ObjectiveTo fabricate the bionic scaffolds of rat spinal cord by combining three dimensional (3D) printer and 3D software, so as to lay the foundation of theory and technology for the manufacture of scaffolds by using biomaterials. MethodsThree female Sprague Dawley rats were scanned by 7.0T MRI to obtain the shape and position data of the cross section and gray matter of T8 to T10 spinal cord. Combined with data of position and shape of nerve conduction beam, the relevant data were obtained via Getdata software. Then the 3D graphics were made and converted to stereolithography (STL) format by using SolidWorks software. Photosensitive resin was used as the materials of spinal cord scaffolds. The bionic scaffolds were fabricated by 3D printer. ResultsMRI showed that the section shape of T8 to T10 segments of the spinal cord were approximately oval with a relatively long sagittal diameter of (2.20±0.52) mm and short transverse diameter of (2.05±0.24) mm, and the data of nerve conduction bundle were featured in the STL format. The spinal cord bionic scaffolds of the target segments made by 3D printer were similar to the spinal cord of rat in the morphology and size, and the position of pores simulated normal nerve conduction of rat spinal cord. ConclusionSpinal cord scaffolds produced by 3D printer which have similar shape and size of normal rat spinal cord are more bionic, and the procedure is simple. This technology combined with biomaterials is also promising in spinal cord repairing after spinal cord injury.
【Abstract】Objective To investigate the anatomic structure and experimental methods of peribiliary vascular plexus(PVP) in rat’s hepatic portal bile duct.Methods To observe the morphological structure of PVP in rat’s hepatic portal bile duct after the hepatic artery was perfused with Chinese ink and transparency management, performed and to make three dimensional reconstruction of PVP’s spacial structure in MoticBuaa3Dvol software.Results The microvascular distribution and plane structure of PVP in rat’s hepatic portal bile duct could be shown clearly through Chinese ink perfusion and transparency management. The three dimensional structure of PVP could be reconstructed effectively by MoticBuaa3Dvol software, its effect was verisimilitude. Conclusion Chinese ink perfusion and vitrification is a simple and easy method in PVP’s morphologic study of rat’s hepatic portal bile duct. MoticBuaa3Dvol software is useful in microvascular study of hepatic portal bile duct.
Objective To discussion the diagnostic significance of CT three dimension reconstruction in local recurrence after surgery for gastric cancer. Methods Thirty-nine patients with gastric cancer recurrence after radical surgery were performed multislice CT scan between December 2004 and December 2008 in The Third Affiliated Hospital of Harbin Medical University, and the images were reconstructed by three dimension reconstruction in workstation. The axial CT images and three dimension images of gastric cancer recurrence patients were diagnosed and compared. Results The detection rates of axial images and three dimensional CT images were 82.1% (23/28) and 100% (28/28) for pathological morphology, 62.5% (10/16) and 93.8%(15/16) for extension of tumors, 66.7% (10/15) and 93.3% (14/15) for lymph node metastasis, 87.5% (7/8) and 87.5% (7/8) for distant metastasis, respectively. Conclusions CT three dimension reconstruction can carry out more direct and solid results, such as measuring the vertical thickness of the thickened gastric wall, observing the infiltration situation with proximal organ, and metastasis of the lymph node. The method of three dimension reconstruction used for the diagnosis of local recurrence after surgery for gastric cancer is better than the axial image, and it can supply data which would be useful for the tumor advancing treatment.
ObjectiveTo investigate the feasibility and early effectiveness to treat osteonecrosis of the femoral head (ONFH) with pedicled iliac bone graft assisted by individual digital design and three dimensional (3D) printed navigation templates. MethodsBetween February and June 2014, 15 patients (24 hips) with ONFH underwent pedicled iliac bone graft assisted by individual digital design and 3D printed navigation templates. There were 11 males (17 hips) and 4 females (7 hips) with a mean age of 38 years (range, 18-56 years) and a mean disease duration of 7.5 months (range, 1-24 months); the left hip was involved in 2 cases, the right hip in 4 cases, and both hips in 9 cases. There were 7 cases (12 hips) of steroid-induced ONFH, 5 cases (8 hips) of alcohol-induced ONFH, 1 case (1 hip) of traumatic ONFH, and 2 cases (3 hips) of idiopathic ONFH. The preoperative Harris score was 56.60±6.97. According to Association Research Circulation Osseous (ARCO) staging system, 5 hips were classified as stage IIB, 8 hips as stage IIC, 6 hips as stage IIIB, and 5 hips as stage IIIC. The navigation templates were designed and printed to assist accurate location and debridement of necrosis area according to preoperative CT scanning at the beginning of pedicled iliac bone grafting procedure. ResultsThe mean operation time was 135 minutes (range, 120-160 minutes), mean amount of bleeding was 255 mL (range, 200-300 mL). All the wounds healed primarily, no complication of deep vein thrombosis or infection was observed. All patients were followed up 12-16 months (mean, 14 months). The location of necrosis area was in accordance with preoperative design, which was removed completely without penetration of joint surface, pedicled iliac bone graft was performed at the right site according to postoperative imaging examination. Radiographically, graft fusion was achieved at 2.7 months (range, 2-3 months) in all patients. All the hips had no collapse during follow-up. Hip pain was relieved, and range of motion was improved. The Harris score was significantly improved to 89.53±5.83 at last follow-up (t=14.319, P=0.000). The results were excellent in 12 hips, good in 10 hips, and fair in 2 hips according to Harris score standard. ConclusionPedicled iliac bone graft assisted by individual digital design and 3D printed navigation templates for treatment of adult ONFH has the advantages of accurate location and complete debridement of necrosis area, so satisfactory results can be obtained.
ObjectiveTo study the digital anatomy and application value of the thoracic dorsal artery based on CT angiography (CTA). MethodsBetween September 2012 and June 2014, aorta CTA images were chosen from 10 cases (20 sides) undergoing aorta CTA. By using Mimics 17.0 software for three dimensional (3D) reconstruction of image post-processing, the digital vascular anatomical information were obtained after observing and measuring the origin of the thoracic dorsal artery, the number of perforators, type, inner diameter, and pedicle length; and the body surface location of perforator vessel was determined, and then the thoracic dorsal artery perforators tissue flap harvesting was simulated. Results3D reconstruction images showed that the thoracic dorsal artery originated from subscapular artery, 76 perforator vessels were found, including 32 perforators (42.1%) from the medial branch of the thoracic dorsal artery and 44 perforators (57.9%) from the lateral branch of the thoracic dorsal artery, of which 69 were intramuscular perforators (90.8%) and 7 were direct skin artery (9.2%). The inner diameter of the thoracic dorsal artery was (1.69±0.23) mm, and its pedicle length was (2.12±0.64) cm. The first lateral perforator of the thoracic dorsal artery located at (1.65±0.42) cm above the horizontal line of the inferior angle of scapula and at (1.68±0.31) cm lateral to vertical line of the inferior angle of scapula. The first medial perforator located at (1.43 ±0.28) cm above the horizontal line of the inferior angle of scapula and at (1.41±0.28) cm lateral to vertical line of the inferior angle of scapula. The thoracic dorsal artery perforators flap harvesting was successfully simulated. ConclusionCTA is a more intuitive method to study the thoracic dorsal artery in vivo, it can clearly display 3D information of the main blood supply artery course and distribution after flap reconstruction, so it can effectively and accurately guide the design of the flap.
ObjectiveTo study the difference of femoral condylar twist angle (CTA) measurement in three dimensional (3-D) reconstruction digital models of human knee joint based on the two dimensional (2-D) images of MRI and CT so as to provide a reference for selecting the best method of CTA measurement in preoperative design for the femoral prosthesis rotational position. MethodsThe CTA of 10 human cadaveric knee joint was measured in 3-D digital models based on MRI (group A), in 3-D digital models based on CT (group B), in the cadaveric knee joint with cartilage (group C), and in the cadaveric knee joint without cartilage (group D), respectively. The statistical analysis of the differences was made among the measurements of the CTA. ResultsThe CTA values measured in 3-D digital models were (6.43±0.53)° in group A and (3.31±1.07)° in group B, showing significant difference (t=10.235, P=0.000). The CTA values measured in the cadaveric knee joint were (5.21±1.28)° in group C and (3.33±1.12)° in group D, showing significant difference (t=5.770, P=0.000). There was significant difference in the CTA values between group B and group C (t=5.779, P=0.000), but no significant difference was found between group A and group C (t=3.219, P=0.110). ConclusionThe CTA values measured in the 3-D digital models based on MRI are closer to the actual values measured in the knee joint with cartilage, and benefit for preoperative plan.
ObjectiveTo evaluate the ectopic osteogenesis of recombinant human bone morphogenetic protein 2 (rhBMP-2) loaded chitosan (CS)/dextran sulfate (DS) by micro-CT. MethodsrhBMP-2/CS/DS microspheres were prepared by the ionic crosslinking and its shape was observed under the scanning electron microscope. The release of rhBMP-2 was determined from resultant microspheres by ELISA assay. Forty-eight Sprague Dawley male rats were randomly divided into 4 groups (n=12), quadriceps muscle bag model was made, gelatin sponge (group A), CS/DS microspheres (group B), rhBMP-2 (group C), and CS/DS/rhBMP-2 microspheres (group D) were implanted into the bags respectively. The tissue samples with heterotopic ossification were harvested for micro-CT scanning at 4, 8, 12, and 16 weeks. The tissue mineral density (TMD), bone volume fraction (BVF), trabecular thickness (Tb.Th), trabecular number (Tb.N), bone mineral density (BMD), and tissue mineral content (TMC) were measured. ResultsThe prepared rhBMP-2/CS/DS microspheres with smooth surfaces were spherical and evenly disperses without obvious agglomeration. At 2 hours, microsphere started a sudden release period in vitro; the release reached a peak at 2 days; and the release cycle lasted about 20 days. The rats survived to the end of the experiment. At each time point after operation, no radiation developed and no osteogenesis was observed by three dimensional reconstruction in groups A and B. However, radioactive strength and reconstructed bone tissue gradually increased in groups C and D, and group D had more radioautography and more bone tissues than group C. At each time point, TMD, BVF, Tb.Th, Tb.N, BMD, and TMC of groups A and B were zero. Ectopic bone formed with time, the other parameters showed an increasing trend except Tb.N in groups C and D, showing significant difference when compared with groups A and B at each time point (P < 0.05). There was no significant difference between groups C and D at 4 weeks (P>0.05); the parameters of group D were significantly higher than those of group C at 8-16 weeks (P < 0.05). ConclusionrhBMP-2/CS/DS microspheres have stronger ability of ectopic bone formation than single rhBMP-2.
Objective To establish a model for studying on mechanical responses of osteoblasts seeded in 3 dimensional(3D) scaffold. Methods Fifty pieces of bioderived cancellous bones, whose holes were 500 to 800 μm and density was 0.36 to 0.45g/cm3, were obtained as the scaffolds. They were cultured with the third passage suspension of Wistar rat. Twenty-four of the 50 scaffolds were constructed under apparent strain sine waveform with amplitude of 1 000 με, frequency of 3 Hz, and duration of 3 min/d, as experimental group. The other scaffolds were control group. After 3day coculture, osteoblasts were observed with scanning electron microscope. The proliferation of the osteoblasts was checked by MTT on scheduled date. Results Scanning electron microscopic observation showed that osteoblasts ttached and spread on the trabeculae, which presented the validity of the model under proper mechanical condition. Experiment showed that mechanical environment promoted theproliferation of osteoblasts. The observation of proliferation of osteoblasts showed that the quantity of osteoblasts in the experimental group was higher than that in the control group 1,4,8,12,16,20,24, and 28 days after culturing. Therewas significant difference between the two groups 12,16,20,24,and 28 days afterculturing(P＜0.05). Conclusion The establishment of the model can facilitate the study of mechanical responses of osteoblasts under different conditions.
ObjectiveTo observe the in vivo three-dimensional (3-D) transient motion characteristics of the subaxial cervical spine in healthy adults. MethodsSeventeen healthy volunteers without cervical spine related diseases were recruited for this study, including 8 males and 9 females with a mean age of 26 years (range, 23-41 years). The vertebral segment motion of each subject was reconstructed with CT, and Rhinoceros 4.0 solid modeling software were used for 3-D reconstruction model of the subaxial cervical spine. In vivo cervical vertebral motion in flexionextension, left and right bending, left and right rotation was observed with dual fluoroscopic imaging system (DFIS). Coordinate systems were established at the vertebral center of C3-7 to obtain the intervertebral range of motion (ROM) and displacement at C3, 4, C4, 5, C5, 6, and C6, 7. The X-axis pointed to the left along the coronal plane, the Y-axis pointed to the back along the sagittal plane, and the Z-axis perpendicular to the X-Y plane pointed to the head. The ROM along X, Y, and Z axises were represented by rotation in flexion-extension (α), in left-right bending (β), and in left-right twisting (γ) respectively, and the displacement in left-right direction (x), in anterior-posterior direction (y), and in proximaldistal direction (z), respectively. ResultsIn flexion and extension, the displacement in anterior-posterior direction of C6, 7 was significantly less that of other segments (P<0.05), but the displacements in left-right direction and in proximaldistal direction showed no significant difference between segments (P>0.05); the ROM values in flexion-extension of C4, 5 and C5, 6 were significantly larger than those of C3, 4 and C6, 7 (P<0.05), and the ROM value in left-right twisting of C4, 5 was significantly larger than those of C5, 6 and C6, 7 (P<0.05), but the ROM value in left-right bending showed no significant difference between segments (P>0.05). In left and right bending, there was no significant difference in the displacement between other segments (P>0.05) except that the displacement in anterior-posterior direction of C3, 4 was significantly larger than that of C4, 5 (P<0.05), and that the displacement in proximal-distal direction of C6, 7 was significantly less than that of C3, 4 and C4, 5 (P<0.05); no significant difference was shown in the ROM value between segments (P>0.05), except that the ROM value in left-right twisting of C3, 4 was significantly larger than that of C5, 6 and C6, 7 (P<0.05). In left and right rotation, the ROM value in left-right twisting of C3, 4 was significantly larger than that of C4, 5 and C6, 7 (P<0.05), and the displacement and ROM value showed no significant differece between other segments (P>0.05). ConclusionThe intervertebral motions of the cervical spine show different characters at different levels. And the 6-degree-of-freedom data of the cervical vertebrae are obtained, these data may provide new information for the in vivo kinematics of the cervical spine.
Early screening based on computed tomography (CT) pulmonary nodule detection is an important means to reduce lung cancer mortality, and in recent years three dimensional convolutional neural network (3D CNN) has achieved success and continuous development in the field of lung nodule detection. We proposed a pulmonary nodule detection algorithm by using 3D CNN based on a multi-scale attention mechanism. Aiming at the characteristics of different sizes and shapes of lung nodules, we designed a multi-scale feature extraction module to extract the corresponding features of different scales. Through the attention module, the correlation information between the features was mined from both spatial and channel perspectives to strengthen the features. The extracted features entered into a pyramid-similar fusion mechanism, so that the features would contain both deep semantic information and shallow location information, which is more conducive to target positioning and bounding box regression. On representative LUNA16 datasets, compared with other advanced methods, this method significantly improved the detection sensitivity, which can provide theoretical reference for clinical medicine.