Post-Defense Interview: Ashley Ulm

A research project or thesis exploring a question related to the field of biomedical visualization is one aspect of completing a Masters in Biomedical Visualization here at UIC. This original investigation enables greater insight into scholarship, understanding of the research process, and emphasizes original and critical thinking. Graduate students complete a written proposal, final research or thesis paper, give a final oral presentation and defense which all enable a student to develop advanced communication skills. This year, we are sitting down with our graduate students after their final defense for a quick chat about them and their research.

This past week, Ashley Ulm defended her project: “Visualizing the attachments and internal architecture of the masseter muscle in Cavia porcellus using contrast enhanced micro-CT


Ashley Ulm

Taking a page from, how would you describe your research in one sentence?

I spent a year meticulously dissecting one muscle on a guinea pig . . . surprise! it chews.

Although quite cute critters, why a guinea pig? and why this muscle?

Guinea pigs belong to a specific group of rodents that have a unique set of masticatory muscles, or the muscles used to gnaw and chew. The ZM is the muscle that really makes this group of rodents unique, in that it passes through a hole in the skull called the infraorbital foramen and inserts on the snout. This means that it crosses over bone, which allows it to act like a pulley system when the muscle contracts. Dr. Druzinsky plans to study the biomechanics of this pulley system using the models generated in this study.

Where did your research-project come from?

Dr. Druzinsky is a faculty member of the University of Illinois at Chicago College of Dentistry. He had access to contrast-enhanced micro-CT (CE micro-CT) scans of a guinea pig, and thought that the extreme detail shown in this new type of CT scan could be utilized somehow. He reached out to the Biomedical Visualization department to find someone to help him visualize the data, and I was eager to work with him.

Can you talk a little bit more about these new CT scans? How are they being used currently? Where do you think they will go in the future?

These CT scans are called contrast-enhanced because the specimen that is scanned is first soaked in an iodine solution that penetrates the muscle fascicles but not the connective tissue between them. In traditional CT scans, bone shows up white and everything else is black. The iodine solution causes details in the soft tissue, such as the muscle fascicles, to show up as white more like the bone. This means that you can see a lot of detail in the soft tissue that traditional CT scans do not show.

This process is still fairly new, and many studies such as this one are investigating how to best utilize the information written in these scans. I am interested to see what scientists will do once they have access to 3D models of this detail that they can interact with.

Can you give us an overview of the workflow in creating your research project?

I used the CE micro-CT scans from Dr. Druzinsky and the Materialise Mimics Innovation Suite® to segment the zygomaticomandibularis portion of the guinea pig masseter muscle. This muscle starts along the snout then travels down through the skull to connect to the lower jaw. I first found the whole muscle, then segmented out each muscle fascicle, which was visible in the CE micro-CT scans. I aligned the muscle with a 3D model of the guinea pig skull. Then I embedded the models into a 3D interactive PDF. Inside here, you can rotate and pan the model, change color and transparency of the models, and toggle on and off a slice plane. This helps to view the anatomy spatially and in cross-section.

What insights have you gained from studying this technique? And do you have any advice to other visualizers looking into this methodology?

It is well established that different muscle architectures exist, such as unipennate and multipennate. The ZM is multipennate, meaning that the muscle fascicles are arranged in several directions in relation to the line of action of the muscle. Knowing this, and having the ability to interact with a 3D model of this data will help artists to think a bit more critically about muscles as they draw them. Since form begets function, knowing the muscle architecture and knowing that the fascicles that make up a muscle do not run the entire length of each muscle will help inform both 2D and 3D representations.

You recently attended the Experimental Biology conference in Chicago and met with professionals in other fields such as paleontology using this technique. What did you learn from them?

In speaking with attendees of the EB conference, I learned that this contrast technique is reversible, so it can be used on museum specimens in order to avoid dissecting rare or precious samples, and then it can be reversed and the specimen can be restored to the museum intact.

I also discovered that contrast enhanced CT scans are being used to scan “animals of today,” such as horses and rodents, and then the information harvested from the scans is used to map origins, insertions, and muscle architecture to fossilized bones. This may lead to advances in understanding dinosaurs and other prehistoric creatures.

What have you learned from the process of completing your Masters of Science?

I became very familiar with the Mimics software. With this, I learned how to re-slice image data, explored interpolation, and did extensive mask editing in 2D and 3D. I went from looking at the CE micro-CT scans in bewilderment to confidently differentiating between soft tissue structures within the image data. Finally, I got to practice low poly modeling with a high poly look to optimize my models for the 3D PDF environment.

In the BVIS program, I’ve grown as both a scientist and an artist while honing my attention to detail and critical thinking skills. I cannot wait to use this skill set to inspire learning, appreciation, and advancement of the sciences. I have had opportunities to work with people in fields such as neurosurgery, plastic surgery, evolutionary biology, nursing, and the talented BVIS faculty. These collaborations have formed a unique, once-in-a-lifetime experience that I will use as the foundation for my career as a medical artist.

Who/what are your inspirations and influences when it comes to artistic style and choices?

Since I have started graduate school, I have tried out many different styles and been influenced by many artists, especially the artists I am surrounded by daily — my teachers and fellow students. In many of our classes we have been encouraged to find inspiration in the world outside of medical illustration. I think taking inspiration from daily life, interactions, and art is something many artists do intrinsically, and because of this, are constantly growing and changing.

What are your plans for after you graduate?

I got engaged over spring break! So I am moving to Portland, Maine to be with my fiance and begin my job search. I plan to work in the healthcare industry and make 2D and 3D images and short animations for patient education and empowerment.


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