Spiral Resonance Research Articles

Analysis of The Value of Multi-Slice Spiral CT and Magnetic Resonance Imaging in The Diagnosis of Carpal Joint Injury

Analysis of The Value of Multi-Slice Spiral CT and Magnetic Resonance Imaging in The Diagnosis of Carpal Joint Injury

Low-frequency broadband vibration reduction based on a square spiral beam local resonance phononic crystal

Low-frequency vibration poses a great danger to both industrial production and human health. Therefore, the development of efficient low-frequency vibration reduction structures remains a focus of academic and engineering research. In this paper, a novel low-frequency vibration reduction local resonance phononic crystal (LRPnC) plate with a square spiral beam LRPnC design is proposed. Through finite element simulation, the band structure and vibration characteristics of the LRPnC are first analyzed. On this basis, a gradient LRPnC plate with rainbow trapping effect is constructed by gradient arranging unit cells with different structural parameters to achieve broadband vibration reduction. Finally, the vibration reduction performance of the designed structure is experimentally verified. The finite element analysis results show that the designed gradient LRPnC plate can provide more than 20 dB of transmission attenuation over the full frequency range of 20–200 Hz. And the experimental results are consistent with the simulation results.

Feasibility of chest spiral 3D ultrashort echo time magnetic resonance imaging for intrathoracic metastasis work-up in breast cancer.

Chest computed tomography (CT) is routinely performed to evaluate intrathoracic metastasis in patients with breast cancer, but radiation exposure and its potential carcinogenic risks are major drawbacks. Furthermore, pulmonary imaging by magnetic resonance imaging (MRI) is limited by low proton density, rapid signal decay, and sensitivity to respiratory and cardiac motions in lung tissue. Recently, a respiratory gating spiral three-dimensional (3D) ultrashort echo time (UTE) volume interpolated breath-hold examination (VIBE) sequence for lung MRI provides high spatial-resolution images with reasonable scan times. Our objective was to investigate the feasibility of chest spiral 3D UTE VIBE MRI to detect intrathoracic metastasis in breast cancer patients. This retrospective study of a prospectively collected database was conducted between February and July 2019 after institutional review board approval. All participants provided informed consent for MRI scans. Ninety-three female patients with breast cancer were retrospectively enrolled and underwent preoperative breast MRI, including a chest spiral 3D UTE VIBE sequence. Two chest radiologists evaluated image qualities of intrapulmonary vessels and bronchial wall visibilities, the presence of pulmonary nodules, significant lymph nodes (LNs), and other lung abnormalities on spiral 3D UTE magnetic resonance (MR) images and compared them using chest CT as a reference standard. Intrapulmonary vessels and bronchial walls were visible up to sub-subsegmental and sub-subsegmental levels, respectively, on spiral 3D UTE MR images, and better than fair quality was obtained for artifact/noise and overall image quality for 95.7% and 98.9% of the patients, respectively. The overall detection rate for pulmonary nodules was 62.8% (59/94). Furthermore, 59 of the 81 solid nodules detected by CT were detected by spiral 3D UTE MRI (72.8%), and 31 of the 33 solid nodules (≥5 mm in diameter) detected by CT were identified by spiral 3D UTE MRI (93.9%). Significant LNs in the axillary area were similarly detected by spiral 3D UTE MRI and chest CT. Preoperative breast MRI with a chest spiral 3D UTE sequence could be used to evaluate breast cancer and axillary LNs and intrathoracic metastasis simultaneously and offers a potential alternative to chest CT for breast cancer patients without additional radiation exposure.

Chondroblastoma of the cervical-thoracic junction: global data and own experience

Chondroblastoma (CB) ‒ a rare benign tumor of the skeleton that is presented by proliferation of chondroblasts with islands of eosinophilic chondroid matrix. CB accounts for less than 1% of all bone neoplasms, while the spine is affected in only 1.4% of all CB cases. Publications devoted to CB of the spine are sporadic and therefore have a considerable scientific interest due to the rarity of the pathology. A clinical case of CB of the cervical-thoracic junction of a 38-year-old patient hospitalized to State Institution "Romodanov Neurosurgery Institute of the National Academy of Sciences of Ukraine" in November 2022 is presented. The anamnesis shows that in 2016 a pathological fracture of the Th2 vertebral body was diagnosed. In 2017, a surgical intervention - an open biopsy of the Th2 vertebral arch was performed in a private clinic, but the histopathological analysis, due to the insufficient amount of material and the absence of clinical data, was descriptive, with a certain diagnostic number of possible nosologies. Additional treatment was not performed. When applying in 2022 to the State Institution "Romodanov Neurosurgery Institute of the National Academy of Sciences of Ukraine", significant negative dynamics were noted: a fracture of the body of the Th1 vertebra, total destruction of the body of the Th2 vertebra, a change in the signal from the body of the Th3 vertebra, which indicated its focal lesion. The surgery was performed in two stages. The first stage included a ventral corpectomy of the Th1‒Th3 vertebrae with fusion using telescopic body replacement implant and a ventral rigid plate. During the second stage laminectomy of the Th1‒Th3 vertebrae with complete resection of the Th2 costotransverse joints and partial of Th1‒Th3 ones was performed. Stabilization system screws were installed transarticularly in the facet joints C6 and C7, transpedicularly in the bodies of the Th4‒Th6 vertebrae. To increase the fusion rigidity, additional fixation of the Th1 vertebra on the right and the Th3 vertebra on the left was performed through the remaining costotransverse joints. The patient was discharged with positive neurological dynamics. The uniqueness of this case, in addition to the rarity of the histological variant of the pathology, lies in the possibility of tracking the dynamics of the disease on the basis of both neuroimaging methods and pathohistological and immunohistochemical diagnostics. Features of the prevalence of spine CB in the population, the specifiс signs when performing a spiral computer and magnetic resonance imaging, macroscopic, histological and immunohistochemical characteristics of the tumor are considered in detail. The literature data on differential diagnosis, treatment methods and prognosis of disease are organized. The material is of interest to specialists, since the timely selection of an adequate treatment method and its volume determines both the probability of tumor recurrence as well as prognosis concerning the patient’s life expectancy.

Locked-in Syndrome

Objective ‒ to sharpen the attention of doctors to a rare, little-known pathology of damage to the ventral parts of the pons, the upper parts of the medulla oblongata ‒ the locked-in syndrome. The extremely important value of this syndrome can be in determining the prognosis of the disease and solving issues of rehabilitation and patient care.Locked-in syndrome is a rare, complex clinical and neurological symptom complex, the basis of which is a lesion of the front parts of the pons with intact functioning of the nuclei and afferents of the brain stem cover. The locked-in syndrome occurs when blood circulation is disturbed in the ventral parts of the brain stem and pons. According to the criteria of the American Congress of Rehabilitation Medicine, the locked-in syndrome is a combination of: 1) stable opening of the eyes; 2) safety of basic cognitive abilities; 3) aphonia or severe hypophonia; 4) tetraplegia or tetraparesis; 5) the main method of communication, used by the patient – movement of the eyes in a vertical or horizontal plane or blinking of the upper eyelid.The definition of this syndrome and the localization of its injuries, which cause it, became possible when long-term lung ventilation and neuroimaging methods ‒ spiral computer tomography and magnetic resonance imaging ‒ were introduced into clinical practice. Three personal observations of the occurrence of the locked-in syndrome of different etiology are given: with ischemic damage to the ventral parts of the pons of the brain, with hemorrhage in the ventral parts of the pons, with traumatic damage to the ventral parts of the brain stem.The dynamics of neurological disorders, their adequate assessment during neuroimaging allow timely diagnosis of the localization of the process and the prognosis of the disease, and therefore the choice of methods of treatment, rehabilitation or long-term care for the patient.

Retracted: Diagnostic Value of Spiral CT and Magnetic Resonance Imaging Scanning in Gastric Cancer and Precancerous Lesions.

[This retracts the article DOI: 10.1155/2022/3627385.].

Motion-robust, multi-slice, real-time MR thermometry for MR-guided thermal therapy in abdominal organs

Purpose To develop an effective and practical reconstruction pipeline to achieve motion-robust, multi-slice, real-time MR thermometry for monitoring thermal therapy in abdominal organs. Methods The application includes a fast spiral magnetic resonance imaging (MRI) pulse sequence and a real-time reconstruction pipeline based on multi-baseline proton resonance frequency shift (PRFS) method with visualization of temperature imaging. The pipeline supports multi-slice acquisition with minimal reconstruction lag. Simulations with a virtual motion phantom were performed to investigate the influence of the number of baselines and respiratory rate on the accuracy of temperature measurement. Phantom experiments with ultrasound heating were performed using a custom-made motion phantom to evaluate the performance of the pipeline. Lastly, experiments in healthy volunteers (N = 2) without heating were performed to evaluate the accuracy and stability of MR thermometry in abdominal organs (liver and kidney). Results The multi-baseline approach with greater than 25 baselines resulted in minimal temperature errors in the simulation. Phantom experiments demonstrated a 713 ms update time for 3-slice acquisitions. Temperature maps with 30 baselines showed clear temperature distributions caused by ultrasound heating in the respiratory phantom. Finally, the pipeline was evaluated with physiologic motions in healthy volunteers without heating, which demonstrated the accuracy (root mean square error [RMSE]) of 1.23 ± 0.18 °C (liver) and 1.21 ± 0.17 °C (kidney) and precision of 1.13 ± 0.11 °C (liver) and 1.16 ± 0.15 °C (kidney) using 32 baselines. Conclusions The proposed real-time acquisition and reconstruction pipeline allows motion-robust, multi-slice, real-time temperature monitoring within the abdomen during free breathing.

5G Magnetic Resonance Coupling Planar Spiral Coil Wireless Power Transfer

Wireless Power Transfer in the 5G frequency band is the most promising technology to power up ubiquitous small electronic devices as well as IoT devices. A strongly coupled magnetic resonance WPT technique that focuses on near-field electromagnetic energy has been proposed in this paper. However, most Magnetic Resonance Coupling Wireless Power Transfer (MRC WPT) applications have been designed in kHz and MHz frequency spectrum. This paper demonstrates Planar Spiral Coil Magnetic Resonance Coupling (PSC MRC) WPT designs at 5G (GHz) frequencies. Also, the transformation technique of the low frequency (kHz and MHz) magnetic resonance circuit model equations to high frequency (GHz) circuit model equations to achieve a high-efficiency power transfer. PSC MRC WPT designs structure antennas are designed at 3.4 - 3.5 GHz in the form of circular and square shapes with 1 turn coil. The proposed antenna structures are firstly being optimized in a full-wave electromagnetic simulator, CST Microwave Studio to resonate at the 3.4 - 3.5 GHz band. Then, the close-loop equations to determine the efficiency of 5G Magnetic Resonance Coupling Planar Spiral Coil Wireless Power Transfer is designed. Lastly, the results are compared with the simulation and calculated parts. The highest efficiency of the PSC MRC circular antenna is 31.58 % when the distance is at 2 mm, and 31.26 and 31.02 % when the distance is at 3 and 4 mm, respectively. The efficiency of circular PSC MRC is found to be 25 % better than the efficiency of square shape design. HIGHLIGHTS IoT devices need to be charged and maintained as the network system has massive numbers of sensors. Wireless power transfer is a promising technology to power up IoT devices This paper proposed, a WPT technique based on strongly coupled magnetic resonance which focuses on the near-field electromagnetic energy. This technique can extend the distance of the power transfer between the transmitter and the receiver The transformation technique of the low frequency (kHz and MHz) magnetic resonance circuit model equations to high frequency (GHz) circuit model equations to achieve a high-efficiency PSC MRC WPT design structure is introduced in this paper This novel technique can be applied to effectively design PSC MRC Antenna WPT for 5G applications. Most reported Magnetic Resonance Coupling Wireless Power Transfer (MRC WPT) applications have been designed in kHz and MHz frequency spectrum GRAPHICAL ABSTRACT

Dynamical Origin for the Collinder 132–Gulliver 21 Stream: A Mixture of Three Comoving Populations with an Age Difference of 250 Myr

We use Gaia DR3 data to study the Collinder 132–Gulliver 21 region via the machine-learning algorithm StarGO and find eight subgroups of stars (ASCC 32, Collinder 132 gp 1–6, Gulliver 21) located in close proximity. Three comoving populations were identified among these eight subgroups: (i) a coeval 25 Myr old moving group (Collinder 132), (ii) an intermediate-age (50–100 Myr) group, and (iii) the 275 Myr old dissolving cluster Gulliver 21. These three populations form parallel diagonal stripe-shape overdensities in the U–V distribution, which differ from open clusters and stellar groups in the solar neighborhood. We name this kinematic structure the Collinder 132–Gulliver 21 stream, as it extends over 270 pc in the 3D space. The oldest population, Gulliver 21, is spatially surrounded by the Collinder 132 moving group and the intermediate-age group. Stars in the Collinder 132–Gulliver 21 stream have an age difference up to 250 Myr. Metallicity information shows a variation of 0.3 dex between the youngest and oldest populations. The formation of the Collinder 132–Gulliver 21 stream involves both star formation and dynamical heating. The youngest population (Collinder 132 moving group) with homogeneous metallicity is probably formed through filamentary star formation. The intermediate-age and oldest populations were then scattered by the Galactic bar or spiral structure resonance to intercept Collinder 132's orbit. Without mutual interaction between each population, the three populations are flying by each other currently and will become three distinct groups again in ∼50 Myr.

Value of MSCT plus MRI in the Detection of Colon Cancer.

Colon cancer is a common digestive system malignancy with nonspecific early symptoms, which necessitates better early detection methods. The present study was conducted to assess the accuracy and clinical value of multislice spiral CT (MSCT) plus magnetic resonance imaging (MRI) for colon cancer. Between January 2019 and July 2020, 100 patients with pathologically confirmed colon cancer treated in Wuxi People's Hospital were assessed for eligibility and recruited. All eligible patients received MRI and MSCT without any treatment prior to scanning. The accuracy of preoperative diagnosis and staging of colon cancer by MRI, MSCT, and MRI plus MSCT were analyzed using postoperative pathological results as the gold standard, and consistency analysis was performed. The receiver operating characteristic curve (ROC) was plotted, and the area under the curve (AUC) was obtained to analyze the preoperative diagnostic value. The accuracy of MRI, MSCT, and MRI plus MSCT was 98.00%, 96.00%, and 100% with good consistency (Kappa = 0.732, 0.703, and 0.756). The AUC of MRI, MSCT, and MRI plus MSCT was 0.889, 0.861, and 0.903, respectively. The preoperative diagnostic accuracy of MRI for colon cancer at T1, T2, T3, and T4 stages was 76.92%, 82.61%, 73.47%, and 86.67%, respectively, those of MSCT was 53.85%, 69.57%, 63.27%, and 40.00%, respectively, and those of MRI plus MSCT was 100.00%, 95.65%, 95.92%, and 86.67%, respectively. Consistency analysis yielded good consistency for the diagnosis of the T-staging of colon cancer (Kappa = 0.754, 0.731, 0.776). MSCT plus MRI yielded higher accuracy, specificity, and sensitivity in the detection of colon cancer versus the standalone MRI or MSCT, which demonstrated great potential in the early detection of colon cancer with a high clinical value.

Diagnostic Value of Spiral CT and Magnetic Resonance Imaging Scanning in Gastric Cancer and Precancerous Lesions.

In order to explore the diagnostic value of spiral CT and magnetic resonance imaging scanning in gastric cancer and precancerous lesions, the author selected 56 gastric cancer patients treated in a medical center (group) as the experimental subjects, and all patients underwent MRI, multislice spiral CT scan, and enhanced CT scan two weeks before surgery; at the same time, the gastric cancer staging results of patients were diagnosed according to surgical pathology. All patients were examined under the condition of knowledge and performed breath-holding exercise before examination. The status, location, and extent of tumor lesions were evaluated. In comparison of T staging of gastric cancer patients with magnetic resonance scanning imaging and postoperative pathological examination results, among them, T staging of 3 patients did not match the results of pathological examination, the accuracy rates of T staging on magnetic resonance scanning imaging were T1 = 94.7%, T2 = 87.6%, T3 = 91.2%, and T4 = 94.7%, and the total accuracy was 92.1%. Comparison of helical CT scan imaging and postoperative pathological examination results is as follows. Among them, T staging of 8 patients did not match the results of pathological examination, 3 patients were ulcerative, 5 were protuberance, the accuracy rates of T staging in spiral CT scan imaging were T1 = 90.8%, T2 = 82.2%, T3 = 76.9%, and T4 = 87.6%, and the total accuracy was 84.5%. The total accuracy rate of imaging N staging was 77.5%, and the total accuracy rate of spiral CT scanning imaging N staging was 80.8%. The accuracy rates of M0 and M1 staging in magnetic resonance imaging were 100.0% and 96.5%, respectively, and the accuracy rates of M0 and M1 staging in spiral CT scan imaging were 96.5% and 96.5%, respectively. The accuracy rate of magnetic resonance imaging for the diagnosis of gastric cancer N staging was 77.4%, and the reason for the low accuracy rate was mainly because the enhancement effect was not obvious due to insufficient enhancement. The accuracy rate of spiral CT in diagnosing N staging of gastric cancer was 80.9%, which was mainly due to the small diameter of the middle celiac artery lymph nodes. Magnetic resonance and spiral CT scans have high value in the early diagnosis and staging of gastric cancer.

Analysis of CT and MRI in the Diagnosis of Shoulder Joint Injury

Objective: To observe the effect of multi-slice spiral CT and magnetic resonance imaging (MRI) in the diagnosis of shoulder injury. Methods: 120 patients with shoulder injury who were treated in our hospital (January 2020 to December 2021) and underwent surgical treatment were diagnosed as shoulder injury. They were divided into CT group, MRI group and joint diagnosis group. The detection rates of the two methods were compared. Results: In the diagnosis of shoulder injury, MRI group was higher than CT group, and the joint diagnosis group was higher than the other two groups. Conclusion: In the diagnosis of shoulder injury, the joint examination of multi-slice spiral CT and magnetic resonance imaging (MRI) can obtain a higher diagnostic rate and ideal effect.

Deep artifact suppression for spiral real-time phase contrast cardiac magnetic resonance imaging in congenital heart disease

PurposeReal-time spiral phase contrast MR (PCMR) enables rapid free-breathing assessment of flow. Target spatial and temporal resolutions require high acceleration rates often leading to long reconstruction times. Here we propose a deep artifact suppression framework for fast and accurate flow quantification. MethodsU-Nets were trained for deep artifact suppression using 520 breath-hold gated spiral PCMR aortic datasets collected in congenital heart disease patients. Two spiral trajectories (uniform and perturbed) and two losses (Mean Absolute Error -MAE- and average structural similarity index measurement -SSIM-) were compared in synthetic data in terms of MAE, peak SNR (PSNR) and SSIM. Perturbed spiral PCMR was prospectively acquired in 20 patients. Stroke Volume (SV), peak mean velocity and edge sharpness measurements were compared to Compressed Sensing (CS) and Cartesian reference. ResultsIn synthetic data, perturbed spiral consistently outperformed uniform spiral for the different image metrics. U-Net MAE showed better MAE and PSNR while U-Net SSIM showed higher SSIM based metrics.In-vivo, there were no significant differences in SV between any of the real-time reconstructions and the reference standard Cartesian data. However, U-Net SSIM had better image sharpness and lower biases for peak velocity when compared to U-Net MAE. Reconstruction of 96 frames took ~59 s for CS and 3.9 s for U-Nets. ConclusionDeep artifact suppression of complex valued images using an SSIM based loss was successfully demonstrated in a cohort of congenital heart disease patients for fast and accurate flow quantification.

Chipless tag detection and recognition based on frequency modulated continuous wave

Towards the commercialization of chipless radio frequency identification (RFID) systems, there are still some pressing issues. The detection and identification of chipless RFID tags are mainly realized by a vector network analyzer (VNA). In practice, this equipment is costly and not convenient enough. This paper designs a maneuverable detection model based on frequency modulated continuous wave (FMCW), the detection target is an 8-bit chipless tag based on a variable-side-length spiral resonance unit and decodes the amplitude and phase information. On this basis, signal processing is performed on the generated amplitude and phase based on the Savitzky-Golay (SG) smoothing algorithm, and then the simulation data of HFSS is compared with ADS model data by the matrix pencil method (MPM). The results show that the proposed FMCW-based method can be effectively implemented in wireless communication, providing a new solution for flexible and inexpensive chipless tag detection and recognition.

Diagnostic Accuracy of Spiral Whole-Heart Quantitative Adenosine Stress Cardiovascular Magnetic Resonance With Motion Compensated L1-SPIRIT.

Variable density spiral (VDS) pulse sequences with motion compensated compressed sensing (MCCS) reconstruction allow for whole-heart quantitative assessment of myocardial perfusion but are not clinically validated. Assess performance of whole-heart VDS quantitative stress perfusion with MCCS to detect obstructive coronary artery disease (CAD). Prospective cross sectional. Twenty-five patients with chest pain and known or suspected CAD and nine normal subjects. Segmented steady-state free precession (SSFP) sequence, segmented phase sensitive inversion recovery sequence for late gadolinium enhancement (LGE) imaging and VDS sequence at 1.5 T for rest and stress quantitative perfusion at eight short-axis locations. Stenosis was defined as ≥50% by quantitative coronary angiography (QCA). Visual and quantitative analysis of MRI data was compared to QCA. Quantitative analysis assessed average myocardial perfusion reserve (MPR), average stress myocardial blood flow (MBF), and lowest stress MBF of two contiguous myocardial segments. Ischemic burden was measured visually and quantitatively. Student's t-test, McNemar's test, chi-square statistic, linear mixed-effects model, and area under receiver-operating characteristic curve (ROC). Per-patient visual analysis demonstrated a sensitivity of 84% (95% confidence interval [CI], 60%-97%) and specificity of 83% [95% CI, 36%-100%]. There was no significant difference between per-vessel visual and quantitative analysis for sensitivity (69% [95% CI, 51%-84%] vs. 77% [95% CI, 60%-90%], P=0.39) and specificity (88% [95% CI, 73%-96%] vs. 80% [95% CI, 64%-91%], P=0.75). Per-vessel quantitative analysis ROC showed no significant difference (P=0.06) between average MPR (0.68 [95% CI, 0.56-0.81]), average stress MBF (0.74 [95% CI, 0.63-0.86]), and lowest stress MBF (0.79 [95% CI, 0.69-0.90]). Visual and quantitative ischemic burden measurements were comparable (P=0.85). Whole-heart VDS stress perfusion demonstrated good diagnostic accuracy and ischemic burden evaluation. No significant difference was seen between visual and quantitative diagnostic performance and ischemic burden measurements. 2 TECHNICAL EFFICACY: Stage 2.

The Potential for Quantifying Regional Distributions of Radial and Shear Strain in the Thoracic and Abdominal Aortic Wall Using Spiral Cine DENSE Magnetic Resonance Imaging.

Aortic displacement encoding with stimulated echoes (DENSE) magnetic resonance imaging (MRI) was recently developed to assess heterogeneities in aortic wall circumferential strain (CS). However, previous studies neglected potential radial and shear strain (RSS) distributions. Herein, we present an improved aortic DENSE MRI postprocessing method to assess the feasibility of quantifying all components of the two-dimensional (2D) strain tensor. 32 previously acquired 2D DENSE scans from three distinct aortic locations were re-analyzed. Contrasting previous studies, displacements of the inner and outer aortic wall layers were processed separately to preserve RSS. Differences in regional strain between the new and old postprocessing methods were evaluated, along with interobserver, intraobserver, and interscan repeatability for all strain components. The new postprocessing method revealed an overall mean absolute difference in regional CS of 0.01 ± 0.01 compared to the prior method, with minimal impact on CS repeatability. Mean absolute magnitudes of regional RSS increased significantly compared to changes in CS (radial 0.04 ± 0.05, p < 0.001; shear 0.04 ± 0.04, p = 0.02). Most repeatability metrics for RSS were significantly worse than for CS. The unique distributions of RSS for each axial location associated well with local periaortic structures and mean aortic displacement. The new postprocessing method captures heterogeneous distributions of nonzero RSS which may provide new information for improving clinical diagnostics and computational modeling of heterogeneous aortic wall mechanics. However, future studies are required to improve the repeatability of RSS and assess the influence of partial volume effects.

Clinical Analysis of Magnetic Nanoparticle Contrast Agent in the Diagnosis of Occult Fracture by Multislice Spiral CT and MRI

To investigate the differences in the diagnosis and treatment of occult fractures between multi-slice spiral CT (CT) and magnetic resonance imaging (MRI) using I/Fe₃O₄ nanometer contrast agent. This retrospective study analyzed the clinical data of 60 patients with occult fractures and compared the diagnosis results of multislice CT (observation group) and MRI (control group). All the contrast agents used were I/Fe₃O₄ nanometer contrast agents. In the control group, 55 cases (91.67%) were detected on T1-weighted imaging versus 58 cases (96.67) on T2-weighted imaging. In the observation group, 47 cases (78.33%) were diagnosed. The intergroup difference was significant (P < 0.05). Clinically, I/Fe₃O₄ nanometer contrast agent can be used to affect imaging. The detection rate of MRI is higher than that of CT, and the ability to obtain detailed data of occult fractures is better.

Spiral 3-Dimensional T1-Weighted Turbo Field Echo: Increased Speed for Magnetization-Prepared Gradient Echo Brain Magnetic Resonance Imaging.

Spiral magnetic resonance imaging acquisition may enable improved image quality and higher scan speeds than Cartesian trajectories. We tested the performance of four 3D T1-weighted (T1w) TFE sequences (magnetization-prepared gradient echo magnetic resonance sequence) with isotropic spatial resolution for brain imaging at 1.5 T in a clinical patient cohort based on qualitative and quantitative image quality metrics. Two prototypical spiral TFE sequences (spiral 1.0 and spiral 0.85) and a Cartesian compressed sensing technology accelerated TFE sequence (CS 2.5; acceleration factor of 2.5) were compared with a conventional (reference standard) Cartesian parallel imaging accelerated TFE sequence (SENSE; acceleration factor of 1.8). The SENSE (5:52 minutes), CS 2.5 (3:17 minutes), and spiral 1.0 (2:16 minutes) sequences all had identical spatial resolutions (1.0 mm). The spiral 0.85 (3:47 minutes) had a higher spatial resolution (0.85 mm). The 4 TFE sequences were acquired in 41 patients (20 with and 21 without contrast media). Three readers rated qualitative image quality (12 categories) and selected their preferred sequence for each patient. Two readers performed quantitative analysis whereby 6 metrics were derived: contrast-to-noise ratio for white and gray matter (CNRWM/GM), contrast ratio for gray matter-CSF (CRGM/CSF), and white matter-CSF (CRWM/CSF); and coefficient of variations for gray matter (CVGM), white matter (CVWM), and CSF (CVCSF). Friedman tests with post hoc Nemenyi tests, exact binomial tests, analysis of variance with post hoc Dunnett tests, and Krippendorff alphas were computed. Concerning qualitative analysis, the CS 2.5 sequence significantly outperformed the SENSE in 4/1 (with/without contrast) categories, whereas the spiral 1.0 and spiral 0.85 showed significantly improved scores in 10/9and 7/7 categories, respectively (P's < 0.001-0.039). The spiral 1.0 was most frequently selected as the preferred sequence (reader 1, 10/15 times; reader 2, 9/12 times; reader 3, 11/13times [with/without contrast]). Interreader agreement ranged from substantial to almost perfect (alpha = 0.615-0.997). Concerning quantitative analysis, compared with the SENSE, the CS 2.5 had significantly better scores in 2 categories (CVWM, CVCSF) and worse scores in 2 categories (CRGM/CSF, CRWM/CSF), the spiral 1.0 had significantly improved scores in 4 categories (CNRWM/GM, CRGM/CSF, CRWM/CSF, CVWM), and the spiral 0.85 had significantly better scores in 2 categories (CRGM/CSF, CRWM/CSF). Spiral T1w TFE sequences may deliver high-quality clinical brain imaging, thus matching the performance of conventional parallel imaging accelerated T1w TFEs. Imaging can be performed at scan times as short as 2:16 minutes per sequence (61.4% scan time reduction compared with SENSE). Optionally, spiral imaging enables increased spatial resolution while maintaining the scan time of a Cartesian-based acquisition schema.

Exploring the Origin of Moving Groups and Diagonal Ridges by Simulations of Stellar Orbits and Birthplaces

Abstract The present paper is the culmination of a series aimed at contributing to the understanding of the kinematic structures of the solar neighborhood (SN), explaining the origin of the Local Arm, and relating the moving groups with the spiral-arms resonances in the disk. With a model for the Galactic potential, with the Sun inside the spiral corotation resonance (CR), we integrate the 2D orbits of test particles distributed in birthplaces along the main spiral arms, the Local Arm, and in the axisymmetric disk. A comparison of the resulting U–V plane of the SN with that provided by Gaia DR2 confirms our previous conclusion that the moving groups of Coma Berenices, Pleiades, and Hyades are associated with the CR, and that the Hercules stream is formed by the bulk of high-order inner Lindblad resonances. The kinematic structures result from stellar orbits trapped by the spiral resonances in a timespan of ∼1 Gyr, indicating the long-lived nature of the spiral structure and challenging recent arguments in favor of short-lived structures originated from incomplete phase mixing in the Galactic disk. As a byproduct, our simulations give some insight into the birthplaces of the stars presently located in the SN; the majority of stars of the main moving groups and the Hercules stream were likely born in the Local Arm, while stars of the Sirius group possibly originated from the outer segment of the Sagittarius–Carina arm. We also propose the spiral resonances as the dynamical origin for the diagonal ridges in the Galactic distribution of rotation velocities.

Water–fat separation in spiral magnetic resonance fingerprinting for high temporal resolution tissue relaxation time quantification in muscle

PurposeTo minimize the known biases introduced by fat in rapid T1 and T2 quantification in muscle using a single‐run magnetic resonance fingerprinting (MRF) water–fat separation sequence.MethodsThe single‐run MRF acquisition uses an alternating in‐phase/out‐of‐phase TE pattern to achieve water–fat separation based on a 2‐point DIXON method. Conjugate phase reconstruction and fat deblurring were applied to correct for B 0 inhomogeneities and chemical shift blurring. Water and fat signals were matched to the on‐resonance MRF dictionary. The method was first tested in a multicompartment phantom. To test whether the approach is capable of measuring small in vivo dynamic changes in relaxation times, experiments were run in 9 healthy volunteers; parameter values were compared with and without water–fat separation during muscle recovery after plantar flexion exercise.ResultsPhantom results show the robustness of the water–fat resolving MRF approach to undersampling. Parameter maps in volunteers show a significant (P < .01) increase in T1 (105 ± 94 ms) and decrease in T2 (14 ± 6 ms) when using water–fat‐separated MRF, suggesting improved parameter quantification by reducing the well‐known biases introduced by fat. Exercise results showed smooth T1 and T2 recovery curves.ConclusionWater–fat separation using conjugate phase reconstruction is possible within a single‐run MRF scan. This technique can be used to rapidly map relaxation times in studies requiring dynamic scanning, in which the presence of fat is problematic.