ISSN 1004-4140
CN 11-3017/P

2017 Vol. 26, No. 5

CT Theory
The Study of Seismic Attenuation Tomography Inversion Based on Spectrum Ratio Method
YU Qian-qian, LI Zhen-chun, ZHANG Min, ZHANG Kai, YU Zhen-nan, ZHANG Xin, PAN Dong
2017, 26(5): 533-541. doi: 10.15953/j.1004-4140.2017.26.05.01
Due to the strong absorption of seismic energy of underground media, seismic data resolution and seismic data processing, interpretation accuracy are reduced. Therefore, it is an effective way to process and interpret the seismic data with high resolution and high precision by selecting the appropriate parameters to describe the formation absorption effectively. Currently, quality factor Q is one of the important parameters to describe elastic parameters. It is an effective way to improve the resolution of seismic data and to improve the accuracy of interpretation of oil and gas strata by using the quality factor Q to measure the attenuation of seismic wave energy when propagating in the medium. In recent years, numerous scholars have proposed a variety of methods to calculate the Q value, in which spectral ratio method is the most widely used Q estimation method. In this paper, on the basis of previous results, we propose improved spectral ratio method combing with travel time tomography method which can fully take advantage of accuracy and stability of spectral ratio method and efficiency of the travel time tomography method as well. By our method, the inversion precision and stability are guaranteed. By using the model test, it is proved that spectral attenuation method can estimate the change of Q value effectively, and has good development prospect.
Non-linear Tomography Inversion Technology for Velocity Modeling
WANG Zhao-qi, ZHUANG Xi-jin, LI Li-sheng, CHEN Jian-wei, YE Yue-ming
2017, 26(5): 543-551. doi: 10.15953/j.1004-4140.2017.26.05.02
The estimation of depth velocity model is a great challenge in seismic imaging, obtaining an accurate depth velocity model and reducing the depth of imaging project turnaround time are of critical importance. The velocity modeling of conventional tomographic inversion is equivalent to a linear inversion, and need to be re-picked up, which leads to very time consuming and low efficiency. A velocity modeling method based on nonlinear tomography is proposed. The RMO of the common imaging point gathers is converted to the pre stack domain as the kinematic invariant, and the model updating is carried out by the iteration of the tomographic inversion. A multiple linear inversion is used to approximate a nonlinear physical process, which avoids the repetitive work and greatly improves the efficiency of project. The validity of method is proved by an example.
Spectral CT
Application of Somatom Definition Flash CT in the Morphological Assessment of Left Atrial Appendage
CHEN Tao, YANG Tao, GU Jing-hua, LI Xin-ming, WANG Wei, FAN Xiao-jun, ZHOU Hua, LI Rong-xian
2017, 26(5): 553-558. doi: 10.15953/j.1004-4140.2017.26.05.03
Objective: To study the relationship and morphological assessment of left atrial appendage (LAA) and adjacent anatomical structure by SOMATOM Definition Flash CT. Methods: 83 patients were selected retrospectively including 62 patients with sinus rhythms underwent coronary angiography and 21 patients with atrial fibrillation underwent left atrial enhancement scanning. The relationship between the LAA and the pulmonary vein was observed, and the diameter of the left atrial appendage was measured quantitatively. Then the data between the two groups were compared. Results: There was no significant difference in pulmonary vein variation rate and anatomical relationship of the LAA to left superior pulmonary vein (LSPV) between the atrial fibrillation patients and the control group (P > 0.05). And there were significant differences in the length, area, volume and the first turning angle of LAA in the two groups (P < 0.05). Conclusion: SOMATOM Definition Flash CT scan can quantitatively measure the diameter of LAA, and it can also clearly show the correlation of LAA and its adjacent anatomy. So it may have an important guiding significance for atrial fibrillation ablation and LAA occlusion.
The Application of Elastic Wave CT to Qualities Detection of High Pressure Swing Jet Cut-off Walls
ZHAO Xiang, YANG Lei, LENG Yuan-bao, PAN Ji-shun
2017, 26(5): 559-564. doi: 10.15953/j.1004-4140.2017.26.05.04
Aiming at the problems existing in the current detection of high-pressure swing jet grouting cut-off wall, in this paper, the basic principle and process of elastic wave CT detection technology are introduced. The quality of high-pressure swing jet grouting cut-off wall of reservoir dam is tested, and core drilling and water injection test are applied in the part of the wall. The results show that the elastic wave CT has the advantages of fast detection speed and high detection accuracy in the quality detection of the cut-off wall, and it has a broad application prospect in the non-destructive testing of the cut-off walls quality.
Micro-faults Identification Technology Based on Seismic Attribute Optimizational Analysis
LI Quan, TONG Li-qing
2017, 26(5): 565-574. doi: 10.15953/j.1004-4140.2017.26.05.05
The article is based on fault interpretation skill and seismic attribute analysis technology, combined the different attribute which shows the positive response to micro-faults. Based on the steering coherence body to control the trend of regional fault and merging the dip-body, Azimuth-body, curvature-body which could meticulous describe the distribution of third or fourth level faults at the same time. In the end, according to the technical flow can figure out the plan and profile character of faults. There are five plane assembly style, including comb-type, anticomb-type, Cha I-type, Cha II-type, broom-type. There are seven profile assembly style, including reverse Y-type, Y-type, duplicate Y-type, X-type, broom-type, ladder-type, fork-type. This technique flow can provide certain experience and guide to the complicated rift basin which full of micro-faults.
Industrical CT
A Novel Reconstruction Algorithm Based-on Projection Transformation for the Rotational Cone-beam CL
WANG Jing-yu, HAN Yu, LI Lei, XI Xiao-qi, SUN Yan-min, YAN Bin
2017, 26(5): 575-582. doi: 10.15953/j.1004-4140.2017.26.05.06
Computed Laminography (CL) has a unique advantage over CT for flat objects. However, the rotational CL does not satisfy the conditions of the filtered back-projection (FBP) reconstruction algorithm. This paper proposes a novel FBP reconstruction algorithm based on projection transformation for the rotational cone-beam CL. Firstly, the structure of the rotational CL is introduced; Secondly, the way generating projections and the method rearranging the data are elaborated; Lastly, the data rearranged is applied to filter and back projection, and the simulations of reconstruction prove that the method of this paper is effective.
Medical CT
CT Findings of Lung Adenocarcinoma in Situ on High-resolution Computed Tomography
PENG Hao, HU Jun-jiao, HUANG Lin-wen, MOU Shu-fang, XU Jian-bo, ZHOU Ying-ying, PAN Xiao-huan, LI Jing-xu, YANG Xin-guan, GUAN Yu-bao
2017, 26(5): 583-589. doi: 10.15953/j.1004-4140.2017.26.05.07
Objective: To imporove the diagnostic level of lung adenoeareinoma in situ (AIS) by analyzing the high- resolution CT (HRCT) performance of lung adenoeareinoma in situ (AIS). Materials and Methods: The HRCT findings of 48 AIS patients were collected from 45 patients who were confirmed by operation and pathology. HRCT features as location, number, margi, size, density, lobulation sign, spiculation, vocule sign, bronchiolectasis sign, pleural indentation and the distance from the adjacent pleura were respectively analyzed. Results: Of the 45 cases (total of 48 lesions), 14 lesions were located in the upper right lung, 16 in the right upper lung, 7 in the lower left lung, 4 in the right middle lung, 7 in the lower right lung. 32 patients showed single lesion, 3 patients showed two lesions, 10 were complicated with AAH and/or MIA. The maximal diameter were 4~19.2 mm, of which 41 lesions maximal diameter less than 10mm. All lesions were pure ground glass density nodules (pGGN). The average CT value of all lesion was (-611 ±82.76) HU. 39 lesions had clear margin, 5 cases had lobulation sign, 3 cases had spiculation,10 cases had vacuole sign, 3 cases had bronchiolectasis sign, 8 cases hadpleura indentation. 30 lesions from the adjacent pleura distance ≤ 10 mm, accounting for 62.5%. Conclusion: The HRCT of AIS were characterized by pGGN, (-611±82.76) HU, less than 20mm, clear edge; the lobulation, spiculation, and vacuole sign were rare. HRCT helps AIS display and early diagnosis.
Clinical Value of CT、MRI in the Diagnosis of Cystic Lesions of the Pancreas and the Pathological Analysis
WU Yan-chun, LIU Yao
2017, 26(5): 591-597. doi: 10.15953/j.1004-4140.2017.26.05.08
Objective: To investigate the clinical value of MRI in the diagnosis and differential diagnosis of cystic lesions of the pancreas. 60 patients with pancreatic cystic lesions methods in our hospital from January 2013 to December 2016 were based on the inspection methods of these cases, patients were divided into MRI group and CT group, compared to two groups of patients, examination results and pathological examination results examination time for statistical analysis. Results papillary myxoma and pathological diagnosis of MRI pseudocyst, cyst, cystadenoma, cystadenocarcinoma, intraductal, malignant islet cell tumor, solid thyroid papilloma coincidence rate was 100.0% (13/13), 100.0% (16/16), 91.7% (11/12), 100.0% (7/7), 100.0% (6/6), 100.0% (3/3), 100.0% (3/3), CT diagnosis and pathological coincidence rate was 84.6% (11/13), 93.8% (15/16), 100.0% (12/12), 85.7% (6/7), 83.3% (5/6), 66.7% (2/3), 100.0% (3/3). The difference of MRI, CT diagnosis and pathological coincidence rate was significant (P > 0.05). The MRI group was significantly longer than that in group CT (P < 0.05). Conclusion MRI diagnosis and differential diagnosis of pancreatic cystic lesions have certain advantages compared with CT, although MRI has a long time to check, but it can have multiple imaging, meanwhile can provide more information on the clinical analysis of cystic components, In particular, more sensitive to the size, number, range, extent, composition, nature, etc. of bleeding and cystic lesions.
The Comparison of Inferior Vena Cava Measurement by Direct and Indirect MSCT Venography
CAO Hong-wei, XING Yuan-yuan, CHOU Heng-zhi, ZHANG Dan, CAO Zhen-dong
2017, 26(5): 599-604. doi: 10.15953/j.1004-4140.2017.26.05.09
Objective: To measure the inferior vena cava diameters by direct and indirect MSCT angiography, and analysis whether there is difference between them. Method: Collecting 30 cases (M 14 cases, F 16 cases, ages 23~65 y, middle age 44y) which were underwent direct inferior vena cava venography, and collecting 30 cases (M 10 cases, F 20cases, ages 20~66 y, middle age 43y) of whole abdominal contrast enhanced CT, get the venous phase image. Original data were transferred to GE adw4.6 workstation for post-processing including MPR, MIP. The major axis, minor axis were individually measured, at the levels of its entrance to the right atrium, the portahepatis, the renal pelvis, above the junction of iliac vein. Measure the CT values where above 1cm the level left renal venous joined Inferior vena cava. Result: At the levels of its entrance to the right atrium, the portahepatis, the renal pelvis, above the junction of iliac vein, the major axis, minor axis of direct CT phlebography individually were (3.02 ±0.44, 2.06 ±0.32), (2.29 ±0.49, 1.39 ±0.52), (2.46 ±0.44, 1.73 ±0.45), (2.30 ±0.38, 1.66 ±0.46), of indirect phlebography individually were (2.88 ±0.43, 1.95 ±0.31), (2.37 ±0.59, 1.17 ±0.37), (2.28 ±0.32, 1.63 ±0.31), (2.25 ±0.21, 1.47 ±0.34), there is no obviously difference between them. The CT values of direct CTP where above 1cm the level left renal venous joined Inferior vena cava is (313.43 ±50.90) HU, much higher than the indirect CTV (95.50 ±22.17) HU. Conclusion: There was no significant difference between direct CTV and indirect CTV of the inferior vena cava diameters.
Dose 4D CARE Technology Combined with Low kV and Low Dose Contrast Agent in MSCT Head and Neck Vascular Imaging Applications
LIANG Hong-sheng, CHEN Jin-jun, CHEN Xiao-yu, LIANG Yu-hao, OU Jian-yang, MA Guan-hua
2017, 26(5): 605-612. doi: 10.15953/j.1004-4140.2017.26.05.10
Objective: To investigate the feasibility and value of 128 slice spiral CT angiography (CTA) using CARE Dose 4D techniques combined with low dose contrast agent to optimize the scanning protocol. Methods: a total of 60 patients with head and neck vascular imaging were selected and randomly divided into control group (A group) and low dose group (B group), each group with a total of 30 cases. The control group (A group) 120 kV tube voltage, using CARE Dose4D technology reference tube current of 120 mA, dosage of contrast agent was 65 ml; double low dose group (B group) tube voltage 80 kV, using CARE Dose4D technology reference tube current of 120 mA, contrast agent dosage is 45 ml. Objective to evaluate the image quality of CT, noise and signal to noise ratio (SNR) of bilateral common carotid artery, bilateral internal carotid artery and bilateral middle cerebral artery (M1). The evaluation of image quality was performed by two double blind methods. Comparison of radiation dose between group A and group B. Results: two attending physicians had a higher consistency of P < 0.05 (Kappa=0.782). There was no significant difference between the two groups in arterial image quality score and SNR score (P > 0.05). The double low dose group arterial enhancement CT value were higher than the control group; double low dose volume CT dose index and dose length product and effective dose were significantly lower than the control group; the differences were statistically significant (P < 0.05). Conclusion: low kV imaging using 128 slice MSCT and CARE Dose 4D head and neck vascular technique combined with low dose contrast scanning scheme, not only reduce the radiation dose of 68%, while the amount of contrast agent is reduced by 30.7%, reduce the contrast agent risk and cost savings, ensure the diagnostic image quality is worthy of promotion.
The Application Study of 64-slice Spiral CT in TLICS Classification System for Thoracolumbar Injury
SUN Yi-feng, ZHANG Ji-chun, LI Jian-rui, QIU Chun-hua, WU Hua-ping
2017, 26(5): 613-618. doi: 10.15953/j.1004-4140.2017.26.05.11
Objective: To investigate application values of the Thoraco-Lumbar Injury Classification and Severity (TLICS) Classification System in thoracolumbar injury by using 64-slice spiral CT scan, multi-planar reconstruction (MPR) and three-dimensional volume reconstruction (VR). Materials and Methods: The retrospective study included 50 patients (27 males and average ages were 44±9.8) with thoracolumbar injury from October 2014 to October 2016. All patients were scanned by 64-slice spiral CT and performed the sagittal MPR and three-dimensional VR for imaging diagnosis. Then we evaluated the severity of posterior ligamentous complex (PLC) injury according to the typical CT features of thoracolumbar injury. When the TLICS score was higher than 4, we compared the CT features with surgical findings. Results: Seventy-six vertebral fractures were checked out in all 50 patients, included 18 compressed fractures, 28 burst fractures, 20 translation/rotation fractures, and 10 stretch fractures. In addition, 14 patients were found the PLC injuries with different CT imaging features, i.e. 5 avulsion fractures of spinous process, 3 translational and rotational malformation of centrum, 2 transverse fractures of articular process, 2 cases with facet dislocation, 2 broadened interspinous space complicated with facet dislocation and fracture of articular process respectively. Conclusions: Combined MPR and three-dimensional VR could effectively detect fractures and dislocations features indicating the injury of PLC. MPR and VR can be applied as the significant diagnostic examination method, especially to the emergency patients, which could be used for early clinical application of TLICS classification system.
The Value of Computed Tomography Angiography in Diagnosis of Lumen Stenosis of Intermediate Coronary Lesions: Compared with Intravascular Ultrasound
LIN Tao, WANG Wei, ZHOU Hua, FAN Xiao-jun, ZHENG Chang-zhu, NING Zhong-ping, YAN Ling
2017, 26(5): 619-626. doi: 10.15953/j.1004-4140.2017.26.05.12
Objective: To explore the value of dual source computed tomography angiography in the diagnosis lumen stenosis of intermediate coronary lesions. Methods: DSCTA were performed in 2670 patients, among which 158 patients underwent both DSCTA and CAG within two weeks. And 41 cases were judged to be intermediate coronary lesions via IVUS. The results of DSCTA were compared with that of IVUS. Results: 41 segments of coronary artery in 33 patients (14 males, 19 females, mean age 65.8 years) were analyzed. There were no statistical differences (P > 0.05) compared with the result of Minimal Lumen Area (MLA) and Plaque Burden (PB) obtained by two methods. Regarding IVUS as the gold standard and MLA for 4mm2 as the critical value, the sensitivity, specificity, PPV and NPV of DSCTA were 69.2%, 92.9%, 81.8%, 86.7%, respectively. Conclusions: DSCTA, as a noninvasive and economic coronary artery examination, can accurately assess the degree of luminal stenosis, higher value to the diagnosis of non-pathological coronary stenosis, reducing unnecessary CAG and IVUS examination.
Correlation between Chylothorax and HRCT Appearances of Lung Cyst Lesions for Lymphangioleiomyomatosis
ZHANG Qi-jin, CHEN Xiao-bo, ZHANG Chun-yan, SHEN Wen-bin, WEN Ting-guo, HUO Meng, FU Yan, WANG Ren-gui
2017, 26(5): 627-632. doi: 10.15953/j.1004-4140.2017.26.05.13
Objective: The study aims to explore the correlation between the amount of chylothorax and HRCT appearance of lung cyst lesions for LAM. Materials and Methods: 36 LAM with chylothorax patients proved by pathology or clinical results were included in the investigating group. HRCT were performed for all the patients. The imaging manifestations were analyzed by 2 doctors, including (1) grades for the amount of chylothorax: grade I, small size; grade II, middle size; grade III, large size. (2) cyst size, cyst involvement area, HRCT severity grades of pulmonary cyst lesions. Analysis of variance was used in the statistical analysis. Results: There is no relationship between the amount of chylothorax and cyst size, and cyst involvement area, and HRCT severity grades of pulmonary cyst lesions. Conclusions: The amount of chylothorax is decided by many factors, and which is related to the etiology of chylothorax of LAM. The amount of chylothorax cannot be used to evaluate the severity of pulmonary cystic lesion involvement for LAM.
Application of MSCT in the Differential Diagnosis of Hepatic Angiosarcoma and Hemangioma
LIU Li, HUANG Jian, HE Xiao-hao, SUN Shu-xia
2017, 26(5): 633-639. doi: 10.15953/j.1004-4140.2017.26.05.14
Objective: To analyze the application value of CT scan and enhanced scan in the differential diagnosis of hepatic angiosarcoma (PHA) and hemangioma (CHH). Methods: The CT imaging data of 8 patients with pathologically confirmed PHA and 30 patients with pathologically confirmed CHH were collected. All patients underwent CT plain scan and enhanced scan after admission. The imaging characteristics of hepatic angiosarcoma and hemangioma and the diagnostic value of CT were analyzed. Results: The proportion of uneven density in PHA nodules scanned by CT was higher than that in CHH nodules (P < 0.05); The non-peripheral rate of enhanced PHA nodules was higher than that of CHH (P < 0.05); The ratio of PHA nodules with peritumoral venous shunt was higher than that of CHH, and the ratio of unclear boundaries was higher than that in CHH nodules (P < 0.05), while the enhancement pattern, delayed enhancement characteristics and CT value showed no significant differences (P > 0.05). Conclusion: PHA is characterized by gradual central patchy enhancement, non-peripheral enhancement, and high ratio of arteriovenous shunt while CT of CHH is characterized by peripheral enhancement and low ratio of arteriovenous shunt.
Clinical Study of TCD Combined with CTP for Severe Stenosis or Occlusion of ICA
XU Wen-tao, LIU Yao
2017, 26(5): 641-648. doi: 10.15953/j.1004-4140.2017.26.05.15
Objective to evaluate the cerebral hemodynamics in patients with unilateral internal carotid artery (ICA) stenosis or occlusion by TCD combined with CT perfusion imaging (CTP). Methods 21 patients with TCD were diagnosed as unilateral ICA stenosis or occlusion of the patients according to their condition, divided into asymptomatic group (11 cases) and symptom group (10 cases), two groups of patients received cranial CTA (angiography) and CTP detection. The reference group was 16 healthy volunteers. The TCD and CTP parameters were compared between the asymptomatic group and the symptomatic group, the symptom group and the control group. Results TCD showed that, in contrast to the reference group, the average blood flow velocity of MCA in the symptomatic group was lower, and the MCA Vm in the asymptomatic group was lower than that in the reference group, but the difference was not significant (P > 0.05). The PI (MCA pulsatility index) in the asymptomatic group was lower than that in the reference group (P < 0.05). Compared with the asymptomatic group, the symptom group had lower MCA Vm, which had a certain correlation with the Uchi Mie cycle. The CTP parameters of the three groups were compared. The results showed that there was no significant change in CBF (cerebral blood flow) in the asymptomatic group (P > 0.05), while the CBF in the symptomatic group decreased significantly (P < 0.05). In the mean transit time and peak arrival time, the asymptomatic group was longer than the symptom group (P < 0.05). There was no significant difference between the two groups of CBV (cerebral blood volume) compared with the reference group P > 0.05). Have a high consistency results conclusion the detection of TCD and CTP, two kinds of detection methods used in combination, can be better for unilateral carotid artery stenosis and occlusion of cerebral perfusion in patients with comprehensive and comprehensive evaluation, and then provide the basis for the best treatment options.
Integral Equation Based-fast Forward and Inverse Algorithms for Complex Targets in Controlled Source Electromagnetic Exploration
LI Jing-he, LUO Dong-de, LI Guang-cong, LI Zhang-wei, LUO Tian-ya
2017, 26(5): 649-659. doi: 10.15953/j.1004-4140.2017.26.05.16
Fast forward and inverse algorithms for complex targets in controlled source electromagnetic exploration (CSEM) is a intense topic in current years. In this paper, the overview of the effective solvers used in complex targets imaging via CSEM is presented. With the analysis of application of modeling and imaging for complex targets via differential methods, it is indicated that the effective parallel computing and the needed boundary conditions are crucial important for the really application of differential methods. The 2D and 2.5D fast imaging algorithms for exploration with terrain based on integral equation (IE) modeling is few considered over the past few years, which is concluded in this paper. The fast algorithms presented in this work will be effectively applied in large scale exploration with high accuracy and resolution via CSEM. The effectiveness of the fast solvers is validated by 2D and 2.5D case studies using integral equation modeling.