BlueLink Anatomy: Capturing anatomical diversity with 3D scans

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BlueLink: a Free Learning Resource for Studying Anatomy

BlueLink is a multimedia-based educational resource developed by Dr. B. Kathleen Alsup and Dr. Glenn M. Fox of the Division of Anatomical Sciences at the University of Michigan Medical School. BlueLink is a portable and scalable approach to engaging students within a digital ecosystem. BlueLink materials are free for educational, non-profit purposes, and are designed for global access and helping to promote education equity. BlueLink has provided medical students at the University of Michigan and beyond with photographs (in addition to numerous other types of learning tools) of expertly dissected donors in a free, massive repository of curated anatomical specimens.

This allows for the ability to engage in high quality studying when not able to enter the lab. While photographs are no replacement for dissection, these help students prepare for dissection, walk them through the process of specific dissection procedures, and serve as a review resource when the dissection is over. In this way, students are more prepared for, confident during, and retain more from their dissection experiences.

Where two-dimensional photographs alone may lose their efficacy is in areas of the body with highly complicated three-dimensional architecture. To address this need, the BlueLink team has begun to create and incorporate 3D resources within their anatomical resources.

Human Diversity: The Challenges of Traditional Anatomy Resources

When medical students dissect anatomical donors, reality is often a bit different from their expectations. When Will Gribbin, current second-year medical student and technical lead for the scanning arm of the project, was dissecting the heart, he recalls being quite confused:

“I had spent the night before studying the photographs of previous dissections the BlueLink team had captured, and the scientific illustrations in textbooks, but when we got to the heart, we just could not locate one of the vital coronary arteries.”

Heart and great vessels with labels

The heart pumps blood throughout your body, but the heart needs to get oxygen from the blood as well. Coronary arteries are the vessels that bring blood to the heart tissue. These vessels sit on the outer surface of the heart, sending smaller vessels to feed the heart tissue itself; however, Will said, “Our donor’s left coronary artery dove into the heart muscle and then reappeared about an inch later at the heart surface. It was nothing like any image or text. I mentioned this to my instructor, who said she had never seen anything like it.”

Dr. Kathleen Alsup, Anatomy faculty at the U-M Medical School and co-PI of the BlueLink project notes, “When teaching foundational anatomy, we often teach, and most BlueLink and other anatomical resources demonstrate, what we refer to as ‘typical anatomy’ or the structural organization most frequently observed. This gives students streamlined study guidance, as these ‘typical’ anatomical relationships are usually the ones tested and most commonly observed. However, ‘typical anatomy’ frequencies can be as low as 30%. Students frequently observe anatomical variation in the laboratory, and can be confused or frustrated when the only resources they have access to depict ‘typical anatomy.’”

Giving students the ability to access the diversity of human anatomy outside of the lab can prove beneficial. When studying the blood vessels in the pelvis, Will recalls, “For me, it was a complete nightmare. There were so many structures, all superimposed on each other. The textbooks looked nothing like what we were seeing in the lab, and the photos couldn’t capture the complicated 3D structures. I thought that there had to be a better way.”

The idea of using 3D capture to preserve delicate specimens is nothing new—the fields of paleontology and archeology have been using these technologies for quite some time. Scanning is not new to the medical field, with optical scanners used for medical device manufacture. Indeed, radiographic and magnetic scanning technologies are a staple in any hospital: CT and MRI. However, application to medical education topics like anatomy has been absent.

The BlueLink Project and Incorporation of 3D Resources

Global access and education equity are core goals of the BlueLink team mission. We believe that the incorporation of 3D resources as the next area of the project is very compelling because while this will serve our students very well as an adjunct to dissection and a self-study guide, it will also provide an amazing 3D resource for students who do not have access to dissection.

Currently, the BlueLink team is focusing on scanning and labeling bones, but this is just a starting point. There are many donors that are in the care of the University that we want to make more accessible. The University of Michigan Medical School has a collection of thousands of plastinated specimens. While these are of great learning value to students, only so many students can see a specimen at any given time.

Left humerus

We are currently working towards creating a massive, professionally curated collection of these anatomical specimens. We are incorporating the tagging feature Sketchfab offers to provide students with guidance regarding the anatomy, while still allowing students to explore for themselves. Scanning the specimens and making them available on Sketchfab will allow us to give students a more immersive look at what they can expect to see before the dissection lab, and let them study anatomical variation asynchronously.

Methods

Hardware:

Using a Shining 3D EinScan-Pro structured light scanner, osteologic and plastinated specimens are digitized and a 3D scan is produced within the EinScan software. Depending on the specimen type, either the handheld mode or a fixed-position scan with an automated turntable is used. We utilize the EinScan texture scanner pack to create UV-mapped textures of our models.

Acquisition:

During acquisition, we utilize a “simple-to-complex” approach to scanning. Initial scans focus on capturing the gross 3D details of the whole specimen. With a good initial model, the feature alignment algorithm is more capable of filling in more difficult spots (recessed spots, areas with homogenous surface geometry). We optimize the acquisition view for each challenging area of geometry and rescan as needed. As more accurate surface geometry is acquired, we remove initial scans to keep the model size down. Any geometry that cannot be adequately captured is reconstructed in post with the help of Ph.D. anatomists, maintaining a high degree of anatomical accuracy.

In the case of the model above, to capture the complex geometry of the roof of the mouth (palatine process of the maxilla) a “framework” scan of the skull with mandible was first acquired. Following this, the jaw (mandible) was removed and unobstructed scans were conducted. As newer, more ideal views were obtained, older initial scans are removed. This allows for optimal detail capture while maintaining robust feature-based alignment. High-detail scans with optimal geometry are then saved as either watertight or non-watertight models within the proprietary Einscan software.

Post Process:

Once the scan is complete a combination of Meshmixer, Maya, and Blender are used to clean the models and finalize them both structurally and aesthetically. Areas of homogenous geometry are chosen to be simplified. Shaders are adjusted using the internal Sketchfab editor.

Distribution:

Sketchfab serves as our primary tool for distributing and annotating models. We provide all finalized models as free resources on Sketchfab. Sketchfab provides an excellent platform to allow functionality within our existing external website (able to seamlessly embed resources), as well as provide others the means to utilize the resources.

BlueLink Website

 

About the author

BlueLink Anatomy

BlueLink is a multimedia-based education resource developed by Dr. B. Kathleen Alsup and Dr. Glenn M. Fox of the Division of Anatomical Sciences at the University of Michigan Medical School. BlueLink includes cadaveric photographs, comprehensive lab manual



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