L22: Art of Cinematic and Dynamic Imaging

Question 1

What is volume rendering (VR)?

Answer 1

represents a computer algorithm used to transform cross-sectional image datasets (from CT or MRI) into a 3D image in two steps

Question 2

What is cinematic rendering (CR)?

Answer 2

uses Monte-Carlo path tracing of light (multi-dimensional and non-continuous rendering equation to integrate light scattered from all possible directions along a ray) – ie. Global Illumination meaning taking into account the effects of all of the light interactions

Question 3

Cinematic Rendering

What is ray tracing?

Answer 3

method of rendering 3D scenes by simulating the paths of light rays as they bounce off objects and materials

Question 4

Cinematic Rendering

What is global illumination?

Answer 4

effects of indirect lighting (such as shadows, reflections, refractions, and ambient occlusion) that result from ray tracing

• main benefit is that it can create more realistic and immersive 3D graphics by adding depth, contrast, and richness to the scene
• can make lighting more consistent and natural, and avoid the flat and artificial look of direct lighting

Question 5

What is cinematic rendering good for visualizing?

Answer 5

• relationship between fracture and underlying vasculature despite extensive metal artifacts (ie. in a ballistic fracture)
• enhanced visualization of soft tissue injuries in addition to underlying bone and vasculature due to inherit ability to change transparency of skin and muscle

Question 6

What is cinematic rendering previously found to be subjectively superior to volume rendering for?

Answer 6

• visualizing masked bone fractures
• realistic quality of rendering
• preference for presenting to patient and pre-surgical planning

Question 7

Why is cinematic rendered images superior in image quality as compared to volume rendered images?

Answer 7

because high dynamic range lightmaps and real-time lighting effects render the dataset

Question 8

How does VR and CR compare in terms of anatomical information?

Answer 8

• VR: can mask anatomical information and pathology
• CR: enhanced delineation of anatomical structures

Question 9

How does VR and CR compare in terms of light?

Answer 9

• VR: synthetic light source for illumination
• CR: high dynamic range (HDR) rendering lightmaps to create natural illumination of rendered data

Question 9

How does VR and CR compare in terms of enhancement?

Answer 9

• VR: lighting effects like reflection, shadows, scatter
• CR: lighting effects in real time (shadows, ambiance, multi-scattering, colour transmittance, camera properties, aperture, exposure, shutter speed) – provides more natural, enhanced perception of depth and shape more life-like images

Question 10

How does VR and CR compare in terms of quality?

Answer 10

• VR: lower in quality compared to CR
• CR: more natural and accurate presentation of anatomy

Question 11

Do not forget to evaluate soft tissue windows. These include:

Answer 11

• tectorial membrane
• apical ligament
• anterior atlanto-occipital membrane
• posterior atlanto-occipital membrane