3-D Anatomic Scanning and Modeling: A Technology with Near-Limitless Potential in Pathology Applications
By Chris Bahnsen • March 26, 2019
In the fall of 2017, Shayla Polanchek, a recent recipient of a heart transplant at Mayo Clinic in Rochester, Minnesota, returned to campus to review the specimen of her old heart, the one that had been removed from her chest. She had asked to be reunited one last time with the organ that, though flawed, had kept her alive for 38 years.
“Shayla and her family wanted to see the specimen, understand more about the disease, and say goodbye to her old heart,” says Joseph Maleszewski, M.D., Section Head of Cardiovascular Pathology in the Department of Laboratory Medicine and Pathology (DLMP).
For the momentous occasion, Polanchek, her husband, and their four children met with Dr. Maleszewski at one of Mayo’s Anatomic Pathology Laboratories.
“I didn’t know what to expect, if I would be emotional or cry,” says Polanchek, who lives in South Dakota and describes herself as an “American farm wife.” “Dr. Maleszewski had my heart behind a glass window that he opened. He touched it and showed it to us, and he had gloves for us if we wanted to touch it . . . . There was such great joy when I saw it. Part of me thought, ‘This is the heart that sustained me all those years, even though it was so sick.’ At the same time, I was so excited about what was to come, with my new heart.”
Besides getting the chance to see her heart, Polanchek was able to take a piece of it back home with her. Well, not the real thing, but almost.
“Dr. Maleszewski had printed a 3-D model of a slice of my heart—where it had the most significant damage,” says Polanchek, who was born with hypertrophic cardiomyopathy (HCM), a genetic condition in which the heart muscle, or a portion of it, becomes enlarged, resulting in the heart losing its ability to pump blood efficiently. “And he had printed out another normal heart, so we could compare how it looked to mine. It was pretty impressive, really amazing, and he let us take both of those home with us so we could show our friends and family.”
Re-Creating Human Organs via 3-D Technology
The meeting, and 3-D heart replicas presented to the Polancheks, were made possible thanks to Mayo’s 3-D Surface Scanning and Modeling Initiative, a collaboration between the 3-D Modeling Laboratory and DLMP.
This nascent technology uses a special image scanner (called a Rotex Spider 3-D scanner) in concert with a photo-realistic full-color 3-D printer (the ProJet® CJP 660Pro) that can replicate models of not only the human heart, but virtually any organ, bone, or tissue specimen in the body.
Naturally, most transplant patients are curious to see the actual biological specimen of their old heart or other removed organ. But accommodating them is logistically challenging. Such organs must be dissected in a careful way that maintains key teaching points for patients. And they must be kept in formaldehyde, rendering them difficult to transport. Also, as with all human tissue, biohazards are an ever-present issue, carrying potential risk of disease or infection, which is why the pathologists are not exactly keen on having patients touch or handle them.
“Now, if we can scan their specimen and then print off a version that is true to size and color, then that is a very nice trade-off because it doesn’t involve biohazards and the cumbersome logistics of handling real human tissue,” says Dr. Maleszewski.
How It Works
At the 3-D Modeling Laboratory, co-directed by Jonathan Morris, M.D., and Jane Matsumoto, M.D., modeling is mostly based on image-acquisition techniques, such as CT scanning or MRI exams. In DLMP, pathologists have been working on surface scanning to replicate hearts and other organs.
A 3-D surface scanner is a device resembling a handheld iron with small cameras all over the bottom surface. The device is moved over the outside contours of a specimen or object, during which the scanner takes multiple pictures and creates a three-dimensional representation.
“It basically gathers two variables on every image,” says Dr. Maleszewski. “It gathers the object’s texture, from every vantage point, and the geometry. By using shadows and light beams, the scanner actually contours the external surface and creates a kind of topographical map of that object.”
Using software algorithms, these two variables are meshed together. Dr. Maleszewski further explains: “We image the entire surface object and build a 3-D structural model,” he says. “And then the software wraps a map of the photos of the object around the 3-D structure. Then, it becomes that 3-D object that looks exactly like whatever you scanned.”
The scanned 3-D image can be manipulated on a computer screen or handheld device (e.g., a tablet or smart phone), and tilted and rotated at every conceivable angle via a mouse or a person’s fingertip. The image can also be sent to the printer, which will create a 3-D model of whatever organ or object has been scanned. The modeling material is a resin, akin to sand, with which the printer lays down a “scaffold” that hardens over time. The 3-D printer can use other materials as well, some being very rubbery and pliable, and others that are hard like ceramic or plastic polymer. And, for maximum realism, it’s able print in multiple colors.
“A 3-D digital rendering of a specimen allows for very portable learning,” says Melanie Bois, M.D., a cardiovascular pathologist at Mayo Clinic. “And, by printing the rendering, you have a tangible 3-D object as a learning tool for pathology and the relevant anatomy around it. Both are really valuable learning tools.”
Facilitating Patient/Pathologist Interface
The 3-D Surface Scanning and Modeling Initiative is changing the paradigm by facilitating, for example, unprecedented relationships between patients and their pathologists.
“Because we get a number of requests from patients who want to review their specimens, we’re beginning to offer this unique opportunity more routinely,” says Dr. Maleszewski. “We’ve started doing this with the transplant population because, normally, they spend a fair amount of time on the transplant list, hoping and waiting for that very special day when an organ becomes available that will basically change their lives. And so, they’re really engaged and invested in both their disease and their health care.”
Besides the opportunity to experience the cool science of 3-D modeling, meeting with a pathologist is a rare chance for patients to learn more about their diseases.
“It makes a lot of sense to approach these patients, initially, to gauge how they’re dealing with being a transplant recipient and how they’re processing this major life event,” says Dr. Maleszewski. “And it offers the opportunity for us—as pathologists—to interface with the patients and tell them, ‘Look, here’s the role that we’re playing in your health care,’ both in confirming—or in some cases, refuting—a clinical diagnosis of a type of heart disease that may have implications for their family members.”
Patients take comfort in going “behind the scenes” of their care to meet diagnosticians, such as Dr. Maleszewski, who make sure their disease is accurately diagnosed and that it’s captured in a meaningful way. The entire process is coordinated by laboratory technicians, led by Andrew (Drew) Caron and Angela Regnier, who coordinate with the patients and engage them when they arrive to review their organs. After the initial specimen review meeting, patients can opt to have additional meetings with their pathologist going forward.
“These patients will routinely be getting endomyocardial biopsies, where little pieces of their new heart are taken so that we can survey them for rejection,” says Dr. Maleszewski. “And they will be waiting on our reports to see whether or not they need to increase or decrease their dosage of immunosuppressants. So, it’s nice to have that face-to-face interaction, when we get to introduce ourselves and start a relationship with these patients that, previously, only existed between patients and their immediate health care providers. It’s very rewarding.”
Over the last year or so, Polenchek has had about 12 endomyocardial biopsies and, hence, has enjoyed continuing the relationship with Dr. Maleszewski. But it was her initial meeting with him that set the tone:
“When I met Dr. Maleszewski, I had such a good feeling about him that I immediately trusted him—and I’ve always trusted Mayo; they’ve always done me right,” she says. “But it was really neat meeting him because now I know one of the doctors who’s doing my biopsies. I didn’t imagine him to be so cool. I thought he would be one of those nerdy guys wearing those little micro-glasses, but he was just really awesome.”
Near Limitless Possibilities
Because 3-D scanning and modeling is so new as a pathology tool, even Mayo Clinic, at the forefront of this technology, is still exploring its potential.
“We’re only beginning to understand the possibilities that this type of technology can bring to our field,” says Dr. Bois. “More immediately, I think being able to introduce digital 3-D images and 3-D models into medical education is a really important initiative for us. I can also foresee us sharing these specimen replicas at multidisciplinary tumor boards to better facilitate conversations about specific patient pathology and how best to treat it.”
It’s already begun. As of August 2018, these models are now being used as part of the Mayo Clinic School of Medicine’s curriculum and in the education of residents and fellows.
Dr. Maleszewski can also envision scanning pathology specimens with specific diseases and then providing them to device manufacturers so that they can help develop new tools to intervene on those diseases. “In particular, if you can scan a heart with a certain disease and then print it with a material that has a certain degree of pliability or plasticity to it, you could then mount that specimen on a table and do practice procedures on it,” he says. “And that can be very helpful in the development of new devices and new interventional tools, for example.”
When looking for opportunities outside the medical community, Mayo is also exploring forensic applications.
“In our autopsy practice, if we have a homicide case of head or neck trauma,” says Dr. Maleszewski, “we can take scans of the head and neck, and not only archive all of those injuries in a very detailed and three dimensional way, but we can then print out models and specimens that could potentially be used in a court of law for homicide trials, as an example. Those kinds of 3-D models bring a realness and an immediacy to forensics that may be helpful in a criminal proceeding.”
Sharing Rare Specimen Replicas Worldwide
By enhancing the reproducibility and transportability of rare organ and tissue specimens, this technology may also allow Mayo Clinic to share them far beyond its own campuses, as teaching tools.
“What we’re thinking about, as a possible long-term goal, is taking these digital images of rare specimens and printing them off as model sets—the ones that would be most valuable for teaching purposes—and perhaps providing them to areas around the country, or even the world, where they may not have access to these amazing specimens,” says Dr. Maleszewski. “So you can envision a medical school in India, or Malaysia, or Africa, for example, potentially having access to the same great resources we have here at Mayo Clinic, as we share our experience with them in a philanthropic way.”
Dr. Bois chimes in: “It’s an exciting field because we can now take disease and pathology and really portray it in a different, novel way,” she says. “And it allows both patients and clinicians to better understand the underlying pathobiology of disease.”
Even Better Than the Real Thing
The initiative is helping to deepen the educational paradigm by transforming these rare specimens into user-friendly, shareable 3-D learning tools.
“In the past, when we interacted with other learners in medicine, we would use two-dimensional photography (of a specimen),” says Dr. Bois. “Or we would have to bring the actual specimen, which we couldn’t do very often because of its fragility and biohazardous risk. It really decreased our ability to transport and share our specimens.”
Conversely, by using 3-D technology, either a digital rendering or the actual printed model, Mayo can share and transport specimens freely for home or office learning, “and they can be used to show all relevant anatomic relationships in a much more real and enhanced presentation than 2-D photography,” says Dr. Bois.
A Beneficial Takeaway for Patients and Pathologists
Amid all the possibilities, perhaps the most profound is how the initiative has opened the door for pathologists at DLMP to have open and meaningful dialogues with transplant patients.
“As pathologists, we really don’t get to interact directly with our patients,” says Dr. Maleszewski. “In fact, we’re often called the ‘doctor’s doctor,’ because we primarily interact with other physicians as they navigate the waters of difficult diagnoses. Situations like this, where pathologist and patient can meet, help me to be a better diagnostician. It’s a chance to learn the patient’s story and marry it up with the pathological findings, while simultaneously helping the patient understand his or her disease on a different level.”
Further, in allowing these patients to see and touch their removed specimen (or an exact replica), there can be a kind of emotional or even spiritual healing, a process that’s different from patient to patient. The farmer’s wife from South Dakota, was ready to say goodbye to her heart and pay it forward, so to speak. During that first meeting with Dr. Maleszewski, he asked her what she wanted to do with her specimen.
“I told him I was hoping he would keep my heart and maybe learn something amazing from it that will help future HCM patients,” recalls Polanchek who, almost one year after her transplant, is doing very well. “He was really happy I chose to leave it there because he said that doctors would fly in from all over the world just to see a rare heart specimen like this. And I was happy, too, because I really feel like maybe there are some answers in my heart and, hopefully, the right person will look at it someday and find them.”
Chris J. Bahnsen covers emerging research and discovery for Mayo Clinic Laboratories. His writing has also appeared in The New York Times, Los Angeles Times, and Smithsonian Air & Space. He divides his time between Southern California and Northwest Ohio.