September 2011

Now Playing in 3D
By Kathy Hardy
Radiology Today
Vol. 12 No. 9 P. 16

Like filmmakers, radiologists and other physicians are learning how to use 3D effectively.

Summer blockbusters with special effects such as 3D attract audiences that want to see their favorite stars in greater detail. With this enhanced view, action appears to jump off the screen, making the movie-going experience more lifelike for viewers. Some movie watchers believe they get more value for their dollar when going to a 3D movie.

In the radiology theater, advanced postprocessing technology such as 3D visualization, when combined with high-quality diagnostic imaging, can provide radiologists and surgeons a blockbuster view of blocked arteries and torn ligaments but without the silly-looking polarized glasses. In fact, 3D visualization’s role in diagnosis, preoperative planning, and selecting treatment options is expanding.

Like in the movies, it appears the variety of ways 3D visualization can enhance both radiologists’ analysis and referring physicians’ preparation for treatment is continuing to expand. While 3D images may have been just “pretty pictures” when they were first introduced, they are now a mainstream way to look at patients’ arteries, bones, and vital organs.

“3D has become an important component of patient care,” says Emilio Vega, BS, RT(R)(CT), manager of the New York University Radiology Image Processing Laboratory. “We’re taking CT data and data from other modalities and extracting more than just 2D images. Physicians are able to diagnose in different perspectives.”

Clinical Use Expanding
When 3D imaging first came on the scene, this enhanced point of view was perceived as good only for limited clinical application. This visualization technology takes the volumes of data generated by cross-sectional CT and MRI studies and creates spatial views of organs and systems, allowing physicians to obtain realistic views of a patient’s anatomy.

Over time, 3D laboratories, such as the one Vega manages at New York University, were established. Acquisition data are transferred to the lab, where specialists load data into advanced visualization software and then perform postprocessing and prepare images for radiologists to interpret and other physicians to use in treatment.

Creating a dedicated 3D lab staffed with image-processing specialists takes the burden of postprocessing many large data sets from the acquisition technologist, allowing the technologist at the scanner to focus on patient care and quality. Also, the initial workup by the lab saves radiologists time. When the radiologists finally interact with the data, they have already been worked up and bookmarked, ready for efficient manipulation in the reading process, Vega says.

According to Rob Jennings, RT(R)(CT), 3D lab director for Fairfax Radiological Consultants in Virginia, 3D imaging’s initial uses were primarily in the cardiovascular field, where radiologists and surgeons looked for diseased arteries. Eventually, 3D lab specialists approached neurologists with the idea of using the technology for patients who had CT exams of the neck and CT angiography exams.

“When examining the head and neck, we can look at arteries in those regions of the body as well,” Jennings says. “We use similar tools as cardiac scanning to see if those arteries are stenosed or occluded.”

Jennings remembers when the vibrant images produced with 3D imaging served a purpose as marketing tools for the technology but didn’t really provide views that could assist in a patient’s diagnosis or treatment. That’s changed, however, as more brilliant images become useful in orthopedics, where complex fractures can become clearer when viewed with this technology.

“With a CT scan, you would use 3D to see greater detail,” he says. “This provides the surgeon with a better idea of what’s really going on. He can use advanced imaging to assist with his diagnosis as well as with surgery. In aiding the diagnosis of a situation, we’re seeing things with these views that we can’t see with regular scans.”

Jennings sees 3D visualization being used as part of a patient’s presurgical planning. “I’ve seen it used by plastic surgeons for breast reconstruction,” he says. “They can map out the course of the arteries and see which ones are healthy and viable.”

Clear the Landscape
3D imaging capabilities include the ability to visually clear the landscape of an injury to reveal where the damage has occurred.

“With 3D, you can remove bone that’s in the way of where the injury is,” Jennings says. “For example, you can get a bird’s-eye view inside the knee by removing the knee cap. You get a better view than when the patient is cut open.”

Vega notes that in some instances, physicians will use 3D images like an index, aiding in the process of viewing 2D images. “With a virtual colonoscopy, for example, 2D images are better viewed with the aid of 3D to confirm what doctors are seeing,” he says.

Vega also finds some differences between how radiologists and surgeons view the 3D world. Some radiologists seem to see in 3D “in their brain,” even when looking at 2D. On the surgical side, they need to see the 3D images. He believes 3D can make the biggest difference for surgeons, and those surgeons who utilize his lab now expect to see all images in 3D.

“3D is making its way into the surgical suite,” he says. “It is not only a good tool for preoperative planning but for intraoperative use as well.”

Surgeons who frequent the University of Michigan’s 3D Imaging Laboratory are adding this view-enhancing technology to their tool set, making the technology an integral part of imaging. Like other 3D labs, the University of Michigan lab supports advanced applications for CT and MRI, including for cardiac analysis, CT perfusion, CT and MRI angiography, functional MRI, and diffusion tensor imaging. The lab provides postprocessing applications and 3D renderings on CT and MRI data sets across the organ-based radiology divisions as well as provides interpretative worksheets for applicable examinations, including preoperative analysis.

“All this information helps determine treatment and surgical planning,” says laboratory manager Karen A. Barber, BS, RT(R)(CT). “Surgeons love this. They like to see and plan their approach before their intervention.”

On the other hand, she believes radiologists still rely more on 2D images and their related analysis.

“Radiologists are used to looking at cross-sectional images,” she says, “although it’s now more routine to look at images in other planes. Today, with exams including more than 1,000 images, it’s faster and easier to view them in another plane.”

Referring Physicians
Vega agrees that advancements in 3D imaging technology make it easier to access: What started out as a report on paper is now displayed in color on PACS and distributed through thin clients that allow radiologists and referring physicians to view images from iPads to operating rooms. 3D technology can be integrated with PACS workstations or viewed on separate 3D-dedicated workstations. Images can be rendered in 3D and then returned to the PACS for viewing and archiving. Thin-client applications also allow more people to view images without having to invest in numerous expensive workstations.

Image quality, however, is still dependent on how the images were captured during a patient’s modality scan.

“The workstation is still only as good as the imaging that it’s given,” Jennings says. “In CT, with improvements in slice thinness and number of slices, 3D lends itself well to this type of imaging. There’s more diagnostic capability for the radiologist and better planning capability for surgeons.”

At the Fairfax facility, Jennings is receiving positive feedback from radiologists.
“What we’re getting from the radiologists is that this is a great tool, even when it’s not being used for diagnostics,” he says. “It’s great for surgeons to use to supplement reports. It gives you a good understanding of what’s going on inside the patient. The help you can give to radiologists and referring physicians with 3D imaging is incredible, and the technology is only getting better.”

The University of Michigan’s 3D lab plays a role in educating technical staff and residents on the use of 3D images, developing and administering curriculum for educating CT personnel on the acquisition protocols and 3D renderings. They also hold conferences on utilizing 3D imaging, particularly in the cardiovascular field.

In addition, the lab is working in conjunction with a radiology and university professor in the medical school to teach human anatomy using 3D images rather than textbooks, with lifelike images replacing cadavers.

Education with 3D goes beyond the medical community, having an impact on patients in a variety of ways. While teaching a course on how to view 3D images in cardiology cases, Jennings used images of arteries in patients with high risk factors, such as being overweight and smoking.

“When you show patients an image of arterial plaque, that has quite an impact on them,” he says. “A report only does so much. Showing them what it looks like gets them to understand the situation better. You just don’t get that with a CT scan.”

3D images are also a valuable tool for providing patients with a detailed description of their injury. Looking at a fracture in 3D is much easier for a patient to understand than a cross-sectional CT image, Jennings says.

Imaging professionals see 3D imaging continuing to star as a marquee feature in the radiology theater, even reaching a point where the data are imbedded into CT scans.

“The ability to access 3D images easier will make the technology more commonplace,” Vega says. “3D will become more of a standard. You can’t be in radiology today and not have some use of 3D.”

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