August 2012

Penguin Anatomy — New 3D Reconstructions Bring New Insight to Veterinary Imaging
By Robert J. Murphy
Radiology Today
Vol. 13 No. 8 P. 26

One interesting difference between animal imaging and human imaging is that much less is known about animal anatomy in many species. In these cases, imaging provides valuable anatomic information that often is not available. Human anatomy has been studied much more thoroughly, and the imaging focuses on identifying abnormalities.

Veterinarians at Brookfield Zoo’s Center for the Science of Animal Welfare in Chicago are using two recent imaging technology upgrades to produce new perspectives on the creatures in their keep.

The first is cloud-based 3D reconstruction software that transforms flat images—mostly CTs in Brookfield’s case—into reconstructions that can be rotated and manipulated in multiple ways for a better view. Clinicians can readily share their images with colleagues anywhere, expediting a telemedicine consult with, perhaps, a penguin specialist.

The second upgrade is an ultrasound unit that yields especially fine details and is particularly useful in examining small animals.

3D Imaging
Here’s a review of some recent cases of how imaging technology has been utilized in the animal world:

• The porcupine’s choppers: This case illustrates 3D imaging’s capacity to provide helpful anatomic guidance for a procedure a Chicago Zoological Society team was preparing at the time of this article’s writing. “We’re getting ready to look at a porcupine that has dental issues,” says Tom Meehan, DVM, vice president of veterinary services for the Chicago Zoological Society, which runs Brookfield Zoo and its hospital. “He’s scheduled for a procedure this week. So we’re following that guy.” (Meehan says each animal in his care is known as a “guy.”)

Knowledge of the anatomy of the animal’s teeth and adjacent structures will prove valuable in the work to come. “Knowing where the organs are and what sort of structures are in the way [is important],” Meehan says. “Among the [issues] we’re talking about in terms of planning procedures was the pluses and minuses of doing tooth removal in that porcupine.”

• Perspectives on a penguin: Meehan says one interesting difference between animal imaging and human imaging is that much less is known about animal anatomy in many species, so the imaging provides valuable routine anatomic information that often is not available. Human anatomy has been studied much more thoroughly, and the imaging focuses on identifying abnormalities.

This issue was illustrated recently in the case of a Humboldt penguin, an endangered species. “We’ve got some links to images of a penguin that we’re just doing to develop a better picture of penguin anatomy,” Meehan says. “We also are involved in a lot of field projects looking at penguin health.”

• Adventures of an aardvark: This was another case of dental problems. “We were really looking at it to see where the openings were between the area where he’d lost a tooth and the sinuses,” Meehan says. “We were able to look at the skull and be able to manipulate that and determine what those relationships were.”

• Sea lion shoulder injury: Meehan and his staff obtained diagnostic images of a California sea lion with an old shoulder injury just to check how it was coming along. In this case, the clinicians were able to focus closely on the area in question and turn and manipulate the images to acquire multiple viewpoints.

• The turtle egg: Yet another case of gaining anatomic knowledge via 3D imaging proved valuable when a turtle, referred by a nearby nature center, could not pass an unusually large egg. Thanks to the sophisticated imaging, the veterinarians first got a good look at the egg in all its oversized glory and then needed only to incise a 2-mm opening in the bone to remove part of the egg so that the animal could expel the rest. The alternative was to cut a major section from the underside of the turtle’s shell.

• The bald eagle’s elbow: Bald eagles are only legally permitted to be kept in captivity if they are injured and unable to survive in the wild. Brookfield’s vets recently used 3D imaging to examine what had been a severe “elbow” injury in a bald eagle’s wing. “We were able to look at that, how the area was healing,” Meehan says.

• Anatomy of an addax: A member of the antelope family, the addax comes from North Africa and recently was the subject of a thorough imaging exam to better understand its anatomy. “This was an animal where we’re looking more at the anatomy and getting renderings on some existing studies that we had,” Meehan says.

• Wolves with nasal tumors: The Mexican gray wolf is the United States’ most endangered wolf species. “In the wild, these guys have a propensity for developing nasal tumors,” Meehan says. Once deceased, the bodies may be sent to the US Fish and Wildlife Service for research. “So we’re looking to do a study where we look at the skulls, and we can use 3D imaging on those to look for the prevalence of tumors,” Meehan says.

3D in the Cloud: How It Works
Implementing the system developed by Seattle-based Vizua at the Brookfield Zoo required little in the way of a learning curve. And since they’ve only had it since December 2011, Brookfield clinicians expect to find new uses over time.

“We’re still learning to use it,” Meehan says. “The [Vizua] folks did a tutorial for us and walked us through using some of the screens. It’s pretty intuitive. Some of the things take a little work, take a little practice—like making movies.”

The nice thing about a cloud-based system is a quick start-up with little up-front cost. “This is simple to learn [and] runs on any existing hardware, such as a PC browser, a Mac browser, an iPad, an iPhone,” says Vizua CEO Dean Lester, who spent 14 years as a manager at Microsoft in addition to medical training at the London Hospital Medical College.

“Zoos, colleges, and clinics have zero hardware costs to adopt our system and an affordable monthly subscription, so they can give this power to everyone who needs it, wherever they are located and for as long as they need it,” Lester says. “Users just need to create an account on our service, and they can get started right away.”

Vizua offers two monthly subscription packages: standard and professional. Both include a maximum amount of service time that currently works out to about $10 to $15 per hour of use.

The minimal up-front cost to join and participate in a cloud-based clinically useful imaging technology such as Vizua sounds like a pretty good deal. Meehan says his costs so far work out to about $10 per hour to access and use the application. Its veterinarian applications presumably translate at least analogously to human medical care. No doubt we’ll see more such 3D systems emerging on the market in the months and years to come.

How does this software compare with similar programs used in human medical care? “The software system is the same since we are not a PACS. We extend an existing PACS to deliver 3D visualization to users wherever they are located,” Lester says.

There are significant advantages to a cloud-based system. “The easiest way to do this is not to have everybody buy this hardware and the proprietary software but rather have it cloud based,” Meehan says. “We log on to a particular website with our password. Then we can upload images directly from our PACS. And then once we’ve got those uploaded, the input works very much like a Mac. There are relatively few controls. You’ve got a slider that can vary the density.”

The 3D image is quickly created by assembling individual slices into a coherent whole image. Once the slices are assembled, “It’s got the soft tissue, the skeletal material, and all the rest in one piece,” Meehan says. “And then it allows you to adjust things like the different tissue densities. Then you can go into a little graph and identify different tissue types and give them different colors. So you can basically see the whole animal with the skeleton inside and transparent levels of other tissue inside of that.”

And if you don’t like your particular viewpoint, you can rotate the image in three dimensions along the Cartesian plane’s X, Y, or Z axis. “You can rotate the cross-section so you can look at it internally from different perspectives,” Meehan says.

And then there are so-called cutaways where specific tissue levels can be isolated from the rest of the image. “You may have a side image of a penguin, you’re seeing the whole animal,” Meehan says. “And then as you bring the image closer as you dial into the image, it cuts away the outermost layer.”

Vizua’s cloud-based 3D imaging system may have numerous applications in veterinary medicine, including for detecting disease- or trauma-related changes, routine checkups, providing anatomic guidelines to assist in surgery and other procedures, as a means to obtain a distant consult, and as a teaching tool both for clinicians and students.

Ultrasound in the Animal Kingdom
In March, the Brookfield Zoo staff installed new GE Healthcare ultrasound equipment. Obtained with support from the Aurelio Caccomo Family Foundation, which is committed to animal well-being, the equipment provides images in detail, something that may be especially helpful when dealing with small animals. The increased processing power can also capture moving images of the heart or circulating blood.

“We have small mammals that we may be looking at,” Meehan says. “We might be looking at an entire animal that’s the size of a human kidney. Tree frogs can weigh less than a dozen grams. We’ve got hedgehogs; a hedgehog is an animal that’s about the size of a human kidney. A ferret, while it’s a somewhat bigger animal, is still a fraction of the size of a house cat.”

But it’s the detail that counts, especially with miniaturized anatomy. “If you’re looking at the internal structures of an animal that size, you can imagine, everything is that much smaller,” Meehan says.

— Robert J. Murphy is a freelance medical writer based in Philadelphia.