Concepts in Magnetic Resonance Part A最新文献

This study was focused on the magnetic resonance-ultrashort time of echo (MR-UTE) imaging technology based on the convolution residual network (CRN) algorithm to evaluate the degeneration of intervertebral disc endplate (DIDCE) and the efficacy of rehabilitation nursing intervention. In this study, 90 patients with intervertebral disc degeneration in the hospital were randomly divided into an intervention group (45 cases) and a control group (45 cases). All patients were scanned by a magnetic resonance imaging system, and the original UTE images were postprocessed. The control group received routine nursing. The intervention group used massage and rehabilitation nursing intervention measures. The CRN algorithm is used to reconstruct the undersampled MR image and compared with ESPIRiT algorithm and the Regridding algorithm. The result found that CRN has more advantages than ESPIRiT and Regridding reconstruction algorithms. The proportion of partial disappearance and complete disappearance of fibrous ring structure in the low back pain group was higher than that in the non-low back pain group, with a statistical difference (P < 0.05). 90 patients with intervertebral disc cartilage endplate degeneration were divided into lumbago group (62 cases) and nonlumbago group (28 cases) according to whether they had lumbago. The nursing satisfaction of patients in the intervention group (97%) is significantly higher than that of patients in the control group (69%) (P < 0.05). In conclusion, the CRN algorithm successfully removes artifacts and noise in the undersampled image. Cartilage endplate, annulus fibrosus, and bony endplate partially disappeared by the MR-UTE imaging technique. Rehabilitation intervention proved to have a positive effect on the treatment of patients with intervertebral disc degeneration and can improve patients’ satisfaction.

This study aimed to investigate the correlation between magnetic resonance imaging (MRI) findings of articular cartilage and clinical symptoms in patients with osteoarthritis (OA). Eighty patients with OA were selected as the study subjects (OA group) and 80 healthy subjects during the same period were also selected as the control group. All subjects underwent knee sagittal PDW-SPAIR, sagittal T1WI-aTSE, sagittal T2WI-TSE, coronal PDW-SPAIR, sagittal 3D-WATSc, and sagittal T2 mapping scans. Thereafter, all subjects underwent clinical assessment. The whole-organ MRI score (WORMS) was adopted for MRI examination and semiquantitative analysis, and the T2 value was calculated. The correlation among T2 value, WORMS, and Western Ontario and Mc Master University OA Index (WOMAC) was then compared and analyzed. The correlation coefficients between T2 values and WORMS in each sub-region of patients with OA were 0.8, 0.55, −0.038, 0.811, and 0.743; the correlation coefficients between WORMS and WOAMC were 0.66, 0.71, 0.46, and 0.88; and the correlation coefficients between T2 values and WOAMC were 0.483, 0.33, 0.282, and 0.636, respectively. There was a significant positive correlation between the results of MRI semiquantitative analysis and clinical symptoms as well as disease severity in patients with OA.

This study was aimed to provide arousal treatment for disturbance of consciousness in patients with massive cerebral infarction, using multimodal magnetic resonance imaging (MRI)-assisted transcranial magnetic stimulation (TMS) under three-dimensional reconstruction algorithm combined with wake-up nursing. The application effect was also evaluated. 80 patients with massive cerebral infarction were selected as the research objects. These patients were divided into the control group (routine nursing and TMS) and the experimental group (routine nursing, multisensory stimulation wake-up nursing, and TMS) according to the even- and odd-numbered admission orders. There were 40 cases in each group, and the treatment effects of the two groups were compared and analyzed. The peak signal-to-noise ratio (PSNR) (800 dB) of the bilateral filtering algorithm was higher than that of the wavelet threshold denoising (321 dB) and the nonlocal mean filtering algorithm (455 dB). The segmentation accuracy of the improved region growing method/fuzzy spatial clustering algorithm (96.21% and 97.22%) was higher than that of the unimproved ones (82.11% and 79.99%). The Glasgow Coma Scale (GCS), Coma Recovery Scale-Revised (CRS-R), and Dysfunction Scale (DFS) scores of the experimental group were significantly higher than those of the control group 1 week and 2 weeks after treatment (P < 0.05). The awakening rate of patients in the experimental group (95%) was also significantly higher than that in the control group (72.5%), and the time needed for waking up was (2.28 ± 2.92) hours, lower than that in the control group (4.34 ± 3.49) hours (P < 0.05). The three-dimensional reconstruction algorithm could effectively improve the display effect of MRI images and assist in the examination of diseases. Multisensory stimulation wake-up nursing combined with TMS could promote patients to wake up more quickly and help the recovery of brain function of patients in the treatment of massive cerebral infarction and disturbance of consciousness.

The Clebsch–Gordan coefficients are extremely useful in magnetic resonance theory, yet have an infamous perceived level of complexity by many students. The Clebsch–Gordan coefficients are used to determine both the matrix elements of the spherical tensor operators and the total angular momentum states of a system of component angular momenta. Full derivations of these coefficients are rarely worked through step by step. Instead, students are provided with tables accompanied by little or no explanation of where the values in it originated from. This lack of direction is often a source of confusion for students. For this reason, we work through two common examples of the application of the Clebsch–Gordan coefficients to magnetic resonance experiments. In the first, we determine the components of the magnetic resonance Hamiltonian of ranks 0, 1, and 2 and use these to identify the secular portion of the static, heteronuclear dipolar Hamiltonian. In the second, we derive the singlet and triplet states that arise from the interaction of two identical spin-1/2 particles.

In this paper, we want to consider what would be involved in calculating the R₂ relaxation of amide protons in a protein caused by dipolar interactions with nearby protons, for which there are many. NMR textbooks give analytical equations and sometimes derivations for solution NMR relaxation due to dipolar interactions between two spins. There are also closed equations for dipolar interactions between three spins, which include relaxation interference, also known as cross-correlated cross-relaxation. We here derive an expression for interference between four spins. For larger systems, such as amide protons in a protein, we develop a local-field methodology, from which solution relaxation interference can be computed for a basically limitless number of interacting spins.

Vertical electrical sounding and magnetic methods were carried out to assess groundwater potential in Adilo catchment, Kembata Tembaro Zone, South Nations, Nationalities and Peoples Regional Government, Main Ethiopian Rift. The data were acquired from eight VES points using Schlumberger electrode arrays with maximum half current electrode spacing (AB/2 = 500) and 253 magnetic data points were analyzed. The qualitative analysis of VES data was accomplished by using curves, apparent resistivity, and pseudodepths, and the quantitative interpretations of the VES data were constructed by the VES data using IPI-Res3, IPI2Win, and surfer software and constructing geoelectric section along with profiles and lithological information from the borehole and Geosoft interpretation was used for magnetic data. The VES results of the data revealed five geoelectric layers which differ in degree of fracturing, weathering, and formation. The upward continued magnetic field map anomaly to 560 m illustrated northwestern to the southwest; areas have a low magnetic anomaly. Examining the potential aquifer of profile one’s geoelectric section, the horizons of layer four were better potential aquifers as the highly fractured and weathered ignimbrite zone of layer five of VES13 was 219 m deeper than the depths of the other VES points, and along with profile two geoelectric sections, the horizon of layer four VES23 layer five has the lowest resistivity with large thickness at a depth of 253 m. Thus, the low resistivity and the large thickness of these formations are an indication of the high yield of groundwater potential in the study area.

Stretched hydrogels make uniformly anisotropic environments for quadrupolar nuclei such as ²H, ²³Na, and ¹³³Cs. Such surroundings cause the partial alignment of nuclear spin bearing ions and molecules that is sufficiently pronounced to alter the nuclear magnetic resonance spectra of the guest species. In most cases, resonance splittings are directly related to the spin quantum number I. The relative intensities of the components of the resonance multiplets can be inferred from basic quantum mechanics.

In MRI, at ultrahigh field, the use of parallel transmit radiofrequency (RF) arrays is very beneficial to better control spin excitation spatially. In that framework, the so-called “universal pulse” technique, proposed recently for head imaging at 7 tesla, gives access to “plug-and-play” nonadiabatic solutions exhibiting good robustness against intersubject variations in the resonant transmit fields. This new type of solution has been defined so far as the result of numerical pulse optimizations performed across a collection of RF field maps acquired on a small population sample (pulse design database). In this work, we investigate an alternative universal pulse design approach in the linear small tip angle regime whereby the database of RF field maps is first transformed into a second-order statistical model and which then exploits a statistical robust design formalism for the optimization of the RF and magnetic field gradient waveforms. Experimental validation with an eightfold transmit RF coil for 7 tesla brain imaging shows that this new approach brings some benefit in terms of computational efficiency. Hence, for a design database composed of 35 maps, the computation time initially of 50 min could be reduced down to 3 min. The proposed statistical approach thus enables integration of large databases, presumably necessary to ensure robust solutions. Finally, it provides means to compute flip angle statistics and, along with it, simple performance metrics for quality assurance (RF pulse performance) or guidance in the optimization of TX array architectures.

The magnetization differential equations of Bloch are integrated using a matrix diagonalization method. The solution describes several limiting cases and leads to compact expressions of wide validity for a spin ensemble initially at equilibrium.

Magnetic resonance imaging based on steady-state free precision (SSFP) sequences is a fast method to acquire T₁, T₂, and $$-weighted images. In inhomogeneous tissues such as lung tissue or blood vessel networks, however, microscopic field inhomogeneities cause a nonexponential free induction decay and a non-Lorentzian lineshape. In this work, the SSFP signal is analyzed for different prominent tissue models. Neglecting the effect of non-Lorentzian lineshapes can easily result in large errors of the determined relaxation times. Moreover, sequence parameters of SSFP measurements can be optimized for the nonexponential signal decay in many tissue structures.