Objective To achieve threedimensional (3D) contour image of boneand articular cartilage for fabricating custommade artificial semiknee joint as segment bone allograft.Methods The distal femora of human and pig were scanned with Picker 6000 spiral X-ray computed tomography with 1.0 mm thick slice. The data obtained were treated in Voxel Q image workstation for 3D reconstruction with volume rendering technique. After being downloaded to personal computer at 0.1 mm interval, the transaxial 2D image data were converted into 2D digitized contour data by using image processing software developed by the team. The 2D digitized data were inputted into image processing software of Surfacer 9.0 (Imageware Company, USA), then the 3D wire frame and solidimages of femoral condyle were reconstructed. Subsequently， based on the clinical experience and the requirement of the design of artificial knee joint, the 3Dcontour image of bone or articular cartilage was extracted from the surrounding.Results The 3D contour image of bone or articular cartilage presented was edited and processed easily for the computer aided design(CAD) of custom-madeartificial knee joint.Conclusion The 3D contour image of boneand articular cartilage can be obtained by spiral CT scanning, and the digitized data can beapplied directly to CAD of custom-made artificial joint and subsequently rapidprototyping fabricating. In addition, the reconstruction method is simple and can be applied widely to clinical implant fabricating practice of dentistry and orthopaedics.
Objective To evaluate the diagnostic value of analyzing the pattern of gallbladder wall enhancement on MDCT to identify the different causes of acute cholecystitis. Methods In January 2009 to December 2012， 169 patients diagnosed with acute cholecystitis caused by various pathologic conditions were performed MDCT scans， the images of portal venous phase and clinical data were retrospectively reviewed by two blinded radiologists. There were 146 cases in non-hepatopathy cholecystitis group and 23 cases in hepatopathy cholecystitis group. The other 5 normal gallbladder cases diagnosed by MDCT scans were retrospectively reviewed as contrast group. Using five patterns according to the enhancement pattern of flat gallbladder wall thickening on MDCT. The study cases were then divided into five patterns and the thickness of the mucous membrane were measured. The occurrence rate of each pattern and the thickness of the mucous membrane between the groups were compared respectively. Results In the non-hepatopathy cholecystitis group， there were typeⅡin 102 cases （69.9%）， typeⅢin 5 cases （3.4%）， typeⅣ in 30 cases （20.5%）， and typeⅤ in 9 cases （6.2%）. In the hepatopathy cholecystitis group， there were typeⅡin 2 cases （8.7%）， typeⅢ in 11 cases （47.9%）， typeⅣin 5 cases （21.7%）， and typeⅤin 5 cases （21.7%）. The occurrence rate of typeⅡin the non-hepatopathy cholecystitis group was significialtly higher than that in the hepatopathy cholecystitis group （P＜0.005）. The occurrence rate of typeⅢ and typeⅤ in the hepatopathy cholecystitis group were significialtly higher than those in the non-hepatopathy cholecystitis group（P＜0.005， P＜0.05）. The occurrence rate of type Ⅳ between the two groups had no significant difference （P＞0.05）. TypeⅠonly present in the contrast group. The non-hepatopathy group’s mean mucous membrane thickness was （2.61±1.30） mm ， which was thicker than the hepatopathy group’s （2.02±0.52） mm（t=2.22， P＜0.05）. Conclusion Analyzing the enhancement pattern of a thickened gallbladder wall on MDCT is helpful in identifying the causes of acute cholecystitis， and the gallbladder perforation or not.
ObjectiveTo investigate the imaging findings of carcinoma of body and tail of the pancreas. MethodsTotally twentythree patients with carcinoma of body and tail of the pancreas were studied. The diagnosis was proven by surgery and pathological findings. The imaging features of twentythree cases were reviewed including the location, size, shape, texture, and enhancement patterns of the tumor masses. Five cases underwent enhanced MRI examination, 18 cases underwent enhanced spiral CT examination. ResultsThe tumors located in the pancreatic body in 5 cases, located in the tail in 7 cases, and located in the body and tail of pancreas in 11 cases. The tumor masses were irregular in shape and heterogeneously hypointense from CT scan. From MR, the masses were slightly hypointense on T1WI, and slightly or mixed hyperintense on T2WI. Nineteen cases showed heterogeneous slight enhancement and four cases had no enhancement. The tumors were well demarcated in five cases, while those were poorly defined in the other 18 cases. Metastatic lymphadenopathy was shown in 16 cases, vascular invasion in 8 cases, and metastatic lesions of other organs in 3 cases. ConclusionThe carcinoma of body and tail of the pancreas shows certain characteristic imaging. CT and MRI examination can reflect the morphologic features, the hemodynamic alterations, and the involvement of adjacent structures and organs.
Objective To investigate differential points of clinical symptoms and pathology of solid-pseudopapillary tumor of the pancreas (SPTP) and islet cell tumor (ICT). Methods Fifteen cases of SPTP and twelve cases of ICT were studied in this retrospective research. Clinical symptom, pathologic feature and computed tomography (CT) image of patients with both tumors were analyzed, and the imaging features were compared with pathological results. Results The mean age of SPTP patients was 22.4 year-old. Twelve patients with SPTP presented a palpable abdominal mass as the initial symptom. It was observed that the tumor cells were located in a pseudopapillary pattern with a fibro-vascular core histologically. On the CT images, a mixture of solid and cystic structures could be seen in all the tumors. After taking enhanced CT scan, the solid portion was slightly enhanced in the arterial phase and the contrast intensity increased in the portal venous phase. On the other hand, the mean age of ICT patients was 39.3 year-old. The major symptom was due to the function of islet cell tumor, which was typical in 8 patients, presenting as Whipple triad. Histologically, cells demonstrated in trabecular, massive, acinar or solid patterns, and the blood supply of the tumor was abundant. On the CT images, most small tumors were difficulty to be detected. ICT could be markedly enhanced in the arterial phase and slightly enhanced in the portal venous phase on post-contrast CT scan. Conclusion Clinical symptom, pathologic feature and CT scanning are helpful to differentiate SPTP from ICT.
Objective To explore the application value of Flash chest CT scan protocol in the follow-up of severe coronavirus disease 2019 (COVID-19). Methods Twenty-eight patients with severe COVID-19 who were admitted to this hospital from February 1, 2020 to March 15, 2020 were included. The follow-up CT examinations used conventional chest CT scan protocol and Flash scan protocol respectively, the image quality, signal-to-noise ratio (SNR) and effective dose of these two scan protocols were compared. Kappa test was used to evaluate the consistency of image quality scores of readers; Mann-Whitney test was used for image quality comparison; paired t test is performed for signal-to-noise ratio and effective dose comparison. Results The scores of the two readers had good consistency (Kappa=0.62, P<0.01 and Kappa=0.67, P<0.01). There was no statistically significant difference in image quality scores (Z=–0.275, P=0.783 and Z=–0.212, P=0.832). The signal-to-noise ratio of Flash protocol was statistically higher than that of conventional protocol (2.30±0.30 vs. 1.76±0.25, P<0.01). The effective dose of Flash protocol was 66.8% lower than that conventional protocol [(1.43±0.32) mSv vs. (4.31±1.36) mSv]. Conclusion Compared with conventional scan protocol, the Flash scan protocol does not require contact with COVID-19 patients, and effectively reduces the radiation dose and improves image quality of severe COVID-19 patients.