Thermochromic Tissue-Mimicking Phantoms for Thermal Ablation Based on Polyacrylamide Gel

In recent years, thermal ablation has played an increasingly important role in treating various tumors in the clinic. A practical thermochromic phantom model can provide a favorable platform for clinical thermotherapy training of young physicians or calibration and optimization of thermal devices without risk to animals or human participants. To date, many tissue-mimicking thermal phantoms have been developed and are well liked, especially the polyacrylamide gel (PAG)–based phantoms. This review summarizes the PAG-based phantoms in the field of thermotherapy, details their advantages and disadvantages and provides a direction for further optimization. The relevant physical parameters (such as electrical, acoustic, and thermal properties) of these phantoms are also presented in this review, which can assist operators in a deeper understanding of these phantoms and selection of the proper recipes for phantom fabrication.     

How structural and functional MRI can inform dual-site tACS parameters: A case study in a clinical population and its pragmatic implications

BackgroundAbnormalities in frontoparietal network (FPN) were observed in many neuropsychiatric diseases including substance use disorders. A growing number of studies are using dual-site-tACS with frontoparietal synchronization to engage this network. However, a computational pathway to inform and optimize parameter space for frontoparietal synchronization is still lacking. In this case study, in a group of participants with methamphetamine use disorders, we proposed a computational pathway to extract optimal electrode montage while accounting for stimulation intensity using structural and functional MRI.MethodsSixty methamphetamine users completed an fMRI drug cue-reactivity task. Four main steps were taken to define electrode montage and adjust stimulation intensity using 4x1 high-definition (HD) electrodes for a dual-site-tACS; (1) Frontal seed was defined based on the maximum electric fields (EF) predicted by simulation of HD montage over DLPFC (F3/F4 in EEG 10–10), (2) frontal seed-to-whole brain context-dependent correlation was calculated to determine connected regions to frontal seeds, (3) center of connected cluster in parietal cortex was selected as a location for placing the second set of HD electrodes to shape the informed montage, (4) individualized head models were used to determine optimal stimulation intensity considering underlying brain structure. The informed montage was compared to montages with large electrodes and classic frontoparietal HD montages (F3-P3/F4-P4) in terms of tACS-induced EF and ROI-to-ROI task-based/resting-state connectivity.ResultsCompared to the large electrodes, HD frontoparietal montages allow for a finer control of the spatial peak fields in the main nodes of the FPN at the cost of lower maximum EF (large-pad/HD: max EF[V/m] = 0.37/0.11, number of cortical sub-regions that EF exceeds 50% of the max = 77/13). For defining stimulation targets based on EF patterns, using group-level head models compared to a single standard head model results in comparable but significantly different seed locations (6.43 mm Euclidean distance between the locations of the frontal maximum EF in standard-space). As expected, significant task-based/resting-state connections were only found between frontal-parietal locations in the informed montage. Cue-induced craving score was correlated with frontoparietal connectivity only in the informed montage (r = ?0.24). Stimulation intensity in the informed montage, and not in the classic HD montage, needs 40% reduction in the parietal site to reduce the disparity in EF between stimulation sites.ConclusionThis study provides some empirical insights to montage and dose selection in dual-site-tACS using individual brain structures and functions and proposes a computational pathway to use head models and functional MRI to define (1) optimum electrode montage for targeting FPN in a context of interest (drug-cue-reactivity) and (2) proper transcranial stimulation intensity.     

空气细颗粒物暴露水平与健康成人大脑灰质体积和认知功能的关联研究

目的:应用磁共振成像(MRI)技术探究空气细颗粒物PM2.5暴露水平对健康成年人大脑灰质体积(GMV)和认知功能的影响。方法:选取487例健康成人,采集一般人口学信息及详细居住信息,并根据居住信息获取各受试近6个月和8岁～15岁期间的PM2.5暴露水平,对所有研究对象完成高分辨率结构MRI扫描,使用中文版精神分裂症认知功能成套测验-共识版(MCCB)进行认知测查,使用相关和回归分析探索空气PM2.5暴露水平与GMV和认知功能的关联。结果:近6个月PM2.5暴露水平与大脑右侧额下回三角部(brodmann分区[BA] 45)和右侧颞中回(BA 22)GMV存在负性关联(FWE校正,P<0.05,团块>10体素);与MCCB认知评估的信息处理速度-连线测试(r=-0.17,P<0.01)和推理和问题解决-迷宫测验评分(r=-0.22,P<0.01)负相关。8～15岁时的累积空气PM2.5暴露量与左侧梭状回(BA 18)和右侧舌回(BA 17)GMV负相关(FWE校正,P<0.05,团块>10体素),且与信息处理速度-连线测试、推理和问题解决-迷宫测验评分...     

Idiopathic Headache as a Possible Risk Factor for Phantom Tooth Pain

Following tooth pulp extirpation, some subjects suffer from persistent pain which affects edentate sites in absence of any local pathology. As regards this peculiar pain, called phantom tooth pain (PTP), what is puzzling is the fact there is a low prevalence of PTP in a very large population showing identical conditions of tooth pulp extirpation. The present investigation indicates that PTP mainly affects migraine (M) and cluster headache (CH) sufferers, whereas it does not affect subjects who have a negative personal and family history for idiopathic headache (IH). These results circumscribe the presence of PTP to a specific section of the population. The present results, besides indicating that PTP may be the result of a peculiar neuronal predisposition relating to IH pathogenesis, suggests some practical therapeutic hints. In fact, successful anti- M and anti-CH prophylactic treatment greatly improve PTP syndrome.     

基于64层CT对心脏体模冠脉狭窄成像的客观评估方法

本文设计了一种心脏冠脉狭窄程度的客观评估方法，并自行开发了工具软件对图像数据进行自动处理和计算。此后，本文采用该方法对四组心脏动态体模冠脉狭窄成像的数据进行了分析，对该客观评估方法各方面的特性进行了检验和评定。     

应用统计学体模评价CR乳腺摄影影像的探讨

目的应用ALVIM统计学体模TRM,探讨乳腺计算机X线摄影(CR)获得尺寸最小的Al2O3斑点(钙化灶)和尼龙纤维(肿块灶)信号的能力。方法将具有各5种大小不同Al2O3斑点和尼龙纤维组成的ALVIM统计学体模TRM置于成像板(IP)上,用钼靶X线机26kV,调节毫安量,选择适当图像处理参数,获得一张密度值D=0·70±0·05的实验照片,用5值判断法取得每一行由5个信号和噪声所组成的10行信号的记分总值,用ALVIM统计学体模的计算公式计算出一组真阳性概率P(S/s)和假阳性概率P(S/n)值,绘制ROC曲线,并计算出每种信号的判断概率值Pdet,再用SPSS10·0统计学单因素方差分析软件处理数据,获得尺寸最小的钙化灶和软组织肿块灶。结果用概率统计方法获得制作ROC曲线的数据和判断概率平均值Pdet,5种大小不同的Al2O3斑点(钙化灶)中,0·20mm的Pdet=0·6250最小,0·55mm的Pdet=0·9000最大,而0·20mm与0·25mm的Pdet差异无统计学意义,与其他的差异有统计学意义;5种大小不同的尼龙纤维(肿块灶)中,0·45mm的Pdet=0·5313最小,1·00mm的Pdet=0·8813最大,而0·45mm的与0·60mm的差异无统计学意义,0·45mm与其他的差异有统计学意义。结论应用ALVIM统计学体模TRM制作ROC曲线和获得判断概率值Pdet的计算简单、快捷,宜于日常临床工作开展的评价影像质量控制,值得推广。     

Development of phantom for radiographic image optimization of standard patient in the lateral view of chest and skull examination

We present the construction of a homogeneous phantom to be used in simulating the scattering and absorption of X-rays by a standard patient chest and skull when irradiated laterally. This phantom consisted of lucite and aluminium plates with their thickness determined by a tomographic exploratory method applied to the anthropomorphic phantom. Using this phantom, an optimized radiographic technique was established for chest and skull of standard sized patient in lateral view. Images generated with this optimized technique demonstrated improved image quality and reduced radiation doses.     

Optical properties of Intralipid: a phantom medium for light propagation studies.

Intralipid is an intravenous nutrient consisting of an emulsion of phospholipid micelles and water. Because Intralipid is turbid and has no strong absorption bands in the visible region of the electromagnetic spectrum, and is readily available and relatively inexpensive, it is often used as a tissue simulating phantom medium in light dosimetry experiments. In order to assist investigators requiring a controllable medium that over a finite range of wavelengths is optically equivalent to tissue, we have compiled previously published values of the optical interaction coefficients of Intralipid, most of which were measured at a wavelength of 633 nm. We have extended the measurements of the absorption and reduced scattering coefficients from 460 to 690 nm and the total attenuation coefficient from 500 to 890 nm. These measurements show that, for stock 10% Intralipid, the absorption coefficient varies from 0.015 to 0.001 cm-1 between 460 and 690 nm, the reduced scattering coefficient varies from 92 to 50 cm-1 between 460 and 690 nm, the total attenuation coefficient varies from 575 to 150 cm-1 between 500 and 890 nm, and the average cosine of scatter varies from 0.87 to 0.82 between 460 and 690 nm. With these data, we discuss the design of an optically tissue-equivalent phantom consisting of Intralipid and black India ink.     

Long-term Outcomes of Patients Undergoing War-related Amputations of the Foot and Ankle

Long-term clinical and functional outcomes for patients undergoing foot and ankle amputations are not well documented. We attempted to document long-term outcomes for patients who required lower extremity amputations as a result of wounds suffered during wartime. For this study, 27 Iranian soldiers who had wounds requiring amputation of the foot and ankle were selected for follow-up. The participants' wartime medical records were reviewed, a clinical examination was performed, and each participant completed a questionnaire. Postamputation follow-up averaged 17.5 years. The most prevalent (66.6%) cause of injury was a land mine. The prevalences of different clinical symptoms reported by the amputees at the time of the last follow-up were as follows: 11 (40.7%) with phantom sensation, 6 (22.2%) with phantom pain, 12 (44.4%) with stump pain, 12 (44.4%) with back pain, 9 (33.3%) with contralateral knee pain, and 4 (14.8%) with ipsilateral knee pain; 20 (74%) reported treatment for psychological conditions. In regard to social conditions, 13 (48.1) were currently employed, or had been employed, for a number of years after the amputation; 26 (96%) had children, and all of the patients were married. The results of this observational study indicate that individuals have significant long-term pain and discomfort after war-related lower extremity amputation. Although all 27 (100%) of the amputees were able to maintain satisfactory family functioning, only 13 (48.1%) of the study participants were able to remain productively employed after undergoing amputation, and 20 (74%) reported long-term psychological problems in addition to their physical pain.