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 Overview Radiologic Anatomy labs Rationale for developing models Materials list/technique Examples Future directions

Radiologic Anatomy labs Human Anatomy—gen taught in 1 st year of medical school, many allied health courses Students benefit from refreshers later in training Radiology at BU is a required 3 rd /4 th year course, depends on anatomic knowledge Special 2 hour lab sessions were developed to tie principles from 1 st year to clinical setting

Anatomy and Radiology in the curriculum Year 1 Year 2 Year 3 Year 4 Anatomy Radiology basic sciencesclinical rotations great opportunity to return to anatomic concepts, reinforce principles

Basic lab design 2 hour session in 2 nd week of 4-week course About 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 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 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) 11 inches enlarged JPG image original CT image 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 slice 3 of 28 colored grid to help in alignment slice number to help in keeping track of cutout pieces and order of stacking 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 velcro dowels

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 Huge knee Inner ear Base of skull Big wrist

Questions

Website Any further questions: –

References Lufler RS, Zumwalt AC, Romney CA, Hoagland TM. Anat Sci Educ 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 May- Jun;3(3): 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 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 Nov-Dec;3(6): Undergraduate student perceptions of the use of ultrasonography in the study of "living anatomy". Shaffer K, Small JE. Acad Radiol. 2004;11(9): Blended learning in medical education: use of an integrated approach with web-based small group modules and didactic instruction for teaching radiologic anatomy.