Simulation of biatrial conduction via different pathways during sinus rhythm with a detailed human atrial model.

In order to better understand biatrial conduction, investigate various conduction pathways, and compare the differences between isotropic and anisotropic conductions in human atria, we present a simulation study of biatrial conduction with known/assumed conduction pathways using a recently developed human atrial model. In addition to known pathways: (1) Bachmann's bundle (BB), (2) limbus of fossa ovalis (LFO), and (3) coronary sinus (CS), we also hypothesize that there exist two fast conduction bundles that connect the crista terminalis (CT), LFO, and CS. Our simulation demonstrates that use of these fast conduction bundles results in a conduction pattern consistent with experimental data.

Mandible reconstruction assisted by preoperative virtual surgical simulation.

Objective: In this study, we evaluated the clinical efficacy of mandible reconstruction with preoperative virtual planning, which focused on esthetics and occlusion.

Study Design: A series of 9 patients were enrolled prospectively to undergo mandibulectomy and simultaneous reconstruction. Preoperative spiral CT scans of the maxillofacial region and the fibula region were performed.

[Six degree-of-freedom acquisition and analysis of jaw opening and closing with motion capture system].

Objective: To explore the six degrees of freedom of jaw opening and closing movement with motion capture and analysis system to establish a quantitative method for studying mandibular movement and a digital basis for virtual reality study of mandibular movement.

Methods: In a male adult with normal dentition without temporomandibular joint disorders, 3 fluorescent markers were pasted in the upper dentition and 4 in the lower dentition. Six cameras of the motion capture system were arranged in a semi-circular fashion.

Mandible reconstruction assisted by preoperative simulation and transferring templates: cadaveric study of accuracy.

Purpose: In this study we tried to define tumor resection, fibula cutting, and positioning by surgical templates to perform the mandible reconstruction surgery according to the preoperative simulation. The accuracy was evaluated through cadaveric surgery.

Materials And Methods: Five cadaveric mandibles and fibulas were obtained.

[Application of three-dimensional laser scanning-based maxillofacial soft tissue reconstruction in orthodontic treatment].

Objective: To establish a convenient and rapid method for constructing a digital model of the maxillofacial soft tissue based on three-dimensional laser surface scanning to allow direct and accurate observation of the soft tissue changes in the course of orthodontic treatment.

Methods: The point cloud data of three-dimensional laser scanning of the maxillofacial region were acquired from a healthy woman with Angle Class I occlusion, who maintained a horizontal Frankfort plane during scanning with the scanner placed at a distance of 80 cm. The scanning was repeated twice after wearing the dental cast for an Angle Class I occlusion.

[Construction of the digital models of masseter and temporal muscles with three-dimensional laser scanning].

Objective: To explore a new method for establishing digital models of the masseter and temporal muscles and superficial soft tissue using three-dimensional laser scanning technique.

Methods: One adult male cadaveric head without malformation was dissected to expose the superficial portion of the masseter and temporalis. Multiple aspects of the sample were scanned with three-dimensional laser scanning system, and the point clouds of the masseter and temporal muscles were generated.

[Three-dimensional design of surgery for mandibular retrusion].

Objective: To explore the feasibility of surgical design for mandibular retrusion using three-dimensional software.

Methods: Three-dimensional reconstruction was performed by Mimics software based on the preoperative CT data. The model of the maxillofacial region was imported into Rapidform software for measuring the associated parameters and Geomagic software for simulation of osteotomy.

[Study on the three dimensional hepatic virtual operation based on the data of 64-slice helical CT scanning].

Objective: To study the surgery plan and simulation effect of the three dimensional (3D) hepatic virtual operation based on the data of 64-slice helical CT scanning and to probe the feasibility of the virtual operation based on the FreeForm Modeling System.

Methods: The volunteer liver was scanned to collect two dimensional (2D) DICOM data of 64-slice helical CT scanning and the 3D hepatic and intrahepatic vessels model were reconstructed by MIMICS software. The reconstructed liver, the intrahepatic vessels model and the artificial tumor models were output into the FreeForm Modeling System in the STL format.

[Establishment of a testing system of three-dimensional spinal kinematics in vivo based on two- and three-dimensional image registration].

Objective: To investigate the feasibility of using two- and three-dimensional (2D/3D) image registration for establishing a testing system of 3D kinematics of the spine in vivo.

Methods: CT data of the adult human lumbar spine were collected and the two orthogonal images of the same specimen were captured using an X-ray fluoroscope at two different positions. The 3D computer models of L3 and L4 vertebrae were reconstructed.

[Construction of artificial nerve bridge by three-dimensional culture of Schwann cells with human hair keratins].

Objective: To culture Schwann cells (SCs) and human hair keratins (HHKs) for artificial nerve bridge construction.

Methods: SCs were purified by primary culture and labeled with BrdU, which were then cultured with HHKs decorated by ECM. The artificial nerve bridge was implanted into the defect of sciatic nerve, beneath the skin, and in the skeletal muscles of SD rat, respectively.

[In vitro study of formalin-fixed bone tissues for allogeneic bone grafting].

Objective: To conduct an in vitro study to assess the preliminary possibility of using formalin-fixed, instead of fresh, human bone tissues for allografting.

Methods: Fresh cadaveric bone tissues were fixed by formalin for more than 6 months and dissected into 5 mmx5 mmx5 mm pieces and 5 mmx5 mmx40 mm sticks, followed by chemical treatments to prepare the allograft bone materials. When alls treatments were completed, the bone grafts were centrifuged and their properties and cellular compatibility assessed in comparison with the currently used bone grafts clinically.

[Registration of the image data of the Virtual Chinese Female No.1].

In this study, the authors attempt to find a solution for the image registration before three-dimensional reconstruction of digitized Virtual Chinese Female No.1 (VCH-F1) image data can be completed. On the basis of a thorough understanding of the features of the image data, the parameters were determined based on the marker outside the specimen and the least-square procedure performed on the outline offset distance between two images, prior to the completion of the image registration by means of rigid body transformation with the parameters.

[Establishment of Internet-based database of the Virtual Chinese Human dataset].

To establish an Internet-based database for the dataset of Virtual Chinese Human that is accessible to the interested researchers, modifications and compression of the original VCH-format dataset of Virtual Chinese Human were performed before it was uploaded to the server, and RAID0+1 storage technology was adopted with specific download accesses designed for different users. After dataset modification and compression, the data size was considerably reduced to allow convenient data storage and transfer. The RAID0+1 storage technology guarantees the security and high-speed download of data through different means established.

Construction of dataset for Virtual Chinese Male No.1.

Objective: To establish digitized Virtual Chinese Human Male No.1 (VCH-M1) image dataset with a 0.2-mm equal interval.

[Research report of experimental database establishment of digitized virtual Chinese No.1 female].

Objective: To establish digitized virtual Chinese No.1 female (VCH-F1) image database.

Methods: A 19 years old female cadaver was scanned by CT, MRI, and perfused with red filling material through formal artery before freezing and em- bedding.