CT理论与应用研究

Imaging Features of Early Covid-19 on Chest Thin-slice Non-Enhanced CT

SUN Ying, LI Ling, LIU Xiaoyan, HAO Qi, ZHANG Yimeng, LI Xingpeng, ZHANG Yan, ZHANG Mingxia, GUO Jia, LIANG Ziyi, DUAN Yongli, LIU Wei, FU Yan, SUN Pengtao, LV Yaping, CHEN Hongmei, HUANG Yong, JIANG Hong, SHI Feng, DUAN Shuhong, WANG Rengui

, Available online , doi: 10.15953/j.ctta.2023.006

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Objective: To explore the characteristics findings of early COVID-19 on chest thin-slice non-enhanced CT. Materials and methods: From November to December 2022, data from 153 patients with COVID-19 with positive chest CT findings confirmed by the Department of Infectious Diseases of our hospital were collected. All patients had relatively complete clinical data and underwent chest CT 1-14 days after the onset. The patients were divided into two groups according to their age (≤60 years old and >60 years old) and the time interval between the onset and CT examination (≤7 days old and >7 days old), and the differences in CT features between the two groups were compared. Result: Among 153 patients with COVID-19, the lung (100%), blood vessels (93.5%), airways (73.4%), and pleura (70.1%) were involved. The comparison between the age groups showed statistically significant differences in the number, location, size, volume, and band shadow of the lesions. There were statistically significant differences in the shape, density, organization, fibrosis, and pleural involvement of the lesions between the patients in the time interval between the onset and CT examination. Conclusion: Chest thin-slice CT can clarify the location and scope of early COVID-19. Some characteristics findings can help for accurate diagnosis and differentiation, such as the diversity of morphology, intrapleural and perivascular distribution, interstitial lesions with alveoli as a unit, early mixed ground-glass shadow often accompanied by obvious organization and fibrosis, localized thickening of the pleura, and few pleural effusions.

Removal of Gridline Artifacts in Cone-Beam CT Based on Wavelet Transform

WANG Yu’ang, GAO Hewei, ZHANG Li

, Available online , doi: 10.15953/j.ctta.2022.233

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In cone-beam computed tomography with flat-panel imagers, scattered X-ray photons lead to reduced image quality. Insertion of an anti-scatter grid between the patient or object and the flat-panel imagers is one of the most used techniques for reducing scattered radiation. However, while the scatter is reduced, gridline artifacts can be visible. Suppressing gridline artifacts in cone-beam computed tomography is significant. In this paper, the existing methods of removing gridline artifacts are summarized. Moreover, the wavelet transform method based on spectrum coalescence is innovatively proposed for removing gridline artifacts. Wavelet transform can remove gridline artifacts effectively and without introducing wavelet transform harmonics thus reducing the loss of object details. The effectiveness of this method is verified by experiments.

Application of New Iterative Reconstruction Algorithm Based on Artificial Intelligence and Low Tube Voltage in Reducing the Radiation Dose of Coronary Computed Tomography Angiography in Obese Patients

FENG Mengya, LI Bing, WU Min, HUA Ting, TANG Guangyu

, Available online , doi: 10.15953/j.ctta.2022.148

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Objective: To explore the feasibility of using a new artificial intelligence (AI)-based iterative reconstruction algorithm with low tube voltage to reduce the radiation dose of coronary computed tomography angiography (CTA) in obese patients. Methods: A total of 40 patients were randomly divided into routine-dose (group A n=20) and low-dose groups (group B n=20). In group A, a tube voltage of 120kV and a tube current of 200mAs, whereas in group B, a tube voltage of 80kV and a tube current of 200mAs were used. The collected data was transferred to the post-processing workstation. The image reconstructions of the conventional and new iterative reconstruction algorithms based on AI were used. Comparative analysis of average CT value of the aorta, signal to noise ratio (SNR) and contrast to noise ratio (CNR) of the aorta and left coronary, SNR and CNR of right coronary in the two groups. Results: The average CT value of the aorta in group B, the SNR and CNR of the aorta and the left coronary artery, the SNR and CNR of the right coronary artery was not significantly different from those of group A. There was no difference in the subjective image quality between the two groups. However, the radiation dose in patients of group B was reduced by 68.2% compared with that of group A. Conclusion: The new iterative reconstruction algorithm can significantly improve the image quality of the reconstruction. The radiation dose can be significantly reduced with a tube voltage of 80kVp, and the coronary CTA image equivalent to the image quality of the conventional dose can be obtained.

CT Spectral Imaging Study in Patients with Carotid Body Tumors at High Altitudes

ZHOU Dongmei, YIN Guixiu

, Available online , doi: 10.15953/j.ctta.2022.059

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Objective: To investigate the value of CT spectral imaging in the study of carotid body tumors (CBT). Methods: Thirty patients with CBT who underwent CT energy spectrum examination and were confirmed by operation were included. Subsequently, 60 keV and 40 keV single energy images were reconstructed through the GSI viewer. The CT value, background noise (SD), contrast noise ratio (CNR), signal-to-noise ratio (SNR), and subjective score of CBT feeding arteries of the 40 keV, 60 keV single energy images and 120 kVp like images were statistically analyzed to evaluate the relationship between CBT energy spectrum parameters and imaging features with surgical results. Results: There was no correlation between energy spectrum parameters in the arterial and venous phases of CBT and the surgical results . However, CBT transverse diameter, longitudinal diameter, and Shamblin classification were strongly correlated with intraoperative bleeding, and the number of feeding arteries was moderately correlated with intraoperative bleeding. Additionally, the transverse diameter, longitudinal diameter, and Shamblin classification were moderately correlated with cranial nerve injury, and the number of feeding arteries was strongly correlated with cranial nerve injury. We also found that 40 keV was the best energy level for the CBT feeding artery display. Furthermore, the CT value, SD, CNR, and SNR of the 60 keV group were significantly higher than those of the 60 keV and 120 kVp like groups, and the CT value and noise of the 60 keV group were significantly higher than those of the 120 kVp like group. However, there was no significant difference in CNR and SNR between the two groups. The subjective evaluation score of the 40 keV group was the highest, and the subjective evaluation of the two radiologists had good consistency. Conclusion: (1) There was no correlation between the energy spectrum parameters in the arterial and venous phases of CBT and GAPP score. (2) The number of CBT feeding arteries is one of the important parameters for evaluating surgical complications and 40 keV single energy imaging can significantly optimize the display of CBT feeding arteries.

Correlation between Arterial Enhancement Fraction on Computed Tomography and Efficacy of Transcatheter Arterial Chemoembolization for Hepatocellular Carcinoma

GONG Na, ZHU Bingjie, YU Peijun, ZHAO Lin, SHI Ke, LI Huian

, Available online , doi: 10.15953/j.ctta.2021.022

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Objective: To explore the correlation between arterial enhancement fraction (AEF) on Computed Tomography (CT) and the curative effect of Transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). Methods: We enrolled 43 patients who presented with HCC to our hospital between January 2019 and January 2020 and extracted their clinical data. Three-phase contrast-enhanced CT was performed 1 month before and after TACE; based on TACE efficacy, the enrolled patients were divided into the “effective” and “ineffective” groups. The alpha-fetoprotein (AFP) level was determined using electrochemical luminescence. Changes in the AEF, AFP level, and tumor size before and after treatment were compared between the two groups. The correlation among AEF, AFP level, and tumor-size changes was explored using Pearson’s correlation coefficient. Receiver operating characteristic (ROC) curves and the area under these curves (AUCs) were used to determine the evaluation value of dynamic enhanced scanning combined with AEF for TACE efficacy. Results: After TACE, the AEF, AFP level, and tumor size decreased in the effective group and were lower than the corresponding values in the ineffective group. Pearson’s correlation analysis revealed that AEF and the AFP level were positively correlated with the tumor size after TACE. ROC analysis revealed that the AUC for dynamic enhanced scanning combined with AEF for TACE efficacy evaluation was 0.902; this was significantly greater than the AUC of dynamic enhanced scanning (0.793) and AEF (0.771) alone. Conclusion: AEF is a reliable parameter for evaluating the therapeutic effect of TACE. The evaluation of TACE efficacy can be further improved by combining AEF with dynamic enhanced scanning; this approach should be used as an auxiliary method for evaluating TACE efficacy for HCC.

Analysis of Multi-slice Computed Tomography Images of Pulmonary Mucosa-associated Tissue Lymphoma

PENG Di, HU Xingrong, HUANG Zhihua, CHENG Shaolei, WANG Qiong, WANG Xianman

, Available online , doi: 10.15953/j.ctta.2022.193

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Objective:To explore the mulyi-slice computed tomograpy (MSCT) imaging characteristics of pulmonary mucosa-associated lymphoma tissue. Methods:The clinical data and MSCT findings of eight cases of pulmonary MALT lymphoma confirmed by pathology in our hospital from February 2014 to July 2022 were analyzed retrospectively. The causes of misdiagnosis were also analyzed. Results: Five patients underwent plain and enhanced chest CT scans, and three underwent plain chest CT scans alone. Among the eight patients, four had a single focus, four had multiple foci, and seven showed large patches of high-density shadows. All patients showed air bronchogram, and one showed mixed density patches. CT enhancement showed moderate enhancement in four cases, slight enhancement in one case, and angiography sign in four cases. Conclusion: Primary MALT lymphoma of the lung is an inert tumor with low-grade malignancy. The MSCT findings have certain characteristics. Therefore, it is necessary to obtain diseased tissues in time for pathological examination and immunohistochemistry to make a clear diagnosis.

Risk Factors of Plaque Progression in Patients with Angina Pectoris and Their Relationships with Coronary Computed Tomography Angiography

ZHU Najun, FANG Xinxin, YIN Yijun, Zhou Shuitian

, Available online , doi: 10.15953/j.ctta.2022.219

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Objective: To investigate the risk factors of plaque progression in patients with angina pectoris and their relationships with coronary computed tomography (CT) angiography. Methods: Clinical data of 236 patients with angina pectoris were retrospectively analyzed from January 2017 to January 2020. All patients were grouped according to whether plaque progression occurred, and the general information and coronary CT angiography indexes were compared between the two groups. A logistic regression model was used to evaluate the independent risk factors of plaque progression in patients with angina pectoris. The receiver operating characteristic (ROC) curve was delineated to analyze the clinical value of the prediction model based on coronary CT angiography indicators in predicting plaque progression risk. Results: There were significant differences in sex, the proportion of hyperlipidemia, proportion of statins, degree of stenosis, minimum lumen area, total plaque volume, RI, and CT-derived fractional flow reserve (FFR) between the two groups (P < 0.05). The results of single factor analysis showed that the degree of stenosis, the minimum lumen area, plaque volume, the volume of non-calcified plaque, RI, and CT-FFR levels were related to the plaque progression in patients with angina pectoris (P < 0.05). Univariate analysis showed that the degree of stenosis, minimum lumen area, plaque volume, non-calcified plaque volume, RI, and CT-FFR levels were associated with plaque progression in patients with angina pectoris (P < 0.05). Multivariate analysis showed that RI and CT-FFR levels were independent factors of plaque progression in patients with angina pectoris (P < 0.05). ROC curve analysis showed that the combination of stenosis degree + RI + CT-FFR was better than that of simple stenosis degree and stenosis degree + RI in predicting the area under the curve of plaque progression (P < 0.05). Conclusion: RI and CT-FFR levels are important factors leading to plaque progression in patients with angina pectoris. The prediction model based on RI and CT-FFR can more accurately identify plaque progression.

The Lithospheric Structure of the Middle Solonker−Xar Moron Suture by Surface-wave Tomography

FENG Mei, AN Meijian, HOU Hesheng, FAN Taoyuan, ZANG Hulin

, Available online , doi: 10.15953/j.ctta.2022.061

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The middle section of the Solonker-Xar Moron suture and its surrounding areas have successively been affected by the closure of the Paleo-Asian Ocean during the Paleozoic, the closure of the Mongolian-Okhotsk Ocean during the Mesozoic, and the subduction of the Pacific Ocean plate since the Meso-Cenozoic, resulting in very complex, deep structures in this area. We conducted a regional-scale three-dimensional, S-wave velocity tomographic study of the area. To do this, we used surface waves from earthquake data and ambient noise data recorded in recent years. The lithospheric tomographic model shows that the regional crustal thickness does not vary considerably, but the crust in the Songliao and the Lower Liaohe basins is thinner than that in the Daxing'an Mountains. The fact that the crustal thickness remains consistent with changes in topography indicates that these areas have reached gravitational equilibrium. However, the crustal thickness of the Liaodong uplift and the Bohai Bay Basin is inversely related with topography, indicating that these areas may still be in a tectonically active state. At depths greater than 80 km, the S-wave velocities spread in an east-west direction approximately parallel to the Solonker-Xar Moron suture. The complexity of the upper-mantle velocity distribution to the north of the Solonker-Xar Moron suture differs significantly from that to its south. Furthermore, south of the Solonker-Xar Moron suture, the complexity of the velocity distribution in the east differs considerably from that in the west. This implies that the destruction resulting from the Pacific Ocean subduction system varies significantly within the study region, and remnants of the paleo-Asian ocean slab may still exist in the south.

Computed Tomography Reconstruction Algorithm Based on Relative Total Variation Minimum

ZHANG Fengjia, QIAO Zhiwei

, Available online , doi: 10.15953/j.ctta.2022.190

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The total variation (TV) minimization algorithm is an effective CT image reconstruction algorithm, which can reconstruct sparse or noisy projection data with high accuracy. However, in some cases, the TV algorithm will produce stepped artifacts. In the field of image denoising, the relative TV algorithm shows better performance than TV algorithm. In view of this, the relative TV model is introduced into image reconstruction, the relative TV minimum optimization model is proposed, and the corresponding solution algorithm is designed under the framework of adaptive gradient descent projection to convex set (ASD-POCS) to further improve the reconstruction accuracy. The reconstruction experiments are carried out with Shepp Logan, Forbild and real CT image simulation models to verify the anti crime ability of the algorithm and evaluate the sparse reconstruction ability and anti noise ability of the algorithm. The experimental results show that compared with TV algorithm, the algorithm can achieve anti crime and can reconstruct sparse or noisy projection data with high precision. Compared with TV algorithm, the algorithm can achieve higher reconstruction accuracy.

Research on the Edge Feature Enhancement of Fluvial Reservoirs Based on Image Processing

ZHANG Junhua, HU Yifu, YU Zhengjun, Ren Ruijun, Liu Xuanliang

, Available online , doi: 10.15953/j.ctta.2022.174

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The identification of channel edge is the key aspect of fine description of fluvial reservoirs. Affected by the factors such as channel overlaying and crossing, thin sand body thickness, low seismic signal-to-noise ratio, and low resolution, the traditional slice interpretation and coherence technology can barely meet the requirements of fine exploration, and the newly developed edge detection based on operator processing still has application misconceptions. In this study, the geometric characteristics of river edges are analyzed as the entry point, and the physical meanings of first derivatives, module values, and second derivatives are clarified. Three-dimensional channel models with different velocity characteristics are established by extracting the coherence attributes of the model and real data; the existing problems of this technique in the fine description of channels are identified. To solve this problem, considering the Sobel operator as an example, the symbolic characteristics of the channel edge after using this technology are illustrated. The coherence technique for channel edge identification using histogram equalization and the fuzzy set theory is proposed, and good application results are obtained. This method can be used as reference to deepen the understanding of channel edge characteristics and improve the ability to identify fluvial reservoirs.

Automatic Identification of Relationship Between Tooth Root and Mandibular Canal Based on One-step Deep Neural Network

ZHOU Yanqi, DAI Xiubin, WANG Dongmiao, ZHU Shujin, MAO Tianyi

, Available online , doi: 10.15953/j.ctta.2022.083

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To improve the accuracy and efficiency of identifying the relationship between the root of the impacted mandibular third molar (M3M) and the mandibular canal in panoramic radiographs, an automatic method based on a deep convolutional neural network was proposed in this paper. This method treats the automatic identification of the relationship between the root of the M3M and mandibular canal as a combination of regression task and classification task. It uses YOLOv5 (You Only Look Once) network as the framework to construct the deep convolutional neural network which can accomplish the detection task and classification task simultaneously. This network, which takes the spatial relationship information extracted from the corresponding cone-beam CT images as the ground-truth, was trained to learn the nonlinear relationship between image features and the root of the M3M contacting with the mandibular canal. When inputting a newly acquired panoramic radiograph into the trained network, the network will output the probability value for the root of the M3M contacting with the mandibular canal. In the meantime, the region which includes the root of the M3M contacting with the mandibular canal can be predicted. The experimental results show that the proposed method can give an accurate judgment of whether the roots of impacted mandibular wisdom teeth in the panoramic radiographs are in contact with the mandibular canal, as well as the location of regions in which there exist the roots of the M3M contacting with the mandibular canals; compared to manual diagnosis and the other methods, the proposed method can obtain more accurate results.

CT and MRI Findings of Multiple Infarcted Regenerative Nodules in Liver Cirrhosis after Variceal Hemorrhage

XU Xiaoli, ZHANG Tao, ZHANG Xueqin

, Available online , doi: 10.15953/j.ctta.2022.063

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Objective: To investigate the CT and MRI features of multiple infarcted regenerative nodules in cirrhosis after variceal hemorrhage. Methods: A total of 21 patients, including 13 males and 8 females, who were diagnosed with multiple infarction regenerating nodules in cirrhosis after variceal hemorrhage, were included in this study. All patients were examined by 3.0TMR scanner or 256 slice spiral CT, the enhancement pattern, signal intensity, shape, number, size, edge, location and distribution of lesions were analyzed. Results: In CT or MRI imaging, 3 patients had 10 or less lesions, and 19 patients had more than 10 lesions. The diameter of liver lesions was 3-26 mm. Most lesions are round nodules, most of the lesions were clustered and distributed. The lesions were mainly distributed in the subcapsular region of liver. After dynamic enhancement of CT and MRI, most nodules have no obvious enhancement, and a few can have marginal enhancement. On T1WI images, all lesions showed equal signal or slightly low signal. On T2WI images, most lesions are high signals with clear boundary. During CT and MRI follow-up, the lesions disappeared in 13 patients and shrank or significantly reduced in 8 patients. Conclusions: CT and MRI can show the imaging features of multiple infarcted regenerative nodules in liver cirrhosis after variceal hemorrhage, which can be differentiated from liver malignancy by image follow-up, clinical history, and tumor indicators.

Clinical Characteristics and Imaging features of Primary Orbital Lymphoma

ZHU Jianbo, LI Bin, ZHANG Hongmei, WANG Ningli

, Available online , doi: 10.15953/j.ctta.2022.245

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Objective: To analyze the clinical characteristics and imaging features of primary orbital lymphoma in order to improve early diagnosis of the disease. Methods: Eighty-two patients were recruited from January 2015 to May 2022 who were diagnosed with orbital lymphomas via histopathology. The data on clinical characteristics, pathological subtypes, and imaging features for those patients were analyzed including symptoms, uni- or bilateral eye involvement, single or multiple lesions, tumor location, growth pattern, MRI signal intensity and MRI/CT enhancement patterns. Results: Eyelid swelling (52/82, 63.4%) and proptosis (43/82, 52.4%) were the two most common symptoms for primary orbital lymphomas, whose pathologic subtypes were mainly B-cell lymphomas, especially mucosa-associated lymphoid tissue lymphoma (60/82, 73.2%), and 59 cases (59/82, 72.0%) had unilateral eye involvement. Conjunctiva was the most common location（29/82, 35.4%）, followed by eyelid (16/82, 19.5%) and muscle cone (11/82, 13.4%). Of the 66 cases who underwent MRI examinations, 60 showed iso-intensity on T1WI (90.9%), and 51 showed hyper-intensity on T2WI (77.3%). The tumors showed obvious enhancement on contrast-enhanced MRI or CT with 74.2% and 70.5%, respectively. Two other cases showed adjacent bone involvement on CT. Conclusion: B-cell lymphoma, especially mucosa-associated lymphoid tissue lymphoma was the most common primary orbital lymphoma subtype. The tumors mostly had unilateral eye involvement and the conjunctiva was the most common location. The typical imaging features were obvious enhancement on contrast-enhanced MRI or CT that would facilitate tumor diagnosis and treatment decision.

Computed Tomography and Magnetic Resonance Imaging Features and Prognosis of Acute Necrotic Collections in Patients with Acute Pancreatitis

YAN Wei, DONG Lining, ZHANG Binbin, YANG Dawei, YANG Zhenghan, WANG Zhenchang, JIN Erhu

, Available online , doi: 10.15953/j.ctta.2022.141

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Objective: To summarize the imaging features of acute necrotic collections (ANC), a local complication of acute necrotizing pancreatitis (ANP), and to explore the factors affecting the prognosis of patients with ANC. Methods: The clinical and imaging data of 31 patients with ANP were analyzed retrospectively. Characteristics of ANC on computed tomography (CT) and magnetic resonance imaging (MRI) were analyzed as well. Based on the follow-up outcomes, patients were divided into the absorption group and the walled-off necrosis (WON) group; a chi-square test was used to compare the two. Results: Plain CT revealed patchy, uneven, low-density shadows in 31 cases of ANC (focal, oval, and iso-density and low-density mixed shadows:23 cases; fatty low-density shadows: 22 cases). Plain MRI revealed mixed low-signal intensities on T1-weighted imaging and mixed high-signal intensities on T2-weighted imaging in 19 cases of ANC; low-signal fragments were seen on Fat suppressed T2-weighted imaging in some of these cases. ANC was complicated with local infection and hemorrhage in 3 (9.7%) and 12 (38.7%) cases, respectively. The necrotic tissues did not show any enhancement, but the surrounding tissues appearedpatchy or with varying degrees of linear-enhancing changes on enhanced scans. Follow-up examination (median: 137 days) revealed that ANC was completely absorbed in 12 cases (38.7%) and had developed into WON in 19 cases (61.3%). The absorption and WON groups differed significantly in terms ofnecrosis involving the pancreas, affected locations of the pancreas, necrotic volumes, and the modified CT severity indexscores. Conclusion: On CT and MRI, ANC appears as uneven liquid densities and heterogeneous signal intensities, respectively. The necrotic tissue itself has no enhancement, but its surrounding tissue presents with different degrees of enhancing changes on enhanced scanning. Follow-up findingsreveal that ANC can completely dissipate or progress to WON, which is related to many imaging factors.

Design and Implementation of a 3D C-arm Control Service Protocol (RoboLINK) Based on DICOM

GAO Chen, CHENG Kun, CHANG Yunheng, ZHANG Fei, TANG Bing, HU Sheng, CHEN Yang, XI Yan

, Available online , doi: 10.15953/j.ctta.2022.015

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3D imaging technology assisted orthopaedic robot for preoperative planning can improve the accuracy and efficiency of surgery. However, traditional surgical navigation systems based on 3D data currently need pre-operative drawing and manual registration. The surgical steps are cumbersome and new errors may be introduced during manual registration, resulting in the reduction of accuracy. To address this need, in this study, we design a remote device control service protocol (RoboLINK) based on the DICOM protocol, which can be used in operation and provides a novel solution to the current problem. Based on supporting data transmission between two medical devices, motion control instructions can also be transmitted to achieve mutual cooperation between devices. In accordance with this design method, the protocol is tested in a shadow medical 3D C-arm experimental environment and a simulated surgical robot. The results indicate that the RoboLINK protocol can effectively complete the tasks of data transmission and equipment control with the advantages of feasibility and security.

Progress of Material Decomposition Algorithms in Dual-energy CT Imaging

GUO Qiao, YAO Xufeng

, Available online , doi: 10.15953/j.ctta.2021.067

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Spectral CT can produce basis materials with different X-ray energies. Subsequently, the generated basis materials can be used for qualitative and quantitative evaluation of tissue components and contrast agent distribution. This approach presents a superior ability to separate and identify imaging materials compared to traditional single-energy CT. Dual-energy spectrum technology is one of the most commonly used modes in spectrum CT, which plays an important role in clinical application. In this study, the decomposition methods of a basis material in the image domain of dual-energy spectrum CT were classified into two categories: two-material decomposition and multi-material decomposition. Finally, these methods are summarized and trend of future development is addressed.

Correlation between Emphysema Volume and Small Shadow Density on Computed Tomography and the Lung Function in Pneumoconiosis

ZHAO Qiqi, FENG Li, LIU Yuquan, WANG Meifang

, Available online , doi: 10.15953/j.ctta.2021.049

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Objective: To compare the influence of emphysema and lung small shadow on the lung function of patients with pneumoconiosis. Methods: We selected 96 patients who were admitted to the Taihe Hospital (Shiyan city) for pneumoconiosis complicated by emphysema between 2015 and 2020. Chest computed tomography (CT) and lung function assessments were performed. The low attenuation volumes (LAV%) of the whole lung; left and right lungs; and upper, middle, and lower lobes of each lung were quantified using 64-slice spiral CT (GE Optima CT680). Based on the LAV% of the whole lung, the patients were divided into groups A (LAV%<15%), B (LAV%: 15%–30%), and C (LAV% >30%). The small shadow density (SSD) of the whole lung; left and right lungs; and upper, middle, and lower lung fields was calculated by applying the criteria for evaluating SSD on chest radiographs to CT images. The correlation between SSD and lung function was also analyzed. Results: The SSD of the whole lung was negatively correlated with the forced expiratory volume in the first second (FEV1), total lung capacity (TLC), peak expiratory flow (PEF), maximum expiratory flow after 75% of the forced vital capacity (FVC) has not been exhaled (MEF75%), and maximum expiratory flow after 25% of the FVC has not been exhaled (MEF25%), and it was positively correlated with residual volume (RV)/TLC. LAV% was negatively correlated with FEV1, ratio of FEV to FEV1 (FEV1%), carbon monoxide diffusion capacity (DLCO), PEF, MEF75%, maximum expiratory flow after 50％ of the FVC has not been exhaled (MEF50%), and MEF25% in the whole lung; left and right lungs; and upper, middle, and lower lung lobes; however, it was positively correlated with RV and RV/TLC%. When LAV% was >30%, the correlation between LAV% and FEV1, FEV1%, DLCO, RV/TLC, PEF, MEF75%, MEF50%, and MEF25% was stronger in group C than in groups A and B. A certain degree of correlation was observed between the SSD in the lungs and the ventilation function and volume parameters; however, the correlation between SSD and the diffusion function was weak. Conclusion: The degree of emphysema and SSD in patients with pneumoconiosis have a certain degree of correlation with the lung function; however, the SSD of emphysema has a relatively better correlation with the lung function. It can be used to evaluate the degree of lung injury in patients with pneumoconiosis to a certain extent and is worthy of clinical application.

Enhanced Computed Tomography-Based Texture Analysis and Machine Learning for Differentiation between Adenolymphoma and Mixed Tumors of the Parotid Gland

MAO Xiaoxiao, MA Shusheng, LU Liang, SHI Jiugang, ZHANG Lei

, Available online , doi: 10.15953/j.ctta.2022.027

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Objective: To explore the application of enhanced computed tomography (CT)-based texture analysis combined with machine learning in the differential diagnosis of adenolymphomas and mixed tumors of the parotid gland. Methods: We retrospectively analyzed 21 and 19 cases of adenolymphomas and mixed tumors of the parotid gland, respectively. Regions of interest (ROI) were chosen on axial enhanced-CT images of the tumor’s maximum cross section using the Mazda software. The optimal texture parameters were selected using Fisher’s coefficient, probability of classification error and average correlation coefficients, mutual information, and a combination of the three. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic efficacy. Finally, the texture parameters were classified and analyzed using the following four machine-learning methods: raw data analysis, principal component analysis, linear discriminant analysis, and nonlinear discriminant analysis (NDA). The diagnostic efficiencies of these classification algorithms were analyzed. Results: WavEnHH_s-4, GrVariance, 45dgr_Fraction, WavEnLL_s-4, and GrSkewness were the statistically significant texture feature parameters for differentiating between parotid adenolymphomas and mixed tumors.. ROC curve analysis revealed that WavEnLL_s-4 had a balanced sensitivity and specificity, and the area under the curve, sensitivity, and specificity were 0.797, 84.2%, and 62.5%, respectively. The misclassification rate of NDA (5.0%–12.5%) was lower than that of the other algorithms. The NDA of FPM had the lowest misclassification rate (5.0%); its accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 95.0%, 95.2%, 94.7%, 95.2, and 94.7, respectively. Conclusion: The optimum enhanced CT-based texture features differed significantly between parotid adenolymphomas and mixed tumors. A combination of FPM and NDA had the lowest misclassification rate; it can contribute toward the identification of parotid adenolymphomas and mixed tumors.

Evaluation of CT in Predicting Central Lymph Node Metastasis of Papillary Thyroid Microcarcinoma

TIAN Jiangyu, TAN Zhiwei

, Available online , doi: 10.15953/j.1004-4140-2023.32.00.00

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Objective: To determine the value of CT in predicting CLNM in PTMC. Methods: 157 patients with PTMC confirmed by pathology in our hospital were enrolled, and the CT and clinicopathological data of the patients were retrospectively analyzed. ROC curve was used to determine the optimal cutoff value of PTMC greatest diameter for CLNM. The binary logistic regression model of PTMC CLNM was established based on CT and clinical pathological data, and the diagnostic value of the model was evaluated by ROC curve. Results: According to the ROC curve, the optimal cutoff value for predicting PTMC CLNM was 6 mm. Univariate analysis: Cookie bite sign , microcalcification, multifocality, PTMC greastest diameter ≥6 mm, male, Age<45 were risk factors for PTMC CLNM. Binary Logistic regression analysis: cookie bite sign with protruding (OR=5.159, 95% CI=1.137 ~ 23.400), multifocality (OR=2.734, 95% CI=1.215 ~ 6.154), PTMC greastest diameter ≥6 mm (OR=3.259, 95% CI=1.326 ~ 8.008), male (OR=3.776, 95% CI=1.339 ~ 10.653), age <45 years (OR=3.222, 95% CI=1.419 ~ 7.777), were independent risk factors for PTMC CLNM. According to the ROC curve, when the Youden index=0.502, the sensitivity and specificity in predicting CLNM were 82.5% and 68.0%, respectively. Conclusion: The binary logistic regression model is helpful in predicting PTMC CLNM. Cookie bite sign with protruding, PTMC greastest diameter≥6mm, male, and age<45 were independent risk factors for PTMC CLNM. For this type of patients, we suggest that surgeons should consider central lymph node dissection.

Correlation between Carotid Atherosclerotic Plaques and Acute Ischemic Stroke

ZAN Qin, CHEN Xiaorong, YANG Wenqiong

, Available online , doi: 10.15953/j.ctta.2022.039

Abstract(63) HTML PDF(3)

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Objective: Carotid artery computed tomography angiography (CTA) was used to analyze carotid atherosclerotic plaques and explore the correlation of plaque properties and other factors with the occurrence of acute ischemic stroke. The aim was to provide a basis for the prevention and treatment of acute ischemic stroke. Methods: Patients who underwent carotid artery CTA and magnetic resonance diffusion-weighted imaging (DWI) within 2 weeks before or after carotid artery CTA were analyzed retrospectively. Based on magnetic resonance DWI data, these patients were divided into the acute ischemic stroke group (n=95) and non-acute ischemic stroke group (n=102). The clinical data, laboratory data, and nature and surface morphology of the carotid plaques on CTA were compared between the two groups. Variables with P<0.05 were included in a multivariate logistic regression analysis to determine the risk factors of acute ischemic stroke. Results: Age, hypertension history, and levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), homocysteine (Hcy), cystatin C (Cys-C), and glycated hemoglobin (HbA1c) differed significantly between the two groups. Multivariate regression analysis revealed that age ≥65 years (odds ratio [OR]: 4.95), hypertension (OR: 9.91), high TC (OR: 2.78), high Hcy (OR: 3.07), high HbA1c (OR: 4.60), and lipid plaque (OR: 4.89) were the independent risk factors for acute ischemic stroke. A high HDL level (OR of 0.13) was identified as a protective factor for the development of acute ischemic stroke. Conclusion: Carotid atherosclerosis is related to acute ischemic stroke occurrence. Furthermore, the presence of lipid plaques is a risk factor for acute ischemic stroke. Combined with some laboratory indicators, carotid artery CTA can judge the nature of carotid plaques and provide a basis for the prevention and treatment of acute ischemic stroke.

Clinicopathological and CT Findings of Cystic Lung Cancer

MENG Hongjia, CHEN Xiaojuan, HUANG Junjie, HE Xiaoxue, CHEN Huai

, Available online , doi: 10.15953/j.ctta.2022.014

Abstract(59) HTML PDF(4)

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Objective: Cystic lung cancer is a rare type of lung cancer with special morphological manifestations on imaging that have not been completely recognized. This study aimed to improve the understanding and diagnosis of this lung cancer by analyzing its computed tomography (CT) features and clinicopathological findings. Methods: The clinical data, pathological types, and CT features of patients with cystic lung cancer who were diagnosed at our hospital between January 2015 and June 2021 were analyzed retrospectively. Results: We identified 44 cases (86.27%) of adenocarcinomas; these included 7 (13.73%) and 35 (68.63%) cases of microinvasive adenocarcinomas and invasive adenocarcinomas, respectively. Regarding the histological type, 11 (21.57%), 8 (15.69%), and 15 (29.41%) cases were of the adjoint, papillary, and acinar types, respectively. Two cases (3.92%) contained micropapillary components that accounted for more than 20% . Furthermore, one case (1.96%) was not classified, and in another case (1.96%), pathological examination after chemotherapy suggested an adenocarcinoma. Lymph node biopsy in one case (1.96%) suggested a metastatic lung adenocarcinoma. Squamous cell carcinoma was observed in five cases (9.80%); these included three (5.89%) and two (3.92%) cases of keratinizing and non-keratinizing squamous cell carcinomas, respectively. A large cell carcinoma and a high-grade mucoepidermoid carcinoma were observed in one case each (1.96%). A peripheral distribution was observed in 40 cases (80.30%). The mean diameter was 4.7± 2.7 cm. A cystic cavity with ground glass, cystic cavity with solid components, and cystic cavity with mixed components were observed in 20 (39.22%), 22 (43.14%), and 9 (17.65%) cases, respectively. According to the Mario classification, 24 (47.06%), 8 (15.69%), 9 (17.65%), and 10 (19.61%) cases were of types I, II, III, and IV, respectively. The cyst wall was uneven in 42 cases (82.35%); furthermore, a lobular lesion edge and the burr sign were observed in 28 (54.90%) and 14 (27.45%) cases, respectively. Moreover, 33 cases (64.71%) showed a separation within the lesions, while 36 cases (70.59%) had a smooth inner lesion wall. Regarding the relationship with the pleura, pleural traction and closed pleura were observed in 24 (47.06%) and 11 (21.57%) cases, respectively. The peripheral blood vessels passed through the lesion in eight cases (15.69%) and adhered closely to the edge of the lesion in 16 cases (31.37%). The surrounding bronchi passed through the lesion in eight cases (15.69%) and moved toward the edge of the lesion in 21 cases (41.18%). Conclusion: Cystic lung cancer has certain features on CT that can allow its suggestive diagnosis.

Fast EPRI Imaging Based on 3MNet Denoising Network

QIAN Peizhang, QIAO Zhiwei, DU Congcong

, Available online , doi: 10.15953/j.ctta.2022.065

Abstract(166) HTML PDF(12)

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Electron Paramagnetic Resonance Imaging (EPRI) is an advanced technique for oxygen imaging. The current bottleneck in EPRI is the slow scanning speed, due to the fact that the projection signal at each angle needs to be repeated thousands of times to suppress random noise. One way to achieve fast scanning is to reduce the number of repeated projection signal acquisitions; however, this, in turn, reduces the signal-to-noise ratio of the projection signal and results in a noisy reconstructed image. To effectively suppress the noise in the reconstructed image, this study proposes a multi-channel, multi-scale, multi-concatenation, and convolutional network (3MNet) based image denoising network to achieve high accuracy and fast EPRI imaging. The proposed network consists of three sub-networks. The first sub-network is an attention-based convolutional network, whose output feature images are stitched with the input images to form the input of the back-end network. The second sub-network is a three-channel convolutional network. Finally, the third sub-network is a multi-scale convolutional network. The experimental results demonstrate that the proposed 3MNet network can achieve high accuracy in denoising EPRI images and fast imaging.

Research on Quadric Surface Fitting Algorithm Based on CT Data

FAN Zhixuan, QUE Jiemin, WEI Cunfeng, LIU Baodong, WEI Biao

, Available online , doi: 10.15953/j.ctta.2022.040

Abstract(90) HTML PDF(7)

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Quadric surface is a common type of workpiece shape in industry. It can be imaged by computed tomography (CT). A sample object was scanned and its slices were reconstructed to measure its internal quadric surface. We used the U-net image segmentation network to obtain the interested region and then detected the edge in the segmentation results and obtained curve fitting results. The curves were stacked into a three-dimensional point set. The three-dimensional spatial coordinate information for the internal quadric surface was computed through surface fitting. The results demonstrate that the proposed method can effectively extract the internal quadric surface parameters, and the fitting error can be controlled within 1%, which is superior to that achieved with a traditional algorithm.

Combined Application of High-density Electrical Method and Transient Electromagnetic Method in Gobi Desert Area

TANG Su, WU Yinting, XING Hao, LOU Xuecong, SHI Haitao

, Available online , doi: 10.15953/j.ctta.2022.081

Abstract(110) HTML PDF(22)

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This study probed the existence of groundwater in a mineral concentration area, using high-density electrical and transient electromagnetic methods. Our objective was to understand the dynamic changes in groundwater resources accurately and support the development of a sustainable ecological environment in the Gobi Desert area. The study demonstrates that the combination of the high-density electrical and transient electromagnetic methods guides the hydrological drilling construction in this area effectively. It also provides a reference for the selection and application of geophysical exploration methods under similar geological conditions for future studies.

Shallow Profile Data Denoising Method Based on Improved Cycle-consistent Generative Adversarial Network

ZHANG Yi, DING Renwei, ZHAO Shuo, SUN Shimin, HAN Tianjiao

, Available online , doi: 10.15953/j.ctta.2022.053

Abstract(112) HTML PDF(12)

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This study applied the cycle generative adversarial network method to the denoising of shallow profile data to realize intelligent denoising. This could help resolve the problem of noise and low resolution of shallow profile data. To do this, the cycle generative adversarial network with special symmetric generation countermeasure network cycle mechanism and "cycle consistency loss" was selected. We improved the performance of e-learning and training by optimizing the network structure. Next, based on the optimized shallow profile sample set training network, random noise was removed from the shallow profile data and the signal-to-noise ratio of the data was improved. The effectiveness and adaptability of this method for denoising shallow profile data were verified by trial calculations of experimental and actual data and by comparison with the traditional band-pass filtering method.

Effect of Computed Tomography Window Technique on the Results of Artificial Intelligence Classification of Lung Lesions

CHENG Xiaoyue, WU Xiaohua, HAO You, HE Wen, LI Hua, LIU Jiabao, CAO Qiuting

, Available online , doi: 10.15953/j.ctta.2022.210

Abstract(20) HTML PDF(1)

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Objective To use three different 3D CNN algorithms and five different computed tomography (CT) window settings to study the effect on the results of artificial intelligence classification of lung lesions in different CT window techniques. Method A total of 172 cases of peripheral lung cancer and 185 of focal pneumonia who underwent chest CT were analyzed. Three different 3D CNN algorithms were selected (ResNet, ResNext, and DenseNet) to divide the lesions into two groups. Five different CT window settings, including lung window (1,500, 600), mediastinal window (350, 40), custom window 1 (SW1) (1,000, 40), and custom window 2 (SW2) (1,000, 100), were used retrospectively. We calculated classification accuracy, receiver operating characteristic (ROC) curve, and area under the curve (AUC). The ROC curve was compared in pairs. Results The average classification accuracy of ResNet was the lowest in the mediastinal window (85.732%; AUC value: 0.871) and the highest in the full window (91.596%; AUC value: 0.946). The average classification accuracy of ResNext was the lowest in the mediastinal window (81.528%; AUC value: 0.814) and the highest in the full window (86.568%; AUC value: 0.882). The average classification accuracy of DenseNet was the lowest in the mediastinal window (87.954%; AUC value: 0.906) and the highest in the SW2 window (93.274%; AUC value: 0.951). MEDCALC was used to compare ROC curves under five windows of three 3D CNN. The AUC values between mediastinal window and lung window, mediastinal window and SW1, and mediastinal window and SW2 were statistically significant. Conclusion There is little difference in the diagnostic efficacy of the three 3D CNN. Different CT window settings have an influence on the results of CNN classification of the lung lesions, and the diagnostic efficiency of the three 3D CNN is the worst under the mediastinal window.

Clinical and Multilayer Spiral CT Diagnosis of Colon Innervation Defect

LI Xiaoyang, TIAN libin

, Available online , doi: 10.15953/j.ctta.2022.161

Abstract(13) HTML PDF(1)

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Objective: To analyze the image performance of colon innervation defect with multilayer spiral CT (MSCT) and clinical manifestations, summarize its image characteristics and make correct diagnosis. Methods: The clinical features of colonic innervations deficiency present with prolonged constipation and incomplete ileus. MSCT imaging data using GE gem energy spectrum, CT 750HD, and Philips MSCT. 1mm layer thickness, 1mm layer spacing, tube voltage, 120kV, automatic tube current from the diaphragm to the bilateral pubic joint. Scan in the natural state of the intestine (No bowel preparation, no cleansing enema and bowel cleansing), after scanning, conduct MPR 3D reconstruction at the CT workstation, and the reconstructed data were archived and analyzed in the PACS system. Clarify the intestinal location of the diseased segment, measure intestinal wall thickness of dilated segment and narrow segment respectively; measure intestinal tube length of diseased segment (narrow segment); observe intestinal peristalsis with multiple-stage MSCT; and observe intestinal blood transport through enhancement. Results: The clinical features of colon innervations defect was constipation and incomplete ileus. In this study group, there were 5 adult patients with colon innervations defect, and the lesion site was located in the spleen and descending colon respectively, among which the diseased segment was located in 3 cases and the spleen was located in 2 cases of colon; MSCT shows relative narrowing of the colon and expansion of the proximal colon; The intestinal wall thickness was normal in the diseased area, and the intestinal wall thickness of the dilated colon section was normal or somewhat thickened, and the thickened intestinal wall in this group is less than 0.9 cm;The intestinal length of the diseased segment in this group was somewhere between 4.3-8.6 cm.The MSCT enhancement scan of mesangic vessels and mesangial density showed no abnormal changes, and no abnormal enhancement of the colon wall in the diseased section, suggesting normal blood supply; MSCT enhanced scan showed rigidity and no peristalsis in the diseased segment, suggesting loss of peristaltic function in the diseased segment. Conclusion: Colonic innervations defect has imaging findings of characteristic post dilating stenosis and clinical features of prolonged constipation and incomplete obstruction in adults, The MSCT combined with clinical data was able to indicate the diagnosis of colonic innervations defect before surgery.

Application of Electromagnetic Waves for Karst Exploration in Urban Tunnels

PENG Jun, LI Qijia, GAO Jianhua, WANG Peng, XIONG Youliang

, Available online , doi: 10.15953/j.ctta.2022.184

Abstract(25) HTML PDF(4)

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With rapid urbanization, the contradiction between traffic and the environmental pollution caused by it is becoming increasingly prominent. To preserve ground buildings, an increasing number of tunnel schemes are adopted. Urban Karst exploration is based on drilling, supplemented by traditional geophysical methods such as high-density electrical method and shallow seismic reflection method, which are inefficient and difficult to implement owing to site conditions. As a geophysical exploration technology developed in recent years, electromagnetic wave technology has the advantages of high resolution and convenient field operation, which can better reveal the development scale and characteristics of underground Karst. Based on traditional data processing, setting the minimum value, choosing the reflection projection result as the initial model, using the low-pass filtering and angle-limiting technology, and adopting the structure program of continuous survey mode to carry out normalized calculation processing can greatly improve the accuracy of electromagnetic wave CT data interpretation. The findings of this study show that the electromagnetic wave detection technology can be applied effectively in Karst exploration, and its detection results have great guiding significance in urban tunnel engineering.

Research on the Application Value of ¹⁸F-FDG PET/CT Comwith Neuronal Antibody Detection in the Diagnosis and Treatment of PNS Patients

YUAN Leilei, CHEN Qian, QIAO Zhen, LI Xiaotong, FAN Di, ZHANG Wei, AI Lin

, Available online , doi: 10.15953/j.ctta.2022.070

Abstract(133) HTML PDF(23)

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Objective: To explore the whole body ¹⁸F-FDGClinical value of PET/CT combined neuroantibody detection in the diagnosis and treatment of paraneoplastic neurological syndromes (PNS). Methods: Clinical, laboratory and imaging data of 56 hospitalized patients with suspected PNS who underwent systemic ¹⁸F-FDG PET/CT and neuropathic tumor antibody detection were retrospectively collected and followed up. ROC curve was performed to compare the diagnostic efficacy of PET/CT, neuronal antibody and the combined detection results of them. Results: Among the 56 patients with suspected PNS, there were 20 patients with malignant tumor, including 19 cases complicated with PNS and 1 patient with spinal cord metastasis which also lead to neurological symptoms. ¹⁸F-FDG PET/CT imaging indicated tumor or possible tumor in 23 cases, of which 20 cases were true positive, 3 cases were false positive (the follow-up results were reflux esophagitis, reactive bone changes, inflammatory lesions in neck), and the remaining 33 cases were true negative. The sensitivity, specificity and accuracy of PET/CT were 100%, 91.7% and 94.6%, respectively. There were 33 cases with positive neuroantibody, including 8 cases of tumor with PNS (3 cases with anti-Amphiphysin antibody encephalitis, 2 cases with anti-GABAb antibody encephalitis, 1 case with anti-Yo antibody encephalitis, and 2 cases with anti-Hu antibody encephalitis). There were 25 cases without tumor (10 cases with LGI1 antibody encephalitis, 3 cases with anti-amphiphysin antibody encephalitis, 1 case with anti-Hu antibody encephalitis, 3 cases with anti-GABAb antibody encephalitis, 3 cases with anti-Yo antibody encephalitis and 1 case with Anti-caspr2, 1 case with GAD65, 1 case with NMDA, 1case with PNMA and 1 case with SOX1 antibody (1 case each) 23 cases were negative (12 cases with tumor). The sensitivity, specificity and accuracy of neuronal antibody test were 40.0%, 30.6% and 33.9%, respectively. The sensitivity, specificity and accuracy of the combined detection were 100.0%, 33.3%, 57.1%, 50%, 94.4%, 78.6%, respectively. ROC analysis showed that AUC were 0.958 (P=0.000<0.05; 95% CI 0.904~1.000), 0.353 (P=0.070>0.05; 95% CI 0.199~0.506), 0.667 (P=0.040<0.05; 95% CI 0.528~0.806) and 0.672 (P=0.034<0.05; 95% CI 0.514~0.830). Conclusion: Whole body ¹⁸F-FDG PET/CT can be the first choice for noninvasive tumor screening in patients with suspected PNS.

Evaluation of Invasion of Pulmonary Subsolid Nodules by Artificial Intelligence Volumetric Density Method

WANG Jingchen, CHAI Jun

, Available online , doi: 10.15953/j.ctta.2022.099

Abstract(67) HTML PDF(9)

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Objective: To explore the value of artificial intelligence (AI) volumetric density method in determining the invasion of pulmonary hyposolid nodules (SSNs). Methods: 108 SSNs and pathological results of 106 patients were reviewed, divided into glandular prodromal lesions group and adenocarcinoma group. Pulmonary nodule AI software was used to measure and compare the CT quantitative parameters of the two groups, including maximum CT value, minimum CT value, average CT value, kurtosis, skewness, Perc.25%, Perc.50%, Perc.75%, Perc.90%, nodule volume and mean nodule diameter. Receiver operating characteristic curve (ROC) was obtained by Medcalc software to evaluate the sensitivity, specificity, positive predictive value and negative predictive value for the diagnosis of SSNs infiltration, and their diagnostic performance was evaluated by logistic regression analysis. Results: There were significant differences in most CT quantitative parameters of SSNs. The highest diagnostic efficiency was Perc.25% and AUC was 0.797. Perc.50% and CT mean, AUC were 0.787. Logistic regression analysis showed that Perc.25% with the highest diagnostic efficiency was combined with Perc.50% and CT mean value, respectively. The model with Perc.25% and CT mean value had the highest diagnostic efficiency, and the combined diagnostic model had higher diagnostic efficiency than Perc.25% and CT mean value alone. According to Medcalc software, SSNs with Perc.25% ≥−578 HU and mean CT value ≥ −468 HU are more likely to be adenocarcinoma group. In this study, Perc.25% was combined with the mean diameter of nodules, and a very valuable combined diagnostic model II was obtained to judge the infiltration of SSNs. Conclusion: AI volume density method has a high diagnostic value for SSNs invasion. The combination of Perc.25% and mean CT value can accurately judge the invasion than the use of average CT value alone, thus providing a quantitative basis for the clinical management of SSNs.

Evaluation of Diagnostic Value of Pulmonary Nodules Based on Two AI Softwares

CHEN Xinhua, HUANG Xiaoqi, LI Jianlong, GUO Youmin

, Available online , doi: 10.15953/j.ctta.2022.087

Abstract(76) HTML PDF(14)

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Objective: To explore the clinical value of two kinds of AI detection software in ≥ 5 mm pulmonary nodules. Methods: A total of 92 patients with pulmonary nodules (483 nodules) were selected from June 2021 to October 2021 in the affiliated Hospital of Yan'an University. The nodules detected by AI software were evaluated and the number and type of nodules were recorded by two senior radiologists. Manual film reading was evaluated by two senior imaging doctors, which was used as the gold standard for nodule recognition. The detection rate, false positive rate and false negative rate of the two software’s were calculated, and the nodule detection value of the two AI software was evaluated. Chi-square test and Fisher precision test are used to compare the differences between different software and gold standard. Finally, the diagnostic value of the combination of two kinds of AI software for pulmonary nodules was calculated. Results: The detection rates of software A and software B nodules were 92.1% and 87.0% respectively. The coincidence degree between software A and manual reading was general (Kappa=0.213), while that between software B and manual reading was weak (Kappa=0.150). There was significant difference in the detection of solid nodules and calcified nodules between software A and manual reading, and between software B and pure ground glass nodules. The detection rate of nodules combined with two kinds of AI software was 97.1%. Compared with manual reading, there was no significant difference in the detection of nodule types. The combination of the two AI software’s had a good agreement with manual reading (Kappa=0.439). Conclusion: Two kinds of AI software association improve the ability of nodule detection and classification analysis. The method of joint diagnosis is recommended for clinical use, and it also provides evidence for further improving the homogenization management of AI data sets.

Application of Comprehensive Geophysical Prospecting Method in Goaf Detection

TANG Su, WU Yinting, XING Hao, WEI Yongshan, WANG Xuan

, Available online , doi: 10.15953/j.ctta.2022.176

Abstract(101) HTML PDF(10)

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To accurately explore distribution of a historical small coal mine goaf in Hami, Xinjiang, integrated application of microtremor and transient electromagnetic is used for goaf exploration researching. This work use different physical properties data into lithology, use microtremor exploration to determine the goaf position and use transient electromagnetic exploration identify goaf water. Two methods can complement each other, verify each other, and effectively reduce the wrong results of single geophysical method. Which also provides a reference for the selection and application of geophysical exploration means in small mine goaf exploration.

Research Progress of Scattering Artifact Correction in Medical Cone-beam Computed Tomography Imaging Based on Deep Learning

ZHANG Wenjun, HUANG Gang, DING Haining, XU Hongchun

, Available online , doi: 10.15953/j.ctta.2022.131

Abstract(94) HTML PDF(19)

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In the medical computed tomography imaging system, Compton scattered photons and Rayleigh scattered photons generated by the interaction between X-ray and objects have serious impact on image quality, especially in cone beam computed tomography and multi-layer detector system compared to fan beam computed tomography system. At present, there have been many scattering artifacts correction methods, which are summarized into three categories: hardware correction methods, software correction methods and hybrid software and hardware correction methods. However, with the advances in computing power of computers and the development of deep learning in medical image processing, some new methods of scattering artifacts correction have appeared in recent years. This paper first introduces the traditional correction methods. Then, the method of scattering artifacts correction based on deep learning is introduced in detail, which is divided into image domain learning method and projection domain learning method. Different deep-learning neural networks in this method are introduced in detail too. Finally, the application prospects of the deep learning method in multi-source computed tomography imaging scattering artifacts are prospected.

Research and Application of Adaptive Multi-channel Matching Pursuit Method to Remove Strong Shielding

WANG Xi'an, ZHANG Junhua, XIA Lianjun, LUO Zhen, HU Yifu, BAO Wei

, Available online , doi: 10.15953/j.ctta.2022.120

Abstract(69) HTML PDF(8)

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The strata with large impedance differences are presented as strong amplitude seismic events on the seismic profile, which will obscure the useful information of the nearby reservoir and need to do the interpretive target processing to remove the strong shielding. To address the problem of poor matching accuracy and spatial continuity of normal multi-channel matching pursuit in the place of strong tectonic changes, this paper proposes a multi-channel matching pursuit de-strong shielding method based on adaptive weights. Firstly, we use the layer structure information to flatten the strong reflection layer locally to weaken the influence of the stratigraphic structure changes on the extraction of the strong reflection layer, and then introduce the correlation coefficient between adjacent seismic traces and the central trace as the weight of multi trace averaging, which improves the stability and lateral continuity of the matching results. Meanwhile, using the interpreted layer time as the initial central time delay of the wavelet can effectively improve the compute efficiency. The analysis of model processing tests and practical seismic data application shows that the new method can effectively strip the strong reflections and highlight the effective reservoir information, and the well seismic match degree is significantly improved, with higher matching accuracy and better spatial continuity and better striping effect than the conventional matching pursuit algorithm.

Imaging Features and Clinical Significance of Segond Fracture

HE Weihong, FU Xi, FANG Tingsong, WANG Guining, WANG Juan

, Available online , doi: 10.15953/j.ctta.2022.112

Abstract(17) HTML PDF(0)

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Objective: To evaluate the imaging features of Segond fracture and explore its clinical value in lateral instability of the knee joint. Methods: Retrospectively analyze 45 cases of Segond fracture. Analyze the characteristics of the fracture, included the relationship between the fracture and the ligaments around the knee joint, meniscus injury, the size and location of the fracture block. The significance of Segond fracture in clinical treatment was discussed. Results: Among 45 cases of Segond fracture, 41 cases (91.11%) had anterior cruciate ligament (ACL) injury, 31 cases (68.89%) had anterolateral ligament (ALL) injury, and 12 cases (26.67%) had iliotibial bundle (ITB) injury. ALL were all attached to the fracture block, and 25 cases (55.55%) were attached to the ITB. The larger the size of the fracture block and the smaller the distance from the center of Gerdy's nodule, the more likely the fracture block will be attached to the ITB. Conclusion: Segond fracture is often associated with ACL injury, involving ALL and ITB. The larger the fracture block and the closer to the center of Gerdy's nodule, the greater the possibility of involving ITB. Patients with Segond fracture should be alert to lateral instability of the knee joint.

Natural Gas Hydrate CT Image Threshold Segmentation Based on Time Evolution

CHEN Liang, YE Wangquan, LI Chengfeng, SUN Jianye, ZHENG Ronger

, Available online , doi: 10.15953/j.ctta.2022.062

Abstract(34) HTML PDF(3)

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Micro-scale X-ray computed tomography (CT) has been widely used to study the occurrence forms of gas hydrate-bearing sediments. However, the similarity on X-ray’s attenuation coefficient of hydrate and water leads to strong non-uniqueness in phase differentiation between them in CT images. In order to improve threshold segmentation accuracy between hydrate and water in CT images, this paper proposed a CT image and histogram normalized method by analyzing the histogram characteristics of CT images at different times in the growth process of natural gas hydrate. Firstly, choose peak gray value baseline of methane gas and quartz sand. Then, use Gaussian function to fit methane gas and quartz sand curves in the current CT image histogram to obtain the peak gray values. In addition, the peak gray values of methane gas and quartz sand in the current CT image histogram were normalized to the chosen peak gray baseline. After that, the normalized histogram is used to normalize corresponding CT images. Finally, according to the changing trend of normalized gray histogram curves, the gray ranges of hydrate increasing and gas-water decreasing in CT images can be obtained quantitatively, which can guide the CT images threshold segmentation. Experimental results show that the proposed threshold segmentation method can provide a basis for the phase differentiation of hydrate and water in CT image, improve the threshold segmentation accuracy.

Application of Real Size Film Printing Technology in Costal Cartilage CT Image

CAO Jie, BI Zihan, LI Bo, WANG Yongzhen, XIN Gang, Mao Xiaoying, LIU Li

, Available online , doi: 10.15953/j.ctta.2022.135

Abstract(44) HTML PDF(8)

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Objective: To explore the film printing technology for displaying the true size of costal cartilage on medical film. Methods: The CT images of costal cartilage of 31 patients were selected and processed 14×17 inches (35×43 cm), calculate the main image display area and 14×17 the scale between the actual image display areas on the film shall be made into physical scales of 10 cm and 5 cm in length. Print the film in 2×2. Four images are arranged in the grid, and the transverse or sagittal images of single rib cartilage are printed on a 5 cm physical scale; with 1×1 The grid is a single image layout, and the 3D images of all the front rib arches (including costal cartilage) are printed on a 10 cm physical scale. The film measurement values of six indicators, including the length of the ascending and transverse parts of the right sixth costal cartilage, the width and thickness of the transverse junction of the ascending part, the thickness of the sternal end of the costal cartilage and the rib end of the costal cartilage, were compared with the solid measurement values during the operation, and statistical analysis was made. Results: (1) The printed film was measured, and the 10 cm and 5 cm scales shown on the film were equal to the actual size of the ruler. (2) There was no significant difference between the measured values of six groups of costal cartilage images on film and the measured values of costal cartilage entities during surgery. Conclusion: The printing technology based on DICOM protocol can realize the real size printing of costal cartilage CT image on film. The morphological data of the target tissue obtained by the operator from the film are reliable.

The Value of Spectral CT in Differential Diagnosis and Radiotherapy Localiation of Central Lung Cancer with Obstructive Atelectasis

LIU Xiuli, ZHANG Jifeng, LIU Jingwang, LI Jian, XU Mei, CHEN Jing

, Available online , doi: 10.15953/j.ctta.2022.164

Abstract(49) HTML PDF(9)

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Objective: To investigate the value of spectral CT in differential central lung cancer from obstructive atelectasis for achieving the accurate delineation and radiotherapy localiation. Methods: The CT radiotherapy localiation images of three phase contrast enchancement by spectral CT of 65 patients confirmed by pathology with central lung cancer and obstructive atelectasis with were collected and analyzed. The scores and detection rates of tumor-lung interface between the polychromatic image (PI), the best monochromatic image (BMI), the effective atomic number (Eff-Z) and the best monochromatic image combined with iodine concentration map (BMI-ICM) were compared. Results: Statistical differences in the scores of tumor-lung interface were observed between PI, BMI, Eff-Z and BMI-ICM; the pairwise comparison showed that the subjective score of BMI-ICM was the highest, and PI was the lowest. The pulmonaty artery phase detection rates of tumor-lung interface of three phase contrast enchancement were the highest. There was statistical difference of iodine concentration (IC) and CT score between lung cancer and obstructive atelectasis. The difference of IC was higher Zhan the CT score. Conclusion: Spectral CT is helpful to distinguish central lung cancer delineation from atelectasis. It provides a new method to delineate the radiotherapy localiation for radiotherapy plan of optimization.

In Vivo Study of the Influence of CT Acquisition and Reconstruction Parameters on Chest CT Number

LI Jingjing, ZHANG Li, LIU Mengwen, YANG Shouxin, LI Meng, JIANG Jiuming, YU Weijun

, Available online , doi: 10.15953/j.ctta.2022.109

Abstract(93) HTML PDF(13)

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Objective: To explore the influence of different CT acquisition and reconstruction parameters on the CT number of the chest in vivo. Methods: The CT number of the trachea, blood vessels, lungs, vertebral bodies, and muscles of the human chest were measured under different CT scanning parameters. Six groups of different scanning parameters and reconstruction algorithms were set respectively: slice thickness 5 mm, 50% multi-model adaptive statistical iterative reconstruction Veo (ASIR-V) and low-dose for S1; slice thickness 5 mm, filtered back projection (FBP) and standard-dose for S2; slice thickness 1.25 mm, 50% ASIR-V and low-dose for S3; slice thickness 1.25 mm, 50% ASIR-V and standard-dose for S4; slice thickness 1.25 mm, FBP, low-dose for S5; slice thickness 1.25 mm, FBP, standard-dose for S6. The radiation dose of the scan was controlled using two noise indexes (NI), including low-dose (NI=40) and standard-dose (NI=10). Differences in CT number between two groups were compared using t-test or rank-sum test. Results: Significant differences of CT number of the trachea were detected between low-dose and standard-dose, but no significant differences of CT number of other tissues were detected between low-dose and standard-dose. No significant differences of CT number of chest tissues were detected between either 5 mm thickness and 1.25 mm thickness or 50% ASIR-V and FBP. Conclusion: The CT number of human chest tissues showed well stability which was scarcely influenced by slices thickness, reconstruction algorithm and scan dose.

Study of Correlations between CT and MRI Findings and Elevated Serum IgG4 Levels in Newly-diagnosed Patients with IgG4-related Sclerosing Cholangitis

DONG Lining, YAN Wei, ZHANG Jie, YANG Dawei, LIU Peng, XU Hui, YANG Zhenghan, Wang Zhenchang, JIN Erhu

, Available online , doi: 10.15953/j.ctta.2022.158

Abstract(31) HTML PDF(7)

Abstract:
Objective: To observe the CT and MRI findings in newly-diagnosed patients with IgG4-related sclerosing cholangitis (IgG4-SC), and to explore their correlations to the serum IgG4 and IgG levels. Methods: The clinical, laboratory and imaging data of 50 newly-diagnosed IgG4-SC patients were retrospectively summarized. The type of lesions, shape of lumen stenosis and degree of dilatation of the diseased bile ducts on MRCP, and the characteristics and enhancement patterns of the thickened bile duct walls, in addition to the number of coexisted other IgG4-RDs on enhanced MRI and CT were observed. Then the correlations of the patients' baseline serum IgG4 and IgG levels with the severity of bile duct lesions and the number of coexisted other IgG4-RDs were analyzed. Results: 41 patients underwent MRCP examinations, IgG4-SC type Ⅰ in 28 cases, type Ⅱa in 11, type Ⅲ in 1, and type Ⅳ in 1 were identified. Extrahepatic bile duct stenosis was funnel-shaped in 37 cases and truncated in 4 cases. All the stenotic segments were long (≥1.0cm) and 1 diverticulum-like outpouching was seen in the pancreatic segment stenosis. Upstream bile ducts of the stenosis showed dilatation in 37 cases, the other 4 cases did not. Contrast-enhanced MRI and CT examinations showed continuous thickening of the extrahepatic bile duct walls in 42 cases, and diffuse thickening of the intrahepatic bile duct walls simultaneously in 15 cases among them. The thickness of the bile duct walls was uniformly concentric. Meanwhile, accompanied other IgG4-RDs included AIP in 50 cases, kidney involvement in 19 cases, salivary gland involvement in 7 cases, retroperitoneal fibrosis in 5 cases, and liver involvement in 4 cases, lung involvement in 4 cases, prostate involvement in 2 cases, sclerosing mediastinitis in 2 cases, thickened gallbladder wall (without stones) in 20 cases, enlarged upper abdominal lymph nodes in 15 cases. Higher baseline serum IgG4 and IgG levels were positively correlated with the number of coexisted other IgG4-RDs, but not with the bile duct wall thickness and stenotic segment length. Conclusions: Localized stenosis of the bile ducts with dilatation or non-dilation of the upstream bile ducts, as well as diffuse thickening of the bile duct walls are the MRI and CT features of newly-diagnosed patients with IgG4-SC. Higher baseline serum IgG4 and IgG levels are not related to the severity of the diseased bile ducts, but related to the number of coexisted other IgG4-RDs.

Progress in Clinical Application of Fractional Flow Reserve Based on Coronary CT Angiography

LI Shihang, ZHANG Xiaoqin

, Available online , doi: 10.15953/j.ctta.2022.037

Abstract(55) HTML PDF(12)

Abstract:
Noninvasive coronary fractional flow reserve derived from CT angiography (FFR_CT) is a major advance in cardiovascular imaging in recent years. It can identify pathology-specific ischemia and provide information for clinical decisions on revascularization, serving as a gatekeeper for invasive coronary angiography.This paper reviews the research progress of FFR_CT and briefly discusses its limitations.

Research Progress of Radiomics in the Diagnosis of Pulmonary Nodules

LIU Yuting, LIU Aishi

, Available online , doi: 10.15953/j.ctta.2022.056

Abstract(47) HTML PDF(11)

Abstract:
In recent years, with the continuous improvement of medical level, people pay more attention to their own health, pulmonary nodules and other space-occupying lesions can be detected earlier, but on a global scale, the number of deaths caused by malignant lung lesions Still rising and remaining high. Radiomics is an emerging field that aims to derive automated quantitative imaging features from medical images to noninvasively predict nodular and tumor behavior. Compared with traditional visual image features, radiomics can extract more nodular features with better reproducibility. The scientific and systematic use of radiomics can not only prevent excessive medical behaviors and reduce the economic burden of patients, but also enable patients with lung lesions to receive early treatment for the best prognosis.

Quantitative CT Analysis of Body Composition in Maintenance Hemodialysis Patients

LV Lei, ZHAI Jian, LI Yuncheng, ZHAO Yazi, LIU Yan

, Available online , doi: 10.15953/j.ctta.2022.050

Abstract(76) HTML PDF(6)

Abstract:
Objective: Analyze body composition information in patients on maintenance hemodialysis, to explore the application value of QCT technology. Methods: A total of 62 patients with maintenance hemodialysis were selected, divided into 3 groups according to different dialysis durations, and the bone density value, abdominal fat and muscle content of patients were determined by quantitative CT technology, and 62 cases of health examination population matching gender and age were selected for comparative analysis. Results: Osteoporosis accounted for 17.70% (11 cases) and bone loss in the dialysis group accounted for 30.60% (19 cases), while in the healthy control group, osteoporosis and bone loss accounted for 6.50% (4 cases) and 16.10% (10 cases), respectively, and the difference between the two groups was statistically significant; the intra-abdominal fat and subcutaneous fat content in the dialysis group were (113.70±63.29) cm², (80.65±59.67) cm², respectively. All were lower than the healthy control group (135.90±58.80) cm², (122.26±54.94) cm², the dialysis group L3-SMA< control group L3-SMA, (107.00±30.70) cm²< (121.37±32.87) cm², all with statistical differences, and the lumbar vertebral bone density value of male dialysis patients was (156.11±51.94) (mg/cm³) in different sex dialysis patients. Compared with women (124.29±50.89) (mg/cm³), the difference was statistically significant, and the subcutaneous fat content was higher than that in men while the difference in intraperitoneal fat content in men and women was not statistically significant; the difference between bone density values and L3-SMA changes in the dialysis group and the length of dialysis time was not statistically significant. Conclusion: The incidence of osteoporosis is higher in patients on maintenance hemodialysis than in healthy people, and the amount of abdominal fat and muscle content are lower than that in healthy people, Quantitative CT body composition monitoring have high accuracy and sensitivity.

Imaging Diagnosis of Nuchal-type Fibroma

LIANG Dezhi, JIN Cangzheng

, Available online , doi: 10.15953/j.ctta.2022.048

Abstract(65) HTML PDF(4)

Abstract:
Objective: To study the CT and MRI findings of nuchal-type fibroma. Methods: 8 cases of surgically resected and pathologically confirmed nuchal-type fibroma were retrospectively analyzed. Results: All lesions were firm and located in subcutaneous tissue of sacrococcygeal region. CT and MRI showed local skin thickening. The lesions were ill-defined and had irregular morphology. The lesions showed slightly high density on CT, low signal intensity on T1WI and T2WI, and isosignal on DWI. Enhancement scanning was performed in 2 patients, with 1 mild enhancement and 1 moderate enhancement. Conclusion: The CT and MRI findings of nuchal-type fibroma have some characteristic features. Combining with the medical history and clinical manifestations, the diagnosis could be made.

Advances in Imaging Research on Prediction of Colorectal Cancer Gene Mutation Status

JIA Jianye, DING Cong, ZHOU Wei, BAI Genji

, Available online , doi: 10.15953/j.ctta.2022.028

Abstract(83) HTML PDF(5)

Abstract:
Clinicians are increasingly demanding personalized treatment strategies for patients with colorectal cancer (CRC), and it is particularly important to detect mutated gene profiles when CRC patients are diagnosed or metastatic. The effective prediction of genetic information of CRC patients by analyzing tumor biological characteristics through non-invasive imaging has become a research hotspot in this field. This review will focus on the application of different imaging methods to predict CRC gene mutation status.

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