In order to study the clinical characteristics of intraventricular meningiomas, we analyzed retrospectively 25 patients and reviewed the literature with regard to incidence, clinical manifestation, imaging features, preoperative diagnosis, surgical findings, and histopathological results. Intraventricular meningiomas are quite rare, but they represent an important differential diagnosis of intraventricular neoplasms. Computed tomography or magnetic resonance imaging enable a correct diagnosis of intraventricular meningiomas in most of the cases. The tumors often grow slowly to a substantial size before they become symptomatic. The operative route should be selected according to the tumor's location. Out of the 24 lateral ventricular meningiomas in our series, 20 were resected via a posterior parieto-occipital transcortical approach, two were resected via a transcallosal approach, and another two tumors, located in the frontal horn and body of the lateral ventricle, were resected via a frontal approach. A median suboccipital craniotomy was performed for the fourth ventricular meningioma. The parieto-occipital route for lateral ventricular meningiomas is a safe surgical approach, which is not necessarily associated with postoperative visual deficits. Piecemeal removal of the tumor can be safely and easily performed and special attention should be paid to the choroidal vessels intraoperatively.
Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for magnetic resonance microimaging were measured using two nearly identical magnetic resonance imaging (MRI) scanners operating at field strengths of 3 and 7 T. Six mice were scanned using two imaging protocols commonly applied for in vivo imaging of small animal brain: RARE and FLASH. An accounting was made of the field dependence of relaxation times as well as a small number of hardware disparities between scanner systems. Standard methods for relaxometry were utilized to measure T1 and T2 for two white matter (WM) and two gray matter (GM) regions in the mouse brain. An average increase in T1 between 3 and 7 T of 28% was observed in the brain. T2 was found to decrease by 27% at 7 T in agreement with theoretical models. The SNR was found to be uniform throughout the mouse brain, increasing at higher field by a factor statistically indistinguishable from the ratio of Larmor frequencies when imaging with either method. The CNR between GM and WM structures was found to adhere to the expected field dependence for the RARE imaging sequence. Improvement in the CNR for the FLASH imaging sequence between 3 and 7 T was observed to be greater than the Larmor ratio, reflecting a greater susceptibility to partial volume effects at the lower SNR values at 3 T. Imaging at 7 T versus 3 T in small animals clearly provides advantages with respect to the CNR, even beyond the Larmor ratio, especially in lower SNR regimes. This careful multifaceted assessment of the benefits of higher static field is instructive for those newly embarking on small animal imaging. Currently the number of 7 T MRI scanners in use for research in human subjects is increasing at a rapid pace with approximately 30 systems deployed worldwide in 2008. The data presented in this article verify that if system performance and radio frequency uniformity is optimized at 7 T, it should be possible to realize the expected improvements in the CNR and SNR compared with MRI at 3 T.
We are developing Monitor of All Sky X-ray Image (MAXI) which will be mounted on the Japanese Experiment Module of the International Space Station. MAXI is an all-sky X-ray monitor which scans the sky in every 90 minutes. The sensitivity will be as high as 7 mCrab (5 σ level) in one scan and 1 mCrab in one-week accumulation. The GSC (Gas Slit Camera) instrument consists of twelve one-dimensional position sensitive proportional counters using the Xe+CO 2 gas and the carbon fiber anodes of 10µm diameter. The window size is 272 × 190 mm. The position is obtained by the charge division method. It is used to identify the source in the long rectangular field-ofview (1.5 × 80 degrees). Three cameras will be set to cover the 1.5 × 160 degrees arc. The position resolution is essentially important, which becomes better in the higher gas gain. We have tested gas mixtures of Xe+CO 2 with CO 2 = 0.2%, 0.5%, 1%, and 3%. The CO 2 = 0.5% showed the most uniform gas gain, but has a little after pulses. We chose the Xe (99%) + CO 2 (1%) combination for the flight counters. It can achieve the uniform gas gain in the cell and negligible after-pulse in high operating voltage. The engineering model of the counter (EM1) was build. We have tested the position resolution and the energy resolution across the counter. The position resolution and the energy resolution depend on the X-ray energy. On the basis of these results, together with the collimator response, we performed a realistic simulation. MONITOR OF ALL-SKY X-RAY IMAGE (MAXI)Monitor of All-sky X-ray Image (MAXI) is the first astronomical payload to be placed on the International Space Station (ISS)'s Japanese Experimental Module (JEM) in 2005 ( Fig. 1 left) [1, 2, 3, 4]. MAXI has the size of 0.8 × 1.2 × 1.85 m and the weight of 500kg. Power, communication, and cooling fluid are supplied from the JEM/ISS. MAXI has two X-ray observational instruments, Gas Slit Camera (GSC) and Solid-state Slit Camera (SSC, Miyata in this meeting). The GSC uses gas counters which is sensitive in 2-30 keV. The SSC uses X-ray CCDs sensitive in the soft X-ray (0.5-10 keV). Both instruments are slit-cameras and have a long rectangular field-of-view (FOV) (Fig. 1 middle). With the combination of one-dimensional X-ray detector, the positions of the X-ray sources in the FOV are determined (Fig. 1 right). The narrow FOV scans across the sky with the 90-minute orbital rotation of the ISS. The GSC has two identical FOVs, one is facing forward and the other zenithal. The forward FOV is tilted up by 6 degrees to avoid the earth and the atmosphere completely. There are non-operational periods in the orbit, such as the South Atlantic Anomaly and the high-radiation polar regions. Although one FOV cannot observe the portion of the sky which to be observed from there, the other FOV can cover that region after or before 21 minutes, because it is offset by 84 degrees. Thus MAXI can monitor almost the whole sky in every 90 minutes, twice in most part.As an all-sky monitor MAXI has unprecedented sensitivity in the hard...
Objective: This study assessed the effect of omentectomy on the prognosis and fertility in patients with clinically early-stage (I, II) malignant ovarian germ cell tumours (MOGCT).Design: A retrospective multicentre study. Setting: Four university teaching hospitals in China.Population: A total of 268 patients with clinically apparent early-stage (I, II) MOGCT.Methods: Data were obtained from the medical records. Additionally, the propensity score matching (PSM) algorithm was adopted.Main outcome measures: Prognostic outcomes were disease-free survival (DFS) and overall survival (OS). Fertility outcomes were pregnancy and live birth rates.Results: A total of 187 (69.8%) patients underwent omentectomy. Kaplan-Meier analysis showed no significant differences in DFS and OS between the omentectomy and non-omentectomy groups before and after PSM (p > 0.05). Additionally, subgroup analysis stratified by age (<18 and ≥18 years) showed similar results. International Federation of Gynecology and Obstetrics (FIGO) stage was the only risk factor associated with DFS (hazard ratio [HR] 14.71, 95% confidence interval [CI] 4.47-48.38, p < 0.001) and OS (HR 37.36,, p = 0.002). Pregnancy and live birth rates in the total population were 80.3% and 66.7%, respectively. There were no significant differences between the two groups before and after PSM. Conclusions: Omentectomy did not improve survival or affect fertility in patients with clinically apparent early-stage (I, II) MOGCT, regardless of the age. The clinical FIGO stage was an independent risk factor for recurrence and death. K E Y W O R D S clinically apparent early stage, malignant ovarian germ cell tumours, omentectomy, prognostic outcomes, propensity score matching, reproductive outcomes
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.