CT理论与应用研究

General Pascal's Law: A Possible Basic Hydrostatic Law

REN Rong, WANG Zhen, FU Guang-hui, SUN Chang-ning, YUAN Li-jun, CAO Tie-sheng

2018, 27(2): 137-143. doi: 10.15953/j.1004-4140.2018.27.02.01

Abstract(559) PDF(4)

Abstract:
We extended the application range of the Pascal's law from incompressible fluid to soft biological tissue when investigated the mechanical principle of heart-lung interaction issues such as pulsus paradoxus. Furthermore, we originally found the Pascal's law could be extended even to incompressible solid inside the fluid. This extended Pascal's law may then have a general meaning. We temporarily name it the General Pascal's law. General Pascal's law states that pressure exerted anywhere in a confined incompressible fluid is transmitted undiminished throughout not only the fluid but also the incompressible solid inside the fluid. Pascal's law is only a special situation of General Pascal's law. This newly proposed General Pascal's law may be a possible basic hydrostatic law, disclosing the rule of the force transmission from liquid to solid, and may lead to a deeper understanding of the mechanical nature of the world and may lead us to rethink about some phenomena that we did not really know. In this paper the mathematical approach and experimental work of ours and other researchers' were included to support this new law.

Fine Structure Research of Crust and Upper Mantle in Western Sichuan Basin and its Adjacent Regions

LI Ping-ping, CHENG Xian-qiong, LIU Yuan

2018, 27(2): 145-153. doi: 10.15953/j.1004-4140.2018.27.02.02

Abstract(394) PDF(8)

Abstract:
This research make use of a large number of teleseism waveform record coming from 123 stations, for the purpose of knowing the crust and upper mantle subtle structure of Sichuan Basin and its adjacent area, furthermore getting more information about the plate movement such as its direction or the process, by means of the receiver function, linear inversion and H-kappa method, ultimately having a comprehensive analysis based on the previous results. there are the conclusions:The crust thickness of our research area vary enormously on the east-west direction, the subtraction between the maximum and minimum is 29 km.The average of the crust thickness in Sichuan Basin is 39.4 km, which exist huge deposits of sediments in the surface, and the lower wave velocity ratio, which is the ratio of the shear wave velocity and the longitudinal wave velocity, illustrating this ares is a kind of the rigid block. There are thicker crust in Longmen Shan fault. The transition region between the south-Longmen Shan fault and Sichuan Basin features higher wave velocity ratio, resulting from the mantle material up welling. Songpan-Ganzi block's crust thickness has lateral variations of 58~65 km, where there is a low velocity layer existing in the shape of trapezoid at the middle and lower crust. The area features higher average of the wave velocity ratio. It could be inferred that under the long-term pressure eastward from the Tibetan plateau, the Songpan-Ganzi block is squeezed and deforming. The crust in Western Sichuan Plateau is much thick, there may be partial melting area because of the higher wave velocity ratio. The average of crust thickness in Chuan-Dian block is 58.5 km.There is a low velocity layer at the middle crust.

Spectral Computer Tomography Combined with Serum Biomarkers in Coronary Plaque Characteristics Analysis

HUANG Ren-jun, DAI Hui, LI Yong-gang, GUO Liang, HU Chun-hong, HE Zhi-song

2018, 27(2): 155-163. doi: 10.15953/j.1004-4140.2018.27.02.03

Abstract(393) PDF(7)

Abstract:
Objective: To study the value of spectral CT in analyzing different coronary plaque components and their correlation with different serum levels of biomarker, and to provide a basis for the diagnosis value and differential diagnosis value of spectral CT. Methods: 107 consecutive patients diagnosed with coronary artery disease (CAD) or acute paroxysmal chest pain and discomfort in the anterior region of the heart (65 males and 42 females; mean age, 60 years) underwent coronary artery gemstone spectral imaging. Plaques were divided into 5 groups according to Multi-slice computed tomography (MSCT) criteria and the size of calcification in mixed plaques. Spectral attenuation curve (SAC), effective atomic number (EAN) and basic material decomposition:FAT and HAP technique were used to analyze the plaques. The vulnerability of plaques was evaluated by serum biomarkers including soluble OX40 ligand (sOX40 L), matrix metalloproteinases (MMP-9) and lipoprotein associated phospholipase A2 (Lp-PLA2). The concentrations of the serum biomarkers were detected by ELISA. Results: 159 coronary artery plaques were counted in total. 90 cases of blood samples (42 cases without coronary plaque, 48 cases with coronary plaque) were obtained. By measuring CT density, the plaques were classified as fibrosis group (group 1), soft plaque group (group 2) and pure calcification group (group 3). In addition, mixed plaques with non-spotty calcification group (group 4) and spotty calcification group (group 5) were also analyzed. There were statistically significant differences of CT density, SAC, EAN, HAP and FAT among the five groups (P<0.05), except the FAT value between group1 and group5 as well as between group 2 and group5. The concentrations of serum biomarkers were significantly higher in subjects with coronary atherosclerotic plaques than those in subjects without coronary plaques (P<0.05). There were significant differences of the MMP-9 concentrations between group 2 and group 3 as well as between group3 and group5 (P<0.05). Negative correlations were found as follow:MMP-9 concentration vs. CT density (r=-0.501, P<0.05), MMP-9 concentration vs. EAN (r=-0.372, P<0.05), MMP-9 concentration vs. SAC (r=-0.378, P<0.05) and MMP-9 concentration vs. HAP material density (r=-0.411, P<0.05). Positive correlation was found between serum MMP-9 concentration and FAT material density r=0.34, P<0.05). Receiver operating characteristic curve (ROC) showed cutoff value and area under the curve (AUC) of SAC and EAN and HAP material was 3.41 (AUC=0.633) and 8.91 AUC=0.652) and 96.07 (AUC=0.648) between group 2 and group 5. Conclusion: The results indicate that spectral CT might be promising in differentiating different kinds of atherosclerotic plaques. These four kinds of spectral CT parameters are associated with serum MMP-9 level.

Assessing Liver Hemodynamics in Children with Cholestatic Cirrhosis before Liver Transplantation with Dual Energy Spectral CT

SHANG Shu-fan, CAO Qiu-ting, HAN Xin-jun, YANG Da-wei, ZHAO Li-qin

2018, 27(2): 165-170. doi: 10.15953/j.1004-4140.2018.27.02.04

Abstract(381) PDF(6)

Abstract:
Objective: To evaluate the value of dual-energy spectral CT in assessing the hemodynamics in children with cholestatic cirrhosis before liver transplant. Methods: 60 children with cholestatic cirrhosis were selected retrospectively. There were 28 Child-Pugh grades A, 20 Child-Pugh grade B, and 12 Child-Pugh grade C cases based on the Child-Pugh classification criteria of liver function. Enhanced CT scan was performed using the gemstone spectral imaging (GSI) mode. The iodine concentrations for the hepatic parenchyma in the arterial phase (I_A) and portal vein phase (I_P) were measured using the iodine-based MD images with Region of interest (ROI) setting in the same location and size. The hepatic artery iodine fraction (AIF) was calculated as:AIF=iodine content (arterial phase)/iodine content (portal venous phase). The I_A, I_P and AIF of children of different Child-Pugh grades with cholestatic cirrhosis were analyzed by one-way ANOVA. Result: The I_A, I_P (100 μg/cm³) and AIF of different Child-Pugh Grades were as follows:Child-Pugh A:(4.34±2.0) 100 μg/cm³, (12.68±2.8) 100 μg/cm³ and 0.34±0.12; Child-Pugh B:(5.65±2.8) 100 μg/cm³, (14.49±3.8) 100 μg/cm³ and 0.38±0.13; Child-Pugh C:(7.09±2.6) 100 μg/cm³, (13.89±3.5) 100 μg/cm³ and 0.51±0.14. The one-way ANOVA showed that the overall difference of I_A and AIF between different Child-Pugh groups was statistically significant (P<0.05), and there was no statistically significant difference in I_P among different Child-Pugh groups (P>0.05). The multiple comparisons results indicated that I_A between grade A and grade C was significantly different. (P=0.004). AIF values were significantly different between Grade A and grade C (P=0.001), grade B and grade C (P=0.015), among which the AIF value of grade C is higher than that of grade B, and the AIF of grade A is the lowest. Conclusion: the AIF obtained by the dual energy spectral CT can be used as an indicator to evaluate the liver hemodynamics of children with cholestatic cirrhosis quantitatively.

The Value of Dual-source CT Dual-energy Imaging in the Diagnosis of Gouty Arthritis

HE Xiao-qing, ZHU Wan-shou, LIANG Han-huan, PENG Ke-yu

2018, 27(2): 171-177. doi: 10.15953/j.1004-4140.2018.27.02.05

Abstract(359) PDF(6)

Abstract:
Objective: To explore the diagnostic value of DSCT in gout arthritis. Methods: Scanning 160 patients with arthritis joint in our hospital using dual-source CT with dual-energy and taking advantage of the configuration instrument with gout recognition software to process the original image, there were two experienced clinical imaging doctors with high qualifications analyzing the obtained images to determine whether there was urate crystal deposition within patients' inspection area. Subsequently, through following up cases and comparing with clinical diagnosis, they analyzed the accuracy of DSCT technique for the screening, early diagnosis and differential diagnosis of gout. Results: In the DSCT examination of those 136 patients with gout, 124 cases were found in the joints with urate crystal deposition and the detection rate of gout was 124/136 (91.2%). Among those patients, 28 out of 33 who have acute arthritis, were found by DSCT examination that there was uric acid deposition in their affected joint, and the detection rate of early gout was 28/33 (84.8%). Within 24 patients with non-gout, 24 were not found to have urate crystal deposition. Conclusion: Scanning the pathogenesis of arthritic patients using DSCT technique could effectively improve the accuracy of screening, early diagnosis and differential diagnosis of gout.

Effect of CT Spectral Diagnosis on Prognosis of Patients with Lymph Node Metastasis and its Prognostic Value

WU Yan-chun, QIAN Bin

2018, 27(2): 179-186. doi: 10.15953/j.1004-4140.2018.27.02.06

Abstract(411) PDF(6)

Abstract:
Objective: To analyze the effect of CT spectrum diagnosis in patients with lymph node metastasis of tumor and its influence on the prognosis quality of patients.Methods: in our hospital from April 2016 to November 2017 were pathologically diagnosed malignant tumor in 60 cases, according to the patient's disease occurrence site will be divided into lymphoma group, lung cancer group and cholangiocarcinoma group three, lymph node number of patients in three groups were 26, 30, 32. For patients in each group received CT spectral imaging value in different energy CT groups were compared for patients with lymph node and prognosis of patients according to the results, the range of spectrum should be kept between the 40~140 keV gradient was 10, comparison of different groups of patients between moisture and iodine content in the same energy in lymph nodes..Results: energy up to 70 kev as the most clear, this value applies in both groups of patients, the same energy state, each group of patients with metastatic lymph nodes of iodine content and CT value size relationship:Lymphoma Group > lung adenocarcinoma group > bile duct group (P<0.05); groups of patients with metastatic lymph nodes the water content of the difference was not statistically significant (P>0.05), the prognosis of patients with lymph cancer group was significantly longer than that of other groups in practice (P<0.05). Conclusion: the application of CT of lymph node metastasis in patients with disease diagnosis through detection of iodine content in judging patients with disease onset, obvious difference in 70 keV the CT node metastatic lymph nodes from different sources, which can be used to transfer energy standard in lymph nodes.

H-k Scanning Method of Receiver Functions and its Application

WANG Xin-yu, WANG You-xue, XIONG Bin, JIANG Chan-jun, ZHANG Qi, CENG Cheng, HU Jin-feng

2018, 27(2): 187-196. doi: 10.15953/j.1004-4140.2018.27.02.07

Abstract(430) PDF(10)

Abstract:
H-k scanning method of receiver function is an important method to study the internal structure of the earth. Since the receiver function does not depend on the source parameters, it can be more accurate to determine the crustal structure below the station. H-k scanning method is simple and efficient, and can be used to obtain the crust thickness below the station and the VP/VS or Poisson's ratio inside the crust. In this paper, the H-k method is applied to the observational seismic data from the portable broadband seismic array in northeastern Guangxi province. The results show that the thickness of the crust varies greatly in this area (28~34 km), and the V_P/V_S (1.801~1.897) or Poisson's ratio (0.277~0.308) in the crust is higher, which is consistent with the fact that the basic and ultrabasic rocks are exposed in the northeast of Guangxi province.

First Arrive Wave Traveltime Tomographic Inversion of Marine Seismic Data

LI Fu-yuan, KANG Ping, LIU Yu-ping, ZHANG Heng, DENG Gui-lin, DING Long-xiang

2018, 27(2): 197-204. doi: 10.15953/j.1004-4140.2018.27.02.08

Abstract(404) PDF(7)

Abstract:
The first-arrival wave traveltime tomographic inversion is a key technology to solve the complex static correction problem of land data as an important means to establish the near-surface velocity model. However, the attention and application of refractive wave information of marine seismic data which possesses widely developed refractive wave have not been paid much attention. In this paper, the seismic tomographic inversion technique is applied to marine seismic data to obtain the velocity structure of the seabed. The main difference with the tomographic inversion of land data is:(1). The pick-up of the first-arrival time should be carried out after the minimum phase processing of the source signal to avoid the error due to the inaccurate first-arrival time picking of the mixed phase wavelet. (2). The depth and the velocity information of the seawater layer are used as the inversion constraint conditions to reduce the iterative error. The results of the actual 2D multi-channel survey line tomography show that the first-arrival wave traveltime tomography can invert the more accurate marine stratigraphic velocity structure.

The Karst Area Perspective Imaging was Performed Using Electromagnetic Wave CT Technique

HU Fu-peng, WU Mao-lin, XU Dian-bo, FU Mao-ru

2018, 27(2): 205-212. doi: 10.15953/j.1004-4140.2018.27.02.09

Abstract(399) PDF(14)

Abstract:
The use of wellhead electromagnetic wave CT technology can be underground Karst, broken belt and other issues for fine exploration. In this paper, the Karst area model is used to simulate the electromagnetic wave CT of Karst area by numerical simulation method, and the attenuation and response characteristics of electromagnetic wave in Karst development area are discussed. The results show that the method has a good effect on the detection of Karst development area, and the results show that the method is effective in detecting the Karst area.

The Discussion on CT Technique Application in Reservoirs Geology

ZHANG Tian-fu, XIONG Ran, WEI Dong-xiao, LI Dong, WANG Ying

2018, 27(2): 213-226. doi: 10.15953/j.1004-4140.2018.27.02.10

Abstract(495) PDF(7)

Abstract:
CT has the unique application in reservoir geology field due to its un-destructive, 3 D, combination with computational simulation and so on. Beginning with its character, this paper summarized the development of CT application in reservoir geology and pointed out CT could be used to component and fabric of reservoir rock, characterize reservoir, and monitor fluid transfer processed in pore system online and analysis the distribution of residual oil. With the development of high resolution industrial CT and digital core technology, the combination between 3 D data from CT and digital could not only help to compute petro physical properties, such as porosity-permeability, formation factor, elastic modulus, V_p & V_s, et al., but also quantitative characterize pore-throat structure and simulate percolation based on pore network. Finally, the paper gave a judgment on CT developing, which would be used in more fields, companying the improvement in computer application and exploration of oil and gas.

Deep Learning Based Beam Hardening Artifact Reduction in Industrial X-ray CT

ZHOU Li-ping, SUN Yi, CHENG Kai, YU Jian-qiao

2018, 27(2): 227-240. doi: 10.15953/j.1004-4140.2018.27.02.11

Abstract(985) PDF(48)

Abstract:
In the nondestructive detection with industrial CT, due to the fact that the actual X-ray source has a wide spectrum, slices reconstructed by most existing reconstruction algorithms will suffer from beam hardening artifacts. It will degrade image quality greatly, affecting important CT image task such as CT diagnosis and so on. In this study, we propose a method to suppress beam hardening artifacts based on deep learning. We train a convolutional neural network using a large number of images with beam hardening artifacts as input and the corresponding artifact-free images reconstructed at a fixed energy as output to establish the mapping between image with beam hardening artifacts and artifact-free image for suppressing beam hardening artifacts. Experimental results show the effectiveness of the proposed method in the beam hardening artifact reduction of CT images.

The Study of 3D-ASL in Assessing Cerebral Blood Flow in Normal Persons

PENG Xiu-hua, GU Xiao-li, ZHANG Shi-yu, LIANG Zong-hui

2018, 27(2): 241-248. doi: 10.15953/j.1004-4140.2018.27.02.12

Abstract(383) PDF(6)

Abstract:
Objective: With the increasing incidence of stroke which is due to the reduction of cerebral blood flow, the quantitative measurement of cerebral blood flow is very important. There are a variety of quantitative detection methods of cerebral blood flow, the commonly used quantitative detection methods are PET and SPECT, but there is radiation of the above detection methods, and the operation is complex. The purpose of this study is to measure cerebral blood flow of normal persons by three-dimensional magnetic resonance arterial spin labeling technique (3 D-ASL). Methods: Sixty-three health persons, who were divided into group A (< 60 years) and group B (≥ 60 years) according to age. The average age of group A was 36 years (including 14 males and 19 females), the average age of group B was 69 years (including 12 males and 18 females), accepted examinations including routine MRI, 3 D-T1 and 3 D-ASL sequences. We got the cerebral blood flow maps and matched it with the 3 D-T1 images. The CBF values of every part of brain were measured, and the variance analysis method was used to compare the CBF values of every lobe, basal ganglia and cerebral hemisphere between the two groups. Results: There was significant differences of the CBF values in frontal lobe and parietal lobe between left and right hemispheres in two groups (P<0.05). A significant difference of the CBF values of bilateral cerebral hemispheres, frontal lobe, parietal lobe, temporal lobe, occipital lobe and basal ganglia was found between group A and group B (P<0.05). The average value of group A was higher than that of group B. The CBF values of bilateral cerebral hemispheres of female group were significantly higher than that of male group. There was a significant difference among the frontal lobe, parietal lobe, temporal lobe, occipital lobe and basal ganglia of CBF value in the same person (P<0.05). Conclusion: The 3 D-ASL can be used to evaluate the cerebral blood flow in health persons, and the CBF value was significantly affected by age, gender and location.

Value of Multi-detector Row Computed Tomography on Preoperative T Staging of Gastric Cancer

HAN Xin, TIAN Feng, YU Sheng-feng

2018, 27(2): 249-255. doi: 10.15953/j.1004-4140.2018.27.02.13

Abstract(366) PDF(5)

Abstract:
Objective: To study the value of multi-detector row computed tomography (MDCT) before operation in the diagnosis of T-staging of gastric cancer. Methods: 616 patients with gastric cancer underwent MDCT before operation. The results were compared with operative and pathologic T (pT) staging. Especially, we evaluated the correlations among the diagnostic accuracy of T staging and various clinicopathologic parameters by focusing on 276 patients who had detectable lesions by MDCT. Results: The overall diagnostic accuracy of preoperative T staging by MDCT was 91% (560/616). For each pathologic T stage, the accuracy was 95% for pT1, 78% for pT2-3, 89% for pT4a, and 75% for pT4b, respectively. Antral tumors (P=0.045), and Borrmann type1 tumors (P=0.0001) were incorrectly T staged by MDCT. Conclusion: Preoperative T staging of gastric cancer by MDCT have higher clinical value.

Analysis of Causes of Root Canal Therapy Failure by CBCT

PENG Jing, SHEN Yan-hua, DING Ya-tong, QIN Yuan-yuan, FANG Shun

2018, 27(2): 257-262. doi: 10.15953/j.1004-4140.2018.27.02.14

Abstract(423) PDF(7)

Abstract:
Objective: To investigate the causes of root canal therapy failure by CBCT (cone beam computed tomography). Methods: 122 cases of root canal therapy failure in our hospital were selected. The causes of failure were analyzed by X-ray periapical film and CBCT. Results: in 122 cases of failure, 32 cases of root canal filling shortage (26.23%), 28 cases of root canal imprecision (22.95%), 23 cases of missing root canal (18.85%), 16 cases of combined periodontal-endodontic lesions (13.11%), 9 cases of root canal overcharge (7.38%), 7 cases of coronal leakage (5.74%), 6 cases of root fracture (4.92%), 1 cases of lateral canal perforation (0.82%). Conclusion: the main causes of root canal treatment failure are the incomplete cleaning of root canal and the inadequate obturation of root canal. The periodontal lesion is an important concomitant disease affecting the prognosis of root canal therapy. CBCT can provide a powerful basis for judging the cause of root canal therapy failure, and has an important guiding role in the follow-up treatment program.

The Application Value of Spiral CT in Diagnosis and Dynamic Observation of Pulmonary Laceration

YANG Feng

2018, 27(2): 263-268. doi: 10.15953/j.1004-4140.2018.27.02.15

Abstract(470) PDF(5)

Abstract:
Objective: To investigate the application value of spiral CT in the diagnosis and dynamic observation of pulmonary laceration. Methods: CT results of twenty patients with pulmorary laceration were retrospectively analyzed. Results: A total of 45 lesions were found in the 20 patients, with 25 on the right side and 20 on the left side. CT manifestations were pneumatocele (n=9), pulmonary liquid-air cavity (n=12), sub-pleural gas-bubble shadow (n=15), intrapulmonary hematoma (n=7) and wedge shaped gas fissures (n=2). Various degrees of lung contusion around the pulmonary laceration could be observed in all patients. The locations of the 45 lesions of laceration included lung surface or sub-pleural region (n=26), deep site of lung (n=5) and paravertebral area (n=14). Rib fracture was detected in all patients and hemopneumothorax was found in 8 patients. The results of CT dynamic observation are as follows:liquid was seen and pulmonary liquid-air cavities were formed in 7 lung cavities, 6 sub-pleural gas-bubble shadow formed into hemopneumothorax, while 5 patients were diagnosed as pulmonary hematoma with pleural effusion. Besides, pneumatocele, pulmonary liquid-air cavity and absorption and shrinkage of pulmonary hematoma were found in one or two months. Conclusion: The characteristic manifestations of pulmonary laceration are pneumatocele, pulmonary liquid-air cavity and sub-pleural gas-bubble shadow, while the wedge shaped gas fissures is a specific sign of the disease. Spiral CT examination plays the most effective role in early detection and diagnosis and dynamic observation of the pulmonary laceration.

Advances in Imaging Methods and Diagnosis of Chronic Pancreatitis

DU Li-juan, JIN Er-hu

2018, 27(2): 269-280. doi: 10.15953/j.1004-4140.2018.27.02.16

Abstract(394) PDF(5)

Abstract:
Chronic pancreatitis is a chronic progressive inflammation of the pancreas, and usually leads to persistent impairment of the pancreatic function. The clinical manifestations of the disease are not specific, and radiologic evaluation is often needed for clinical diagnosis. With the development of various imaging modalities, they play an important role not only in the early diagnosis and severity assessment, but also in guidance of the treatment of the disease. We review the advances of imaging methods and diagnosis of the chronic pancreatitis in this article.

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2018 Vol. 27, No. 2