Title: CSF Flow Model

Names

Tim Eng – Team Leader

Lauren Hensley – BSAC

Mary Lim – BWIG

April Zehm – Communicator

Client

Victor Haughton, M.D.

UW Dept. of Radiology
Phone: 263-5306
email:

Date: 4/13/04 – 4/19/04

Problem Statement

The goal of this project is to create a life-size physical model of the human hindbrain and upper cervical spinal canal. This will be used to study how varying dimensions affect cerebrospinal fluid flow (CSF flow) in terms of velocity and pressure. Oscillatory flow is required in the model, and pressure must be quantifiable.

Last Week’s Goals

  • Meet with Dr. Haughton on Wednesday, April 14 to trace the shape of the spinal canal on each block.
  • Based on a given range for the pressure within the spinal canal, calculate the necessary diameter and length for the pressure-measuring tubes.
  • Search for either glass or hard plastic tubes of the specified diameter and length.
  • Obtain threaded rods (preferably plastic) that will be used for alignment.

This Week’s Goals

  • Meet on Wednesday, April 21 to trace the simplified shapes (circles of varying diameters) onto the blocks. Grooves will be cut into the blocks to accommodate the threaded rods, which will allow alignment.
  • If we are unable to cut the shapes out of the blocks, they will at least be prepared for a shop person Dr. Haughton knows.
  • Drill a hole in the first block in order to fit the pressure-measuring tube.
  • Fix the pump connectors to the two end blocks.
  • Start final poster presentation preparation.

Summary of Accomplishments

  • We met with Dr. Haughton on Wednesday, April 14 to discuss modeling the medulla oblongata and spinal cord. First, we talked about using a solid piece that would be inserted into the canal. This idea limits the interchangeability of the blocks. We then decided to leave a small sliver of plastic connecting the “medulla oblongata” or “spinal cord” to the remainder of the block.
  • During class, we met with Dr. Haughton at the hospital, and he traced the shapes that would eventually need to be cut from the blocks.
  • We met on Saturday, April 17 at ECB to determine and execute a procedure for copying the shapes (from the MRI images given by Dr. Haughton) onto blank sheets of paper for the shop guys to use in cutting the blocks.
  • We had to make sure there was a consistent reference point for each image and that each copied shape was correctly oriented on the blank sheet of paper.
  • Once the image was positioned, we used carbon paper to reproduce it.

Difficulties

  • We discovered from Jeff Hoerning in the ME shop that they charge $55/hour and estimate that cutting the first block would require 3-4 hours. This is financially restricting, since we have 20 blocks to be cut.
  • Some of the images are too large to fit onto the blocks. This is a problem we didn’t think would arise as calculations for block size were based on preliminary size estimations for the images.
  • As the end of the semester approaches, we realize that a highly accurate model is unfeasible due to both budget and time constraints. We proposed a greatly simplified prototype, employing circular shapes, to be completed by the final poster presentation. This was approved by our client, Dr. Haughton.

Activities

Team: 5 hours – Met during class with Dr. Haughton to trace the required shapes on the MRI images, met on Saturday, April 17 to copy these shapes onto blank sheets of paper

Tim Eng: 1.5 hours – Went to buy carbon paper, wrote progress report

Lauren Hensley: 1 hour – Talked to Jeff Hoerning to get a cost estimate for cutting the blocks, went to hardware store to purchase threaded rods, wing nuts, and adhesive.

Mary Lim: 2.5 hours – Went with Lauren to talk to Jeff Hoerning, e-mail correspondence, updated notebook and website

April Zehm: 2 hours – E-mail correspondence, discussed tracing and cutting options with Prof. Williams, talked with the shop guys about the feasibility of cutting the intricate shapes.

Total time this week: 12 hours

Cumulative time: 142.75 hours

Project Schedule

Task / January / February / March / April / May
20 / 27 / 3 / 10 / 17 / 24 / 2 / 9 / 16 / 23 / 30 / 6 / 13 / 20 / 27 / 4 / 11
Deliverables
Progress Reports
Mid-semester Presentation
Preliminary Design Report
Final Poster Presentation
Final Report
Meetings
Client
Final Meeting with Advisor
BSAC
Research
Chiari I Malformation
CSF Flow
Current Patents
Design
Brainstorming
Decide on Final Design
Drawings
Prototype
Order Parts/Materials
Machine Parts
Assemble
Test
Website

Team Tim Eng Lauren Hensley Mary Lim April Zehm

Expenses

Date / Item / Cost / Comments
4/6/04 / Polycarbonate sheet / $25.26 / 12” x 24”x 3/8” (From McMaster-Carr)