Improvement of freehand ultrasound calibration accuracy using the elevation beamwidth profile

This article presents a novel approach that incorporates an ultrasound slice-thickness profile into a filtered, weighted-least-square framework to improve the reconstruction accuracy of a real-time freehand calibration system. An important part of the system is a slice-thickness calibration device that aids in the extraction of the slice thickness across a wide range of imaging depths. Extensive experiments were conducted on a 10,000-image dataset to evaluate the effects of the framework on the calibration accuracy. The results showed that three-dimensional (3-D) reconstruction errors were significantly reduced in every experiment (p < 0.001). Real-time testing showed that the proposed method worked effectively with a small number of input images, suggesting great potential for intraoperative use where only a limited number of data may be available. This new framework can enable efficient quality control of calibration accuracy in real-time operating-room use.     

层螺旋CT后处理技术在泌尿系统梗阻性疾病中临床诊断中的应用

目的探讨层螺旋CT后处理技术对泌尿系统梗阻性疾病的诊断方法和价值。方法抽取我院于2010年1月至2011年1月收治的30例泌尿系统梗阻性疾病患者先后用不同影像学方法检查。对照组30例,行与磁共振尿路成像(MRU)检测。实验组30例,行层螺旋CT检测。比较2组各类型泌尿系统梗阻性病变的阳性检出率。结果 2组阳性检出率相比,实验组优于对照组,差异有统计学意义(P<0.05)。泌尿系统梗阻性疾病以输尿管结石和肿瘤为主,差异有统计学意义(P<0.05)。结论输尿管梗阻性疾病诊断中MRU、层螺旋CT各有其优点,但总体来说层螺旋CT检测阳性检出率较高,因此,早期行层螺旋CT后处理技术对泌尿系统梗阻性疾病的诊断具有重要作用,有利于提高早期治愈率,应当在临床上推广使用。     

Age-related increase of sIAHP in prefrontal pyramidal cells of monkeys: relationship to cognition

Reduced excitability, due to an increase in the slow afterhyperpolarization (and its underlying current sI_AHP), occurs in CA1 pyramidal cells in aged cognitively-impaired, but not cognitively-unimpaired, rodents. We sought to determine whether similar age-related changes in the sI_AHP occur in pyramidal cells in the rhesus monkey dorsolateral prefrontal cortex (dlPFC). Whole-cell patch-clamp recordings were obtained from layer 3 and layer 5 pyramidal cells in dlPFC slices prepared from young (9.6 ± 0.7 years old) and aged (22.3 ± 0.7 years old) behaviorally characterized subjects. The amplitude of the sI_AHP was significantly greater in layer 3 (but not layer 5) cells from aged-impaired compared with both aged-unimpaired and young monkeys, which did not differ. Aged layer 3, but not layer 5, cells exhibited significantly increased action potential firing rates, but there was no relationship between sI_AHP and firing rate. Thus, in monkey dlPFC layer 3 cells, an increase in sI_AHP is associated with age-related cognitive decline; however, this increase is not associated with a reduction in excitability.     

多层螺旋CT诊断壶腹部癌的价值

目的探讨壶腹部癌的多层螺旋CT诊断价值。方法对35例有完整CT资料,经手术或胰胆管逆行造影（ERCP）活检病理证实的壶腹部癌进行回顾性分析。结果 （1）直接征象：35例中30例可见十二指肠降段,其中28例胆总管下段内软组织肿块可见＂截断征＂,2例呈＂杯口征＂。（2）间接征象：26例可见胆总管下段及胰管扩张呈＂双管征＂,胆囊扩大16例。（3）十二指肠近段扩张,肠管壁不规则增厚8例,胰头、钩突部侵犯11例,腹主动旁淋巴结增大6例,肝转移5例。（4）CT正确诊断30例,1例误诊为胰头癌;2例误诊为胆总管下段结石,2例误诊为壶腹部炎症包块。结论多层螺旋CT能显示壶腹部癌的肿块,鉴别胆道梗阻的部位及性质,根据CT征象中的直接征象与间接征象,能明确诊断壶腹部癌。     

Assessment of the cerebellar arteries with multidetector computed tomography angiography benefits from submillimeter slice thickness

Purpose

To evaluate the accuracy of 64-row-multidetector computed tomography (MDCT) with different slice thickness (0.625 vs. 1.25 mm) in assessing the cerebellar arteries.

Materials and methods

A total of 21 consecutive patients who underwent computed tomography angiography (CTA) of the cervicocranial arteries (64-row MDCT; slice thickness, 0.625 mm) because of suspicion of cerebral ischemia were enrolled retrospectively. The MDCT data set was secondarily reconstructed to a slice thickness of 1.25 mm. The examinations were reviewed by three independent blinded observers. Recorded parameters for reconstructed slice thicknesses of 0.625 compared to 1.25 mm were visualization and edge enhancement (based on a developed phantom reference model) of the cerebellar arteries including anterior and posterior inferior cerebellar arteries and the superior cerebellar artery.

Results

With 0.625-mm slices, significantly more vessel segments were visualized and edge enhancement was superior compared to 1.25-mm slices by the three readers, and a significant difference for the interaction between vessel segments and the slice thickness was found (P<.001). Furthermore, for a slice thickness of 1.25 mm, there was a significant difference in visualization (P=.0042) and edge enhancement (P=.0015) of vessel segments between the three readers, whereas for thinner slices (0.625 mm), no significant differences were found (P=.412, P=.465).

Conclusions

MDCT with slice thickness of 0.625 mm is superior to 1.25 mm reconstructed slice thickness regarding the visualization of cerebellar arteries, representative for smallest assessable arteries in CTA. This is paralleled by a sharper edge enhancement of the vessel contours resulting from a reduced partial volume effect. Conclusively, cranial CTA protocols should be routinely optimized to generate submillimeter slices for diagnostic purposes and digital storage as additional diagnostic value can be expected.     

Differentiation/maturation of neuropeptide Y neurons in the corpus callosum is promoted by brain-derived neurotrophic factor in mouse brain slice cultures

Neuropeptide Y (NPY) is widely distributed throughout both the central and peripheral nervous systems in mammals, and plays a role in various functions such as neural modifications affecting feeding, cardiovascular dynamics, or neural diseases. Many NPY neurons exist not only in gray matter in the central nervous system or ganglia in the peripheral system, but also in white matter such as the corpus callosum (cc) especially during development. The functions and regulation of callosal NPY neurons are not well understood, though NPY neurons in the cerebral cortex or hypothalamus are known to be regulated by neurotrophic factors such as brain-derived neurotrophic factor (BDNF). We examined the effect of BDNF on NPY neurons in the cc using organotypic slice cultures to clarify the regulation of callosal NPY neurons. A 3-week administration of BDNF significantly increased the number of NPY-immunopositive neuronal cell bodies and fibers in the cc rather than in the cerebral cortex as assessed with immunohistochemistry. Electron microscopy demonstrated that the NPY immunoreactivity mainly occurred in the regions associated with accumulating synaptic or cored vesicles. NPY-positive fibers had some contacts with several other neuronal fibers and glial processes. BDNF affected these fine structures of NPY neuronal fibers in the cc. These results suggest that BDNF takes part in the development, maturation, and maintenance of NPY neurons in the cc.     

Thermosensitivity of neurons in the paraventricular nucleus of the rat slice preparation

The thermosensitivity of 65 spontaneously active neurons in the paraventricular nucleus (PVN) was investigated by extracellular recording in the rat hypothalamic slice preparation. The firing rate of these cells was comparatively low, ranging from 0.03 to 10.0 (mean 2.46) impulses/s at 37 degrees C, and only a minority showed a phasic firing pattern. Of 65 neurons tested, 23 (35%) increased their firing rate when the slice was warmed (warm-sensitive neurons) and 9 (14%) showed the opposite response (cold-sensitive neurons). Thermosensitivity was also tested in solutions with reduced [Ca2+] and high [Mg2+]. Eight out of 10 warm-sensitive neurons and 5 of 7 cold-sensitive neurons retained thermosensitivity after synaptic blockade. Out of 6 phasic firing neurons tested, one showed warm-sensitivity and another one showed cold-sensitivity. The thermosensitive neurons were diffusely distributed throughout the PVN and were not located in particular areas of the nucleus. Thus a group of cells in the PVN, including probably both magno- and parvocellular neurons, showed an inherent thermosensitivity, which suggests an important role for the PVN in thermoregulation.     

Huwe1-shRNA 靶向沉默L2.3神经干细胞的Huwe1表达

【摘要】 目的 探讨Huwe1 shRNA通过慢病毒载体转染L23神经干细胞，是否可以靶向沉默L23神经干细胞的Huwe1基因。方法 将体外培养的L23神经干细胞分成3组：huwe1 shRNA未转染组（control 组）、阴性序列转染组（control shRNA组）、huwe1 shRNA转染组（Huwe1 shRNA组）。Control组：仅常规体外培养L23神经干细胞。不将阴性序列和Huwe1 shRNA通过慢病毒载体转染L23神经干细胞。Control shRNA组：阴性序列通过慢病毒转染体外培养的L23神经干细胞。Huwe1 shRNA组：Huwe1 shRNA通过慢病毒载体成功感染体外培养L23神经干细胞。分别收集三组体外培养的L23神经干细胞，应用western blot 方法分别检测三组L23神经干细胞Huwe1蛋白的表达。 结果 与control组、control shRNA组比， Huwe1shRNA组体外培养的L23神经干细胞huwe1蛋白表达条带显著减弱、变细（P < 005）。与control组Huwe1蛋白的相对表达量比，Huwe1shRNA组Huwe1蛋白的相对表达量是control组的25%（P < 005）。与control 组比，control shRNA组和Huwe1shRNA组在慢病毒载体转染L23神经干细胞，L23神经干细胞存活率无明显下降（P>005) 结论 Huwe1 shRNA通过慢病毒载体转染L23神经干细胞，可以靶向沉默L23神经干细胞Huwe1基因，却不影响L23神经干细胞的存活率。