Greetings lovely readers!
My second week of this research project has been mostly doing some more background reading (and aggressively ladeling chicken tortilla soup in the cafeteria on Wednesdays because it's always in high demand and low supply). These medical papers are difficult to understand, and I've started keeping a vocab list that I will publish in a page soon on this blog. Perhaps the most infuriating thing about doing background research is how almost every paper costs a good $60, and I am limited to reading abstracts or going on hour long google hunts for a pdf copy of these medical journals. After going through a few research papers, they have all started to blend in with each other so I have decided to break up the main topics of my project into separate blog posts so I can elaborate more on each issue.
Anyways, in this post I will talk about brain shifts in the context of interventional MRI (iMRI).
How much a brain will shift when the patient undergoes minimally invasive DBS surgery via burr hole? When the operation begins, the dura is opened and cerebral spinal fluid is lost and pneumocephaluses (an extremely fancy word for air bubbles in the cranial cavity) develop. Combined, these two can cause brain shift.
My second week of this research project has been mostly doing some more background reading (and aggressively ladeling chicken tortilla soup in the cafeteria on Wednesdays because it's always in high demand and low supply). These medical papers are difficult to understand, and I've started keeping a vocab list that I will publish in a page soon on this blog. Perhaps the most infuriating thing about doing background research is how almost every paper costs a good $60, and I am limited to reading abstracts or going on hour long google hunts for a pdf copy of these medical journals. After going through a few research papers, they have all started to blend in with each other so I have decided to break up the main topics of my project into separate blog posts so I can elaborate more on each issue.
Anyways, in this post I will talk about brain shifts in the context of interventional MRI (iMRI).
How much a brain will shift when the patient undergoes minimally invasive DBS surgery via burr hole? When the operation begins, the dura is opened and cerebral spinal fluid is lost and pneumocephaluses (an extremely fancy word for air bubbles in the cranial cavity) develop. Combined, these two can cause brain shift.
The paper identifies the main area of brain shift to be the frontal lobe (areas associated with planning, judgement, higher thinking, etc.), followed by the temporal (hearing, language processing, and memory) and occipital lobe (visual processing). Fun fact, in Latin, occiput means back of the head, which is where the occipital lobe is conveniently located.
AP Psych refresher: here is a picture of the lobes of the brain!
AP Psych refresher: here is a picture of the lobes of the brain!
There was also some shift observed in the deeper brain structures such as the anterior and posterior commissures and the basal ganglia. In total, the brain shift across all structures ranged from 0.0mm to 10.1mm, with the average brain shift being 0.7mm. Those may seem like small numbers, but neurosurgery is all about precision.
As you can imagine, the brain shifting and moving around (although not that much) poses a serious problem for the surgeon who is trying to insert an electrode into a very specific region of the brain while navigating around vital control/sensory regions. It's like trying to thread a needle in the middle of an elephant dance party. There have been a few studies done on this topic, yet there is no consensus on how to predict brain shift and how significant the impact of brain shift is on the outcome of the surgery. Some believe that the brain shift is due to gravity, and some believe that gravity plays no role in brain shifting and there is no accurate method to predict it. One report discovered that the deep brain structures can shift up to 4mm* during the operation and structures on the surface can shift up to 10mm.**
Brain shift can be measured through iMRI, ultrasonography, and iCT, but the iMRI is the only machine sensitive enough to capture HD images of the deep brain structures that are often targeted during these electrode placement procedures.
There are many technical details I need to familiarize myself with before I can fully immerse myself into this project. Part 2 on brain shifts should be coming soon, so please stay tuned!
Until then,
Holly
Main article:Brain shift during bur hole–based procedures using interventional MRI
*Hata N, Nabavi A, Wells WM III, Warfield SK, Kikinis R, Black PM, et al: Three-dimensional optical flow method for measurement of volumetric brain deformation from intraopera- tive MR images. J Comput Assist Tomogr 24:531–538, 2000
**Hill DL, Maurer CR Jr, Maciunas RJ, Barwise JA, Fitzpatrick JM, Wang MY: Measurement of intraoperative brain surface deformation under a craniotomy. Neurosurgery 43:514–528, 1998
Image source: http://www.riversideonline.com/health_reference/nervous-system/ds00810.cfm
As you can imagine, the brain shifting and moving around (although not that much) poses a serious problem for the surgeon who is trying to insert an electrode into a very specific region of the brain while navigating around vital control/sensory regions. It's like trying to thread a needle in the middle of an elephant dance party. There have been a few studies done on this topic, yet there is no consensus on how to predict brain shift and how significant the impact of brain shift is on the outcome of the surgery. Some believe that the brain shift is due to gravity, and some believe that gravity plays no role in brain shifting and there is no accurate method to predict it. One report discovered that the deep brain structures can shift up to 4mm* during the operation and structures on the surface can shift up to 10mm.**
Brain shift can be measured through iMRI, ultrasonography, and iCT, but the iMRI is the only machine sensitive enough to capture HD images of the deep brain structures that are often targeted during these electrode placement procedures.
There are many technical details I need to familiarize myself with before I can fully immerse myself into this project. Part 2 on brain shifts should be coming soon, so please stay tuned!
Until then,
Holly
Main article:Brain shift during bur hole–based procedures using interventional MRI
Michael e. ivan, M.D.,1 Jay yarlagaDDa, M.D.,2 akriti P. Saxena, M.D.,3
alaStair J. Martin, Ph.D.,4 PhiliP a. Starr, M.D., Ph.D.,1 W. keith SootSMan, r.t., anD Paul S. larSon, M.D.1
alaStair J. Martin, Ph.D.,4 PhiliP a. Starr, M.D., Ph.D.,1 W. keith SootSMan, r.t., anD Paul S. larSon, M.D.1
*Hata N, Nabavi A, Wells WM III, Warfield SK, Kikinis R, Black PM, et al: Three-dimensional optical flow method for measurement of volumetric brain deformation from intraopera- tive MR images. J Comput Assist Tomogr 24:531–538, 2000
**Hill DL, Maurer CR Jr, Maciunas RJ, Barwise JA, Fitzpatrick JM, Wang MY: Measurement of intraoperative brain surface deformation under a craniotomy. Neurosurgery 43:514–528, 1998
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