Published August 10, 2017
Department of Pathology and Anatomical Sciences researchers are studying ways to develop a hybrid gross anatomy curriculum that fuses digitized CT scans with actual cadaveric dissection.
Gross anatomy programs are expensive and extremely resource-intensive, requiring a lot of infrastructure to set up and operate.
The Jacobs School of Medicine and Biomedical Sciences is fortunate to have a productive and generous Anatomical Gift Program, but many institutions do not have the necessary resources and are looking at replacing their cadaver programs with an entire digital way of learning — using standard CT data sets or downloads from the Internet as a way of learning human gross anatomy.
“Students benefit from a tactile and kinesthetic mode of learning,” says Scott T. Doyle, PhD, assistant professor of pathology and anatomical sciences. “Dissection, the process of learning through doing, is really important and we think it’s critical for students to learn that while they are going through their training.”
The amount of raw data that digital scans provide can be used to build upon the inherent value that exists in cadaveric dissection, he says.
Doyle and Stuart D. Inglis, PhD, instructor of pathology and anatomical sciences, are co-principal investigators on a 2017 Seed Grant for Promoting Pedagogical Innovation through the Center for Education Innovation, that will study the best ways to integrate the data from CT scans into a gross anatomy curriculum.
The medical school receives about 600 donations a year through its anatomical donation gifts program, and initiated a CT scan project in 2014 in order to create a database.
Raymond P. Dannenhoffer, PhD, director of the anatomical gift program, felt that high-resolution scans of some of the cadavers coming through the gross anatomy program would be useful for teaching students not only about the human form, but also about human variation.
“That often doesn’t come through if you are using a classic textbook example because in that instance you get one example of what the human form is like and you don’t really get an appreciation for all the things you might see in clinical practice or the real world,” Doyle says.
As part of their gross anatomy lab, medical students are given CT scans on USB drives to refer back to throughout the course.
Inglis notes there are several advantages to using CT scans in a gross anatomy setting.
“Being able to look at scans prior to dissection, students can identify some interesting pathologies,” he says. “They can see kidney stones, pacemaker units or joint replacements. When they are about to dissect, it gives them a better perspective on what they are about to find.”
Inglis says it also allows students to start to make direct comparisons between the dissected body and the radiological images.
“It’s one experience to dissect, but as they move on in their careers they will be looking at digital representations of problems they see in MRIs and CT scans,” he adds.
In its gross anatomy labs, the medical school utilizes a device called a visualization table that is manufactured by Sectra, a Swedish company.
“It has a giant touchscreen, a computer inside it and USB ports on the side. Students can plug in a USB drive and upload their scan,” Doyle says. “It allows you to visualize the CT scans in 3-D. It takes a certain range of CT values and makes them look solid, and then renders them, so you can spin it around and zoom in and look at the data that way.”
Inglis says the best analogy is thinking of the CT scans as slices of bread and the visualization table putting them together to present the whole picture.
“When you look at the literature on replacing cadaveric dissection with digital models, you see the students find the digital models more convenient because they don’t have to come to a physical lab and deal with all of the technicalities of performing a dissection, but they value the education they get from actual dissection,” Doyle says.
“There is inherent value in both of these modes of teaching and that is why we are thinking about this as a hybrid program that uses traditional cadaveric dissection as well as digital modeling of the CT scans.”
“For this project I am interested in looking at the variation structure from a quantitative standpoint,” Doyle adds. “From an engineering standpoint, all the data for these 3-D models is contained in these grayscale images and the question is how best to represent them in 3-D space.”
As part of the study, the researchers plan to seek student feedback, Doyle says.
“We definitely want to know how they are using it. Students are very good at prioritizing what they are going to spend their time on,” he says. “They want to excel in the course so they are going to find the most efficient way of using the data.”
“One of the big concerns we have is to make sure we are doing this in a way that is not going to inconvenience them or not going to hamper their ability to learn.”
Inglis notes that many institutions that are thinking about adopting the digital-only model intend to use a single, unified body for teaching purposes.
“In recent years, there have been scans of two bodies that have been used from school to school, but it has been documented in the literature that in those cases, there have been a number of anatomical variations identified in these bodies that are now being presented as the norm, which is problematic.”
“In some cases, there are advantages to all medical students from around the country learning from the same sort of content map, but at the same time there are also some very serious issues with that,” he says.
Whereas, if a more diverse data set were available, students could gain a better sense of appreciation for variation, Inglis says.
Looking at the human body in 3-D form is extremely helpful for students trying to find different anatomical landmarks or anatomical structures they need to know, Doyle says.
“A good example that is a problem for students are cranial nerves, which tend to have loops and insert into the skull in different ways so they are often difficult to see, both on a flat CT scan and during dissection,” he adds.
“Having a 3-D model where they can identify those nerves and where they enter the skull and how they move is going to be very useful.”
While the grant is focused on the educational side of the equation, Doyle notes other researchers working in areas such as 3-D printing and surgical planning are interested in the study.
“In the course of figuring out how to work with this data, we anticipate there are different directions this could go from a research standpoint,” he says.
One example is a project they are undertaking with a hepatic surgeon who is interested in the biliary tree that lies between the gallbladder and the liver.
The way in which the ducts connect the gallbladder to the main trunk of the biliary tree can have implications for how a surgeon goes in to remove a tumor.
In about two-thirds of individuals, the artery to the gallbladder lies behind the duct that needs to be cut, which means that in one-third it lies in front, Inglis says.
“If you go in and are not precise as to where it is and if the artery is severed first, that becomes a medical emergency because that creates a massive internal hemorrhage.”
Being able to take a scan of a patient and reconstructing a 3-D structure before printing it out to provide to a surgeon is going to be very useful in terms of planning, Doyle says.
“At the end of the day, what we are trying to do is improve patient care by making better doctors on the education side or by using the data in a way to help practicing physicians treat their patients better,” he says.