Hollywood legacy clarifies diagnostic studies for doctors and patients

Three-dimensional technology developed by the motion picture industry to create intergalactic space battles or an Hawaiian seascape when you can't leave Burbank to shoot the tropics is being used increasingly at SHC across a wide spectrum of services.

Geoffrey D. Rubin, section chief of cardiovascular imaging and co-director of the Department of Radiology's 3-D Medical Laboratory, explained that 3-D imaging not only offers accurate, accessible and diagnostically appropriate information for a wide spectrum of physicians, but also provides an unprecedented educational tool for patients.

"We take CT or MRI scans comprising thousands of cross-sections and distill them into one or several summary images that can convey the disease process far more effectively than any individual traditional cross section could," said Rubin, an associate professor of radiology.

"Frequently, 3-D imaging provides practicing doctors with a convenient mechanism to communicate effectively with their patients. It helps them explain not only the patient's disease process but frequently even how the treatment will proceed," explained Rubin, who completed both his residency and a fellowship in body imaging at Stanford before joining the faculty in 1993.

"Any surgeon who has ever had to leaf through a stack of two-dimensional images to track a series of crossing vessels can appreciate getting even better, clearer images in a single view.

"Even when surgery isn't required, the technology can help the doctor and patient keep tabs on the disease process over time." While the department's 3-D lab is clinically focused, Rubin said that the facility, which is co-directed by electrical engineer and radiology professor Sandy Napel, provides training for engineers, physicians and technologists from around the world who often bring innovative ideas to share with Stanford colleagues.

Reimbursement for 3-D studies is either automatically built into CPT codes (such as for CT angiography), or physicians can request 3-D studies by adding a modifier code accepted by virtually all payers, Rubin noted.

As for reliability, Rubin said that "anytime you manipulate data there is of course the risk that a study can be misinterpreted. There is a danger when a commercial lab processes 'mail order' CDs without physician review and direct input," said Rubin. "That's why it's important to have a study produced by a lab staffed with skilled technologists and experienced radiologists to present and interpret data."

On rare occasions the radiologist or referring physician will need to go back and review an individual segment, which is stored and readily available.

"But keep in mind that capabilities of the MRI and CT scans - particularly CT - have undergone a phenomenal growth. Just five or six years ago, for example, a CT scan of the abdomen represented 30 cross sections. Now we have the benefit of CT scans that comprise 600 cross sections, giving larger images with much higher resolution. These would be almost impossible for a clinician to read individually but easy to read when combined."

The lab has evolved quickly. "We were among the first in the world to initiate 3-D diagnostic imaging when we started our lab in 1996 with one technologist, Laura Logan Pierce, who is now our lab manager. At that time we were performing 15 to 20 cases a month. Currently, five full-time technologists - licensed RT technicians with extensive additional training in compiling the 3-D study images - run up to 600 clinically requested examinations each month." Rubin said. The lab offers 24-hour turnaround for most studies, which take about 45 minutes to complete and are packaged in several different formats, depending on each physician's preference. Everybody gets a printed report with high quality color prints in a folder that fits in patient charts and is suitable to show patients during consultations.

"We can also make the images available securely through the World Wide Web or via e-mail. (Although a huge amount of data is rendered, the individual picture files are similar to prints produced by digital cameras. The lab can send about fifteen 3-D images in a single e-mail transmission accepted by most commercial providers, such as Earthlink or AOL.)

Rubin noted that the written reports include clinically accurate quantitative data not available through analog pictures, such as traditional X-rays. By using tools available on their computer workstation, the technologists can characterize the anatomy of an aneurysm by measuring diameters, vessel lengths, and angles to help a physician choose an intervention. Decisions, such as predicting the stent size needed to repair an aneurysm, can also be made more accurately with quantitative data produced by the 3-D imaging.

"There are few subspecialties where the technology is not at least intermittently useful," Rubin said. For example, "we measure the volume of the cortex and the volume of the medulla to help nephrologists determine the status of kidney disease. Or we can help a urologist planning a minimally invasive ureteral pelvic junction obstruction (UPJ) procedure determine in advance if any crossing blood vessels would cause complications," he said.

The software packages that produce the 3-D images are compatible with MRI and CT scans produced by most full service radiology practices, Rubin said. "Most of the commercial software packages offer templates that can generally produce automated results that may not offer the customized disease- and anatomy-specific approaches that we have developed here at Stanford over the past nine years," Rubin added.

"Every patient is different," said lab manager Pierce, who noted that one of the satisfactions of her job is the stimulation that results from treating each study as a unique opportunity.

For further information, visit: http://3dradiology.stanford.edu