Week 3 (Jason Chang)


After returning to work after the July 4 holiday, I attended morning rounds on Wednesday and Thursday. Over the last two weeks, I made a list of commonly used terms, medications, and conditions, which has made rounds easier to follow. Dr. Mangat, who was the attending on call this week, taught me a few basics on interpreting head CT scans. Using CT scans from the patients in the Neuroscience ICU, Dr. Mangat pointed out how acute subdural bleeds (i.e. fresh blood) appear as hyperdense (white and bright) masses over the cortical surface of the brain, while chronic subdural bleeds (i.e. old blood) are hypodense (dark). Additionally, Dr. Mangat showed how to measure a midline shift, which is a deviation of the brain past its center line, and how to identify abnormalities in the brainstem. From CT alone, clinicians can make conclusions regarding impairments to the patient’s consciousness, cognitive function, and determine whether brain swelling, stroke, or trauma has occurred.

Interestingly, I learned that brain hemorrhage can be brought on by non-traumatic factors, such as hypertension or vascular malformation in the brain. For example, a young adult was admitted to the Neuroscience ICU after experiencing a hemorrhage brought on by strenuous exercise. The patient was diagnosed with a brain arteriovenous malformation (AVM), an abnormal tangle of weakened blood vessels that is prone to rupturing with pressure or damage to the vessels (Figure 1). I did not get to hear the cause of the bleed, but I suspect that the patient’s high-intensity activity could have elevated their blood pressure, ultimately causing their AVM to rupture. Brain AVMs occur in less than 1% of people, so it was especially interesting to observe this case. An angiogram was ordered to get an x-ray photograph of the patient’s blood vessels before proceeding with a prognosis.



Figure 1. Brain arteriovenous malformation (AVM) [1]

Last week, Dr. Forgács suggested analyzing the electrode channels in a specific brain area to minimize the different types of artifacts that could arise from sources other than the brain. Fortunately, the EEG data for my research project was collected using the 10-20 International System of Electrode Placement (10-20 system; Figure 2), an internationally recognized method for the placement of EEG electrodes on the scalp to ensure standardized reproducibility and interpretable records of EEG experiments. On Monday, Dr. Mangat and I decided that I could start by analyzing a few of the frontal and parietal electrode channels.  

Figure 2. 10-20 system for the placement of EEG electrodes [2] 

In addition to reading about EEG technology and subarachnoid hemorrhage (SAH), I have been reading literature on signals processing techniques, specifically on computational methods that have previously been used to remove artifacts in EEG signals. I am worried that the programming and signals processing knowledge required for my project may be too high-level and extremely challenging with only a month left. However, Dr. Min and Dr. Prince suggested trying to breakdown my project into smaller, achievable tasks, so I am determined to keep trying. 

WCMC has cleared me for my clinical observership under Dr. Dean Lorich, Chief of Orthopaedic Trauma at NYP, so I hope to start observing orthopaedic surgery procedures next week. Next week, I also plan to start testing an open source artifact rejection toolbox in MATLAB using the EEG data from the SAH study.

References
[1] https://www.mayfieldclinic.com/Images/PE-AVM_Figure1a.jpg
[2] L. V. Marcuse, M. C. Fields, and J. Y. Y. Yoo, “Origin and technical aspects of the EEG,” in Rowan’s Primer of EEG, 2nd ed. Elsevier, 2016, ch. 1, pp. 3. 

Comments

Post a Comment

Popular posts from this blog

Week7

With the end of our summer immersion approaching, I feel sad to say goodbye to all the persons I've met in the hospital during this summer. The past 7 weeks has been very fulfilling and exciting to me, and I will never forget my experience here. As a student will electrical engineering background, I never thought that I can be able to go to a real operation room in the hospital and observe doctors operating on surgeries. But in the past 7 weeks, I was able to go to OR every week, and there's always surgery techniques that are impressing to me. Beside clinical experience, I also had a research project, automatic segmentation of zebra fish neuron images. As I have presented in my previous bloggers, for my project, I have tried several different algorithms. The first is simple thresholding. It is usually used as a preprocessing step in image analysis. The second method is watershed algorithm. It works pretty well, but, it's very sensitive to noise, resulting in over segmenta...
Read more

Week 5: Prostates & Autopsies

Image
This was a fun and interesting week! The prostate biopsy chip slides from last week were evaluated, and more testing was done. On Wednesday and Thursday, two people from the company were here to do some trials with the new chips. This time, real prostate biopsies were taken, and sections were used to evaluate the quality of the tissue. Each chip holds up to 6 biopsies inside the little grooves. The color of the dividers (blue, yellow, and black) orient each sample to distinguish where in the prostate each biopsy came from. It also allows six biopsy cores to be placed on one slide which saves space and resources [1]: Instead of all 12 of the slides on the left (although that is a little excessive), you just need two with the BxChip. It also seems to keep the cores flat and aligned. This is what a magnified core might look like [2]: The tissue fits right inside the little grooves (although it can be slightly difficult to get them in there), and then the whole chip can be ...
Read more

Week 5: Spine Surgeries and Excel Files

Image
On the context of my clinical research project, I continue extracting the different demographic and skeletal specific factors for the patients of our study. I was also able to attend an additional spinal fusion surgery under the supervision of Dr. Kim at HSS. During this week, I was particularly interested in the surgical equipment that he uses for the procedure. Dr. Kim uses the Zimmer Biomet Vitality Spinal Fixation System for his spine surgeries. The components of the system are made from medical grade titanium alloy and medical grade cobalt chromium alloy. In summary, these were the main steps of the process for installing the screws into the patient spine which, personally, was the most interesting part of the procedure.  Initially, the pedicle area of the vertebrae is localized, and an insertion is made in the cortical shell. Then, a probe, included with the system, creates a pathway for the polyaxial pedicle screw to be inserted into the pedicle and the vertebral body. ...
Read more