Analysis of White Matter Tracts in Relation to Tumor Growth using Diffusion Tensor Imaging

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Analysis of White Matter Tracts in Relation to
Tumor Growth using Diffusion Tensor Imaging

• Nelson Chuang,
• Michael Schlosser M.D.,
• Susumu Mori Ph.D.

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Epidemiology

• 35,000 adult Americans each year
• More adults die of primary brain tumors than
  Hodgkins disease or Multiple Sclerosis
• Malignant gliomas are third leading (2.5) cause
  of death from cancer (15-34 yrs)
• Little is known of etiology-maybe cranial
  irradiation and exposure to chemicals

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Tumor Background

• Gliomas
• Astrocytomas
• Oligodendrogliomas
• Meningiomas
• Classified in grades (I,II,III, )
• Many other brain tumors

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Gliomas - Astrocytomas

• Astrocytomas (II,III,IV)
• Grade II (low grade) are more benign and
  infiltrating
• Grade III has malignant features
• Grade IV (glioblastoma multiform, GBM) have a
  central mass with infiltration around the mass

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Gliomas - Oligodendrogliomas

• Oligodendrogliomas (II,III)
• Grade II low grade
• Grade III more malignant

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Patient 1 - GBM
FLAIR
GAD
T2
DTI
Mike Schlosser 2005
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Patient 2 Astrocytoma (Gr.II)
MPRAGE
T2
DTI
Mike Schlosser 2005
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Patient 3 Astrocytoma (Gr.III)
T2
MPRAGE
DTI
Mike Schlosser 2005
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Patient 4 Unknown Glioma
GAD
MPRAGE
T2
DTI
Mike Schlosser 2005
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Meningiomas

• Tumors of meninges
• Arises in the arachnoid
• Outside CNS, but can push into brain
• Cells do not invade the brain

Mayo Clinic 2005
http//www.neuropat.dote.hu/meningeo.htm
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Current Surgical Methods

• Cautery
• Ultrasonic aspiration
• Blunt dissection

http//www.chclibrary.org/micromed/00044260.html
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Cautery

• Bipolar forceps with a cauterizing tip
• Monopolar cautery
• Suction away

Scanlan International 2005
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Ultrasonic Aspiration

• Vibrating tip (50,000hz)
• Suction away
• Less bleeding

Radionics 2005
36kHz
23kHz
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Diffusion Tensor Imaging

• Utilizes random water movement inside the brain
• Measure diffusion constant along 30 different
  axes
• Calculate tensor and determine diffusion
  directionality (FA)
• Fiber direction estimated from the first
  eigenvector of the tensor

Susumu Mori 2005
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3D Fiber Tracking
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Specific Aims

• Perform 2D and 3D image processing of white
  matter tracts around the tumor mass
• Characterize the ways tumors deform or infiltrate
  adjacent fiber tracts
• If the tumor is an infiltrating type, determine
  if it grows along the fiber tracts
• Determine surgical significance of data
• Implement into computer assisted navigation
  systems for preoperative planning

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Project Deliverables
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Timeline

• Weekly meetings with Professor Mori on Thursdays
  at 5pm
• Meetings with Dr. Schlosser by appointment
  tentatively

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Dependencies

• Minimum Expectations
• Availability of workstations
• Medium Expectations
• Reproducibility of the categorized results
• Patient availability and scheduling
• Maximum Expectations
• Financial backing from chosen company

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Budget

• Minimum Expectations
• DTI software and workstations will be provided
  by Susumu Mori
• Medium Expectations
• If more patient scans are required Susumu Mori
  will pay for it
• Maximum Expectations
• Medical imaging companies, i.e. Medtronic

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Project Extensions

• Integration of DTI fiber tract maps into
  StealthStation or other computer assisted
  navigation systems
• Assist surgical planning pre-op and procedure
  during intra-op

Medtronic 2005
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References

• Yasargil, M.G. (1994) Microneurosurgery. Volume
  IVA. Stuttgart, New York.
• Mori, Susumu. Imaging White Matter Architecture
  and its Relationship to Tumor Growth using
  Diffusion Tensor Imaging. 2002.
• Schlosser, Michael. Interview. 2/20/05.