Keywords: joint disease; fracture; body layer photography, x-ray computer
[Abstract] Objective To evaluate the application value of spiral CT three-dimensional imaging for the diagnosis of bone and joint fractures and lesions. Methods Spiral CT units (Picker 5000, VOX Q workstation) were used to perform spiral scanning and three-dimensional reconstruction of 31 cases of bone and joint fractures and lesions, and the three-dimensional reconstructed images were observed from multiple directions. Results Spiral CT three-dimensional imaging technology can display the lesion site and scope in three dimensions. Conclusion Spiral 3D imaging technology can provide valuable information for the preoperative diagnosis of bone and joint lesions and fractures.
【Category】 R684
Three-dimensional helical CT imaging of bones and joints
Pan Yiguang,L Jianjun
(Lu’an Prefectural People’s Hospital, Lu’an, Anhui 237005)
[Abstract】 Objective To evaluate the usefulness of three-dimensional(3D) helical CT in diagnosing lesions and fractures of bone and joint. Three-dimensional images were obtained from helical CT scans in 31 patients with bone and joint disorders and three-dimensional images were observed The scanner was Picker 5 000 and 3D images were reconstructed with VOX Q workstation.Results Three-dimensional images The scanner was Picker 5 000 and 3D images were reconstructed with VOX Q workstation.Results Three-dimensional images reconstructed from helical CT could clearly demonstrate the location and extent of disorders in bone and joint. Conclusion Three-dimensional helical CT can provide valuable information in preoperative evaluation of bones and joints.
Key words】 joint diseases; fractures; tomography, X-ray computed
In recent years, three-dimensional spiral CT imaging has been gradually used for all parts of the body, which can make up for the lack of overall intuition in multiple levels of two-dimensional images [1, 2]. Our hospital introduced Picker 5000 spiral CT and VOX Q workstation in April 1998, carried out spiral CT scanning of bone and joint, and made 3D reconstruction images of 31 patients with complete data among them, and achieved satisfactory results.
1. Materials and methods
1.1 Case data There were 31 cases in this group, 26 males and 5 females, aged 12-72 years old. There were 23 cases in the trauma group, including 12 cases of hip joint, 3 cases of knee joint, 7 cases of spine and 1 case of shoulder joint. There were 8 cases in the lesion group, including 2 cases of malignant tumor, 1 case of osteochondroma, 3 cases of aseptic necrosis of the femoral head, 1 case of inflammatory lesion, and 1 case of lipoma.
1.2 CT technique The American-made Picker 5000 spiral CT with 4800 fixed detectors was used to sample all cases with <5 mm layer thickness spiral scan, and the reconstructed images with 60-80 layers and 1.5 mm interval were obtained by the thinning bone algorithm technique. The thinned images were then transferred to VOX Q workstation for 3D reconstruction of the sensitized area, selected bone conditions and soft tissue conditions were observed and analyzed, and 2D and 3D images were compared in parallel.
2. Results
2.1 Trauma group 22 out of 23 cases were reconstructed in 3D; 12 cases of compound trauma with dislocation of the hip were made with bone thinning algorithm, among which 6 cases were made with the technique of separating the femoral head from the acetabulum, so that the acetabular rim with or without fracture could be observed more clearly in multi-axis position (Figure 1); 7 cases of spinal fracture, the 3D reconstructed images were very good for showing the stability of bony spinal canal, transverse process, spinous process and vertebral body; 3 cases of knee trauma, among which 1 case Three cases of knee trauma, one of which showed a comminuted fracture of the right lower femoral epicondyle with a fragmented bone mass entering the joint cavity, and the 3D images showed the location of the bone mass. One case showed a posterior dislocation of the shoulder joint with a large nodal avulsion fracture.
2.2 Lesion group Among the 8 cases, there were 3 cases of aseptic necrosis of the femoral head, 2 of which were bilateral, and the reconstructed 3D images showed uneven contours and heterogeneous density of the femoral head with map-like hypodense foci (Figure 2); 1 case of chronic inflammatory lesion of the lower end of the femur was seen in 3D imaging with bone destruction, coarse disorganization of bone trabeculae and cortical fracture on both sides of the rim; 1 case of osteochondroma of the lower end of the femur was seen in 3D imaging with cortical thickening and vesicular hypodense shadow. Two cases of malignant tumors of the hip bone showed irregular bone defects and partial swelling changes on both sides of the hip bone; one case of lipoma of the heel bone showed cystic hypodense shadow with a CT value of -99 Hu on 2D images and several intervals within the hypodense shadow on 3D reconstructed images (Figure 3), and the extent of the lesion was more clearly defined.
Figure 1 After separation of the femoral head from the acetabulum, an avulsion fracture of the posterior edge of the acetabulum was seen, and several small bone fragments were visible in the joint space.
Figure 2 Uneven density of the femoral head with map-like hypodense foci
Figure 3 Several bony intervals within the hypodense shadow are seen in the 3D reconstruction image
3. Discussion
The application of three-dimensional imaging technology of spiral CT scan shows the trauma and lesion of bone and joint in three dimensions, and provides important reference for clinicians to develop treatment plans.
Bone joint axial scan, the image is tomographic, the upper and lower structures are difficult to form a three-dimensional concept when reading the film, which brings inconvenience to clinicians in diagnosis, treatment, especially pre-surgical planning; three-dimensional imaging three-dimensional display similar to large specimens, to show the overall image of joint changes, which can reduce the difference between physicians reading the film, thereby improving diagnostic accuracy and reducing misdiagnosis.
Spiral scan three-dimensional imaging technology needs to pay attention to the following issues: (1) to determine the scanning site, scope, scanning plan as far as possible to choose 5 mm layer thickness, in order to facilitate the reconstruction of thinning bone algorithm for image post-processing, so that the three-dimensional image obtained rarely distorted; (2) three-dimensional imaging should be carried out in an independent workstation system, multi-directional observation, change the different window width, window position, the use of separation techniques to observe the structure of overlapping parts (3) The 3D reconstructed images of patients with sparse bone are similar to plaque bone destruction, but the bone contour is bright and neat, the bone trabeculae exist in 2D images, and there are no signs of destruction in the bone cortex; (4) The 3D images are stereoscopic, but the fine structures are poorly displayed, and need to be combined with conventional plain films and 2D images for comprehensive analysis.
Author’s profile: Pan Yiguang, male, 39 years old, attending physician. Research interests: bone and joint imaging
Lv Jianjun, male, 42 years old, chief physician, vice president. Research interests: bone and joint
References
1. Gong Hong-Han, Kumiko Hirakata, Tarabayashi Y. Application of spiral CT three-dimensional imaging in temporal and facial areas. Chinese Journal of Radiology, 1998;32(11):765-767
2. Ma S K, Sun Y, Chen S Q. Guidance of three-dimensional CT imaging in the treatment of pelvic fractures. Journal of Practical Radiology, 1999;15(2):73～75
Received 1999-05-27, revised 1999-08-12
Journal of Clinical Orthopaedics 1999, Vol. 3, No. 2 Treatment Experience