Digital Anatomy And Virtual Reality Of The Larynx

The digital anatomy is a recently developed subject, which firstly digitize the anatomic structures and their functions and then process the digital information with the digitized technology in order to observe, measure or operate virtually. With the development of CT,MRI and 3D visualization technique, it makes the digitized 3D anatomic structures more and more possible, especially when American VHP and Chinese CVH were established, which provided the high-quality color cross section images of human body and also provided the high-quality data to reconstruct the 3D models of human organs or structures. By using these data sets, we can build the digitized human models, such as geometric models or voxel models. Based on these models and combined the anatomic teaching methods, we can display the sectional anatomy and gross anatomy clearly; furthermore, by using these models, we can carry out the arbitrary section acquisition function, undamaged specimen display and tele-education, etc. Now the digital anatomy is still in the initial phase, there remains questions, such as data acquisition, image segmentation, 3D model reconstruction and virtual reality, to be overcome or solved.Our study is focused on the implementation of digital anatomic teaching, providing theoretical basement and building the technical platform basded on digitized human modeling technique, including data acquisition and processing, image segmenting and reconstruction, model visualization and virtual reality, etc.In our study, we selected the images of laryngeal region (between the angle of mandible and the inferior margin of the thyroid gland )from the CVH 2, one set of coronal sections and one set of sagittal sections of head and neck acquired by frozen milling-cutting. After registration of the images automatically through reserved fiducial rods, the high-accuracy data sets were built.We reconstructed structures of 3 data sets by using Amira software in the graphic workstation. Based on resampling technique, we built the volume models of the larynx, which can display arbitrary section of the model and provide the virtual dissection function. We also precisely segmented the laryngeal structures manually on 2D images of laryngeal region from the CVH 2, then transited the segmented images into several formats according to different visualization systems by using our own software. The laryngeal structures were reconstructed and 3D displayed in the virtual reality system of Dextrobean and Amira, which can help anatomic teaching and simulating clinical practice in the laryngeal region. We also improve the method of precise segmenting, virtual reality technique and platforms of software and hardware used on the digital anatomic field.By using Amira software, we transformed the surface laryngeal model into VRML type after the model was simplified and smoothing processed. Based on the characters of visualization and interactive of the VRML model, and combined the HTML and JavaScript languages, we built the network of digital laryngeal anatomy teaching, and approached the possibility of transmission the 3D model and virtual simulation of anatomy. It was very helpful in the field of anatomic research, teaching and application the visual technique and platform.Results and conclusions:1. according to the reserved fiducial rods on the images, the datasets were aligned automatically by our own software, and the mismatch was less one pixel.2. Acquired the transverse, coronal and sagittal sections of the same specimen based on the digital resampling technique. It was convenient to observe and measure the different structures on the different sections and carry out the virtual sectional anatomy, which provided the reference for clinical diagnosis and practice.3. The laryngeal structures were precisely segmented on the 2D images of laryngeal region from the CVH 2 manually, then transited the segmented images into several formats according to different visualization systems by using our own software. The segmented data can be used in different visualization systems。4. Reconstructed the laryngeal models of surface rendering and volume rendering, respectively. They provided the interactive 3D models for anatomic teaching and dissection, also provided the supplementary for the anatomic textbook.5. Reconstructed the laryngeal model of VRML, carried out the visual controlling of the 3D model. Combined the HTML and JavaScript languages, we built the network of digital laryngeal anatomy teaching, which can be distantly read, locally displayed and manipulated interactively. It was very helpful in the field of anatomic research, tele-teaching and application the visual technique and platform.