Inexpensive models
for teaching
imaging anatomy
From CT to 3D for
under $100
Raul Arya, MD
Trevor Morrison, MD
Ann Zumwalt, PhD
Kitt Shaffer, MD PhD
topics
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Overview Radiologic Anatomy labs
Rationale for developing models
Materials list/technique
Examples
Future directions
Radiologic Anatomy labs
• Human Anatomy—gen taught in 1st year of
medical school, many allied health courses
• Students benefit from refreshers later in
training
• Radiology at BU is a required 3rd/4th year
course, depends on anatomic knowledge
• Special 2 hour lab sessions were developed to
tie principles from 1st year to clinical setting
Anatomy and Radiology in the curriculum
Year 1
Year 2
Year 4
Year 3
Radiology
Anatomy
basic sciences
clinical rotations
great opportunity
to return to anatomic
concepts, reinforce
principles
Basic lab design
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2 hour session in 2nd week of 4-week course
About 20-25 students per group
Students count-off into 4 groups
Students rotate among 4 stations during the
session, about 20 min per station
in the lab
Typical stations
• Model building (the opposite of dissection)
– Construct a complex part of the body from simple
parts
• Poster demonstrating typical imaging of the
body area, structures to identify
• Computer station showing video clips and
labeled images of body area
• Ultrasound station where students can scan
each other or models
stations
Station 1:
poster
Station 2:
building models
stations
Station 3:
computer
Station 4:
ultrasound
Initial models
• Using relatively inexpensive plastic skeletons
• Building muscles, organs from inexpensive
materials
– Foam
– Duct tape
– Plastic tubing
– Electrical wire
• Fastened to skeleton with velcro
model example
Some body areas are too complex
and small for this method
• Life-size skeletons limit models of some areas
– Pelvis
– Heart
– Brain
– Knee
– Inner ear
Can we start from CT to build
a larger model?
Materials list
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Art foam board ($15 for 2 sheets, ½ inch)
Wood glue ($6 for 16 oz)
Rubber cement ($3 for 4 oz)
Hand saw ($15)
Acrylic paint (interior white $20/gal, colored with
artists paint, basic colors $12)
• Wood or dry wall screws ($10)
• Heavy duty Velcro fasteners ($15)
• Wood dowels ($3, depending on diameter)
Total: $99
Materials
Software
• Osirix
– free clinical imaging software for Mac
– allows manipulation of CT or MR data
– can do measurements, change slice thickness
– export images into JPG format
• Photoshop
– NOT free (but Elements version is good enough,
$100 at OfficeMax)
– allows overlay of grid, numbers, resizing, printing
Technique-1
• Decide how large you want your model (width)
• Using Osirix, measure the actual width and height
of original object
• Calculate the desired height of your model, and
how many ½ inch foam board slices you will need
to get that height (could use thicker foam board)
• Using Osirix, generate a set of the desired
number of image slices by changing thickness
Getting the proportions right
enlarged JPG image
original CT image
11 inches
actual size: 13 cm tall, 10 cm wide
desired model size: 14 in tall, 11 in wide
=28 slices (if using 1/2 inch thick foam)
Use Osirix to generate 28 slices at 0.5 cm thickness
Technique-2
• Export the images from Osirix to an image
processing program like Photoshop
• Enlarge the images to the actual desired size
of your model
• For complex shapes, it may be helpful to draw
a colored grid on the images to help with
alignment when building the model
• Print the images actual size (may need to tape
together if larger than standard paper)
Printing the images
original CT image, exported from Osirix as JPG
(slice 3 of 28 total)
Printing the images
typical slice from the cardiac model
(note: flipped right/left so images can be stacked from
ABOVE rather than BELOW)
enlarged using Photoshop to desired size of final model
Printing the images
colored grid
to help in
alignment
slice number
to help in keeping
track of cutout
pieces and order of
stacking
slice 3 of 28
colored outline
of where to cut
(helpful for very
complex shapes)
Printing the images
tape the printed images together
Technique-3
• Glue the printed images onto the foam board
with rubber cement
• Use the hand saw to cut out the desired
structures
• Glue each layer on the BOTTOM of the previous
layer using wood glue (align the grid if you
included it on the images)
• If you flip R/L, then you can glue each with the
image on the TOP (which is a bit easier)
• Remove the paper after each layer is in place
Working with foam board
cut out the relevant areas
Working with foam board
apply rubber cement to back of paper
Working with foam board
glue printed image to foam board
Working with foam board
cut out pieces with hand saw
Working with foam board
glue slices on top of each other and remove paper
(this model has been painted)
Technique-4
• If desired, paint with acrylic paint
• Attach velcro to assembly points, reinforcing
with screws
• If needed, drill holes to insert wooden dowels
for more support, attaching with wood glue
Final touches
dowels
velcro
Total time for pelvis model
• ~2 hours to figure out proportions, print
images and tape together
• ~2 hours to cut out pieces
• ~1 hours to assemble pieces (in stages, letting
them dry between)
• 1 hour to paint
• 1 hour to add reinforcements
total: 7 hours
Total time for heart model
• ~2 hours to figure out proportions, print
images and tape together
• ~3 hours to cut out pieces
• ~2 hours to assemble pieces (in stages, letting
them dry between)
• 1 hour to paint
• 1 hour to add reinforcements
total: 9 hours
If you can get the images,
you can make the model
• Sources of images
– CT
– MR
– Actual tissue sections, photographed
Future directions
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Huge knee
Inner ear
Base of skull
Big wrist
Questions
Website
• www.shafferseminars.net
• Any further questions:
– kitt.shaffer@bmc.org
References
• Lufler RS, Zumwalt AC, Romney CA, Hoagland TM. Anat Sci Educ. 2012
Jan;5(1):3-9. Effect of visual-spatial ability on medical students’
performance in a gross anatomy course.
• Zumwalt AC, Lufler RS, Monteiro J, Shaffer K. Anat Sci Educ. 2010 MayJun;3(3):134-40. Building the body: active learning laboratories that
emphasize practical aspects of anatomy and integration with radiology.
• Griksaitis MJ, Sawdon MA, Finn GM. Anat Sci Educ. 2012 Jan;5(1):20-6.
Ultrasound and cadaveric prosections as methods for teaching cardiac
anatomy: A comparative study.
• Ivanusic J, Cowie B, Barrington M. Anat Sci Educ. 2010 Nov-Dec;3(6):31822. Undergraduate student perceptions of the use of ultrasonography in
the study of "living anatomy".
• Shaffer K, Small JE. Acad Radiol. 2004;11(9):1059-70. Blended learning in
medical education: use of an integrated approach with web-based small
group modules and didactic instruction for teaching radiologic anatomy.