Lab Values
By Kathy Hardy
Radiology Today
Vol. 19 No. 11 P. 16

Taking a 3D modeling lab from bench to bedside requires work, but it's a solid investment.

When setting up a workplace office, business managers focus on selecting the right space, staff, equipment, and costs. When it comes to printing needs, outsourced options provide a stopgap solution for a growing organization. However, that can come at an increased cost and diminished ability to schedule events, and it can compromise quality.

Those same factors come into play when the workspace is a surgery suite, with imaging needs being a big consideration. Today, that includes 3D printing. From entry-level 3D printers and free modeling software available on the internet to high-end printers and enhanced software, more hospitals are beginning to utilize 3D models for things such as surgery planning and education.

Radiologists, surgeons, and other specialists at the Mayo Clinic in Rochester, Minnesota, have been using 3D-printed models since planning separation surgery for conjoined twins in 2007. The infant girls were joined at the abdomen and shared a liver. As Kent Thielen, MD, chair of radiology at the Mayo Clinic, explains, pediatric surgeons on the case were looking for tools to assist in planning for the surgery, to help guide them through the conjoined anatomy of the two children. Surgeons turned to neuroradiology specialist Jonathan Morris, MD, and pediatric radiologist Jane Matsumoto, MD, who proposed creating a 3D model of the twins' shared anatomy using CT images.

"This was instrumental in planning the separation procedure," Thielen says. "It's been 10 years since the procedure was performed, and the twins are thriving today."

With the success of this endeavor came the seed for developing a full-blown 3D printing lab. They purchased large-scale printer and processing software and, with that, the Mayo Clinic launched its Anatomical Printing Lab.

"We had a single 3D printer in engineering at the time but nothing to the scale that we and other facilities have today," he says.

And in a "build it and they will come" scenario, Thielen notes that the volume of clinical cases utilizing 3D modeling has doubled each year since the dedicated lab opened in radiology in 2013. For 2018, they've already seen nearly 2,000 cases go through the lab.

Equipment Needs
3D printers have entered the mainstream, showing up on shelves at chain technology stores. With that, and free software, it's easy to enter the 3D modeling space, says Justin Cramer, MD, a radiologist at the University of Nebraska Medical Center in Omaha.

"It's just a matter of scaling up from there—investing in more high-end printers and more sophisticated software," Cramer says.

3D printers use 2D medical images to create, layer by layer, 3D models that are anatomically correct in size and shape to parts of the body. Not only does this help educate surgeons about the complex structures inside the body, but it also helps them talk to patients and their families about procedures and any risks that may be involved.

"Patients can gain a much better understanding of their situation and the anticipated course of treatment by looking at 3D models, as opposed to CT or MRI scans," Thielen says.

"3D models bridge the gap between radiologic images and the patient's body," says Lincoln Wong, MD, pediatric radiologist at Children's Hospital & Medical Center in Omaha, Nebraska.

Models can also help reduce surgery times, as doctors have an opportunity to practice on the anatomical reproductions before entering the operating room.

"Anything that provides information to surgeons that will give them more confidence and allow them to perform less-invasive surgeries is a valuable tool," Wong says.

Use Cases
One of the factors to consider when thinking about starting a 3D lab is how often it will actually be used. At the Mayo Clinic, Thielen says 3D printing is primarily used for surgical planning purposes or planning for image-guided procedures such as tumor resections, pediatric scoliosis surgery, and cardiology procedures.

"Orthopedics was one of the early adopters of 3D modeling," Thielen says. "It has now spread to almost all specialties. It also plays a role in education and research."

Pediatrics lends itself well to utilizing 3D modeling, Wong says. There is significant value in being able to recreate child-sized organs to study prior to surgery.

"Being able to visualize a smaller organ as a 3D model is like a translation of what you see in an image on a screen," says Gabe Linke, 3D printing coordinator at Children's.

While there are significant benefits to using 3D modeling, Cramer suggests using caution when it comes to long-term planning.

"You need to think about how to sustain a program like this," he says. "Start with a few printers and then scale up to get the program off the ground. There's also an element of marketing involved. You need to make doctors aware that you have something to provide them. You need to communicate within the department. Find out what the 3D needs are and whether there is a demand for 3D models."

Next, Cramer recommends reaching out to the specialties that might find 3D modeling useful. Find out which imaging methods they're currently using, and ask what they are looking to do.

Having a method for finding cases that could benefit from 3D modeling is a goal of many programs. Currently, at Children's, Wong finds cases that would lend themselves well to this technology. He talks to other physicians. He makes sure that the available scans are the best ones to represent the patient's disease. In other instances, cases find him.

"I can be walking down the hallway and a doctor will stop me and say, 'Could you make a model for me? I have a case where it would be helpful,'" he says.

Finding appropriate staff to run and operate a 3D printing lab is a matter of gathering personnel with knowledge of the technology, as well as the anatomy being imaged. For example, Linke calls on his background as a radiologic technologist. He specializes in cardiac imaging; his first models were hearts.

"There is currently no specific training for 3D modeling," Linke says. "So when you're putting together your team, it's good to have someone from the radiology technologist side, who knows the anatomy, and a biomedical engineer, who knows the design side."

According to Wong, Children's has been developing life-sized 3D models since February 2016 to better understand where cancerous tumors might be located or assist surgeons in the operating room. They use Materialise Mimics, software that takes images and converts them into a format that allows them to be printed as 3D models.

Children's originally outsourced its 3D modeling but wanted to bring it in-house in order to gain better control over the process. The in-house printing lab operates 24/7, Wong says.

Finding enough room to establish a 3D printing lab is another challenge, Wong says; 3D printers are large. There also needs to be work space available for cleaning and preparing the models for use by the medical team.

And then there's storage. Models, and the data files from which they are created, are part of a patient's medical record, which means all HIPAA requirements need to be met. Linke notes that current PACS do not accept STL files, but that people are looking at secure methods for storing them. At the Mayo Clinic, Thielen says there is dedicated storage space for the actual model, but the digital file from which the model was printed is saved, along with a photo of the actual model. He says steps are taken to ensure patient privacy and to be in keeping with HIPAA requirements.

"The physician on the case signs off on the model, once it's been completed," Thielen says. "Also, we embed a patient identifier number in the model and make it a part of the patient's record."

Quality Assurance
With any new technology, there is a rush to see what it can do, while at the same time, a bit of reservation to make sure that the result is a quality tool that will help improve patient outcomes. The Mayo Clinic brought in biomedical engineers, who, with their design expertise, were significant in helping to expand the applications for 3D modeling.

"You also need physicists to handle quality control," Thielen says. "They make sure that the models are accurate. If a 3D re-creation of a portion of the anatomy is supposed to be life sized, you need to make sure that it is actually life sized."

Quality control specialists are also tasked with making sure that the correct images are used in the creation of the model, that the images are of the correct patient, and that the correct organ or area of concern is being re-created.

University of Utah clinical neuroradiologist Edward Quigley, MD, PhD, notes that the quality of models plays a vital role not only in surgery planning but also in the quest for CPT codes. Positive patient outcomes are a big part of the reimbursement process.

"It's important to look at the data being acquired and used to create the 3D models," Quigley says. "You need to compare the original patient data, such as CT and MRI images, to the resulting 3D-printed model, to ensure quality."

Linke says it's important to find a champion in radiology to approach leadership with the proposal of establishing a 3D modeling program. After that, there's the matter of funding. Children's was fortunate to receive a large donation to cover the costs of purchasing a printer and software for 3D modeling, he says. Funding can also help with adding administrative and support staff, as well as purchasing supplies and materials.

"Without reimbursement, it is a philosophical decision on the part of the facility to invest in and establish a 3D printing lab," Linke says. "We don't let the lack of a CPT code drive usage. Our support comes from administration."

Finding budget funds for a 3D printing lab can be a challenge, particularly as there is currently no CPT code for reimbursement of 3D modeling. However, Cramer notes that facilities such as the University of Nebraska Medical Center have clinicians or third-party sources who are willing to cover the cost of 3D modeling.

"Academic medical facilities and large community-based hospitals can do this if they want to," Thielen says. "Reimbursement does not yet exist, but medical facilities and radiology groups may be short-sighted if they delay setting up 3D printing labs."

Thielen says that when the 3D printing concept was pitched to the Mayo Clinic's institutional leadership, the presenters explained that "there would be no direct immediate financial gains from this," he says. "However, in the long run, they would see the benefits."

Among the benefits are the ability to more accurately plan for surgical procedures and take a more thoughtful approach to procedure planning, an enhanced confidence level among physicians involved in the case, a reduction in surgery times, and better patient outcomes.

"When you hear surgeons talk about the impact 3D modeling has on patients and the medical care they receive, it's an emotional story," Thielen says.

The groundswell for establishing an internal 3D lab most often comes from the specialists facing the medical challenges of their patients on a daily basis. That not only includes surgeons and radiologists but also the frontline technologists who will most likely be managing these new labs.

"It takes a passionate physician and someone on the allied health side to champion the need for a 3D printing lab," Thielen says. "In our case, we had Drs. Matsumoto and Morris leading the cause. [Both] are world leaders in their field. They were able to demonstrate what a difference having 3D models makes in patient care."

— Kathy Hardy is a freelance writer based in Phoenixville, Pennsylvania. She is a frequent contributor to Radiology Today.