Structural Footprint of Minimally Invasive Brain Cannulation

Structural Footprint of Minimally Invasive Brain Cannulation Assessing the Structural Footprint of Minimally Invasive Brain Cannulation on Cerebral White Matter: A Cadaveric DTI Model Abstract Background: Minimally invasive approaches to brain tumors offer the potential of decreased iatrogenic trauma related to tumor visualization compared to conventional approaches. Currently there are no validated models to examine axonal damage after minimally invasive entry into the brain. Object: The authors present and evaluate a cadaveric model of brain cannulation using diffusion tensor imaging fractional anisotropy measurements. Two different methods of access are compared. Methods: Freshly harvested unfixed cadaveric brains were cannulated using both direct and indirect methods. Specimens were subjected to 68-direction DTI scans and proton density imaging. FA data from a â€Å"region of interest† surrounding the entry zone was extracted from scans using imaging software and analyzed. Results: FA values were significantly higher following indirect cannulation (less invasive method) than they were following direct cannulation. FA values for undisturbed brain were significantly higher than in either of the cannulated groups. Conclusion: Axonal damage following brain cannulation can potentially be evaluated by FA analysis in a cadaveric model. Future studies will focus on histologic analysis and clinical validation. Introduction Diffusion tensor imaging (DTI) is a magnetic resonance imaging methodology that can be utilized to visualize neuronal microstructure. Diffusion of water inside the human brain is largely limited by the neurolemma. Since the nerves of the brain travel in large fascicles, this diffusion process can be exploited to visualize white matter tracts using DTI. Furthermore, degree of water flow along these axonal tracts can be quantified by using a measurement called fractional anisotropy (FA). (1-3) FA is a scalar value, calculated from the eigenvalues of the diffusion tensor, which describes the independency of a diffusion process. High FA values indicate diffusion in a uniform direction whereas low FA values indicate more random motion of water. Therefore, lowering of relative FA values within specific white matter tracts has been postulated as a marker of neuronal injury in clinical studies and animal models of stroke, traumatic brain injury, radiation-induced injury, and epilepsy (4-8). Iatrogenic white matter injury from surgical trajectories into the brain can also be quantified using tractographic methods (9, 10). Traditional open approaches to subcortical lesions are difficult to perform without causing significant trauma to the overlying normal tissue. For deep lesions, extensive retraction may be required. Minimally invasive cylindrical brain retractors have been deployed over a dilator device with success in multiple case series (5, 11-14), building on prior work demonstrating feasibility of a microsurgical cylindrical brain retractor (15-17). There are even reports of using minimally invasive approaches for hematoma evacuation18. However, the degree of brain trauma incurred from this method of brain access has yet to be radiographically assessed in human models19. In addition, potentially less invasive techniques, such as inflating a balloon within the brain to create a channel for brain surgery, have not been comparatively assessed (20-22). This study sought to apply diffusion imaging techniques to assess iatrogenic brain injury in a cadaveric model of brain surgery. Rather than test conventional retraction methods of the brain using spatulas and brain dissection, emerging minimally invasive techniques for brain retraction were evaluated. Methods All specimens were procured from the hospital morgue following a protocol internally approved by the department of pathology. Within 6 hours after death, brains were harvested from patients with no known pre-existing neurologic disorders. Specimens were sectioned into two approximately 5cm by 3cm blocks to facilitate cannulation and transport. Cuts were made anteriorly at the level of the anterior genu of the corpus callosum, posteriorly at the level of the precentral sulcus, and along the midline. Lateral areas of cortex were removed to make the blocks symmetrical. Two distinct cannulation techniques were used to access the brain, working sequentially from anterior to posterior for each block (Figure 1A). The â€Å"direct cannulation† technique was performed by passing the cannula plunger through cortex approximately 1 cm posterior to the anterior genu, and allowing the cannula to follow, similar to placement of a guide sheath for working channel neuroendoscopy. 2 cm of undisturbed cortex was maintained between cannulations. Indirect cannulations were performed using a 1.5 cc dilatable fogarty catheter. The balloon segment of the catheter initially punctured the cortex. After this, 1.5cc of air was injected to inflate the balloon. Using the balloon as a guide, the cannula was passed into cortex (Figure 1B). After cannulation, specimens were stored in sealed water filled containers and kept in refrigerated conditions until scanning. Scans were performed within 12 hours of cannulation on a Siemens (Siemens, Erlangen, Germany) 3T Trio system. Scanning protocol included a 68-direction, 30 slice DTI scan with echo/repetition time TE/TR=99/4000ms and voxel size of 1.35 by 1.35 by 2. mm. Fractional anisotropy maps were calculated online, using the scanner software. Additionally, 75 slice proton density scans were acquired with TE/TR=9.8/3000ms and with voxel size of .45 by .45 by .8 mm. After scanning, specimens were kept in storage in 10% formalin. All data were analyzed using OsiriX Imaging Software (http://www.osirix-viewer.com/). FA maps were co-registered to the proton density scans for anatomical accuracy. Two Regions of Interest (ROIs) were drawn as concentric circles centered on the cannula (Figure 1C). The larger circle had a constant radius of .5cm radii around the cannulae. The smaller circle was constructed to cover the area of the cannula. â€Å"Average FA† was recorded for both direct and indirect cannulation for a given slice and both ROIs. The FA of the cannula ROI was subtracted from the FA of the .5cm ROI to obtain the â€Å"Adjusted FA† of the area immediately around the cannula. (Equation 1) A third ROI, constructed to match the radius of the cannula, was placed between the two cannula ROIs in an equidistant fashion. This ROI served as a control, measuring the FA of undisturbed brain. This technique was repeated on a slice-by-slice basis over a depth of 5 slices and the resulting data was averag ed to determine the total FA for a given cannulation. Equation 1 This data was subjected to a paired T-Test using Microsoft Excel. The p value of .05 was prospectively determined to be statistically significant. Results Six specimens were analyzed for FA changes after cannulation using both direct and indirect methods. For each specimen 13 slices of MR data were used for analysis. The mean average FA for direct and indirect cannulation was, respectively, 0.1893 and 0.2956. Average Adjusted FA for direct cannulation varied from 0.0267 to 0.105 with a mean value of 0.0645 while indirect varied from 0.0596 to 0.208 with a mean of 0.137. (Table 1) Analysis of all 78 slices revealed an Adjusted FA range of .0211 to .241 for direct cannulation and .0545 to .611 for indirect. Control FA varied from 0.0648 to 0.2152, with a mean of 0.1576. Not a single slice exhibited direct cannulation FA greater than indirect. Paired 2 tail t-tests were conducted between direct and indirect datasets using both average and adjusted values. All analyses were statistically significant. (Table 2). Discussion Minimally invasive brain retraction systems offer the potential to decrease trauma to normal brain during surgical removal of deep-seated intraparenchymal masses. However, an assessment of the utility of such systems requires an appropriate experimental model that can quantify brain injury incurred via various access routes through the cortex. The investigators have developed such a model, via MRI assessment of cadaveric specimens. Previous research in an animal model has demonstrated that a dilatable balloon retraction system causes less damage to white matter as compared to blunt microsurgical dissection (23). In this particular study, both histological and clinical evidence demonstrated that balloon dilation resulted in less brain injury as compared to standard techniques. In addition, recent research has demonstrated that iatrogenic white matter injury can be quantified following brain surgery using fiber tracking methods (9, 11). The investigators submit that the above imaging method is a relatively simple technique for assessing iatrogenic white matter injury following brain dissection, which can then be correlated with functional outcomes in live patients. The concept of FA correlation to axonal integrity is not new. Many investigators across multiple different disciplines in brain research have used FA as a metric of neuronal injury. (6-8, 24) FA is highest when there is uniformity in a diffusion process such as in intact white matter tracts. It decreased progressively to a theoretical value of zero as diffusion becomes more dimensional. In the case of traumatized axons, damage increases the degrees of freedom of diffusion and thus decreases FA. (25) The use of fresh cadaveric specimens with diffusion tensor imaging has also been previously reported and validated26, 27. Using unpreserved specimens ensures the retention of brain tissue fluidity. Thus, retraction in these specimens directly mimics operative conditions. In addition, cadaveric brains can be imaged easily and accurately, without motion artifact. Many authors have previously used diffusion imaging in postmortem brain tissue to study neuropathologic features of the brain28-30. In fact, Seehaus et al (31) published a histological validation of postmortem DTI. Perhaps most convincing, Budde et al32 published a recent study evaluating blast traumatic brain injury in rats using DTI. In their study, rats were subjected to controlled shockwave exposure. After running post-trauma functional tests the authors sacrificed the rats and performed tractography on the formalin fixed post-mortem brain specimens. The authors found significant differences in FA in multiple cortical regi ons that furthermore correlated to poor functional outcome. For example, a significant decrease in FA was discovered in the hippocampus, which correlated to poor performance on the Morris Water Maze task. In light of this evidence, the authors believe that this model is a reasonable estimation of iatrogenic brain injury following tissue manipulation in cadaveric specimens. However, live imaging in vivo would clearly be superior to a cadaveric model, and is planned for future studies. The data clearly illustrates a general increased fractional anisotropy using the indirect cannulation technique in comparison to the direct cannulation method. Fractional anisotropy is a scalar measurement of the independency of a diffusion process. Higher values indicate more uniform diffusion. In the case of neural tissue, diffusion is largely limited by the cell membrane. Thus, lower FA values indicate compromised neuronal integrity. We believe the statistically significant difference in FA between indirect and direct cannulation is evidence for increased preservation of neural tissue using indirect, balloon-guided cannulation. Generally increased FA values in the control specimens is further evidence of this hypothesis. Conclusion Brain cannulation for minimally invasive access to deep-seated brain tumors is an area of growing interest in neurosurgery. To assess the collateral damage to surrounding neural tissue, validation studies need to be conducted to assess white matter integrity following manipulation. Diffusion imaging provides unique visual and quantitative measurements that can be utilized to answer these critical questions. The application of DTI to assess cannulation techniques is a simple but novel idea. The authors hope that this work facilitates analysis of brain cannulation and retraction technology with the goal of maximum preservation of cerebral white matter. Acknowledgement We would like to thank Dr. Julia Koeffler (UPMC Neuropathology) and Denise Davis (UPMC Radiology) for their assistance on this project.

Armenian Genocide †Forgotten Fire Essay

1.The author included the quote from Hitler as the epigraph because he wrote â€Å"Who does now remember the Armenians† before the question and Hitler’s quote answered it. The quote answers the question because only Hitler remembered the Armenians and did the same to the Jews. My ideas didn’t change after reading Forgotten Fire because I already knew the story about the Armenian Genocide. 2.Vahan couldn’t discuss his fear with his mother because first of all, he was too scared to say a word and he wasn’t confident enough to say anything. Also he was imagining things in his mind of what might have happened to his father and maybe if he told his mother, he would burst out in tears. He didn’t also want to disturb his mother because his mother was very depressed when her husband left and it seemed like her heart wasn’t there. Also, her mother would have lied to him anyway and not tell him the truth for why the Turks took his father. 3.The attitude of the Armenian community changed in various ways. No one knew something was going to happen to them, so once everything started; everyone began to only care about themselves. Some people just didn’t want to go any longer and just wanted to be shot before getting tortured in any way. Also they were shocked of what the Turks had done and they started hating them. Every Turk they saw, they started to hate. 4.The Kenderian family was a very wealthy family and lived a great Armenian life. The father had great honor in his community. Vahan greatly admires his father because he always followed his father’s rules and the only way he survived was staying strong and admiring what his father told him to do step by step. The memory of his father gave him a lot of courage to survive because every time he had a hard time, he would close his eyes and imagine what his father told him and then move on. 5.I was aware of the Armenian Genocide before reading the book. The only ethnic war I know of before World War 11 was the Jewish Holocaust. 6.After the murder of Vahan’s brothers, he had a hard time. He didn’t feel  like himself anymore and thought that there was no point of living any longer because he knew that the soldiers would come back and kill him also. He was in pain and couldn’t stand the fact that his brothers had died, he thought everything was imaginary. After that, he stood up more and became aggravated tat he was going to survive through everything. 7.After violent experiences on his journey to Constantinople, his behavior changed afterward. He witnessed many things so after a while, if he saw someone get shot or people begging for something, he did not care because it was normal to him already just because he seen it so many times. The graphic descriptions didn’t disturb my reading because I knew about the Armenian Genocide before I read the book and also I saw an Armenian movie which had more details so the description in the book didn’t seem so harsh. 8.Vahan reveals his spiritual doubt when all the time he prayed about someone or something he got no answer. For example he would always pray to find his family members and when he didn’t, he started to doubt praying. After that, he finally found out that God really exists and he answered as many of his prayers as he could. 9.Vahan knew that Selim Bey wasn’t a polite person but the way he treated him, his first impression of Selim Bey was surprising. Vahan actually â€Å"liked† Selim Bey and couldn’t believe he had done anything to harm the Armenians. Vahan discovers Selim Bey’s true nature when he sends him to his father’s house and doesn’t ever visit Vahan again. Selim Bey betrayed Vahan which showed he didn’t care about him. 10.What Vahan means when he says I would be free an would never be free is the it was unbelievable that he was free from everything now and didn’t have to worry about hiding from Turkish soldiers, but then he still didn’t fell free because he didn’t have his family and everything he once had which made him seem like he had something missing in himself. I don’t think there are countries that deny freedom to certain citizens based on their ethnicity. 11.Mr. and Mrs. Tashian help Vahan on his journey to a new life in many ways.  Vahan learned how to take care of himself and form a family of his own one day. Also, he learned how to do different types of tasks that he learned from Mr. and Mrs. Tashian. Also, they influenced him to move on and not give up which gave him the courage to continue. 12.Everyone in Vahan’s past gave him courage to contribution to freedom in many ways. Every time Vahan was in a dark room or some place he was not sure what he can do, he would close his eyes and imagine something that someone said or did from the past which helped him move on and do what the person once told him to do. Each person gave him courage because he would imagine something each person told him to do and then he would gain more courage and confidence with his journey. 13.The meaning of the tile Forgotten Fire is the death of all the Armenians that was forgotten by the Turks. 14.The quote from Hitler was related to the Armenian Genocide because the world did indeed forget the extermination of people after the war. As well as the Jewish Holocaust, the extermination of humans was forgotten by everyone and never came to mind after such a cruel person such as Hitler committed such an act that was done to the Armenians. It also relates to the Armenian Genocide because Hitler tried to do the sane thing to the Jews as the Turks tried to do to the Armenians. http://www.armenian-genocide.org/Education.73/current_category.123/resourceguide_detail.html

A Review of Casual Essay Topics

A Review of Casual Essay Topics After you've decided on the topic question, it would be recommended to browse through the web to discover some plausible responses. You can easily locate a list of the most frequent logical fallacies online and check your writing. Once you get your subject, you will need to place your ideas in the appropriate format. Think of original and intriguing ideas. What You Need to Know About Casual Essay Topics Such analysis helps not just to define why something has occurred, but also to understand the character of phenomena and the way to behave in a specific case. When you compose a causal essay, you need to carefully look into the reasons or consequences of a particular event or phenomenon based on this issue. In the instance of a causal analysis essay, your thesis statement must include things like the precise causes and effects you're examining and why. If you're writing about global warming, as an example, you might want to devote a paragraph on each one of the causes identified in your research. The Little-Known Secrets to Casual Essay Topics Television has played a major role in the progression of modern American culture. Parents, students, and the community need to learn more regarding the problem. This form of essay writing is particularly assigned to students at each level. The cost of an essay is dependent upon the quantity of effort the writer has to exert. For a causal analysis essay, the author might decide to illustrate the many different causes of the topic available. Reading cause and effect essay examples can help you produce your own writing. A cause and effect essay is comparable in structure to the majority of other essays, as it requires an introduction, a body, and a conclusion. Make a list of potential topics that you wish to describe in your cause and effect essay. The truth is many a causal argument essay that doesn't produce a definitive answer can still get a great rating. The Chronicles of Casual Essay Topics The review is going to teach you all you will need to understand and then it is possible to place your purchase confidently. If however, it's still true that you doubt your writing skills or just do not have enough to attack the assignment, you don't have to worry! Last, you've got to examine the paper on multiple occasions. In the majority of instances, the info you already have won't be sufficient to compose a detailed, captivating paper, that's the reason you'll be asked to perform research to acquire as much additional information as you are able to. The Lost Secret of Casual Essay Topics You must also explain why and the way the event influenced the circumstance or someone's life. To concentrate on causes, consider why events transpire since they do. Television played a vital part in the battle against racism in the usa. The degree of development of television in america has no analogs on the planet. All the information that are included in knowledge-based television and movies are largely fact-based. It is one of the ways to spend leisure time. Nevertheless, it also has a negative impact on American society. For instance, a paper focusing on effects might include a paragraph about how exercise helps diabetics by boosting muscle mass. To put it differently there are lots of long-term effects which come along with drinking plenty of alcohol for a prolonged period of time. Even though a bright, sunny day can set you in an excellent mood equally as easily as a rainy day can set you in a poor mood, consider that Seasonal Affective Disorder (SAD) is a true disorder that can impact an individual's mood and, in some instances, can cause severe depression. The primary goal of informal essay is pleasure both for the author as well as the audience, even though it doesn't signify you're able to just ramble about one thing unintelligible for a couple a large variety of terms. The sole important point to understand is what the principal goal of such writing is. Based on the circumstance, it's important to select the paragraph style accordingly. Choose one particular tenet of educational philosophy to concentrate on. In the end, it is going to impact a society in a lot of ways that are related to psychological and wellness problems. Social networking supplies a trendy means to stay in contact with new buddies. Nurses will need to supply the very best service in accordance with their wisdom and capacity to attain the very best life and extend the life expectancy in th e society.

The Salem Witch Trials Essay - 1349 Words

Before 1692, the supernatural was a part of people’s everyday normal life. This is so as people strongly believed that Satan was present and active on earth. Men and women in Salem Village believed that all the misfortunes that befell them were the work of the devil. For example, when things like infant death, crop failures or friction among the congregation occurred, people were quick to blame the supernatural. This concept first emerged in Europe around the fifteenth century and then spread to Colonial America. Formerly, peasants heavily relied on particular charms for farming and agriculture. But, over time, white magic transformed into dark magic and it became associated with evil. Even though the people of Salem believed that Satan†¦show more content†¦The residents of Salem Village were desperate for an explanation. If the source of the affliction was not attributable to a physical malady, the community reasoned that it must be the work of Satan and so the finge r pointing toward witchcraft started. Of all the executed, none confessed to the use of witchcraft, as they believed it would condemn their soul. â€Å"Everyone was so frightened that the unlucky prisoners could not hope for a fair trial.† Even though it was not solid evidence, â€Å"the hysterical ravings of the ‘bewitched’ girls were accepted as testimony.† During the later trials where none of the suspects were punished, dispute broke out over whether or not there had ever been any witchcraft in the community in the first place. It is highly possible that Abigail Williams and Ann Putnam could have been falsely creating their accusations and imitating the strange illnesses recorded, and if this were indeed the case it would explain some of their mistakes; such as their failure to identify Mrs. Cary after accusing her by name. â€Å"Twenty people had been executed for witchcraft, while over 100 more lay in prison, their property confiscated, and the n ame of Salem had become a synonym for mindless and cruel persecution.†Show MoreRelatedSalem Witch Trials And The Witch Trial1494 Words   |  6 PagesFirst of all, I wanted to talk about what Salem Witch Trial is and who are the persons involve in this event. Salem Witch Trials, according to Encyclopedia Britannica is â€Å"A series of investigations and persecutions that caused 19 convicted â€Å"witches† to be hanged and many other many suspects to be imprisoned in Salem Village in the Massachusetts Bay Colony.† There are many people involve in Salem Witch Trials and I’ll be going to describe their role in this event, followed by the different case studiesRead MoreSalem Witch Trials And The Witch Trial Essay2225 Words   |  9 Pagesaccused of witchcraft in Salem Village, Massachusetts, many more died in jail, and around 200 people total were accused of witchcraft during the Salem Witch Trials. Records from the event indicate that the Salem Witch Trial s started when a group of young girls began acting strange, claiming they had been possessed by the Devil and bewitched by local villagers. The Salem Witch Trials is a much debated event; historians argue over the motivation and causes behind the trials and executions, not overRead MoreThe Trial Of The Salem Witch Trials905 Words   |  4 PagesI. Introduction In January 1692, when a group of juvenile girls began to display bizarre behavior, the tight-knit Puritan community of Salem, Massachusetts couldn’t explain the unusual afflictions and came to a conclusion. Witches had invaded Salem. This was the beginning of a period of mass hysteria known as The Salem Witch Trials. Hundreds of people were falsely accused of witchcraft and many paid the ultimate price of death. Nineteen people were hung, one was pressed to death, and as many asRead MoreThe Salem Witch Trials691 Words   |  3 Pageswere the Salem Witch Trials? The Trials happened in 1692 in Puritan Massachusetts, in a town called Salem. Nineteen men and women were hanged on grounds of practicing dark magic and making a pact with Satan (in other words, for being witches). Hundreds of people were imprisoned; several died there. Additionally, one man (of over seventy years!) was crushed to death with heavy stones and the lives of many were irrevocably changed. (Salem Witch Museum) IQ #2- How and why did the Salem WitchRead MoreThe Salem Witch Trials1202 Words   |  5 PagesThe Salem Witch Trials were a prime part of American history during the early 17th century. During this time, religion was the prime focus and way of life within colonies. This was especially true for the Puritan way of life. Puritans first came to America in hopes of practicing Christianity their own way, to the purest form. The Puritans were fundamentalists who believed every word transcribed in the Bible by God was to be followed exactly for what it was. The idea of the devil controlling a womanRead MoreThe Trials Of The Salem Witch Trials1866 Words   |  8 Pagessurrounding the cause of the Salem Witch Trials 1692 makes the topic captivating as many historian perspectives offer explanations for the causation of the trials, yet the personal context of each historian has determined its historic reliability. This questions the level of objectivity each historian has in their responses to the Trials. The aims and purposes of a historian, as well as their differing methodologies may alter the approach the have towards the investigation of the Trials. Many interpretationsRead MoreThe Trials Of Salem Witch Trials Essay1267 Words   |  6 PagesThe notorious witch trials in Salem began in Spring of 1692. This started after a young group of girls in Salem Village, Massachusetts, professed they were possessed by the devil. These young girls even went as far as accusing some local women of practicing witchcraft. As a frenzy spreaded throughout colonial Massachusetts, a specific court was summoned to hear cases. Bridget Bishop was the first convicted witch and she was hung in that June following her trial. Eighteen other people followed BishopRead MoreThe Trials Of Salem Witch Trials1069 Words   |  5 PagesEven though the Salem witch trials were made to seem formal, they were actually subjective and not based on fact. Since there were multiple people being accused of witchcraft, the trials were short and quick to sentence. The witch trials lasted less than a year. The first arrests were made on March 1, 1692, and the final hanging day was September 22, 1692. The Court of Oyer and Terminer was dissolved in October of 1692. The Salem Witch Trials occurred in the spring of 1692, when a groupRead MoreThe Trials Of The Salem Witch Trials1635 Words   |  7 Pagesovercome was the Salem Witch Trials. The Salem Witch Trials occurred in 1692 and 1693 in colonial Massachusetts. â€Å"More than 200 people were accused of practicing witchcraft – the Devil’s magic – and 20 were executed† as detailed by Jess Blumberg on the web article A Brief History of the Salem Witch Trials (Blumberg 2007). The trials had a major impact on the American society and the effects could be seen in colonial America as well as today. Why did the injustice of the Salam Witch Trials occur and whyRead MoreThe Trials Of The Salem Witch Trials2197 Words   |  9 Pagesestablish colonies based on the word of God. Salem, like many other towns at the time, had little distinction between church and state and focused all aspects of their society on God. (Roach) Due to these conditions, Salem became the site of the largest and most violent witch hunts in America. The significance of the trials comes from the large impact they had on American law. The conditions before, during, and after the Salem Trials were unlike the witch hunts in any other colonies in the New World