Li-Wen Tan

The Chinese Visible Human (CVH) datasets incorporate technical and imaging advances on earlier digital humans

We report the availability of a digitized Chinese male and a digitzed Chinese female typical of the population and with no obvious abnormalities. The embalming and milling procedures incorporate three technical improvements over earlier digitized cadavers. Vascular perfusion with coloured gelatin was performed to facilitate blood vessel identification. Embalmed cadavers were embedded in gelatin and cryosectioned whole so as to avoid section loss resulting from cutting the body into smaller pieces. Milling performed at −25 °C prevented small structures (e.g. teeth, concha nasalis and articular cartilage) from falling off from the milling surface. The male image set (.tiff images each of 36 Mb) has a section resolution of 3072 × 2048 pixels (∼170 µm, the accompanying magnetic resonance imaging and computer tomography data have a resolution of 512 × 512, i.e. ∼440 µm). The Chinese Visible Human male and female datasets are available at http://www.chinesevisiblehuman.com. (The male is 90.65 Gb and female 131.04 Gb). MPEG videos of direct records of real‐time volume rendering are at: http://www.cse.cuhk.edu.hk/~crc

Active contours driven by localizing region and edge-based intensity fitting energy with application to segmentation of the left ventricle in cardiac CT images

Dual source CT of the heart is a well-known and accepted method for detection of cardiac disease. However, weak edges, touching characters, intensity inhomogeneities and complex background lead LV segmentation to leakage and false boundary, in cardiac CT images. This difficult task is accomplished in this work by establishing a new active contour model in a variational level set formulation. Its external energy functional incorporates an edge-based information fitting term, which is an adaptive diffusion flow (ADF), and responsible for extracting object boundaries, especially segmenting the weak and missing borders, and a localizing region intensity fitting, which localizes the Chan-Vese external energy against intensity inhomogeneity and complex background to improve the robustness of the proposed method. For improving the adaptability of the model, the weighted parameter between them is then designed according to the gradient information of image. Besides, the regularity of the level set function is intrinsically preserved by the length regularization term to ensure the curve smooth. Experimental results demonstrate desirable performance of our extension method for real-world dual source cardiac CT images.

Creation of the digital three-dimensional model of the prostate and its adjacent structures based on Chinese visible human.

We managed to provide three-dimensional digitized visible model of the prostate and its adjacent structures and to provide morphological data for imaging diagnosis and male urological surgery. With 3D-DOCTOR software, the contour line of prostate and its adjacent structures including rectum, bladder, male urethra, ureter, seminal vesicle, ductus deferens, ejaculatory ducts, obturator internus, levator ani, coccygeus, male pelvis, femur, prostatic nervous and venous plexus, internal and external iliac arteries were segmented from the Chinese visible human (CVH)-1 data set and the three-dimensional surfaces of intrapelvic visceras were successfully and accurately reconstructed via surface rendering, which can also be manipulated individually and interactively. Combined with AMIRA software, surface rendering reconstructed model of male urological organs and its adjacent structures via volume rendering reconstruction can be displayed together clearly and actually. It provides a learning tool of practicing virtual anatomy and virtual urological surgery for medical students and younger surgeons.

MRI Findings for Frozen Shoulder Evaluation: Is the Thickness of the Coracohumeral Ligament a Valuable Diagnostic Tool?

Background Recent studies have demonstrated that the coracohumeral ligament (CHL) is shortened and thickened in a frozen shoulder. We analyzed the rate in CHL visualization between patients with frozen shoulder and normal volunteers using Magnetic Resonance Imaging (MRI) to determine the CHL thickness in the patients with a frozen shoulder. Methods and Findings There were 72 shoulder joints in 72 patients (50 femles and 22 males with a mean age of 53.5 years) with clinical evidence and MR imaging evidence of frozen shoulder. These were prospectively analyzed to identify and measure the maximum thickness of the CHL. The control group, which included 120 shoulder joints in 60 normal volunteer individuals (30 females and 30 males with a mean age of 50.5 years) was also referred for MR imaging. A chi-square test was used to analyze the data of the rate of CHL visualization between the patients with frozen shoulder and the control group. A two-way ANOVA was used to analyze the mean maximal thickness of CHL. The CHL was visualized in 110 out of 120 shoulders in the control group (91.7%), and in 57 out of 72 shoulders for the frozen shoulder group (79.2%), there was significant difference, using a chi-square test (P<0.05). The CHL was not visualized in 10 out of 120 shoulders in the control group (8.3%), and 15 out of 72 shoulders in the frozen shoulder group (20.8%), there was a significant difference (P<0.05). The CHL thickness (3.99±1.68 mm) in the patients with frozen shoulder was significantly greater than that thickness (3.08±1.32 mm) in the control group, using a two-way ANOVA (P<0.001). The CHL thickness (3.52±1.52 mm, n = 97) in the female shoulders was no significantly greater than that thickness (3.22±1.49 mm, n = 70) in the male shoulders, using a two-way ANOVA (P>0.05). Conclusions MR Imaging is a satisfactory method for CHL depiction, and a thickened CHL is highly suggestive of frozen shoulder.

Thin sectional anatomy, three-dimensional reconstruction and visualization of the heart from the Chinese Visible Human

The research aimed to provide sectional anatomic and three-dimensional (3D) virtual anatomic bases for imaging diagnosis and surgical operation by the use of data from the heart of the first Chinese digitized Visible Human. Data from the series of thin sections of the heart were analyzed and input into an SGI workstation, and 3D reconstruction and virtualization of the heart were performed. Each image of sectional anatomy was clear and the 3D structures of the heart were reconstructed in their entirety. All reconstructed structures can be displayed by multiple structural and color modes, individually or jointly, and can be rotated continuously in any plane. The model of the virtual heart clearly showed fine structures of the heart in random orientation. The dataset of the sectional anatomy provides a fine and integrated morphologic base for imaging diagnosis. The 3D reconstructed images clearly show the internal and entire structures of the heart.

Segmentation and three-dimension reconstruction of Chinese digitized human cerebrum

OBJECTIVE A 3D digitized visible model of human cerebrum was built to provide anatomical structure for making plans of cerebral surgical operation and realizing accurate simulation of cerebrum on computer. METHODS Transverse sectional anatomy data of the cerebrum were chosen from the first Chinese visible human (one male and one female). Semi-automated segmentation and Photoshop software were selected to segment cerebral cortex, white matter, basal nuclei, lateral ventricle, hippocampus, etc. On personal computer, the segmented structures were reconstructed in 3D with volume rendering reconstruction and surface rendering reconstruction. RESULTS Two accurately segmented images of the main structures of cerebrum were completed. The reconstructed structures can be displayed singly, in small groups or as a whole and can be continuously rotated in 3D space at different velocities. CONCLUSION Combining volume-rendering reconstruction with surface rendering reconstruction overcomes the defects of surface rendering reconstruction that lack of internal anatomical information, which provides a new method for 3D reconstruction. The reconstructed cerebrum and the main internal structures are realistic, which demonstrates the natural shape and exact position of the structures. It provides an accurate model for the automated segmentation algorithmic study and provides a digitized anatomical mode of cerebrum.

Computerized 3D-reconstructions of the ligaments of the lateral aspect of ankle and subtalar joints*

Abstract3D-reconstruction images of the structures of lateral aspect of the ankle and subtalar joints were produced using plastination to make equidistant serial sections of 1.2 mm in thickness. A SGI workstation was employed to reconstruct the structures of the ligaments of the lateral aspect of ankle and subtalar joints in three dimensions. Reconstructed structures were displayed singly, in groups or as a whole, and these were rotated continuously at different velocities in 3D space. Different diameters and angles of the reconstructed structures could be measured easily. Improved results could be achieved with the use of a special sectional anatomical technique, i.e. contours + marching cubes algorithm.

Creation of a female and male segmentation dataset based on Chinese Visible Human (CVH)

OBJECTIVE Segmentation is a necessary step when creating realistic three-dimensional (3D) models. In order to build 3D models of whole body structures and have a wider lateral application, the thin sectional anatomical images of the Chinese Visible Human (CVH) dataset should be segmented. The more detailed structures are segmented to provide greater potential for wider application of the segmented images. MATERIALS AND METHODS All the images based on the CVH male and female dataset were segmented semi-automatically using PHOTOSHOP software. This research lasted about 7 years. RESULT In this study, 869 structures of CVH male and 860 structures of CVH female were semi-automatically segmented, and the formats for the segmented color-filled image data were PSD and PNG. In these segmented structures, nearly all skeletal muscles included muscle belly and tendon, and hollow organs included their organ walls and their lumen. Most nerve trunks, small arteries, lymph nodes, and lymph ducts were also segmented. Many surface-rendering and volume-rendering organ models were created using these segmented images. CONCLUSION The CVH male and female images represent the normal Asian population. After segmentation, the images can be reconstructed directly in 3D and greatly facilitate the biological modeling of physical and physiological information, a great help in improving medical and biological science in China.

The pre-styloid compartment of the parapharyngeal space: a three-dimensional digitized model based on the Chinese Visible Human

To build a digitized visible model of the parapharyngeal space of the Chinese Visible Human and to provide a sectional anatomic basis for radiological and clinical diagnosis of the parapharyngeal space, sectional anatomy data of the parapharyngeal space were selected from the Chinese Visible Human male and female to compare with MR imaging findings in the axial planes. From these data the parapharyngeal space and surrounding structures were segmented. They were then reconstructed in three dimensions on PC. In the axial planes of the sectional anatomy and MR imaging, the shape, content and relations of the parapharyngeal space were clearly displayed and the dominant plane for showing the parapharyngeal space was elicited. The three-dimensional reconstructed images displayed perfectly the anatomic relationships of the parapharyngeal space, parotid, muscles, mandible and vessels. All reconstructed structures can be displayed singly, in groups or as a whole; any diameter or angle of the reconstructed structures can be easily measured. The Chinese Visible Human male and female data set can provide complete and accurate data. The digitized model of the parapharyngeal space and its surroundings offers unique insights into the complex anatomy of the area, providing morphologic data for imaging diagnosis and surgery of the parapharyngeal space.

Anatomical education and surgical simulation based on the Chinese Visible Human: a three-dimensional virtual model of the larynx region

Anatomical knowledge of the larynx region is critical for understanding laryngeal disease and performing required interventions. Virtual reality is a useful method for surgical education and simulation. Here, we assembled segmented cross-section slices of the larynx region from the Chinese Visible Human dataset. The laryngeal structures were precisely segmented manually as 2D images, then reconstructed and displayed as 3D images in the virtual reality Dextrobeam system. Using visualization and interaction with the virtual reality modeling language model, a digital laryngeal anatomy instruction was constructed using HTML and JavaScript languages. The volume larynx models can thus display an arbitrary section of the model and provide a virtual dissection function. This networked teaching system of the digital laryngeal anatomy can be read remotely, displayed locally, and manipulated interactively.