Reducing signal loss of the parahippocampal gyrus improves imaging of the default‐mode network in 3.0‐T MRI: the effect of susceptibility‐induced field gradients

Previous investigations have indicated that the default‐mode network (DMN) is highly involved in memory processing in the parahippocampal gyrus (PHC). However, because of susceptibility‐related signal loss, parahippocampal activation in the DMN is difficult to detect in resting‐state functional MRI experiments that are conducted using a 3.0‐T MRI scanner. This study investigated the magnetic field gradients of various brain regions and attempted to compensate for signal loss in the PHC using an optimized slice orientation. The field gradients, signal intensities and DMN functional connectivity (FC) of the PHC were investigated using datasets acquired from 18 healthy volunteers. The results show that the field gradient component parallel to the main magnetic field dominates the PHC. The results indicate that the signal intensities and FC of the DMN are significantly low in the PHC when the slice orientation of the imaging plane is transversal. Whether the voxel dimension is isotropic or anisotropic exerts a minimal effect in altering the slice orientation dependence. In conclusion, the results of this study support the selection of the coronal or sagittal planes for imaging of the DMN. Copyright © 2015 John Wiley & Sons, Ltd.     

High-resolution simulation of B0 field conditions in the human heart from segmented computed tomography images

B₀ inhomogeneity leads to imaging artifacts in cardiac magnetic resonance imaging (MRI), in particular dark band artifacts with steady-state free precession pulse sequences. The limited spatial resolution of MR-derived in vivo B₀ maps and the lack of population data prevent systematic analysis of the problem at hand and the development of optimized B₀ shim strategies. We used readily available clinical computed tomography (CT) images to simulate the B₀ conditions in the human heart at high spatial resolution. Calculated B₀ fields showed consistency with MRI-based B₀ measurements. The B₀ maps for both the simulations and in vivo measurements showed local field inhomogeneities in the vicinity of lung tips with dominant Z3 spherical harmonic terms in the field distribution. The presented simulation approach allows for the derivation of B₀ field conditions at high spatial resolution from CT images and enables the development of subject- and population-specific B₀ shim strategies for the human heart.     

Clinical characteristics of COVID-19 in patients with preexisting ILD: A retrospective study in a single center in Wuhan,China

Since the outbreak of 2019 novel coronavirus (SARS-CoV-2) pneumonia, many patients with underlying disease, such as interstitial lung disease (ILD), were admitted to Tongji hospital in Wuhan, China. To date, no data have ever been reported to reflect the clinical features of Corona Virus Disease 2019 (COVID-19) among these patients with preexisting ILD. We analyzed the incidence and severity of COVID-19 patients with ILD among 3201 COVID-19 inpatients, and compared two independent cohorts of COVID-19 patients with pre-existing ILD (n = 28) and non-ILD COVID-19 patients (n = 130). Among those 3201 COVID-19 inpatients, 28 of whom were COVID-19 with ILD (0.88%). Fever was the predominant symptom both in COVID-19 with ILD (81.54%) and non-ILD COVID-19 patients (72.22%). However, COVID-19 patients with ILD were more likely to have cough, sputum, fatigue, dyspnea, and diarrhea. A very significantly higher number of neutrophils, monocytes, interleukin (IL)-8, IL-10, IL-1β, and D-Dimer was characterized in COVID-19 with ILD as compared to those of non-ILD COVID-19 patients. Furthermore, logistic regression models showed neutrophils counts, proinflammatory cytokines (tumor necrosis factor-alpha, IL6, IL1β, IL2R), and coagulation dysfunction biomarkers (D-Dimer, PT, Fbg) were significantly associated with the poor clinical outcomes of COVID-19. ILD patients could be less vulnerable to SARS-CoV-2. However, ILD patients tend to severity condition after being infected with SARS-CoV-2. The prognosis of COVID-19 patients with per-existing ILD is significantly worse than that of non-ILD patients. And more, aggravated inflammatory responses and coagulation dysfunction appear to be the critical mechanisms in the COVID-19 patients with ILD.     

唇裂Ⅱ期鼻畸形修复术后患者佩戴硅胶鼻模初始时间的探讨

目的探索唇裂Ⅱ期鼻畸形修复术后患者佩戴硅胶鼻模适宜的初始时间。方法选取我科唇部整形门诊2016年3月-2018年1月收治的鼻修复手术的47例唇裂Ⅱ期鼻畸形患者,根据患者门诊号的奇偶数分为观察组(25例)和对照组(22例),观察组于术后拆线日起佩戴硅胶鼻模,对照组于术后即刻佩戴硅胶鼻模。比较两组术后即刻、术后6个月患者和手术医生对鼻部外型满意度;比较两组术后拆线日切口愈合恢复情况及患者自我清洁能力和舒适度。结果术后即刻、术后6个月患者和手术医生对鼻部外型满意度比较两组差异无统计学意义(P>0.05)。伤口愈合率、患者自我清洁能力和舒适度观察组明显优于对照组,差异有统计学意义(P<0.05)。结论术后拆线日开始佩戴硅胶鼻模,既不影响术后鼻部外型的巩固与维持,又有利于患者的自我护理和观察,改善术后早期舒适度的体验,有利于伤口愈合,增加手术成功率。