Concepts in Magnetic Resonance Part A最新文献

Radiofrequency (RF) transmit field (B₁) mapping is a promising method in mitigating the B₁ inhomogeneity in various magnetic resonance imaging (MRI) applications. Although several phase- or magnitude-based B₁ mapping methods have been proposed, these methods often require complex modeling, long acquisition time, or specialized MRI sequences. A recently introduced simultaneous echo refocusing (SER) technique can be applied in the B₁ mapping method to extend the three-dimensional (3D) spatial coverage only without long data acquisition. Therefore, in this study, a multislice B₁ mapping method using composite spin echo sequences and SER techniques is proposed to obtain more accurate B₁ mapping with short data acquisition time. To evaluate the performance of the proposed B₁ mapping method, computational simulations were performed and compared with Morrell’s method, double angle method, and Yarnykh’s method. These results showed that the angle-to-noise ratio of the proposed B₁ mapping method has wider B₁ range compared to that of other B₁ mapping methods. In addition, the proposed B₁ mapping methods were compared to the multislice iterative signal intensity mapping method in both phantom and in vivo human experiments, and there was no remarkable difference between the two methods regarding the flip angle distribution in these experiments. Based on these results, this study demonstrated that the proposed B₁ mapping method is suitable for accurately measuring B₁ propagation under the condition providing reduced scan time and wider 3D coverage of B₁ mapping by applying composite RF pulse and SER techniques into the phase-sensitive method.

The dynamics of an identical pair of entangled spin-1/2 particles, both subjected to the same random magnetic field, are studied. The dynamics of the pure joint state of the pair are derived using stochastic calculus. An ensemble of such pure states is combined using the modified spin joint density matrix, and the joint relaxation time for the pair of spin-1/2 particles is obtained. The dynamics can be interpreted as a special kind of correlation involving the spatial components of the Bloch polarization vectors of the constituent entangled spin-1/2 particles.

This research was aimed to investigate the magnetic resonance imaging (MRI) features of brain structure and neuroendocrine levels in patients with first-episode schizophrenia. 25 hospitalized patients with first-episode schizophrenia were selected as the observation group, while 25 healthy people were selected as the control group. All the objects underwent MRI examination, and the images as well as gray matter density of the original image data were analyzed under voxel-based morphometry (VBM). The cortisol and prolactin in the observation group were detected, and the levels were compared. The Pearson correlation analysis was adopted to analyze the correlation between cortisol and prolactin levels and the total score of the Positive and Negative Syndrome Scale (PANSS). The results showed that the gray matter volume of the precentral gyrus, superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus, postcentral gyrus, inferior parietal lobule, superior parietal lobule, and anterior cingulate cortex of the observation group decreased, while the volume of cerebellar gray matter increased. The levels of cortisol and prolactin in the observation group (387.54 ± 117.69 μg/L and 804.16 ± 267.13 μIU/mL, respectively) were significantly higher than those in the control group (138.46 ± 62.47 μg/L and 397.54 ± 203.82 μIU/mL, respectively), and the differences were statistically significant (P < 0.05). The results of the Pearson correlation test showed that the higher the cortisol level, the more severe the schizophrenia (r = 0.421 and P = 0.013), while the prolactin level was not directly related to the severity of schizophrenia (r = 0.019 and P = 0.568). In conclusion, the MRI features based on the VBM technology can accurately assess the changes of gray matter; the levels of cortisol and prolactin in patients with first-episode schizophrenia were significantly higher than those in healthy people; and the higher the cortisol level, the more severe the schizophrenia symptoms. This study provided a certain research basis for MRI features of brain structure and neuroendocrine changes in patients with first-episode schizophrenia.

To explore the functional changes in the whole brain network in patients with sudden sensorineural hearing loss (SHL) at the acute stage from functional magnetic resonance imaging (fMRI) imaging evaluation results, 80 patients with sudden right SHL were selected as subjects (patient group). In addition, 40 healthy volunteers who underwent physical examination in the hospital during the same period were recruited as a control group. fMRI imaging was performed to analyze functional parameters and core nodes of the whole brain network. It was found that at all thresholds, the fMRI parameters C_p and L_p of the patient group were dramatically superior to those of the control group. The fMRI parameter E_global of the patient group was substantially lower than that of the control group (P < 0.05). At most of the thresholds, the fMRI parameter λ in patients was dramatically superior to that in the control group (P < 0.05). There were ten specific network core nodes in patients, including the right parahippocampal gyrus, right supra-occipital gyrus, left suboccipital gyrus, right fusiform gyrus, right parietal lobule, right subparietal lobule, right superior temporal gyrus, left superior marginal gyrus, and right superior temporal gyrus. In summary, the whole brains of patients with sudden SHL still had small-world attributes, but some characteristics of the brain network had changed, and there was a trend of transformation to a regular network. The connection between the auditory brain area and the functional areas related to language and vision was weakened, and the distribution of core nodes changed. This study provides a reference basis for exploring the changes in local brain and connectome levels in patients with sudden sensorineural hearing loss in the acute phase based on resting-state fMRI.

The MR diffusion-weighted imaging technique was used to evaluate the efficacy and safety of CalliSpheres drug-loaded microspheres for transarterial chemoembolization in the treatment of advanced bladder cancer. 35 patients with advanced bladder cancer were treated with CalliSpheres DLMS for transarterial chemoembolization. Imaging techniques such as magnetic resonance (MR) diffusion-weighted imaging were used to evaluate the therapeutic effect. The changes in serum tumor markers, immune function indexes, and oxidative stress indexes in patients before and after treatment were compared, and the quality of life of patients and the incidence of adverse reactions during follow-up were also evaluated. The results showed that the overall response rate (ORR) was 74.29% and that the disease control rate (DCR) was 97.14%. Compared with that before treatment, the ADC value of the tumor in patients with advanced bladder cancer detected by MR diffusion-weighted imaging technology was significantly increased after treatment and the maximum tumor diameter was significantly decreased (P < 0.05). Compared with those before treatment, the levels of serum tumor markers (CA199, CA724, and CA125) in advanced bladder cancer patients after treatment decreased (P < 0.05). The levels of T-lymphocyte subsets (CD3+ and CD4+) decreased, and CD8+ levels increased (P < 0.05). The levels of superoxide dismutase decreased (P > 0.05). At the same time, the subscale evaluation of function, symptoms, quality of life, adverse reactions, and economics of patients with advanced bladder cancer on the QLQ-C30 scale improved after treatment, and the incidence rate and recurrence rate during the follow-up period were 8.57% and 11.43%, respectively. It showed that CalliSpheres DLMS had a good clinical effect and high safety in the treatment of advanced bladder cancer and was a safe and feasible treatment method. The use of MR diffusion-weighted imaging technology could achieve quantitative evaluation of clinical efficacy of advanced bladder cancer.

MRI of prostate cancer (PCa) was performed using a projection onto convex sets (POCS) super-resolution reconstruction algorithm to evaluate and analyze the treatment of prostate-specific antigen (PSA) and provide a theoretical reference for clinical practice. A total of 110 patients with PCa were selected as the study subjects. First, the modified POCS algorithm was used to reconstruct the MRI images, and the gradient interpolation algorithm was used instead of the traditional bilinear algorithm to preserve the edge information. The diagnostic and therapeutic effects of MRI examination, PSA examination, and MRI combined with PSA based on a super-resolution reconstruction algorithm were then compared. The simulation results showed that the POCS algorithm was superior to the bilinear interpolation results and was superior to the common POCS algorithm. After adding noise artificially, the restoration algorithm was effective and could preserve the details in the image. The performance indexes of PSA in the diagnosis of PCa were 75.4%, 60.1%, 70.08%, 72.2%, and 60.3%, respectively; the performance indexes of MRI in the diagnosis of PCa were 84.6%, 61.4%, 71.11%, 73.08%, and 61.9%, respectively; and the performance indexes of MRI combined with PSA based on the super-resolution reconstruction algorithm in the diagnosis of PCa were 96.05%, 88.3%, 95.1%, 93.6%, and 92.7%, respectively. The indicators of MRI combined with PSA based on the super-resolution reconstruction algorithm were significantly higher than those of the other two methods (P < 0.05). The signal-to-noise ratio of MRI of PCa based on the super-resolution reconstruction algorithm has been greatly improved, with good clarity, which can improve the diagnostic accuracy of PCa patients and has certain advantages in the examination. MRI based on the super-resolution reconstruction algorithm has a high value in the diagnosis and treatment of PCa.

Objectives. The aim of the paper is to explore the clinical efficacy and prognosis of the modified implantation of atrial septal defect (ASD) closure device to treat bronchopleural fistulas (BPFs). Methods. This paper has reviewed the results of 13 BPF patients implanted with a modified ASD closure device in Shaw Hospital Affiliated with the Medical College of Zhejiang University from October 2018 to November 2021. Anesthesia was selected based on the patient’s condition. Different sizes of ASD closures were selected based on the characteristics of fistulas. The modified implantation of the ASD closure device was applied to treat BPFs. The closure effects, closure time, and Borg score were observed at 4 weeks, 8 weeks, and 12 weeks after the surgery. Results. All 13 BPF patients were successfully implanted with the ASD closure device, and the immediate clinical remission rate was 100%. Follow-up at 4 weeks after the surgery showed that 2 cases were automatically discharged within a few days and 4 cases had closed fistula at 1 day after the surgery; follow-up at 8 weeks after the surgery showed that 1 case with fistula closure was observed at 55 days after the surgery; follow-up at 12 weeks after the surgery showed that 1 case with fistula closure was observed at 82 days after the surgery. T/P values (T = 7.90, 5.99, 7.44, P < 0.05) of paired t-tests before surgery and 4 weeks, 8 weeks, and 12 weeks after the surgery were rated by the Borg scale. The data were statistically different, and the clinical symptoms improved significantly. As of publication, the follow-up at 12 weeks after the surgery showed that the clinical remission rate was 9/11, namely, 81.8%, 3 of 11 cases had relieved clinical symptoms but still needed continuous drainage, and 2 cases had fistula closure. The median time of thoracic extubation was 63 (3,120) days. No patients died from surgical complications or BPF recurrence during the prognosis and the follow-up period. Conclusions. The modified implantation method has a high success rate and clinical remission rate, quick and early fistula closure, and simple and noninvasive operation, without the need for a dedicated delivery sheath and rigid endoscopy. Moreover, it has accurate positioning, reliable closure efficiency, and prognosis, and can be completed under local anesthesia. This reduces the operation time, difficulty, and risks of anesthesia.

The equation of motion of the density matrix of an ensemble of identical spin-1/2 nuclei subject to a rotating-frame radiofrequency field and Zeeman frequency offset is derived from the Schrodinger equation and shown to be equivalent to the magnetization differential equations originally proposed by Bloch (excluding relaxation). The quantum and classical differential equations are then integrated.

This study was aimed to investigate the changes of brain MRI features and serum biological parameters in patients with TLE. 30 patients with unilateral TLE confirmed by surgical pathology were selected as study subjects, and 30 subjects without a history of epilepsy who underwent health examinations during the same period were selected as controls. The brain MRI features of the patients were explored and the T2 relaxation time (HCT2) indexes of the bilateral hippocampus were extracted. The differences in levels of peripheral blood T lymphocyte subsets, inflammatory cytokines, and miRNAs were measured. The results showed that the hippocampal volume of TLE patients was significantly reduced, and the HCT2 value of the hippocampus was greater than that of the control group (P < 0.05). CD³⁺ (77.9 ± 4.4)%, CD⁴⁺ (45.6 ± 2.2)%, CD⁸⁺ (22.1 ± 1.9)%, and CD³⁺/CD⁸⁺ (2.24 ± 0.22) in peripheral blood T lymphocyte subsets of epileptic patients, compared with control group, CD³⁺, CD⁴⁺, and CD⁴⁺/CD⁸⁺ levels were significantly increased and CD⁸+ concentration was significantly decreased in epileptic patients (P < 0.05); inflammatory cytokines TNF-α was (2.63 ± 0.26) pg/mL, IL-1β was (4.61 ± 0.57) pg/mL, IL-2 was (1.59 ± 0.21) pg/mL, IL-6 was (2.28 ± 0.19) pg/mL, and ICAM-1 was (1.89 ± 0.30) pg/mL in peripheral blood of epileptic patients, which was significantly increased compared with control group, while IL-10 was significantly decreased in epileptic patients (P < 0.05); miR-146a was (2.14 ± 0.28) and miR-210 was (1.89 ± 0.31), miR-221 (2.44 ± 0.35), miR-34a (0.59 ± 0.14), miR-135b (10.17 ± 0.16), miR-33 (0.26 ± 0.09) in peripheral blood miRNA levels of epileptic patients, and miR-146a, miR-210, miR-221, and miR-34a levels of epileptic patients were significantly increased compared with control group, while MiR-135b and miR-33 levels of epileptic patients were significantly reduced (P < 0.05). In summary, patients with TLE have hippocampal lesions, which may be related to peripheral blood T lymphocyte subsets imbalance, chronic inflammatory response, and abnormal expression of miRNAs.

This study was focused on the clinical efficacy and safety of magnetic resonance imaging (MRI)-based Siwu decoction for poststroke hemiplegia complicated with osteoporosis. 120 patients with poststroke hemiplegia and osteoporosis were divided into an observation group (modified Siwu decoction based on the treatment scheme of control group, 60 cases) and a control group (conventional drugs in neurology + neurology-based rehabilitation training treatment of muscle enhancement surgery, 60 cases). They all underwent MRI scans. The results showed that the bone mineral density (BMD) of lumbar spine, ipsilateral femoral neck, and ipsilateral patella in the observation group was higher than that in the control group 180 days after treatment (P < 0.05). MRI showed restricted diffusion and edema in the left frontoparietal cortex and subcortical white matter. The levels of 25-hydroxy-vitamin D (25-OH-VD) and bone gla-containing protein (BGP) in the observation group 180 days after treatment were higher, and the type I collagen n-terminal propeptide (PINP) and type I collagen cross-linked C-terminal telopeptide (β-CTX) were lower (P < 0.05). The visual analogue scale (VAS) score of the observation group at 180 days after treatment was lower, while the quality of life score was higher (P < 0.05). The median cell count in the observation group at 180 days after treatment was less, while the lymphocytes showed a higher level (P < 0.05). In conclusion, the Siwu decoction could effectively improve the bone metabolism of patients with poststroke hemiplegia and osteoporosis, promote the proliferation and differentiation of osteocytes, and improve the BMD and quality of life of patients.