated that this method could be used to obtain a phase-controlled NQR excitation pulse sequence, providing an effective excitation source for subsequent NQR signal detection.

Nuclear magnetic resonance (NMR) is a non-invasive technology which has been widely used in chemical, biological and medical researches. This paper presents a new NMR pulse sequence based on Hadamard spatial encoding and intermolecular single-quantum coherence (iSQC) transfer. The principle of the sequence was analyzed and the theoretical considerations were presented. The performance of the sequence in accurate spatial localization and fast acquisition under inhomogeneous magnetic field were verified with phantom experiments and the brain metabolites experiments. The results demonstrated that the sequence can quickly obtain high-resolution localized spectra under inhomogeneous magnetic fields, while suppressing the solvent peaks efficiently.

Transcranial direct current stimulation (tDCS) noninvasively modulates the excitability of the brain, and is a promising method for treating diseases in the central nervous system. tDCS is safe, effective and affordable, and has been increasingly applied in neuroscience research. Functional magnetic resonance imaging (fMRI) is a widely-used tool to evaluate the therapeutic effects and the underlying neural mechanisms of tDCS. Herein we briefly reviewed the progresses of applications of fMRI in tDCS research. Both clinical trials and animal model experiments were discussed, as well as the perspectives of future applications.