Infection of Cranioplasty Seen Twenty Years Later

Cranioplasty is performed using autograft and allograft materials on patients to whom craniectomy was applied previously due to the facts that, this region is open to trauma and the scalp makes irritation and pressure onto the brain paranchyma causing brain atrophy and convulsions. Dramatical improvement of neurological deficits, control of convulsions and partial prevention of cerebral atrophy are achieved after these operations. One of the most important complications of cranioplasty is late infection. Here, we report a 43-year-old male patient admitted with the history of purulant discharge from the right temporal incission site for one year to whom cranioplasty had been performed with allograft material 20 days after craniectomy which had been performed in 1989. Allograft cranioplasty material was removed and cranioplasty was performed using new allograft material with the diagnosis of late cranioplasty infection.     

超声造影不均匀低增强对甲状腺乳头状癌的诊断价值

目的:探讨超声造影（CEUS）不均匀低增强对甲状腺乳头状癌的诊断价值。方法:选取2015年2月至2017年2月于延安大学附属医院行甲状腺手术并于术前行超声造影检查的患者，回顾性分析，将增强模式表现进行分类，并与病理结果进行对照。结果:72例患者共74个结节。不均匀低增强43个结节，其中31个乳头状癌，9个结节性甲状腺肿，2个桥本氏甲状腺炎，1个髓样癌；超声造影不均匀低增强诊断甲状腺乳头状癌的敏感性、特异性及准确率分别为86.11%(31/36)、68.42%(26/38)和77.03%(57/74)。结论:超声造影诊断甲状腺乳头状癌具有其独特的优势，但是仅仅依靠“不均匀低增强”诊断PTC存在较高的误诊率，所以诊断过程中还应注意结节增强后的边界、形态及甲状腺包膜完整性等观察指标。     

Improving evoked response audiometry

Normative studies were carried out with 8 adult subjects whose averaged evoked responses to auditory stimuli were scored visually and by a number of differently defined quantitative methods (machine scoring). In order to compare different scoring methods a common signal-to-noise ratio measure was introduced based on a model where noise is distributed normally and signal is additive. Visual and machine scoring proved to be approximately equally sensitive, but the latter lends itself to a superior testing procedure which takes only one-third as long for equivalent results and is not contaminated by subjective error. The authors believe that the greatest promise for improving evoked response audiometry lies in the exploration of the new techniques proposed earlier. Progress in proving out one of these techniques, fast periodic stimulation, is reported.     

Accuracy in the quantification of chemical exchange saturation transfer (CEST) and relayed nuclear Overhauser enhancement (rNOE) saturation transfer effects

Accurate quantification of chemical exchange saturation transfer (CEST) effects, including dipole–dipole mediated relayed nuclear Overhauser enhancement (rNOE) saturation transfer, is important for applications and studies of molecular concentration and transfer rate (and thereby pH or temperature). Although several quantification methods, such as Lorentzian difference (LD) analysis, multiple‐pool Lorentzian fits, and the three‐point method, have been extensively used in several preclinical and clinical applications, the accuracy of these methods has not been evaluated. Here we simulated multiple‐pool Z spectra containing the pools that contribute to the main CEST and rNOE saturation transfer signals in the brain, numerically fit them using the different methods, and then compared their derived CEST metrics with the known solute concentrations and exchange rates. Our results show that the LD analysis overestimates contributions from amide proton transfer (APT) and intermediate exchanging amine protons; the three‐point method significantly underestimates both APT and rNOE saturation transfer at ?3.5 ppm (NOE(?3.5)). The multiple‐pool Lorentzian fit is more accurate than the other two methods, but only at lower irradiation powers (≤1 μT at 9.4 T) within the range of our simulations. At higher irradiation powers, this method is also inaccurate because of the presence of a fast exchanging CEST signal that has a non‐Lorentzian lineshape. Quantitative parameters derived from in vivo images of rodent brain tumor obtained using an irradiation power of 1 μT were also compared. Our results demonstrate that all three quantification methods show similar contrasts between tumor and contralateral normal tissue for both APT and the NOE(?3.5). However, the quantified values of the three methods are significantly different. Our work provides insight into the fitting accuracy obtainable in a complex tissue model and provides guidelines for evaluating other newly developed quantification methods.     

妊娠晚期绝对羊水过少阴道分娩的分娩结局与护理对策

目的通过对67例妊娠晚期绝对羊水过少孕妇阴道分娩结局的分析，总结该类孕妇分娩期的护理措施。方法对67例妊娠晚期绝对羊水过少孕妇病例进行回顾性分析，分娩前充分的评估，确定胎儿的储备，根据宫颈条件不同，采取不同的分娩方式，第一产程严密产程观察，注意孕妇体能的储备，及时处理异常，密切注意胎心的变化，破水后采取有利的体位，减少羊水的流出，并与同时期正常妊娠孕妇67例进行比较。结果67例孕妇均顺利分娩，且得到了良好的分娩结局。结论对妊娠晚期绝对羊水过少孕妇分娩前充分评估，严密产程观察，可以得到良好分娩结局，可明显降低剖宫产率。     

Cell layers and neuropil: contrast‐enhanced MRI of mouse brain in vivo

Contrast‐enhanced T₁‐ and T₂‐weighted MRI at 9.4 T and in‐plane resolutions of 25 and 30 µm has been demonstrated to differentiate between neural tissues in mouse brain in vivo, including granule cell layers, principal cell layers, general neuropil, specialized neuropil and white matter. In T₁‐weighted MRI of the olfactory bulb, hippocampus and cerebellum, contrast obtained by the intracranial administration of gadopentetate dimeglumine (Gd‐DTPA) reflects the extra‐ and intracellular spaces of gray matter in agreement with histological data. General neuropil areas are highlighted, whereas other tissues present with lower signal intensities. The induced contrast is similar to that in plain T₂‐weighted MRI, but offers a 16–30‐fold higher contrast‐to‐noise ratio. Systemic administration of manganese chloride increases the signal‐to‐noise ratio in T₁‐weighted MRI to a significantly greater extent in principal cell layers and specialized neuropil than in granule cell layers, whereas gadolinium‐enhanced MRI indicates no larger intracellular spaces in these tissues. Granule cell layers are enhanced no more than general neuropil by manganese, whereas gadolinium‐enhanced MRI indicates significantly larger intracellular spaces in the cell layers. These discrepancies suggest that the signal increase after manganese administration reflects cellular activity which is disproportionate to the intracellular space. As a result, principal cell layers and specialized neuropil become highlighted, whereas granule cell layers, general neuropil and white matter present with lower signal intensities. Copyright © 2013 John Wiley & Sons, Ltd.     

Wireless amplified NMR detector for improved visibility of image contrast in heterogeneous lesions

To demonstrate the capability of a wireless amplified NMR detector (WAND) to improve the visibility of lesion heterogeneity without the use of exogenous contrast agents, a cylindrically symmetric WAND was constructed to sensitively detect and simultaneously amplify MR signals emitted from adjacent tissues. Based on a two‐leg high‐pass birdcage coil design, this WAND could be activated by a pumping field aligned along the main field (B₀), without perturbing MR signal reception. Compared with an equivalent pair of external detectors, the WAND could achieve more than 10‐fold gain for immediately adjacent regions. Even for regions with 3.4 radius distance separation from the detector's cylindrical center, the WAND was at least 1.4 times more sensitive than an equivalent pair of surface arrays or at least twice as sensitive as a single‐sided external surface detector. When the WAND was inserted into a rat's rectum to observe adjacent tumors implanted beneath the mucosa, it could enhance the detection sensitivity of lesion regions, and thus enlarge the observable signal difference between heterogeneous tissues and clearly identify lesion boundaries as continuous lines in the intensity gradient profile. Hyperintense regions observable by the WAND existed due to higher levels of blood supply, which was indicated by a similar pattern of signal enhancement after contrast agent administration. By better observing the endogenous signal contrast, the endoluminal WAND could characterize lesions without the use of exogenous contrast agents, and thus reduce contrast‐induced toxicity.