Using CINEMA 4D for Visualizing Subtle Structures of the Human Retina

"CINEMA 4D was chosen because of its truly intuitive interface, immense versatility, competent support staff, and, off course, its superior rendering speed and quality."

Dr. Carl Glittenberg

The human retina is an organ with a complex structure and intricate functions. It is also susceptible to many different diseases that can lead to severe vision impairment, and even blindness. These diseases are often very difficult to evaluate using conventional light microscopes and retinal cameras.

In the last several years however a new kind of technology has emerged that is of great value to ophthalmologists in their assessment of and research into retinal diseases. This technology is called Optical Coherence Tomography (OCT). This technology enables Ophthalmologists to acquire cross-sectional images of the retina of live patients.

The acquisition is completely painless and in no way harms the patient. With the further development of OCT technology to so-called Spectral Domain OCT it is now possible to acquire hundreds of these images within just a few seconds, which in turn makes it possible to re-create three dimensional volume stacks of the area of the retina that has been scanned. This volume is then visualized using various 3D rendering engines. The problem that each of the commercial and non-commercial rendering engines has is that they are all ray-casting and not ray-tracing systems. This is done because ray casting is significantly faster and can therefore be used in a real-time system. The downside of a ray-cast system is that it produces no real shading, which means that the reconstructions have no contrast.

This is why we decided to try to use CINEMA 4D's very fast and reliable Ray-Tracing algorithms to correctly calculate the intra-specimen shadows. CINEMA 4D was chosen because of its truly intuitive interface, immense versatility, competent support staff, and, off course, its superior rendering speed and quality. The use of CINEMA 4D in this project made it possible for us to significantly increase the amount of information that we get from the OCT data, which may in turn lead to an increased understanding of retinal pathologies, as well as a method of monitoring their treatment. The Ludwig Boltzmann Institute has won numerous Awards in conjunction with this research and has published several articles on the subject.

Figure 1: Healthy Retina. The top two pictures show reconstructions created with CINEMA 4D. The bottom left image shows an example of cross-sectional data of this patient acquired with the Carl Zeiss Meditec Cirrus HD-OCT.

Figure 2: Membranes on the Retina. These two images show the difference that CINEMA 4D ray-tracing system makes when evaluating the data. The top image shows the data set with ray-tracing. The bottom shows the same data set without ray-tracing. The structures and membranes around the retina are significantly clearer in the top image. The bottom image amounts to a simulation of what this patient's data would look like on conventional visualization systems.

Figure 3: Macular hole. These images show a type of disease that presents itself as a hole in the middle of the retina. The ray-traced image on the top left shows the details much clearer than the non-ray-traced image on the right.

Figure 4: Macular hole. These images show the same macular hole as in Figure 3. In this instance we created a ray-traced reconstruction of a "retinal thickness map". It shows the relative thickness of the retina in different areas. This can give us additional information as to the condition of the retina.

The data was acquired using the Carl Zeiss Meditec Cirrus HD-OCT.

Relevant Links

Download complete article as pdf.

http://www.lbg.ac.at/de/life-sciences/2008/03/17/lbi-fuer-retinologie-und-biomikroskopische-laserchirurgie