Contact:
Raymond Schulz, Voxel 714-348-3200, [email protected]
Kay Paumier, Communications Plus 510-656-8512, [email protected]
For Immediate Release
Holograms of CT Scans Display Neurovascular & Spine Pathology More Accurately and Clearly Than Software Renderings
2-D Preview of 3-D Holograms Unveiled
December 1, 1997 ó Chicago ó A physician reporting at the Radiological Society of North America (RSNA) annual meeting this week will describe how the Digital Holographyô System from VoxelÆ (NASDAQ:VOXL) improves display of cerebral vasculature and reduces or eliminates image artifacts in patients with surgical hardware. Additionally, Voxel will introduce software for previewing three-dimensional holograms on a computer.
The Digital Holography System uses data routinely collected by Computed Tomography (CT) and Magnetic Resonance (MR) scanners to produce true three-dimensional images. A proprietary multiple-exposure process holographically superimposes all the cross-sectional data from the tomographic studies onto a single piece of 14"x17" holographic film. When the film is viewed on a special lightbox, the transparent VoxgramÆ images literally extend out in space, enabling physicians to interact in, around and through the life-size holograms as if they were real specimens of anatomy.
Holograms of Neurovascular CT Display Anatomy More Easily and Accurately
Dr. Wayne J. Olan, Chief of Neuroradiology at George Washington University Medical Center (Washington, D.C.), examined whether the Digital Holography System could obviate the problems inherent in surface renderings of cerebral vasculature from CT Angiography (CTA).
Helical CTA exams of the cerebral vasculature of 22 patients were acquired and life-size holograms generated. Dr. Olan used the holograms to duplicate the exact perspective of the anatomy and pathology seen at surgery.
Three-dimensional holograms "allow the reader to quickly choose the optimal perspective for viewing pathology with nearly infinite adjustability within a 45∫ volumetric viewing cone." The VoxgramÆ images allow viewers great freedom because "the film can be flipped to see the anatomy from the opposite perspective." Additionally, "greater appreciation of depth is afforded through normal physiological depth cues operating subconsciously. This allows rapid identification of normal anatomy, obvious pathology and the important anatomical relationships between the two."
Dr. Olan concluded that "CTA-based neurovascular pathology is easily visualized" with the Voxgram images. "The transparency and easily adjustable viewing perspective of the holograms allow a much greater appreciation of pathology and related anatomy as compared with surface renderings." (Digital Holographic Reconstructions vs. Surface Renderings of Neurovascular Pathology from CTA Data, Olan WJ, Bank WO, Schulz RA, Geil GE, Ridel CJ, Sekhar LN; Neuroradiology Section, Scientific Presentation 1122; Wednesday, December 3, 10:57-11:05 a.m.; Room S405-AB)
Holograms of Spine CT Eliminate Artifacts Common to Renderings
Dr. Olan also tested the hypothesis that holograms of spinal plates and screws would be less prone to artifacts than computer renderings.
Holograms and 3-D computer renderings were prepared from helical 3-D CT scans of 20 patients with hardware. Dr. Olan found that "hardware-induced beam-hardening artifacts are significant on both the ë3-Dà surface renderings and the conventional axial images. This artifact has been a frequent source of frustration to both clinicians and radiologists as important data in the area of interest cannot be evaluated." However, the "holographic display virtually eliminated the artifact and clearly displayed the hardware, post-surgical changes and resultant anatomy."
Dr. Olan concluded that "the lack of artifact allows both the clinician and the radiologist to evaluate the post-op patient without the guesswork required by current display techniques." Holographic display of helical 3-D CT in the post-op spine patient allows "the clinician and the radiologist to accurately assess the 3-D relationships in those patients with spinal hardware." (Holographic Display of Helical 3D-CT in Patients Status Post-Spinal Hardware Eliminates Display Artifacts, Olan WJ, Schulz RA, Ridel CJ, Levine Z, Bank WO, Sekhar LN; Neuroradiology Section, Scientific Presentation 1459; Thursday, December 4, 11:15-11:23 a.m.; Room S405-AB)
Simulation Technology Facilitates Workstation Preview of Volumetric Holograms
Michael Dalton, co-founder of the Digital Holography System and Director of Technical Business Development at Voxel, has also recently developed the Voxplanô technology for more accurately simulating volumetric data sets on desktop computers.
Although no substitute for true three-dimensional holograms, Voxplan offers a convenient two-dimensional preview of the Voxgram image. Compared to other two-dimensional images, the "Voxplan image is more complete than Maximum Intensity Projections (MIPs), much quicker than conventional software renderings, and close in quality to digital photographs of the corresponding Digital Holography images."
Potential applications include volumetric representations of studies in digital patient archives; monitoring simulated scout views of real-time tomographic acquisitions; and presentation of holographic images in research journals, on the World Wide Web and in teleradiology applications. Dalton noted that "Voxplan can potentially reduce costs, increase accuracy and improve productivity."
Voxel is currently incorporating Voxplan into the Digital Holography System. This particular exhibit was chosen by the RSNA as one of a select few for which CME (Continuing Medical Education - Category I) credit will be given to attendees who visit the exhibit between 12:00 and 1:00 during the meeting Monday through Thursday. The full text of the Voxplan paper with all its images will be available on-line (http://www.voxel.com) after the conference. (Simulation of Digital Holography Images for Computer-Based Medical Imaging Systems, Multisystem/Special Interest Section, Scientific Exhibit 255; Dalton MN, Hunter JV, Olan WJ, Robertson DD, Wetzner SM, Andre MP)
Other Studies
In addition to the research cited above, physicians at several other prominent medical institutions throughout the country have studied Digital Holography, including Massachusetts General Hospital-Harvard Medical School; ChildrenÃs Hospital of Philadelphia-University of Pennsylvania; Irvine Medical Center-University of California at Irvine; and Mallinckrodt Institute of Radiology-Washington University (St. Louis).
The Digital Holography System was awarded FDA clearance in September 1995. In January 1997, Voxel was awarded a US patent covering 13 claims, including five independent claims for the companyÃs method of making multiple-exposure holograms. Based in Laguna Hills, California, Voxel is a public company founded to develop, manufacture and market volumetric display systems based on multiple-exposure holography. ###
Voxel and Voxgram are registered trademarks and Digital Holography and Voxplan are trademarks of Voxel.
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