ISSN 1004-4140
CN 11-3017/P
Articles Online First have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
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Research on the Edge Feature Enhancement of Fluvial Reservoirs Based on Image Processing
ZHANG Junhua, HU Yifu, YU Zhengjun, REN Ruijun, LIU Xuanliang
 doi: 10.15953/j.ctta.2022.174
Abstract(306) HTML PDF(28)
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 coherent enhancement 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.
Clinical and Multilayer Spiral CT Diagnosis of Colon Innervation Defect
LI Xiaoyang, TIAN Libin
 doi: 10.15953/j.ctta.2022.161
Abstract(32) HTML PDF(4)
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.
Spectral CT Combined with Tumor Markers to Predict Ki-67 Expression in Lung Adenocarcinoma
DOU Peipei, ZHAO Hengliang, CAO Aihong
 doi: 10.15953/j.ctta.2022.172
Abstract(21) HTML PDF(3)
Purpose: To investigate the predictive value of energy spectrum CT quantitative parameters combined with serum tumor markers (CEA, CA-125) on ki-67 expression in lung adenocarcinoma. Methods: The clinicopathological and imaging data of 64 patients with lung adenocarcinoma confirmed by pathology from June 2020 to February 2022 were retrospectively analyzed. All patients underwent dual-phase energy spectrum CT examination, and serum CEA and CA-125 levels before treatment were clear. Based on postoperative pathological results, patients were divided into two groups, the high expression group of Ki-67 (>30%) and the low expression group of Ki-67 (≤30%). The iodine value (IC), standardized iodine ratio (NIC), and the slope of the energy spectrum curve (λHU) were measured by a dual-energy post-processing workstation. The expression levels of SERUM CEA and CA-125 before treatment were obtained according to medical records. Statistical analysis of the data was performed with SPSS22.0; t-test or Mann−Whitney U test and χ2 tests were used to compare the differences in parameters between the two groups, and the ROC (receiver operating characteristic curve, ROC) curve was used to evaluate the prediction efficiency of the parameters. Results: The IC, NIC, and λHU values in the low expression group were higher than those of the high expression group, and the differences were statistically significant. Serum CEA and CA-125 levels in the ki-67 high expression group were higher than those of the low expression group, and the difference was statistically significant. There were no significant differences in other parameters between the two groups. ROC curve analysis showed that CEA had the best predictive efficiency for KI-67, with an area under the curve of 0.697, sensitivity of 39.17%, and specificity of 100%. Conclusions: The quantitative parameters of energy spectrum CT in the venous phase, serum CEA, and CA12-5 levels have a certain value in predicting the expression of KI-67, which can provide a basis for selecting a clinical treatment plan.
Advances in the Preoperative Prediction of the Spread of Lung Adenocarcinoma Through Air Spaces Using CT Features
BA Wenjuan, ZHU Yanlin, WEI Mei, YIN Ke
 doi: 10.15953/j.ctta.2022.236
Abstract(35) HTML PDF(5)
The spread through air spaces (STAS) is one of the aggressive behaviors of lung adenocarcinoma. It is a risk factor for recurrence and an indicator of poor prognosis after sublobectomy. The association between computed tomography (CT)-based features and STAS can predict the STAS status of patients with lung adenocarcinoma, and thus, assist in the clinical selection of the appropriate type of surgery. This article reviewed the aggressiveness of STAS in lung adenocarcinoma and the current research on the preoperative CT prediction of STAS, as well as related new techniques.
Diagnostic Value of Dual-source CT Dual-energy Virtual Non-contrasting Extramural Vascular Invasions of Rectal Cancer
YANG Zhenxing, ZHANG Yuqi, LIU Aishi, WU Hui, ZHAO Lei, GAO Wei, SHI Lin, HAO Fene
 doi: 10.15953/j.ctta.2022.231
Abstract(41) HTML PDF(8)
Objective: To investigate the value of dual-source CT dual-energy virtual plain scan in the preoperative diagnosis of extramural vascular invasion (EMVI) in rectal cancer. Methods: A total of 150 patients with rectal cancer (64 females (42.7%) and 86 males (57.3%), with an average age of (62.3±11.8) years) who were scheduled for surgical treatment in our hospital from November 2019 to December 2021 were selected for the preoperative dual-source CT dual-energy virtual plain scan;. Two senior radiologists independently analyzed preoperative imaging data (including ctEMVI status, local lymph node infiltration, and distant metastasis) to determine the existence of preoperative EMVI. With pathological results as the gold standard, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of VNC in the diagnosis of EMVI were evaluated, and the area under the receiver operating characteristic curve (ROC) was used to evaluate the diagnostic efficiency. Results: Among 150 patients with rectal cancer, 56 (37.3%) were positive for EMVI and 94 (62.7%) were negative for EMVI. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of EMVI evaluation by physician 1 were 86%, 80.36%, 89.36%, 81.82%, and 88.42%, respectively, and the AUC was 0.831 (95%CI, 0.756~0.905). The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of physician 2 were 88.67%, 80.36%, 93.62%, 88.24%, and 88.89%, respectively, and the AUC was 0.870 (95%CI, 0.802−0.938). The consistency of the evaluation results between physician 1 and physician 2 was high (k=0.943, P<0.05). Conclusion: Dual-source CT dual-energy virtual plain scan has a certain diagnostic value in the preoperative evaluation of EMVI of rectal cancer.
Research Progress of High-resolution Magnetic Resonance Vessel Wall Imaging in the Identification of Intracranial Arterial Stenosis Etiology
LIN Xiaoyi, JIANG Ningping
 doi: 10.15953/j.ctta.2022.215
Abstract(30) HTML PDF(3)
Ischemic stroke caused by intracranial arterial stenosis (ICAS) is characterized by high morbidity and mortality. Conventional clinical examination methods include transcranial Doppler ultrasound, CT angiography, magnetic resonance angiography, and X-ray digital subtraction angiography. These methods are aimed at vascular stenosis and do not show vascular wall lesions. High-resolution magnetic resonance vessel wall imaging (HR-VWI) is a new imaging method that can non-invasively display vascular wall lesions and has important value in judging the nature of ICAS lesions. In this paper, the application of HR-VWI in the identification of ICAS etiology is reviewed.
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
 doi: 10.15953/j.ctta.2022.109
Abstract(147) HTML PDF(27)
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.
Rapid and Continuous Detection Method for Soil-compaction Degrees of Fill Foundation Based on Multichannel Transient Rayleigh Wave Detecting
WU Chuanyang
 doi: 10.15953/j.ctta.2022.243
Abstract(19) HTML PDF(2)
To address the large treatment area and tight construction period of large-scale engineering site filling foundations and to ensure the quality and progress of the project, understanding the foundation-reinforcement treatment quickly and accurately is essential. Additionally, to ensure the safety and stability of projects, large-scale projects often have higher requirements for the uniformity of the foundation-soil reinforcement effect. The quality-evaluation indices of foundation-soil compaction and reinforcement mainly include the foundation-bearing capacity, foundation-soil deformation modulus, and compaction coefficient. Conventional testing methods primarily include in-situ loading tests, in-situ sand filling, and soil-sample testing. These methods are either labor-intensive and time-consuming or harmful to the reinforced foundation-soil mass, preventing rapid and continuous detection of the foundation-soil mass. To perform rapid and continuous detection of the compaction and reinforcement effects of foundation-soil mass, the multichannel transient Rayleigh wave-detection method, considering the time difference phase between channels, was used in this study. Additionally, the method was supplemented by the sampling tests of soil mass at selected points in this study. Consequently, continuous three-dimensional imaging of the elastic wave velocity of the foundation-soil mass was obtained, along with the horizontal slice of the Rayleigh wave phase velocity imaging and the horizontal-distribution imaging of the depth-average compaction coefficient of the foundation-soil mass. The results reveal that the foundation-soil mass imaging can accurately reflect the compaction and reinforcement effects of the foundation-soil mass, thereby providing a reliable basis for evaluating the quality of foundation-soil mass reinforcement.
Application of New Iterative Reconstruction Algorithm Based on Artificial Intelligence and Low Tube Voltage in Reducing the Radiation Dose of Coronary CTA in Obese Patients
FENG Mengya, LI Bing, WU Min, HUA Ting, TANG Guangyu
 doi: 10.15953/j.ctta.2022.148
Abstract(39) HTML PDF(7)
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 120 kV and a tube current of 200 mAs, whereas in group B, a tube voltage of 80 kV and a tube current of 200 mAs 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.
Application of Electromagnetic Waves for Karst Exploration in Urban Tunnels
PENG Jun, LI Qijia, GAO Jianhua, WANG Peng, XIONG Youliang
 doi: 10.15953/j.ctta.2022.184
Abstract(52) HTML PDF(13)
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.
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
 doi: 10.15953/j.ctta.2022.135
Abstract(89) HTML PDF(8)
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.
Removal of Gridline Artifacts in Cone-beam CT Based on Wavelet Transform
WANG Yu’ang, GAO Hewei, ZHANG Li
 doi: 10.15953/j.ctta.2022.233
Abstract(76) HTML PDF(21)
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.
Imaging Features and Clinical Significance of the Segond Fracture
HE Weihong, FU Xi, FANG Tingsong, WANG Guining, WANG Juan
 doi: 10.15953/j.ctta.2022.112
Abstract(44) HTML PDF(3)
Objective: To evaluate the imaging features of the Segond fracture and explore its clinical value in lateral instability of the knee joint. Methods: We retrospectively analyzed 45 cases of the Segond fracture. This involved the analysis of the characteristics of the fracture, including the relationship between the fracture and the ligaments around the knee joint, meniscus injury, and the size and location of the fracture block. Moreover, the significance of the Segond fracture in clinical treatment was discussed. Results: Among 45 cases of the Segond fracture, 41 (91.11%) had anterior cruciate ligament (ACL) injury, 31 (68.89%) had anterolateral ligament (ALL) injury, and 12 (26.67%) had iliotibial bundle (ITB) injury. The 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 that the fracture block was attached to the ITB. Conclusion: The Segond fracture is often associated with ACL injury, involving the ALL and ITB. The larger the fracture block and the closer to the center of Gerdy's nodule, the greater the possibility of ITB involvement. Therefore, patients with Segond fractures should be alert to lateral instability of the knee joint.
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
 doi: 10.15953/j.ctta.2022.193
Abstract(61) HTML PDF(16)
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.
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
 doi: 10.15953/j.ctta.2022.210
Abstract(43) HTML PDF(5)
  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.
2023, 32(2).  
CT Theory
Computed Tomography Reconstruction Algorithm Based on Relative Total Variation Minimization
ZHANG Jiahao, QIAO Zhiwei
2023, 32(2): 153-169.   doi: 10.15953/j.ctta.2022.190
Abstract(90) HTML PDF(36)
The total variation (TV) minimization algorithm is an effective CT image reconstruction algorithm that can reconstruct sparse or noisy projection data with high accuracy. However, in some cases, the TV algorithm produces stepped artifacts. The relative TV algorithm outperforms TV algorithm in the field of image denoising. In view of this, the relative TV model is introduced into image reconstruction, a relative TV minimum optimization model is proposed, and the corresponding solution algorithm is designed under the framework of adaptive gradient descent projection to the convex set (ASD-POCS) to further improve reconstruction accuracy. The reconstruction experiments were conducted with Shepp Logan, Forbild, and real CT image simulation models to verify the anti-crime ability of the algorithm and evaluate the sparse reconstruction and anti-noise abilities of the algorithm. The experimental findings reveal that the algorithm outperforms the TV method in terms of anti-crime capability and the ability to reconstruct sparse or noisy projection data with high precision. Compared with the TV algorithm, the algorithm can achieve higher reconstruction accuracy.
Natural Gas Hydrate CT Image Threshold Segmentation Based on Time Evolution
CHEN Liang, YE Wangquan, LI Chengfeng, SUN Jianye, ZHENG Ronger
2023, 32(2): 171-178.   doi: 10.15953/j.ctta.2022.062
Abstract(63) HTML PDF(6)
Micro-scale X-ray computed tomography (CT) has been widely used to study the occurrence forms of gas hydrate-bearing sediments. However, the similarity between the X-ray attenuation coefficient of hydrate and that of water leads to a strong non-uniqueness in their phase differentiation in CT images. To improve threshold segmentation accuracy between hydrate and water in CT images, this study proposes a CT image and histogram normalized method by analyzing the histogram characteristics of CT images at different times during the growth process of natural gas hydrate. First, the peak gray value baseline of methane gas and quartz sand was selected. Then, a Gaussian function was used to fit the curves corresponding to methane gas and quartz sand 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. Subsequently, the normalized histogram was used to normalize the corresponding CT images. Finally, according to the changing trend of normalized gray histogram curves, the increasing gray ranges of hydrate and decreasing gray ranges of gas-water in CT images were obtained quantitatively, which guided threshold segmentation of CT images. Experimental results show that the proposed threshold segmentation method can provide a basis for phase differentiation between hydrate and water in CT images, improving the threshold segmentation accuracy.
Adaptive Weight Multi-channel Matching Pursuit Algorithm-Based Strong Shielding Removal Method
WANG Xi'an, ZHANG Junhua, XIA Lianjun, LUO Zhen, HU Yifu, BAO Wei
2023, 32(2): 179-188.   doi: 10.15953/j.ctta.2022.120
Abstract(92) HTML PDF(10)
The strata with large impedance differences are presented as strong amplitude seismic events on the seismic profile, which obscure useful information of nearby reservoirs and need interpretive target processing to remove the strong shielding. Therefore, this study proposes a multi-channel matching pursuit algorithm based on adaptive weight to remove strong shielding. Moreover, to address the problem of poor matching accuracy and spatial continuity of normal multi-channel matching pursuit at area where strong tectonic changes occur, a multi-channel matching pursuit de-strong shielding method based on adaptive weights is proposed. First, we used the layer structure information to flatten the strong reflection layer locally to weaken the influence of stratigraphic structure changes on the extraction of the strong reflection layer. Subsequently, we introduced a correlation coefficient between adjacent seismic traces and the central trace as the weight of multi trace averaging, which improved the stability and lateral continuity of the matching results. The result analysis of model processing tests and practical seismic data application shows that the proposed method can effectively strip the strong reflections and highlight the effective reservoir information; the well seismic match degree is significantly improved with higher matching accuracy, better spatial continuity, and better striping effect than those of the conventional matching pursuit algorithm.
Application of AVO Information-constrained Matching Pursuit Technique in Rich Coal Reservoir Characterization
LIU Qingwen, QIN Dewen, HU Wei
2023, 32(2): 189-197.   doi: 10.15953/j.ctta.2022.218
Abstract(29) HTML PDF(2)
To address the low accuracy of reservoir characterization in XiHu Sag in a coal-rich environment, this study developed a matching pursuit technology based on AVO information constraints combined with the AVO intercept and gradient characteristics of coal. It can suppress the strong reflectance lithologic artifacts caused by coal and highlight actual and effective reservoir signals. Based on the negative intercept P and positive gradient G of the AVO of coal, the seismic–sensitive factor PG of coal identification was developed to amplify the seismic response of coal and suppress the high-amplitude response of non-coal. Then, to accurately identify the location of coal, the seismic information of coal was used as the original signal that needs to be decomposed and reconstructed by matching pursuit. Additionally, the efficiency of signal-matching decomposition was improved using the technology of complex seismic track analysis. Finally, the strong reflection elimination of coal was completed. Model trials and practical applications indicate that this method could accurately identify the seismic response location of coal and improve the efficiency of the matching pursuit algorithm. Moreover, the coal-eliminated seismic data can better highlight the lateral distribution changes of the reservoir and improve the vertical characterization accuracy of the main gas layer.
Industrical CT
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
2023, 32(2): 198-208.   doi: 10.15953/j.ctta.2022.083
Abstract(79) HTML PDF(12)
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, we proposed an automatic method based on a deep convolutional neural network. This method treats the automatic identification of the relationship between the root of the M3M and the mandibular canal as a combination of regression and classification tasks. It uses the YOLOv5 (You Only Look Once) network as a framework for constructing a deep convolutional neural network that can accomplish detection and classification tasks 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 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 the mandibular canal. In the meantime, the region that includes the root of the M3M contacting the mandibular canal can be predicted. The experimental results show that the proposed method can provide an accurate judgment of whether the roots of impacted mandibular wisdom teeth in the panoramic radiographs are in contact with the mandibular canal and the location of regions in which the roots of the M3M are in contact with the mandibular canals; compared to manual diagnosis and the other methods, the proposed method can obtain more accurate results.
Medical Imaging and Image Processing
Research on the Application Value of 18F-FDG PET/CT Combined with 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
2023, 32(2): 209-215.   doi: 10.15953/j.ctta.2022.070
Abstract(147) HTML PDF(27)
Objective: To explore the clinical value of whole-body 18F-FDG PET/CT combined with 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 on. ROC curve analysis was performed to compare the diagnostic efficacy of PET/CT, neuronal antibodies, and their combined detection results. Results: Among the 56 patients with suspected PNS, there were 20 with malignant tumors, including 19 cases complicated with PNS and 1 patient with spinal cord metastasis which also le d to neurological symptoms. 18F-FDG PET/CT imaging indicated tumors or possible tumors 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, or inflammatory lesions in the 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 neuroantibodies, including 8 cases of tumors 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). Moreover, there were 25 cases without tumors (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, 1 case with Anti-caspr2, 1 case with GAD65, 1 case with NMDA, 1 case with PNMA, and 1 case with SOX1 antibody (1 case each). Of these, 23 cases were negative (12 cases with tumor). The sensitivity, specificity, and accuracy of the neuronal antibody test were 40.0%, 30.6%, and 33.9%, respectively. Furthermore, the sensitivity, specificity, and accuracy of the combined detection were 100.0%, 33.3%, 57.1%, 50%, 94.4%, and 78.6%, respectively. ROC analysis showed that the AUC was 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 has the potential to be the first choice for noninvasive tumor screening in patients with suspected PNS.
Risk Factors of Plaque Progression in Patients with Angina Pectoris and Their Relationships with Coronary CT Angiography
ZHU Najun, FANG Xinxin, YIN Yijun, ZHOU Shuitian
2023, 32(2): 217-222.   doi: 10.15953/j.ctta.2022.219
Abstract(33) HTML PDF(8)
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. 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. 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. Multivariate analysis showed that RI and CT-FFR levels were independent factors of plaque progression in patients with angina pectoris. 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. 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.
Clinical Characteristics and Imaging features of Primary Orbital Lymphoma
ZHU Jianbo, LI Bin, ZHANG Hongmei, WANG Ningli
2023, 32(2): 223-230.   doi: 10.15953/j.ctta.2022.245
Abstract(59) HTML PDF(17)
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.
Medical CT
A Study of the 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
2023, 32(2): 231-239.   doi: 10.15953/j.ctta.2022.158
Abstract(57) HTML PDF(10)
Objective: To observe the CT and MRI findings in newly diagnosed patients with IgG4-related sclerosing cholangitis (IgG4-SC) and explore their correlations with 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, degree of dilatation of the diseased bile ducts on MRCP, characteristics and enhancement patterns of the thickened bile duct walls, and the number of other coexisting IgG4-RDs on enhanced MRI and CT were observed. Subsequently, the correlations of the patients' baseline serum IgG4 and IgG levels with the severity of bile duct lesions and the number of other coexisting IgG4-RDs were analyzed. Results: Forty-one patients underwent MRCP examinations, and the following types of IgG4-SC were identified: type Ⅰ in 28 cases, type Ⅱa in 11, type Ⅲ in 1, and type Ⅳ in 1. Extrahepatic bile duct stenosis was funnel-shaped in 37 cases and truncated in 4 cases. Moreover, all the stenotic segments were long (≥1.0 cm) and one diverticulum-like outpouching was seen in the pancreatic segment stenosis. Upstream bile ducts of the stenosis showed dilatation in 37 cases, while the other 4 cases did not show this. 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 was simultaneously observed in 15 cases among them. The thickness of the bile duct walls was uniformly concentric. Meanwhile, other accompanying IgG4-RDs included AIP in 50 cases, kidney involvement in 19, salivary gland involvement in 7, retroperitoneal fibrosis in 5, liver involvement in 4, lung involvement in 4, prostate involvement in 2, sclerosing mediastinitis in 2, thickened gallbladder wall (without stones) in 20, and enlarged upper abdominal lymph nodes in 15 cases. Moreover, higher baseline serum IgG4 and IgG levels were positively correlated with the number of other coexisting 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. Furthermore, higher baseline serum IgG4 and IgG levels are not related to the severity of the diseased bile ducts but are related to the number of other coexisting IgG4-RDs.
Evaluation of the Invasion of Pulmonary Subsolid Nodules by the Artificial Intelligence Volumetric Density Method
WANG Jingchen, CHAI Jun
2023, 32(2): 241-248.   doi: 10.15953/j.ctta.2022.099
Abstract(98) HTML PDF(12)
Objective: To explore the value of the artificial intelligence (AI) volumetric density method in determining the invasion of pulmonary hyposolid nodules (SSNs). Methods: A total of 108 SSNs and the pathological results of 106 patients were reviewed, and these were divided into a glandular prodromal lesions group and an adenocarcinoma group. Pulmonary nodule AI software was used to measure and compare the CT quantitative parameters of the two groups, including the 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. Moreover, a 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 SSN 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 the AUC was 0.797, while the AUC was 0.787 for Perc.50% and the mean CT value. Logistic regression analysis showed that Perc.25% with the highest diagnostic efficiency was combined with Perc.50% and the mean CT value. The model with Perc.25% and the mean CT value had the highest diagnostic efficiency, and the combined diagnostic model had a higher diagnostic efficiency than Perc.25% and the mean CT value alone. According to MedCalc software, SSNs with Perc.25% ≥−578 HU and mean CT values ≥ −468 HU were more likely to be in the 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: The AI volume density method has a high diagnostic value for SSN invasion. Moreover , the combination of Perc.25% and mean CT value can accurately judge the invasion than the use of average CT value alone, providing a quantitative basis for the clinical management of SSNs.
Imaging Diagnosis of Nuchal-type Fibroma
LIANG Dezhi, JIN Cangzheng
2023, 32(2): 249-255.   doi: 10.15953/j.ctta.2022.048
Abstract(95) HTML PDF(10)
Objective: To study the CT and MRI findings of nuchal-type fibromas. Methods: Eight cases of surgically resected and pathologically confirmed nuchal-type fibroma were retrospectively analyzed. Results: All lesions were firm and located in the subcutaneous tissue of the sacrococcygeal region. Upon CT and MRI, local skin thickening was observed . The lesions were ill-defined and had irregular morphology. Moreover, the lesions showed slightly high density on CT, low signal intensity on T1WI and T2WI, and isosignal on DWI. Enhancement scanning was performed in two patients, with one mild and one moderate enhancement. Conclusion: The CT and MRI findings of nuchal-type fibromas have some characteristic features. Combined with medical history and clinical manifestations, these can assist in diagnosis
Quantitative CT Analysis of Body Composition in Maintenance Hemodialysis Patients
LV Lei, ZHAI Jian, LI Yuncheng, ZHAO Yazi, LIU Yan
2023, 32(2): 256-262.   doi: 10.15953/j.ctta.2022.050
Abstract(115) HTML PDF(10)
This study analyzes body composition information in patients on maintenance hemodialysis and explores the application value of QCT technology. Methods: A total of 62 patients on maintenance hemodialysis were selected and divided into three groups according to different dialysis durations. The bone density value, abdominal fat, and muscle content of patients were determined by quantitative CT technology and 62 cases of the health examination population matched by sex and age were selected for comparative analysis. Results: In the dialysis group, osteoporosis accounted for 17.70% (11 cases) and bone loss 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. The difference between these two groups was statistically significant. Moreover, the intra-abdominal and subcutaneous fat content in the dialysis group were (113.70±63.29)cm² and (80.65±59.67)cm², respectively, which were lower than that of the healthy control group ((135.90±58.80)cm² and (122.26±54.94)cm², respectively). Additionally, the dialysis group had a significantly lower L3-SMA (107.00±30.70)cm² than the control group (121.37±32.87)cm², and the lumbar vertebral bone density value was significantly lower in male dialysis patients (156.11±51.94)mg/cm³ than in female dialysis patients (124.29±50.89)mg/cm³. Moreover, the subcutaneous fat content was significantly higher in females than in males; however, the difference in intraperitoneal fat content between males and females was not statistically significant. Additionally, the difference between bone density values and L3-SMA changes in the dialysis group and the length of dialysis time were 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. Moreover, quantitative CT body composition monitoring has high accuracy and sensitivity.
Clinical Case
The Diagnosis of Cronkhite-Canada Syndrome with CT Enterography: A Clinical Case Analysis
ZHAO Xuesong, MIAO Fei, SUN Jing, DONG Yihan, ZHANG Huan, YAN Fuhua, DING Bei
2023, 32(2): 263-270.   doi: 10.15953/j.ctta.2023.017
Abstract(124) HTML PDF(41)
Cronkhite-Canada syndrome (CCS) is a rare cause of chronic diarrhea and malabsorption where patients develop multiple polyps throughout the gastrointestinal (GI) tract, accompanied by ectodermal changes. Due to its rarity, its early detection and diagnosis can be challenging for physicians. This case report described a 58-year-old male patient with CCS who presented with chronic watery diarrhea, hematochezia, weight loss, and skin changes including nail dystrophy and hyperpigmen-tation. Laboratory results showed anemia and hypoalbuminemia. He underwent CT enterography (CTE) which identified diffuse edematous polyposis in the GI tract. The CTE results were highly suspicious of CCS and a subsequent endoscopic examination confirmed the diagnosis. The patient received supportive treatment which improved his symptoms. Based on CTE and endoscopy at 1-year follow-up, the patient was deemed to be in remission. We included a literature review of CCS. The case report aimed to improve the understanding of CCS and explored the key CTE features relevant to its early diagnosis.
Imaging Diagnosis of a Rare Case of Cervical Necrotizing Fasciitis (CNF) in the Nasopharynx: A Clinical Case Analysis
DENG Kan, XU Hui, CHEN Lingling, GONG Lingyan, LI Shuping
2023, 32(2): 271-277.   doi: 10.15953/j.ctta.2023.011
Abstract(64) HTML PDF(11)
This case report describes a rare case of cervical necrotizing fasciitis (CNF) of the nasopharynx. The patient presented with intractable chronic suppurative otitis media and underwent radiological examination including CT, MRI, and PET/CT. All of the images misdiagnosed this condition as nasopharyngeal carcinoma. Finally, the patient underwent a nasopharyngeal mass biopsy and CNF was diagnosed. A retrospective analysis of the radiological scans was performed and the causes of the misdiagnosis were evaluated. The CT, MRI, and PET/CT characteristics and key features for the early diagnosis of CNF were summarized. Our findings may contribute to current knowledge of the precise diagnosis of CNF.
Progress in the Clinical Application of Fractional Flow Reserve Based on Coronary CT Angiography
LI Shihang, ZHANG Xiaoqin
2023, 32(2): 279-284.   doi: 10.15953/j.ctta.2022.037
Abstract(74) HTML PDF(13)
Noninvasive coronary fractional flow reserve derived from CT angiography (FFRCT) is a major advance within 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 FFRCT and briefly discusses its limitations.
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
2023, 32(2): 285-296.   doi: 10.15953/j.ctta.2022.131
Abstract(150) HTML PDF(30)
In medical computed tomography imaging systems, Compton scattered photons generated by the interaction between X-rays and objects have a serious impact on image quality, especially in cone-beam computed tomography and multi-layer detector systems. Currently, there are many scattering artifact correction methods, which can be classified into three categories: hardware, software, and hybrid software and hardware correction methods. However, with the advances in computing power and development of deep learning in medical image processing, new methods of scattering artifact correction have appeared in recent years. This study first introduces traditional correction methods. Then, a method of scattering artifact correction based on deep learning is described in detail, which is divided into the correction method based on image domain and the correction method based on projection domain. Various deep-learning neural networks for this method are also introduced in detail. Finally, the application prospects of the deep learning method in multi-source computed tomography imaging scattering artifacts were probed .
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