Nuclear Magnetic Resonance Values Research Articles

Retracted: The Value of Nuclear Magnetic Resonance in Liver Nodular Lesions.

[This retracts the article DOI: 10.1155/2022/8165950.].

The Value of Nuclear Magnetic Resonance in Liver Nodular Lesions.

In order to analyze the value of contrast-enhanced ultrasound (CEUS) combined with functional magnetic resonance imaging (fMRI) in the early differential diagnosis of liver nodular lesions, the authors studied the value of MRI in liver nodular lesions. A total of 82 patients with liver nodular lesions admitted to the hospital were selected for retrospective analysis; all of them underwent CEUS and fMRI examinations, and taking a biopsy or postoperative pathological examination results as the gold standard, the diagnostic value of CEUS, fMRI single item, and the two combined examinations for liver nodular lesions was analyzed by four-table. The biopsy or postoperative pathological examination results showed that a total of 88 lesions were detected in 82 patients, including 51 patients with benign lesions, with 54 lesions, and 31 patients with malignant lesions, with 34 lesions. Taking biopsy or pathological examination results as the gold standard, the four-table analysis CEUS had a sensitivity of 79.63%, a specificity of 82.35%, an accuracy of 80.68%, and a Kappa value of 0.603 for diagnosing benign and malignant liver nodular lesions. The sensitivity of fMRI in diagnosing benign and malignant liver nodular lesions was 83.33%, the specificity was 85.29%, the accuracy was 84.09%, and the Kappa value was 0.672; the combined sensitivity of the two in the diagnosis of benign and malignant liver nodular lesions was 94.44%, the specificity was 91.18%, the accuracy was 93.18%, and the Kappa value was 0.856, both of which were superior to single detection, and the difference in accuracy was statistically significant (χ2 = 5.683, P < 0.05). CEUS and fMRI have a certain value in the differential diagnosis of liver nodular lesions; the combination of the two can improve the diagnostic sensitivity and accuracy, and has more clinical application value.

Synthesis and Theoretical Characterization of 4-(p-tollyl)-5-(thiophen-2-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione Using Experimental and Quantum Chemical Calculations.

The aim of the study was to synthesize 4- (p-tollyl) -5- (thiophene-2-yl) -2,4-dihydro-3H-1,2,4-triazole-3-thione and detect its experimental and the quantum chemical properties. 4-(p-tollil)-5-(tiyofen-2-il)-2,4-dihidro-3H-1,2,4-triazol-3-tiyon was synthesized using by the nucleophilic sübstitüsyon reaction. The synthesized title compound has been characterized both experimentally and theoretically using quantum chemical calculations and spectral techniques. The molecular geometry, vibrational frequencies, and 1H and 13C NMR chemical shifts of the title compound in the ground state were calculated using the density functional method (B3LYP) with the 6–311G(d, p) basis set. It was seen that the calculated infrared and nuclear magnetic resonance values were compatible with the experimental values. To determine conformational flexibility, the molecular energy profile of 4- (p-tollyl) -5- (thiophene-2-yl) -2,4-dihydro-3H-1,2,4-triazole-3-thione was obtained by DFT calculations with respect to the selected torsion angle, which was varied from 180°to +180°in steps of 20°. In addition, the HOMO- LUMO energies of this conformational structure were calculated.

Brief Analysis of Application Value of Nuclear Magnetic Resonance and Spiral CT in Diagnosis of Spinal Trauma

Brief Analysis of Application Value of Nuclear Magnetic Resonance and Spiral CT in Diagnosis of Spinal Trauma

Determination of nuclear magnetic resonance T2 cutoff value based on multifractal theory — An application in sandstone with complex pore structure

The cutoff value of nuclear magnetic resonance (NMR) transversal relaxation time [Formula: see text] is vital for pore structure characterization, permeability prediction, and irreducible water saturation calculation. Conventional default values often lead to inaccurate results for rocks with complex pore structure. Based on NMR experiments and multifractal theory, we have developed an effective statistical method to predict [Formula: see text] cutoff values without other petrophysical information. The method is based on multifractal theory to analyze the NMR [Formula: see text] spectrum with the assumption that the [Formula: see text] spectrum is an indicator of pore size distribution. Multifractal parameters, such as multifractal dimension, singularity strength, and mass exponent, are calculated to investigate the multifractal behavior of [Formula: see text] spectrum via NMR experiments and a dyadic scaling-down algorithm. To obtain the optimal [Formula: see text] cutoff value, the rotation speed and time of centrifugation are enlarged increasingly to optimal centrifugal state. A predicating model for [Formula: see text] cutoff value based on multiple linear regressions of multifractal parameters was proposed after studying the influential factors. On the basis of the multifractal analysis of NMR [Formula: see text] spectrum, a reasonable predication model for [Formula: see text] cutoff value was rendered. Upon testing, the predicted results were highly consistent with the experimental results.

The structure and conformation analysis of N-2-fluorobenzoyl- N′-2-methoxyphenylthiourea

The structure of the N-2-fluorobenzoyl- N′-2-methoxyphenyl thiourea (C 15H 13FN 2O 2S, M r=304.34) derived from X-ray diffraction on single crystal has been presented. The crystal is triclinic, space group: P−1 (#2), a=7.058(4), b=9.067(5), c=11.907(8) Å, α=89.00(2), β=86.59(2), γ=69.02(1)°, V=710.2(8) Å 3, Z=2. FTIR, NMR and X-ray diffraction determination give the existence of hydrogen bond interactions. Density functional theory (DFT) using Becke's three-parameter hybrid method with the Lee, Yang, and Parr correlation functional (B3LYP) methods have been used to determine the structure and energies of stable conformers. The optimized geometry corresponding to crystal structure is the most stable conformation. This has partly been attributed to multi six-tempered and five-tempered ring formation resulting from the N(2)–H(2)⋯(1), N–(1) H(1)⋯F(1), N(2)–H(2)⋯O(2) and C(6)–H(6)⋯O(2) intra-molecular hydrogen bonds, respectively. With the basis sets of the 6-311G** quality, the DFT calculated bond parameters, harmonic vibrations and nuclear magnetic resonance values are in a very good agreement with experimental results.

Postoperative pulmonary flow dynamics after fontan surgery: Assessment with nuclear magnetic resonance velocity mapping

Objectives. This study was performed to assess the value of nuclear magnetic resonance (NMR) velocity mapping for the measurement of pulmonary blood flow after Fontan surgery.Background. Echocardiographic studies of pulmonary flow after Fontan surgery are not always satisfactory. The newly developed technique of NMR velocity mapping may contribute to the elucidation of the Fontan circulation.Methods. At frequent intervals during the cardiac cycle, forward and backward flow volumes in the pulmonary arteries of nine volunteers were measured, summed and compared with right ventricular stroke volume to validate the velocity mapping technique. In 14 patients after Fontan surgery, assessment of pulmonary flow volumes enabled the evaluation of atriopulmonary and atrioventricular (AV) Fontan connections. The findings were correlated with precordial echocardiography.Results. Validation of the NMR technique, obtained from volunteer experiments, showed a high correlation (r = 0.97) between right ventricular stroke volume and volumetric pulmonary stroke flow. In all patients with an atriopulmonary Fontan connection (n = 8), forward flow in the pulmonary artery was biphasic, similar to normal venous Sow. Monophasic systolic pulmonary flow curves indicating right ventricle-dependent pulmonary blood flow were found in three of six patients with an AV Fontan connection. Is the remaining three patients, the pulmonary flow pattern did not reflect right ventricular contraction. Measurement of flow velocity alone may give a false impression of forward flow and thus of right ventricular contribution. Pulmonary regurgitation was demonstrated in six of eight patients with an atriopulmonary connection.Conclusions. Nuclear magnetic resonance velocity mapping provides accurate and valuable information oe pulmonary flow volume and velocity after Fontan surgery. The success of AV Fontan surgery can be deduced from the presence of a monophasic systolic pulmonary flow pattern as demonstrated by NMR velocity mapping. With NMR flow volume analysis, substantial pulmonary regurgitation occurring after atriopulmonary Fontan surgery can be measured.

Experience with NMR tomography of the skeletal system

The value of nuclear magnetic resonance (NMR) tomography in the skeleton is analysed in 27 patients who had been examined by a prototype NMR scanner (resistive magnet, 0.2 Tesla). Anatomical structures and detail can be seen using the spin-echo mode and brief sequences. There is marked contrast difference between normal and abnormal tissues. Pathological changes lead to marked alterations in relaxation times. Inflammatory conditions, tumours and aseptic bone necrosis are demonstrated with a high degree of sensitivity. Tomography in the three geometric planes, with any desired additional plane, shows the extent and localisation of bone abnormalities.

Erste klinische Erfahrungen mit der Kernspintomographie (KST)

Previous work on adults with carcinomas, benign polyps, postoperative changes or inflammatory or radiation induced swellings in the facial skeleton has shown that it is possible to demonstrate the local anatomy, and particularly the orbits and sinuses without subjecting the patients to radiation. Differentiation between fat, oedema and malignant tissue appears to be possible, as has been demonstrated by our early cases. Early attempts at examining the trunk could only be carried out in infants. These suggest that in the thorax and abdomen differentiation of anatomical structures is not possible. The value of nuclear magnetic resonance in clinical diagnosis is still uncertain. Its advantage depends on the ability to differentiate tissues because of their varying water content. It raises the possibility of differentiating soft tissues by a non-invasive method and without using radiation. Further investigations are necessary in order to evaluate the clinical usefulness of the new technique. The physical basis of the method, compared with conventional radiology, permits only guarded optimism.