Objective: To explore an automatic landmarking method for anatomical landmarks in the three-dimensional (3D) data of the maxillary complex and preliminarily evaluate its reproducibility and accuracy. Methods: From June 2021 to December 2022, spiral CT data of 31 patients with relatively normal craniofacial morphology were selected from those who visited the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology. The sample included 15 males and 16 females, with the age of (33.3±8.3) years. The maxillary complex was reconstructed in 3D using Mimics software, and the resulting 3D data of the maxillary complex was mesh-refined using Geomagic software. Two attending physicians and one associate chief physician manually landmarked the 31 maxillary complex datasets, determining 24 anatomical landmarks. The average values of the three expert landmarking results were used as the expert-defined landmarks. One case that conformed to the average 3D morphological characteristics of healthy individuals' craniofacial bones was selected as the template data, while the remaining 30 cases were used as target data. The open-source MeshMonk program (a non-rigid registration algorithm) was used to perform an initial alignment of the template and target data based on 4 landmarks (nasion, left and right zygomatic arch prominence, and anterior nasal spine). The template data was then deformed to the shape of the target data using a non-rigid registration algorithm, resulting in the deformed template data. Based on the unchanged index property of homonymous landmarks before and after deformation of the template data, the coordinates of each landmark in the deformed template data were automatically retrieved as the automatic landmarking coordinates of the homonymous landmarks in the target data, thus completing the automatic landmarking process. The automatic landmarking process for the 30 target data was repeated three times. The root-mean-square distance (RMSD) of the dense corresponding point pairs (approximately 25 000 pairs) between the deformed template data and the target data was calculated as the deformation error of the non-rigid registration algorithm, and the intra-class correlation coefficient (ICC) of the deformation error in the three repetitions was analyzed. The linear distances between the automatic landmarking results and the expert-defined landmarks for the 24 anatomical landmarks were calculated as the automatic landmarking errors, and the ICC values of the 3D coordinates in the three automatic landmarking repetitions were analyzed. Results: The average three-dimensional deviation (RMSD) between the deformed template data and the corresponding target data for the 30 cases was (0.70±0.09) mm, with an ICC value of 1.00 for the deformation error in the three repetitions of the non-rigid registration algorithm. The average automatic landmarking error for the 24 anatomical landmarks was (1.86±0.30) mm, with the smallest error at the anterior nasal spine (0.65±0.24) mm and the largest error at the left oribital (3.27±2.28) mm. The ICC values for the 3D coordinates in the three automatic landmarking repetitions were all 1.00. Conclusions: This study established an automatic landmarking method for three-dimensional data of the maxillary complex based on a non-rigid registration algorithm. The accuracy and repeatability of this method for landmarking normal maxillary complex 3D data were relatively good.
Male ; Female ; Humans ; Adult ; Imaging, Three-Dimensional/methods* ; Reproducibility of Results ; Algorithms ; Software ; Tomography, Spiral Computed ; Anatomic Landmarks/anatomy & histology*

This article briefly describes the imaging performance standards of the kilovolt X-ray image guidance system used in radiotherapy, analyzes the main aspects that should be considered in the image quality of X-IGRT system, and focuses on parameters that should be considered in the imaging performance evaluation criteria of the CBCT X-IGRT. The purpose is to sort out the imaging performance evaluation standards of kilovolt X-IGRT system, clarify the image quality requirements of X-IGRT equipment, and reach a consensus when evaluating the imaging performance of X-IGRT system.
Radiotherapy Planning, Computer-Assisted/methods* ; Cone-Beam Computed Tomography/methods* ; Spiral Cone-Beam Computed Tomography ; Radiotherapy, Intensity-Modulated/methods* ; Radiotherapy, Image-Guided/methods*

Objective: To provide scientific evidence for early lung cancer screening, to analyze the incidence of pulmonary nodules among petroleum company staffs in Sichuan-Chongqing Area. Methods: In January 2021 , 6002 petroleum company staffs in Sichuan-Chongqing Area which scanned by low-dose spiral computed tomography (LDCT) of chest in medical examination center in 2020 were retrospectively collected as objects. Their imaging and clinical data were collected. χ(2) test was used to analyze the differences in the detection rates of lung nodules and suspected lung cancer nodules among workers in petroleum company staffs of different genders, ages and types of work. Results: Among the 6002 objects, 3853 (64.2%) were male and 2149 (35.8%) were female, with an average age of (47.25±12.13) years old. A total of 431 cases (7.2%) of pulmonary nodules and 57 cases (0.9%) of suspected lung cancer nodules were detected. 45 cases were followed up with surgical treatment, and 41 cases (91.1%) of lung cancer were diagnosed by postoperative pathology. There were significant differences in the detection rates of pulmonary nodules and suspected lung cancer nodules between different age groups (χ(2)=51.23, 18.81 , P<0.001). The detection rates of pulmonary nodules in the age groups 51-60 years old and ≥61 years old were higher than those in the age groups≤40 years old and 41-50 years old (P<0.05). The detection rate of suspected lung cancer nodules in the age group≥ 61 years old was higher than those in the age groups≤40 years old, 41-50 years old and 51-60 years old (P< 0.05) . And the detection rate of suspected lung cancer pulmonary nodules in oil workers was higher than that of ordinary workers (P<0.05) . Among female objects, the detection rate of pulmonary nodules in oil workers was higher than that in ordinary workers (χ(2)=8.09, P=0.004) . The detection rate of pulmonary nodules in oil workers aged ≥61 years old was higher than ordinary workers (χ(2)=37.94, P<0.001) . Among male objects, the detection rate of suspected lung cancer pulmonary nodules in oil workers was higher than that in ordinary workers (χ(2)=8.42, P=0.004) . The detection rates of suspected lung cancer pulmonary nodules in oil workers aged 51-60 years old and ≥61 years old groups were higher than those of ordinary workers (χ(2)=4.70, 8.74; P=0.030, 0.003) . Conclusion: LDCT is suitable for early lung cancer screening for petroleum company staffs. During the clinical screening process, LDCT should be used as a routine physical examination item for petroleum workers older than 51 years old.
Adult ; Early Detection of Cancer/methods* ; Female ; Humans ; Lung Neoplasms/diagnosis* ; Male ; Mass Screening/methods* ; Middle Aged ; Multiple Pulmonary Nodules/diagnostic imaging* ; Petroleum ; Retrospective Studies ; Tomography, Spiral Computed

OBJECTIVE: To investigate the diagnostic value of multislice spiral CT (MSCT) and MRI in occult fracture of knee joint with meniscus and ligament injury. METHODS: From January 2020 to March 2021, 63 patients with knee occult fracture with meniscus and ligament injury, including 41 males and 22 females, aged from 21 to 67 years old, with an average of (44.35±8.77) years old, the course of disease ranged from 1 to 6 days, with an average of (4.64±1.75) days, the body mass index (BMI) was (19.85±2.78) kg/m². MSCT and MRI data of 63 patients were collected and statistically analyzed to evaluage their diagnist value. RESULTS: The detection of MRI for occult knee fravtures with meniscus and ligament injury, joint cavity effusion, bone marrow edema, and articular surface injury were 100.00% (63/63), 95.24% (60/63), 42.86% (27/63) and 36.51% (23/63), respectively. The detection rates of MSCT were 49.21% (31/63), 41.27% (26/63), 0.00% (0/63) and 1.59% (1/63), respectively, significantly lwver than that of MRI (P<0.05). The diagnostic sensitivity, specificity and accuracy of MRI were significantly higher than those of MSCT(P<0.05). CONCLUSION The sensitivity, specificity and accuracy of magnetic resonance imaging in the diagnosis of occult fracture of knee joint with meniscus and ligament injury are significantly better than that of MSCT. MRI has higher accuracy in the diagnosis of peripheral tissue diseases such as joint cavity, articular surface and bone marrow, and can reduce the risk of clinical misdiagnosis.
Male ; Female ; Humans ; Young Adult ; Adult ; Middle Aged ; Aged ; Tibial Meniscus Injuries/diagnostic imaging* ; Fractures, Closed/diagnostic imaging* ; Arthroscopy/methods* ; Knee Injuries/diagnostic imaging* ; Knee Joint/diagnostic imaging* ; Magnetic Resonance Imaging/methods* ; Ligaments ; Meniscus ; Tomography, Spiral Computed ; Fractures, Bone ; Anterior Cruciate Ligament Injuries

OBJECTIVE: To build a helical CT projection data restoration model at random low-dose levels. METHODS: We used a noise estimation module to achieve noise estimation and obtained a low-dose projection noise variance map, which was used to guide projection data recovery by the projection data restoration module. A filtering back-projection algorithm (FBP) was finally used to reconstruct the images. The 3D wavelet group residual dense network (3DWGRDN) was adopted to build the network architecture of the noise estimation and projection data restoration module using asymmetric loss and total variational regularization. For validation of the model, 1/10 and 1/15 of normal dose helical CT images were restored using the proposed model and 3 other restoration models (IRLNet, REDCNN and MWResNet), and the results were visually and quantitatively compared. RESULTS: Quantitative comparisons of the restored images showed that the proposed helical CT projection data restoration model increased the structural similarity index by 5.79% to 17.46% compared with the other restoration algorithms (P < 0.05). The image quality scores of the proposed method rated by clinical radiologists ranged from 7.19% to 17.38%, significantly higher than the other restoration algorithms (P < 0.05). CONCLUSION The proposed method can effectively suppress noises and reduce artifacts in the projection data at different low-dose levels while preserving the integrity of the edges and fine details of the reconstructed CT images.
Algorithms ; Artifacts ; Tomography, Spiral Computed ; Tomography, X-Ray Computed/methods*

Lung cancer is one of the malignant tumors with the highest morbidity and mortality in the world. The low early diagnosis rate and poor prognosis of patients have caused serious social burden. Regular screening of high-risk population by low-dose spiral computed tomography (LDCT) can significantly improve the early diagnosis rate of lung cancer and bring new opportunities for the diagnosis and treatment of lung cancer. In recent years, LDCT lung cancer screening programs have been carried out in many countries around the world and achieved good results, but there are still some controversies in the selection of screening subjects, screening frequency, cost effectiveness and other aspects. In this paper, the key factors of LDCT lung cancer screening, screening effect, pulmonary nodule management and artificial intelligence contribution to the development of LDCT will be reviewed, and the application progress of LDCT in lung cancer screening will be discussed.
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Artificial Intelligence ; Early Detection of Cancer/methods* ; Humans ; Lung Neoplasms/diagnostic imaging* ; Radiation Dosage ; Tomography, Spiral Computed/methods*

Primary malignant small bowel tumor as a rare kind of intestinal tumor is associated with a poor prognosis. The pathological types were various and complicated, such as adenocarcinoma, neuroendocrine tumor, malignant lymphoma, and malignant stromal tumor. The atypical early stage symptom resulted in difficult diagnosis at early stage, high misdiagnosis rate and lack of standard therapy schemes and means. In the past, X-ray, CT, MRI, and PET-CT were the main examination methods for primary small bowel tumor. However, with the development of radiology, a series of new diagnosis methods, including electronic enteroscopy, capsule endoscopy, multi-slice spiral CT enteroclysis and so on, promotes the diagnosis accurate rate. Surgery is still the most important method in the small bowel tumor treatment, and the alternative of the surgical method should depend on the tumor location, size and relationship with the adjacent organs. Application of the laparoscopic surgery for the small bowel tumor is still in the initial stage. Besides, some researches have confirmed that chemotherapy, radiotherapy, target therapy and endocrinotherapy have effects on the specific kind of small bowel tumor. Therefore this article will review the epidemiology, pathology, diagnosis and treatment of the primary malignant small bowel tumors.
Adenocarcinoma ; diagnosis ; epidemiology ; pathology ; therapy ; Capsule Endoscopy ; Gastrointestinal Stromal Tumors ; diagnosis ; epidemiology ; pathology ; therapy ; Humans ; Intestinal Neoplasms ; diagnosis ; epidemiology ; pathology ; therapy ; Intestine, Small ; diagnostic imaging ; pathology ; Laparoscopy ; methods ; Lymphoma ; diagnosis ; epidemiology ; pathology ; therapy ; Neuroendocrine Tumors ; diagnosis ; epidemiology ; pathology ; therapy ; Tomography, Spiral Computed

OBJECTIVETo explore the anatomic basis and clinical application of the horn shaped perforator flap pedicled with the angular artery for the reconstruction of midface defect.

METHODS(1) 10 fresh cadavers were perfused with a modified guiding oxide gelatin mixture for three-dimensional visualization reconstruction using a 16-slice spiral computed tomography scanner and specialized software (Materiaise' s interactive medical image control system, MIMICS). The origin and distribution of the angular artery perforator were observed. (2) Between July 2012 and July 2014, twenty-one patients underwent operations for the reconstruction of midface defect. Ten patients had squamous cell carcinoma, nine patients had basal cell carcinoma and two patients had nevus. The flaps' size ranged from 1.5 cm x 3.5 cm to 2.5 cm x 5.0 cm.

RESULTSThe facial artery branches the lateral nasal artery 1 cm from the outside corner of the mouth, subsequently strenches to inner canthus continuing as the angular artery. The angular artery anastomoses extensively with the dorsal nasal artery and the infraorbital artery. All the flaps survived. The patients were satisfied with the final aesthetic and functional results.

CONCLUSIONSThe flap can be designed flexibly and simply with reliable blood supply. The donor sites could be closed directly without skin graft, it is a simple and fast method for the reconstruction of midface defect.

Anastomosis, Surgical ; methods ; Arteries ; anatomy & histology ; Cadaver ; Carcinoma, Basal Cell ; surgery ; Carcinoma, Squamous Cell ; surgery ; Face ; blood supply ; Facial Neoplasms ; surgery ; Humans ; Nevus ; surgery ; Nose ; blood supply ; Perforator Flap ; blood supply ; transplantation ; Skin Neoplasms ; surgery ; Skin Transplantation ; Software ; Tomography, Spiral Computed

PURPOSE: This study was performed to determine the usefulness of three-dimensional computed tomography (3D-CT) in measuring periacetabular osteolysis by comparing the real volume of osteolysis in revision surgery. MATERIALS AND METHODS: Twnety-three patients who had undergone revision surgery due to periacetabular osteolysis but not included septic osteolysis and implant loosening. The mean age of patients at the time of surgery was 55.2 years. And the mean time interval between the primary total hip arthroplasty and revision surgery was 13.3 years. We measured the polyethylene wear in plain radiographs using computer assisted vector wear analysis program, the volume of acetabular osteolytic lesions in high-resolution spiral CT scans using Rapidia 3D software version 2.8 algorithms before the revision surgery were performed. Intraoperative real osteolytic volume was calculated as the sum of the volumetric increments of the acetabular cup and impacted allo-cancellous bone volume. RESULTS: Strong correlation was found between the volume of acetabular osteolytic lesions measured on 3D-CT and intraoperative real osteolytic volume which was calculated as the sum of the volumetric increments of the acetabular cup and impacted allo-cancellous bone volume. CONCLUSION: 3D-CT is considered a useful method for assessing and measuring the volume of periacetabular osteolysis before revision surgery.
Acetabulum ; Arthroplasty ; Arthroplasty, Replacement, Hip* ; Humans ; Methods ; Osteolysis* ; Polyethylene ; Tomography, Spiral Computed

OBJECTIVE: The aim of this study was to evaluate whether the difference in the degree of collateral ventilation between canine and swine models of bronchial obstruction could be detected by using xenon-enhanced dynamic dual-energy CT. MATERIALS AND METHODS: Eight mongrel dogs and six pigs underwent dynamic dual-energy scanning of 64-slice dual-source CT at 12-second interval for 2-minute wash-in period (60% xenon) and at 24-second interval for 3-minute wash-out period with segmental bronchus occluded. Ventilation parameters of magnitude (A value), maximal slope, velocity (K value), and time-to-peak (TTP) enhancement were calculated from dynamic xenon maps using exponential function of Kety model. RESULTS: A larger difference in A value between parenchyma was observed in pigs than in dogs (absolute difference, -33.0 +/- 5.0 Hounsfield units [HU] vs. -2.8 +/- 7.1 HU, p = 0.001; normalized percentage difference, -79.8 +/- 1.8% vs. -5.4 +/- 16.4%, p = 0.0007). Mean maximal slopes in both periods in the occluded parenchyma only decreased in pigs (all p < 0.05). K values of both periods were not different (p = 0.892) in dogs. However, a significant (p = 0.027) difference was found in pigs in the wash-in period. TTP was delayed in the occluded parenchyma in pigs (p = 0.013) but not in dogs (p = 0.892). CONCLUSION: Xenon-ventilation CT allows the quantification of collateral ventilation and detection of differences between canine and swine models of bronchial obstruction.
Airway Obstruction/*radiography ; Animals ; Bronchial Diseases/*radiography ; Bronchography/*methods ; Disease Models, Animal ; Dogs ; Pulmonary Ventilation/*physiology ; Respiration ; Swine ; Tomography, Spiral Computed/*methods ; Xenon