Advancing Advanced Visualization
Advanced visualization workstations and software have grown up. The fancy computer in the corner of the reading room has become an essential diagnostic tool, and most likely found a more central spot in the reading room and role in diagnosis - enabling radiologists to produce higher quality results in less time than ever before, opening the doors to new exams, more tools for specialists and better patient education. In just a few mouse-clicks, 3D-savvy radiologists (or technologists) can transform axial CT data into smooth, sleek and high-resolution volumetric reconstructions of anything from coronary arteries to complex fractures or the colon. It's a far cry from the early clunky 3D reconstructions that took an arduous 30 to 45 minutes to complete and resembled a kindergartener's block drawing.
Although CT tends to hog the 3D limelight, MRI also benefits from advanced visualization. "Advanced visualization is extremely useful for MRI imaging, particularly soft tissues and MR angiography," reports Vamsi Narra, MD, co-director of body MRI at Mallinckrodt Institute of Radiology in St. Louis.
Advanced visualization solutions bring a number of benefits to the radiology department including:
- A manageable means of handling the massive data output of multislice CT scanners
- The ability to produce high-quality reconstructions to enable more accurate and efficient diagnosis of orthopedic trauma, coronary artery disease, aneurysms, colon cancer and more
- The ability to grow a practice with new exams like virtual colonoscopy or CT angiography
The heart of the matter
Atlantic Medical Imaging (Galloway, N.J.) relies on GE Healthcare's Advantage Workstation (AW Workstation) and 3D software as the powerhorse of advanced visualization. The GE solution handles CT angiographies, virtual colonoscopies, skeletal and spine studies and cardiac exams.
Medical Director David Dowe, MD, says the Advantage Workstation has made a tremendous difference in the practice and quality of coronary CT angiographies. "At 16 frames per second in a 512 x 512 matrix, image reconstruction and transfer is remarkably fast," states Dowe. The software snips additional time from the procedure via a simultaneous multiphase reconstruction feature, which allows radiologists to process the same vessels at multiple points in time simultaneously, eliminating the need to reload images. Phase registration simplifies the process by creating images of blood vessels using multiple phases. In contrast, manually constructing vessels in individual phases forces radiologists to determine which phases have been complete. Finally, simultaneous multi-vessel analysis enables users to analyze all seven branches of the left coronary artery without stopping and reloading. As a result, Dowe can process most coronary CT angiographies in less than 10 minutes.
While the high-speed process presents a workflow plus, Dowe says the real benefit comes in patient care. Typically, Dowe provides immediate feedback and shows each patient his images before he leaves the office. "Once patients see their [clogged] coronary arteries, they are motivated to take action and go back to their physicians demanding statins," says Dowe.
U. Joseph Schoepf, MD, director, CT research and development and co-director, Center for Advanced Imaging Research at Medical University of South Carolina (Charleston), has seen a brisk increase in cardiac CT business since deploying Siemens Medical Solutions' Somatom Sensation 64 and Leonardo workstation late last year, with the CT scanner and workstation increasingly called on as the solution to detect coronary artery disease. The university's heart and vascular center relies on the Leonardo workstation for 2D and 3D post-processing, reconstruction, visualization and archiving.
"We want to achieve a diagnosis that's as accurate as possible," notes Schoepf. "The heart requires a combination of different approaches [such as maximum intensity projections (MIPs) and 3D volume renderings] to appreciate the full gist of coronary artery disease."
The university center employs streamlined advanced visualization workflow processes. After scanning the patient, techs preview raw data on the acquisition console and select the optimal phase for reconstructions. Techs complete MIPS and multi-planar reformations (MPRs) at the Leonardo workstation according to pre-defined task cards. The final step for techs - 3D volume rendering - is completed in less than five minutes before the images are sent to PACS. Physicians pull 3D images from PACS to Leonardo for manipulation as needed. 3D images are easily shared with referring physicians; any physician who needs to access the 3D images can view them on PACS workstations located throughout the hospital.
Virtual colonoscopy made real
When University Radiology Associates at the State University of New York (SUNY-Syracuse) began exploring advanced visualization platforms in 2004, radiologists understood that virtual colonoscopy would be a primary application. They wanted to deploy a visualization platform that could provide a superior 3D colon experience and handle other 3D images. The practice installed Viatronix V3D-Colon along with V3D-Explorer, V3D-Vascular and V3D-Calcium Scoring in November 2004.
"There is some variation in how virtual colonoscopy is done," says Len Hojnowski, MD, associate professor of radiology at SUNY. "The ideal is a virtual fly-through of the colon. Viatronix V3D Colon provides a virtual fly-through that looks like an actual colonoscopy."
Other features add to the utility of the 3D tool. For example, an e-cleansing feature electronically subtracts residue and fluid in the colon, virtually replacing the physical scope used to clean the colon in a traditional colonoscopy. The difference in image quality between a cleansed and an uncleansed colon is substantial, says Hojnowski. Surfaces that would be otherwise obscured are visible to the radiologist after e-cleansing.
One of the trickier aspects of virtual colonoscopy is absolute interrogation of the entire colon surface. It's easy to feel that a crack or cranny has been overlooked, says Hojnowski. V3D Colon provides a read-out percentage of the visualized surface and tracks overlooked patches, so the radiologist can easily return to those areas. "By the time I've finished my fly-through, it's assured me that I've looked at the entire surface of the colon," sums Hojnowski.
Hojnowski and his colleagues bookmark select reconstructed images that demonstrate pathology to include in reports. The Viatronix workstation is connected to the network backbone, so images can be sent electronically to referring physicians. Hojnowski admits the e-files don't provide the true virtual colonoscopy experience. Nevertheless, static JPEGS do suffice for most referring physicians.
Simpler CT
The prime driving force behind advanced visualization tools is multi-detector CT scanners that produce massive amounts of data for radiologists to view, interpret and manage. Per study data volume amounts to about 150MB for about 300 images (according to the National Lung Screening Trial) of .5 to 1MB each. But many facilities are logging 3,000 CT images per study, with 500 to 700 more the norm - so the data storage and network issues are significant for sure.
"We're reaching a stage where the only way to handle data is with different advanced visualization techniques," explains Murray Miller, MD, site chief at Trillium Healthcentre in Toronto. "To gain the maximum value from new CT scanners, radiologists need to portray data in various ways like thick slab and MPR."
Trillium Healthcentre turned to Cedara Software Corp.'s CT Works workstation to complement and boost the utility of its multislice CT scanner.
"We're able to offer more services with this workstation," notes Miller. CT Works makes CT angiography possible, with "more or less" instant reconstruction, says Miller. Orthopedic surgeons at Trillium Healthcentre appreciate the newfound ability to view 3D images of complex fractures prior to surgery.
Miller asserts that the most important consideration in advanced visualization tools is an intuitive, easy-to-use user interface. CT Works meets the challenge. For example, radiologists completing a carotid segmentation can select a few points before the software shows the vessel. Miller says sites can further simplify advanced visualization tools with an in-house super-user. When Trillium Healthcentre deployed CT Works, Cedara trained one technologist as a super-user, who could troubleshoot common issues and complete reconstructions if radiologists became overburdened.
Like Trillium Healthcentre, Swedish Medical Center in Englewood, Colo., reports that advanced visualization tools have improved CT imaging. The radiology department implemented Barco's Voxar 3D in December 2002. "The software has enhanced the ways both radiologists and referring physicians appreciate CT images," says Matthew J. Fleishman, MD, medical director of the department of radiology.
In addition to orthopedic trauma and vascular studies, the radiology department employs Voxar 3D for CT endograph studies. The hospital's active endograph program benefits from the software, confirms Fleishman. Voxar 3D adds another level of certainty to detecting, diagnosing and localizing aneurysms via CT endograph.
While patients at Swedish Medical Center benefit from improved diagnostic certainty, the radiology department also realizes gains. Voxar 3D is integrated with the hospital PACS. Reconstructed cases are pushed back into PACS, and referring physicians can view the images on PACS workstations throughout the hospital. "This is really valuable from a marketing standpoint," says Fleishman.
Other sites have seen CT imaging blossom after implementing advanced visualization solutions. "Multislice-CT and 3D imaging has been a boon to our CT practice. We're able to do better work faster than before, and our clinical practice has increased significantly," says Larry Carl, MD, co-section chief of body imaging at New York Hospital Queens and Main Street Radiology (Bayside and Flushing, N.Y.). Like many practices, Main Street Radiology realized the need for an advanced visualization solution after installing a multislice CT scanner. "It became apparent that we needed a tool to view slices in a volumetric fashion. TeraRecon's AquariusNet offers a solution for a daily clinical problem," says Carl.
Carl and his colleagues rely on the server and workstation for a variety of exams including vascular studies, stent pacing planning, small bowel studies and volumetric follow up of lung nodules. "Radiologists need 3D for all types of work," explains Carl. "Even in routine cases, the ability to manipulate data in multiple ways is very helpful."
Distribution considerations
The imaging department at Long Beach Memorial Medical Center in Long Beach, Calif., has relied on Vital Images Vitrea workstation as its advanced visualization solution since 2002. "This is an essential diagnostic tool. As important as it is to have a good multislice CT scanner that produces a good dataset, it is equally important to have a good 3D workstation to process images," confirms Scott Lipson, MD, vice chair of imaging. Vitrea lives up to the mark, but after 2D data have been reconstructed into 3D and 4D images, the job is only partially completed. Sharing reconstructed images with referring physicians closes the circle and puts data in the hands of clinical decisionmakers.
"We can export key snapshots to PACS. Then the images are accessible to anyone in the hospital or offsite via the web product," explains Lipson. The department also burns occasional CDs depending on physician preference. Finally, neurosurgeons and vascular surgeons review reconstructed images at one of the two Vitrea workstations located in the imaging department.
"It's not quite the same as 3D access everywhere like with Vital Images VITALConnect [web-based 3D visualization and distribution system]," admits Lipson. Indeed, Lipson anticipates transitioning to VITALConnect at some point. This would benefit users who prefer to access and view images remotely, says Lipson. He cites orthopedic surgeons as one user group that would benefit from more remote access.
Other beneficiaries of VITALConnect include radiologists. Mallinckrodt Institute of Radiology implemented VITALConnect earlier this year; the new option allows on-call radiologists to bypass late night drives to the hospital (and 3D workstation) for cases that require 3D post-processing. Instead, the images are post-processed from home, improving patient care and saving physicians' time.
2D-3D integration
Mallinckrodt Institute of Radiology is one of a handful of sites that has implemented a 2D (or PACS)-3D model, with soft-copy 2D reading integrated in Vitrea workstations. MRI data are sent from the scanner to a three-monitor Vitrea workstation; two monitors are dedicated to soft-copy 2D reading and one to 3D processing. The radiologist can read 2D images, process 3D data, take snapshots, annotate and illustrate images and create a report on one workstation, posting reports on the web within minutes of receiving data. The result is gains in both workflow and patient care. Prior to the 2D-3D integration, radiologists saved 3D work until the end of the day as it meant opening and loading data onto a separate workstation, delaying results and adding to the length of the radiologists' day. Narra estimates that a mere 10 percent of sites have implemented 2D-3D integration, but predicts that it will become standard practice within the next five years.
Peering into the future
Where is advanced visualization heading in the next few years? On the hardware side, workstations will become faster with more memory and 64-bit processors to handle the ever-growing CT data output. On the software side, look for more automated tools. For example, CT peripheral runoffs can take anywhere from 15 minutes to an hour or more of post-processing. "Next-generation software will be smart enough to load the data, recognize it as a runoff and spit out 3D images, curved MIPs and automatic measurements in five minutes," predicts Lipson.
"We need to increase accuracy for reliable detection," says Schoepf of the Center for Advanced Imaging Research at Medical University of South Carolina. One way to achieve increased accuracy is with dedicated visualization platforms targeted to particular diseases.
The heart may be the next 3D frontier. Sandy Napel, PhD, co-director of the 3D Lab at Stanford University School of Medicine, sees cardiac applications growing with the advent of 64-slice CT scanners. Napel says new cardiac modules could nearly automate cardiac segmentation and provide point and click curved planar reformations of the coronary arteries.
