Cinematic rendering algorithms create more photorealistic images
A new 3D visualization method for computed tomography, called cinematic rendering, can provide more detailed, realistic images than current imaging technologies, according to a new study in Abdominal Radiology.
Volume rendering has become a commonly used software tool for the 3D visualization of CT image data, working with computational algorithms and light to provide information about a disease process or complex region of the anatomy that conventional images can’t provide. The technique is particularly helpful in dealing with hard to see areas of the body, such as the kidneys or urinary tracts.
Cinematic rendering, which has been recently approved by the Food and Drug Administration, is similar to volume rendering but is more complex. The volume rendering computation models use only one light ray per pixel. In contrast, cinematic rendering uses a global lighting model that takes into account many light rays as they move through the imaged volume and includes effects on the light rays, such as scatter.
The actual creation of the cinematic rendering images is done on a separate workstation optimized for 3D imaging. The result of the process yields enhanced surface detail and shadowing effects, producing better quality images.
The researchers, from Johns Hopkins University School of Medicine in Baltimore, reviewed the effectiveness of cinematic rendering by comparing it with volume rendering when evaluating kidney pathologies.
For example, an important part of planning for kidney surgery is knowing the number and location of renal arteries and veins, which can vary, especially as surgeons deal with kidney abnormalities. Volume rendering has been shown to be accurate in identifying accessory arteries and variant vein anatomies before surgery. But cinematic rendering may perform better.
“The highly detailed vascular maps produced by the [cinematic rendering] technique may provide similar information to that obtained from (volume rendering) but with a more photorealistic appearance,” the study authors state.
Another potential area where cinematic rendering may be superior is in treating kidney cancer. For instance, renal cell carcinoma is the most common type of kidney cancer and can manifest as one or more tumors. However, the aggressiveness of each tumor varies. Noninvasive imaging can’t differentiate the aggressive tumors from non-aggressive ones, or whether a mass is malignant or benign. As a result, most patients with a mass are presumed to have an aggressive tumor and undergo a full or partial nephrectomy.
Cinematic rendering may be better than other 3D visualization techniques in dealing with this cancer because it adds the photorealistic lighting and shadowing that enhances detail of the masses’ positions and may help differentiate which tumors are benign. This will greatly help in preoperative planning.
In addition, an experienced radiologist can create and review the cinematic rendering images for most cases in approximately five minutes, according to the study.
Cinematic rendering enables “a new level of anatomic detail with 3D CT visualization. The role of (cinematic rendering ) in renal pathology has yet to be thoroughly explored, although the potential suggested by the photorealism of the ﬁgures in this review indicates that further study would be warranted. Ultimately, studies that explore the utility of (cinetimc rendering) in a wide range of conditions and that are backed by extensive surgical and/or pathological correlation are needed to establish the potential diagnostic beneﬁts of this new technique,” the authors conclude.