Study on real-time force feedback for a master–slave interventional surgical robotic system

In robot-assisted catheterization, haptic feedback is important, but is currently lacking. In addition, conventional interventional surgical robotic systems typically employ a master–slave architecture with an open-loop force feedback, which results in inaccurate control. We develop herein a novel real-time master–slave (RTMS) interventional surgical robotic system with a closed-loop force feedback that allows a surgeon to sense the true force during remote operation, provide adequate haptic feedback, and improve control accuracy in robot-assisted catheterization. As part of this system, we also design a unique master control handle that measures the true force felt by a surgeon, providing the basis for the closed-loop control of the entire system. We use theoretical and empirical methods to demonstrate that the proposed RTMS system provides a surgeon (using the master control handle) with a more accurate and realistic force sensation, which subsequently improves the precision of the master–slave manipulation. The experimental results show a substantial increase in the control accuracy of the force feedback and an increase in operational efficiency during surgery.     

颅底转移瘤的影像诊断

目的 本文分析１２例颅底转移瘤的ＣＴ和ＭＲ影像表现特征。方法 １２例经手术病理证实为转移瘤。男性７例,女性５例。９例ＭＲ检查;２例ＣＴ,ＭＲ检查;１例ＣＴ检查。结果 单发１０例;多发２例。８例转移瘤位于中颅窝;２例位于前颅窝;２例位于后颅窝。８例有不同程度颅底骨质破坏。结论 颅底转移瘤在ＣＴ和ＭＲ有一定特征性表现,但必须结合病史、年龄、是有原发恶性肿瘤手术史及颅骨受损情况及综合分析做出诊断。     

松果体区生殖细胞瘤扩散的MRI研究

目的分析松果体区生殖细胞瘤扩散的途径和MRI表现。方法24例松果体区生殖细胞瘤均经手术和病理证实,其中13例经临床和诊断性放疗证实为松果体区生殖细胞瘤的扩散。结果16例沿脑脊液(CSF)种植;9例沿室管膜下扩散;13例向邻近脑组织浸润蔓延。侧脑室旁扩散为等T1长T2或稍长T2,多个结节或连接成片;小脑幕、大脑镰和软脑膜扩散多表现为“绳索”样增粗,也可为多个或单个结节;环池、第4脑室和小脑上蚓池多为强化结节。除3例透明隔和1例脊髓马尾瘤灶外,MRI均显著均匀强化。结论扩散除具有恶性肿瘤扩散的共性———直接浸润蔓延和沿CSF种植外,还可沿室管膜下扩散,MRI增强扫描可清楚显示多发的和较小的转移灶。     

改良的大鼠脑局部缺血模型

目的介绍一种快速、稳定的大鼠脑局部缺血模型。方法32只Wistar雄性大鼠，按照Longa的线栓法制作局部脑缺血模型，但在放入栓塞线时不结扎翼腭动脉(PPA)，通过局部脑血流监测、动物行为学评分、脑含水量测定、红四氮唑(TTC)染色和病理学检查等方法评价该模型的可靠性。结果动物麻醉后一般只需15min左右即可完成栓线手术，术后大鼠大脑中动脉区域血流量下降，神经功能损伤明显，脑含水量增高，TTC染色脑梗死区苍白，病理学检查显示缺血灶星形胶质细胞肿胀，神经元固缩坏死。结论不结扎PPA的大鼠脑局部缺血模型，缺血效果明确可靠，手术时间短，是理想的研究脑缺血的实验模型。     

脑部CT平扫图像直方图分析鉴别肿瘤性与非肿瘤性脑出血

目的 观察脑部CT平扫图像直方图分析鉴别诊断肿瘤性与非肿瘤性脑出血的价值。方法 收集116例非肿瘤性脑出血（非肿瘤组）和44例肿瘤性脑出血（肿瘤组），分析其脑部CT平扫图像直方图，获得病灶的直方图参数，包括最小值，第5、25、50、75、95百分位CT值、最大值、标准差、平均值、偏度和峰度。比较2组间直方图参数的差异，以ROC曲线分析各参数鉴别诊断肿瘤性与非肿瘤性脑出血的效能。结果 肿瘤组最大值、第5、25、50、75、95百分位CT值、平均值、标准差均小于非肿瘤组（P均<0.05），偏度和峰度大于非肿瘤组（P均<0.05），最小值与非肿瘤组差异无统计学意义（P>0.05）。ROC曲线分析结果显示，最大值、第25、50、75、95百分位CT值、平均值及标准差鉴别肿瘤性与非肿瘤性脑出血的诊断价值中等，其中第50百分位CT值的AUC最高（0.82），敏感度和特异度分别为0.92和0.68。结论 脑部CT平扫图像直方图分析可作为鉴别诊断肿瘤性与非肿瘤性脑出血的辅助手段。     

基于3D深度残差网络和多模态MRI的脑胶质瘤自动分级

目的:利用3D深度残差网络和多模态MRI实现对脑胶质瘤的自动分级。方法:利用BraTS2020公共数据集的293例高级别胶质瘤（HGG）和76例低级别胶质瘤（LGG）的多模态MRI数据训练和测试3D深度残差卷积网络模型。多模态MRI图像经过3D剪裁、重采样和归一化的预处理,随机分组为训练（64%）、验证（16%）和测试（20%）样本,将预处理后的多模态MRI图像和分级标注输入到网络模型进行训练、验证和测试。利用准确率（ACC）和受试者工作特征（ROC）曲线下面积（AUC）评价分级结果。结果:在59例（48例HGG和11例LGG）验证数据集上,ACC和AUC分别为0.93和0.97,在75例（62例HGG和13例LGG）测试数据集上,ACC和AUC分别为0.89和0.93。结论:3D深度残差网络在多模态MRI数据集上获得了较好的脑胶质瘤自动分级结果,可以为确定治疗方案和预测预后方面提供重要参考。     

JNK inhibition and inflammation after cerebral ischemia

The c-Jun-N-terminal kinase signaling pathway (JNK) is highly activated during ischemia and plays an important role in apoptosis and inflammation. We have previously demonstrated that D-JNKI1, a specific JNK inhibitor, is strongly neuroprotective in animal models of stroke. We presently evaluated if D-JNKI1 modulates post-ischemic inflammation such as the activation and accumulation of microglial cells.Outbred CD1 mice were subjected to 45 min middle cerebral artery occlusion (MCAo). D-JNKI1 (0.1 mg/kg) or vehicle (saline) was administered intravenously 3 h after MCAo onset. Lesion size at 48 h was significantly reduced, from 28.2 ± 8.5 mm³ (n = 7) to 13.9 ± 6.2 mm³ in the treated group (n = 6). Activation of the JNK pathway (phosphorylation of c-Jun) was observed in neurons as well as in Isolectin B4 positive microglia. We quantified activated microglia (CD11b) by measuring the average intensity of CD11b labelling (infra-red emission) within the ischemic tissue. No significant difference was found between groups. Cerebral ischemia was modelled in vitro by subjecting rat organotypic hippocampal slice cultures to oxygen (5%) and glucose deprivation for 30 min. In vitro, D-JNKI1 was found predominantly in NeuN positive neurons of the CA1 region and in few Isolectin B4 positive microglia. Furthermore, 48 h after OGD, microglia were activated whereas resting microglia were found in controls and in D-JNKI1-treated slices.Our study shows that D-JNKI1 reduces the infarct volume 48 h after transient MCAo and does not act on the activation and accumulation of microglia at this time point. In contrast, in vitro data show an indirect effect of D-JNKI1 on the modulation of microglial activation.