CT理论与应用研究

Research on RTM and Kirchhoff Migration Gathering

KONG Xue, HU Qiu-yuan, LIU Dan, WANG Wei, YANG Jian-lei, LI Xiao

2016, 25(5): 507-514. doi: 10.15953/j.1004-4140.2016.25.05.01

Abstract(616) PDF(3)

Abstract:
Common Imaging gather(CIG) can be used to velocity modeling, migration quality control, subsurface attribute interpretation and so on. Prestack AVO inversion is valuable for reservoir characterization, fracture prediction and fluid detection on complicate carbonate reservoir. However, the accuracy of AVO inversion relies on the amplitude information of CIG to a large extent. Therefore, Prestack migration should not only image reflectors correctly but also preserve the amplitude of CIG, which is the input data of AVO/AVA inversion. In this paper, we analyze the amplitude-preserved extent and adaptability on complicate structure imaging of the two imaging methods. The test results show that both RTM(Reverse Time Migration) and Kirchhoff migration are of high amplitude preservation on plain structure, and RTM are better amplitude-preserved and imaging accuracy than Kirchhoff migration on complicate structure.

The Preliminary Study of Spectral CT and Machine Learning Method in Identifying Serosa Invasion of Gastric Cancer

SHI Cen, ZHANG Huan, PAN Zi-lai, YAN Fu-hua, LI Chao, ZHANG Su, DU Lian-jun

2016, 25(5): 515-522. doi: 10.15953/j.1004-4140.2016.25.05.02

Abstract(529) PDF(4)

Abstract:
Objective: To evaluate the value of spectral CT and machine learning method in identifying serosa invasion of gastric cancer. Method: Total of 24 cases of gastric cancer who underwent dual-phasic scans(arterial phase(AP) and portal phase(PP)) with GSI mode on high-definition computed tomography were retrospectively enrolled in our study, including 8 patients in p T2, 4 patients in p T3, and 12 patients in p T4. 12 patients(p T4 patients) were classified as serosa positive group, and 12 patients(p T2 and p T3 patients) were classified as serosa negative group. The clinical information(e.g. sex, age) of these two groups were compared by using independent sample t test or chi square test. In addition, GE AW4.4 workstation was used for image post-processing, and the dual phase spectrum information of these two groups was obtained. Support Vector Machine Recursive Feature Elimination(SVM-RFE) algorithm was used to analyze the spectrum information of these two groups. Results: Among the clinical information, only tumor long axis and short axis had statistically significant difference between two groups(all P < 0.05). The accuracies of SVM-RFE were 87.5%~94.4%. The output features of SVM-RFE were fat(calcium)(PP), uricacid(calcium)(PP), calcium(iodine)(AP), water(calcium)(PP), and iodine(water)(PP). Conclusion: Tumor size, fat(calcium)(PP), uricacid(calcium)(PP), calcium(iodine)(AP), water(calcium)(PP), and iodine(water)(PP) were helpful for the diagnosis of gastric cancer serosa invasion.

The Analysis of Comprehensive Geophysical Detection and Seismicity of Fracture of Mount Qianfo

SONG Wen-jie, CHEN Shi-jun, GE Fu-gang, WU Zi-quan, LV Chun-shuai

2016, 25(5): 523-530. doi: 10.15953/j.1004-4140.2016.25.05.03

Abstract(773) PDF(4)

Abstract:
Fracture of Mount Qianfo is an important hidden fracture. To analyze the exact position of fracture, the habitat of rifts and the seismicity of fracture is of great significance. This thesis makes a comprehensive detection and analysis of this fracture with the techniques and strategies of Remote Sensing, Geophysical Detection, Geologic Structure and Engineering Geological Investigation, offers this fracture a precise localization and provides an analysis for the seismicity property of fracture. This thesis also gives measurement result according to the tectonic characteristics of the fault, the geological features, fault materials and the overlying quaternary strata age, and makes sure that this fracture is the active fault in the early Pleistocene to Pleistocene. And there's no significant sign of activity from the Pleistocene to now. The main movement property of fracture of Mont Qianfo is extensional normal fault, and also includes the left-lateral strike-slip motion. From the aspect of the relationships between the structures of the fault surface, the fracture had experienced polystage activities before the early and mid period of Pleistocene.

A Primary Study on Wide-band Holographic Reconstruction Algorithm Applied to Submillimeter-wave Imaging System

NIU Yi-jie, WANG Zi-ye, QIAO Ling-bo

2016, 25(5): 531-538. doi: 10.15953/j.1004-4140.2016.25.05.04

Abstract(516) PDF(5)

Abstract:
Millimeter-wave holographic imaging technique is important means for human body security inspection. In order to further improve imaging resolution and image quality, the research of wide-band and high-frequency submillimeter-wave imaging system has great significance. Based on the construction of submillimeter-wave holographic imaging system, this paper proposes an appropriate wide-band holographic reconstruction algorithm. The target image is obtained by the measured phase and amplitude information reconstruction using submillimeter-wave holographic imaging system. Experimental results show that, the wide-band holographic reconstruction algorithm can efficiently reconstruct image within sub-millimeter wave band, to validate the use of wide-band imaging can effectively improve image resolution and suppress speckle effect.

Cupping Artifacts Calibration in CT Image Based on Radon Transform

ZHANG Xue-song, ZHAO Bo-shan

2016, 25(5): 539-546. doi: 10.15953/j.1004-4140.2016.25.05.05

Abstract(734) PDF(10)

Abstract:
Objective: At present, most of beam hardening calibration algorithms required spectrum, the detector characteristics and other information. As the beam hardening calibration algorithm's complexity, we propose a method based on image post-processing. Methods: Firstly, the water portion with cupping artifacts is segmented in the water phantom CT image and done Radon transform to obtain projection information. The calibration model with unknown coefficients is built with above projection information. Secondly, an ideal water phantom image without beam hardening artifacts is constructed and compared with calibration model. When the difference between them is minimal, the unknown coefficients of correction model is determined. Finally, use the calibration model that combined the determined parameter and the projection information of segmented soft tissue to correct the practical CT images so that eliminate the cupping artifacts. Results: The result of computer simulation shows that this method can efficiently remove the cupping beam hardening due to a medical CT beam-hardening caused. Conclusion: The proposed method without need for projection data and spectrum information can be carried out in beam hardening cupping artifacts calibration, improved beam hardening correction flexibility.

Clinical Application of ECG Gated CTA in Evaluation of Acute Aortic Dissection

CHEN Feng-li, LIU Ai-shi

2016, 25(5): 547-554. doi: 10.15953/j.1004-4140.2016.25.05.06

Abstract(531) PDF(4)

Abstract:
Objective: In this study, we would compare to the routine aorta CTA and ECG gated aorta CTA image quality, in order to know the advantage of ECG gated aorta CTA in evaluation of aortic dissection. Methods: Through the imaging system retrospectively selected 62 patients who underwent aorta CTA from 2013 January to 2016 March, divided into two groups. Group A underwent triple rule out scanning(13 cases), group B underwent aortic CTA(49 cases). Evaluation of aortic image quality and assessment of various indexes of aortic dissection. The measurement data were compared by two independent samples t test, and count data were compared using chi-square test. A(P< 0.05) consider the statistical significance difference. Results: Attenuation of aortic root in Group A was 367.000 HU ± 28.73 HU, in Group B was 335.24 HU ± 45.73 HU(t=1.653, P=0.104), the difference was not statistically significant. The position and number of break, the aorta valve morphology, coronary artery morphology of group A and group B can be assessed statistically significant difference(P< 0.05). intima morphology, branches of the aortic arch and true/false lumen could assessment showed no statistical significance(P> 0.05). Conclusions: Applying the ECG gated aortic CTA compared with the conventional spiral aorta CTA, it could clearly display the index of aortic dissection, evaluate prognosis of aortic dissection, guide the therapy and formulate operation/endovascular treatment plan.

Radiographic Analysis of the Dose of Bone Cement in Percutaneous Vertebroplasty and Kyphoplasty in Spinal Fractures

DENG Gang, ZHANG Li-li, ZHANG Shu-hui, WU Ge, DENG Mao-song, JIN Guang-wei, YIN Xiao-ming, LIU Jian-xin, ZENG Qing-yu

2016, 25(5): 555-561. doi: 10.15953/j.1004-4140.2016.25.05.07

Abstract(490) PDF(3)

Abstract:
Objective: To explore a best does(method, standard and accurate calculation) of bone cement in PKP, based on the CT and MRI image data of thoracolumbar vertebrae with new compression fracture. Methods: 42 new compression fracture patients with thoracolumbar vertebrae injury underwent PKP and examined by CT and MRI before surgery no more than 1 week. Retrospectively analyzed the image data and compared the statistical image data followed a variety of reconstruction. Results: Of 42 cases, new compression fracture located in the T10(n=2), T11(n=5), T12(n=9), L1(n=11), L2(n=7), L3(n=5), L4(n=3). The average fracture compression rate of bone cement in PKP ranged from 1.6 to 6.3ml. Conclusion: It is practicable to predict the best dose of bone cement in PKP that by reprocessing the image of preoperative CT and MRI, which can make the treatment more effective, at the same time, the interrelated complication can be avoided.

A Primary Study of Magnetic Resonance Imaging-diffusion Weighted Imaging of Pancreas in Type 2 Diabetic Mellitus Patients

XIE Wan-meng, CHEN Jun, WANG Jun, XIE Xin-jia

2016, 25(5): 563-569. doi: 10.15953/j.1004-4140.2016.25.05.08

Abstract(473) PDF(3)

Abstract:
Objective: To investigate the value of MRI diffusion weighted imaging(DWI) in the diagnosis of pancreatic examination in patiens with type 2 diabetes mellitus. Methods: 75 patients with diabetic patients were divided into 3 groups according to the duration of the patients, 2 years 2~10, 10 years. At the same time, 25 healthy people were selected as the control group. The diffusion coefficient(ADC) of pancreatic lesions was measured by MRI scan, and DWI scan, and the imaging features of MRI and DWI were observed. Results: DWI examination and measurement of healthy control group and the ADC values of pancreatic lesions in the three groups were(2.00 ± 0.17) × 10^-3 mm²/s,(1.94 ± 0.09) × 10^-3 mm²/s,(1.86 ± 0.13) × 10^-3 mm²/s,(1.77 ± 0.25) × 10-3 mm²/s. Compared with healthy controls, the P values were 0.023, 0.010, 0.008, and the difference was statistically significant between the two groups. 75 cases of diabetic patients with MRI examination of the pancreas, 1 case were eventually diagnosed as pancreatic cancer Conclusion: The DWI signal of pancreas in diabetic patients gradually decreased with the extension of the course. Some functional changes of the pancreatic cells. Screening early patients with pancreatic cancer whose manifestation was just as diabetic.

The CT Findings of Mass-forming Type Intrahepatic Cholangiocarcinoma without Peripheral Bile Duct Dilatation

ZHAO Yue, TAN Hong-wen, CAI De-zong, LUO Peng, HE Jin-hua, DENG Ying-ying, YANG Bin

2016, 25(5): 571-577. doi: 10.15953/j.1004-4140.2016.25.05.09

Abstract(450) PDF(3)

Abstract:
Objective: To investigate CT findings and pathological features of the mass-forming type(MF type) intrahepatic cholangiocarcinoma(ICC) without peripheral bile duct dilatation. Methods: This study involved 22 patients with ICC diagnosed by pathological data. All CT data were retrospectively analyzed and no peripheral bile duct dilatation found on CT imagings. Results: 22 cases were adenocarcima, 3 cases was mixed cholangiocarcinoma and hepatocellular carcinoma. 16 cases were well or medium differentiated staging on pathology. The macroscopic type of 22 cases were MF type, which had general features of MF type cholangiocarcinoma, such as: irregular mass 14 cases(with shallow lobulated edge), like-round mass 8 cases; a large number of fibers or mucus in the center of the lesion(15case were with a large number of fibers, 3 case were with a large number of mucus); calcification(3/22); the capsular retraction sign(10/22); 19 cases with delayed enhancement feature. However, there were some features different from the typical mass forming cholangiocarcinoma, included no peripheral bile duct dilatation, there were no relative satellite lesions and lymph metastasis. Conclusion: The ICC without peripheral bile duct dilatation mostly was well or medium differentiated carcinoma and showed MF type features without feature of peripheral bile duct dilatation on MR imagines, easily misdiagnosed as atypical hepatocellular carcinoma or infectious disease.

The Value of DR and MSCT in Diagnosis of Traumatic Diaphragm Rupture

ZUO Kai-hua, HE Lin, WU De-hong

2016, 25(5): 579-585. doi: 10.15953/j.1004-4140.2016.25.05.10

Abstract(507) PDF(3)

Abstract:
Objective: To compare the value of DR with MSCT in diagnosis of traumatic diaphragm rupture(TDR), and provide reliable imaging basis for the surgical treatment. Methods: collected the TDR image data of 25 confirmed cases by surgery who received DR and MSCT diagnosis from January 2013 to January 2015. Analyze the collected materials with double-blind method by two senior doctors to find the following characteristic as diagnostic basis: abnormal evaluation of the diaphragm, diaphragm defect, mobility of diaphragmatic muscles, collar feature, place and size of the rupture and the contents of hernial sac. Then calculate the diagnostic accuracy of DR and MSCT referring to the results of surgery. Results: among all the 25 cases, the surgical result and DR & MSCT diagnosis result have consistency. And the diagnosis accuracy of abnormal evaluation of the diaphragm displayed on the axial images of DR & MSCT and diaphragm defect, the contents of hernial sac displayed on MSCT post-processing is 100%. Compared with surgical results, the axial MSCT diagnosis accuracy of place and size of the rupture is 20%; diaphragm defect, 48%; collar feature, 55.56%, hernial sac, 55.56%. Compared with surgical results, the MSCT post-processing diagnosis accuracy is showed below, place and size of the rupture, 92%; collar feature 77.78. DR diagnosis has some value on mobility of diaphragmatic muscles and the contents of hernial sac, and the diagnosis accuracy were 52% and 24%. But it is not so ideal on diaphragm defect, collar feature and place and size of the rupture. Conclusion: MSCT post-processing technique demonstrates high diagnostic accuracy; it can provide accurate imaging information and optimal operation plan. So it should be the preferred imaging diagnosis method in traumatic diaphragm rupture(TDR)

CT Diagnostic Value of Ectopic Bronchial Cyst

QIN Meng, LIU Shun, HUANG Jing-bo

2016, 25(5): 587-592. doi: 10.15953/j.1004-4140.2016.25.05.11

Abstract(446) PDF(4)

Abstract:
Objective: To investigate the value of CT on diagnosing ectopic bronchogenic cyst(EBC). Materials and Methods: The CT findings of 2 cases of EBC confirmed by pathology were retrospectively analyzed. Results: Of 2 cases of EBC, 1 case was located in the stomach esophagus district, another 1 case in left retroperitoneal region. It all showed mass with clear boundary and relatively high density, no enhancement in the cystic. One of 2 cases of EBC was smooth and thick wall, enhance performance for circular reinforcement. Another one was septum and calcification. Conclusion: CT scan and enhanced scan contributed to the diagnosis and differential diagnoses, CT were conductively to judge the location and characteristics of the lesions. It could clearly show the lesion area, shape, size, density, boundary and enhancement, but it was diagnosed with bronchial cyst by pathology only.

The Value of Multi-slice Spiral CT in Follow-up of the Tracheal Stent

YANG Ying, DENG Mao-song, ZU De-gui, XU Tong-jiang, YIN Xiao-ming

2016, 25(5): 593-599. doi: 10.15953/j.1004-4140.2016.25.05.12

Abstract(469) PDF(4)

Abstract:
Objective: Comparing the multi-slice helical CT with bronchoscopy findings of proximal-airways stenting to assess the value of multi-slice spiral CT. Methods: 130 patients with 130 endobronchial stents inserted for malignancy(n=109) or benign diseases(n=21) underwent follow-up multi-slice helical CT and with subsequent multi-slice reformation and three dimensional reconstruction at 3 months or complications aggravated. Bronchoscopy was carried out in(1.2 ± 0.6) days. Of the stent location, shape, and adjacent lumen airway patency were evaluated by two experienced doctors. Kappa test was used to the check the consistency of the results of two doctors. Paired chi-square test to determine the diagnostic accuracy of CT stent complications. Results: CT results of 61(46.9%) patients showed no complications, 5 patients showed discrepancies, the latter bronchoscopy show tracheal stent granuloma, a slight narrowing of the lumen(< 25%). 69 cases(53.1%) showed abnormal changes in the lumen on CT. 4 cases were misdiagnosis as tumor recurrence and confirmed granuloma by bronchoscopy, the CT result of remaining 65 cases were consistent with the diagnosis of the bronchoscope. The sensitivity, specificity and accuracy of CT diagnosis was 96.2%, 100% and 93.1%, respectively. Conclusion: Computed tomography is an accurate noninvasive method for evaluating endobronchial stents. CT is a useful technique for follow up of patients who have undergone endobronchial stenting.

CTA Evaluation of Carotid Plaque Composition and Volume Correlation with Cerebral Vascular Symptoms

LI Yang, CHA Yun-fei

2016, 25(5): 601-607. doi: 10.15953/j.1004-4140.2016.25.05.13

Abstract(529) PDF(8)

Abstract:
Objective: The purpose of this work was to evaluate the differences of plaque composition and volume between carotid artery bifurcation and carotid siphon and its predictive value for cerebrovascular events. Materials and Methods: A total of 100 patients(65 men, 35 women; mean age,(55 ± 9) years) who underwent CT angiography experiment were enrolled. Plaque component types of the carotid artery bifurcation and the carotid siphon were defined depending on its attenuation values(lipid, < 60 HU; mixed tissue, 60~130 HU; and calcification, > 130 HU), and the components volumes were calculated. Statistical analyses were performed using Student's t test and Chi-square test to evaluate the plaque volumes and constituent ratio difference among plaque components between carotid artery bifurcation and carotid siphon. The ROC curve and Az were calculated to evaluate the predict accuracy of the total and each component plaque volumes for cerebrovascular events. Result: There was a statistically significant difference(P< 0.05) between the total volume of the carotid artery bifurcation(mean value,(752.3 ± 3.4) mm³) and the carotid siphon(mean value,(56.2 ± 5.541) mm³)) plaque. The constituent ratio of lipid, calcified, and mixed components were 16.8%, 49.1%, 34.1%, respectively, in the carotid artery bifurcation and 33.3%, 32.0%, 34.6%, respectively, in the carotid siphon, showing a statistically significant difference(χ²=26.077; P< 0.05). Statistical analysis approved the high predict accuracy of the carotid artery bifurcation total, lipid and mixed plaque volumes for cerebrovascular events with Az values of 0.682, 0.773, and 0.653, respectively. The best cut-point for the predict accuracy for cerebrovascular events in the plaque was 203.383 mm³ of fatty components, with sensitivity and specificity of 75% and 82%. Conclusion: Resultsof this study suggest there were significant differences in plaque volumes and constituent ratio among plaque components between carotid artery bifurcation and carotid siphon, and indicate the high predict accuracy of lipid plaque for cerebrovascular events.

The Application of CTA on Head and Neck Anatomy of the Styloid Process

CHEN Zhong-qiang, CHEN Jun, WANG Jun, ZHANG Bo, XIE Peng, CHEN Shun-xin

2016, 25(5): 609-618. doi: 10.15953/j.1004-4140.2016.25.05.14

Abstract(709) PDF(3)

Abstract:
Objective: The anatomical study of the styloid process of the head and neck by CTA. Methods: 200 cases of head and neck CTA imaging in patients were randomly enrolled(by age into A, B two groups, group A < 60 years, B group is over 60 years old) in this study. After the original data were sent to GE AW4.5 workstation, volume rendering(VR), multi planar reformat(MPR) were used and morphological observation of styloid process, and typing, and the measuring styloid process length, inner angle and anteversion and the shortest distance between the tip of the styloid process and the internal and external carotid artery were performed.Results: Average length of styloid process was about 26.79 mm, inner angle about 21.07° and anteversion about 25.03°. The tip of styloid process and internal carotid artery in the shortest distance average is about 6.26 mm, and the external carotid artery of the shortest distance average is about 4.15 mm, there were 44 cases of the shortest distance between the tip of styloid process and the external carotid artery with zero, accounting for 11.2% of the total number. Bilateral styloid process length, inner angle, the shortest distance between the tip of styloid process and external carotid artery and the right side of the front angle of gender difference showed significant differences(P<0.05); inner angle, the shortest distance between the tip of styloid process and external carotid artery between the left and right side of a statistically significant difference(P<0.05). Styloid process was divided into four types: complete type(71.75%); dysplasia type(22.75%); segmental type(4.25%); undeveloped type(1.25%). Conclusion: Head and neck CTA can display styloid process shape, measure the length of the styloid process within the inclination and anteversion, more clearly show the relationship between the styloid process and the internal and external carotid artery to measure the shortest distance between the tip of the styloid process and arteries. It helps to the diagnosis and treatment of the styloid process related diseases.

Analysis of Clinical Manifestations and CT and MRI Findings of Venous Cerebral Embolism

JU Min-hao, GUO Yue-feng, WANG Yan-yan, ZHANG Xiao-lu

2016, 25(5): 619-624. doi: 10.15953/j.1004-4140.2016.25.05.15

Abstract(508) PDF(3)

Abstract:
Objective: To investigate the pathogenesis, clinical manifestations, CT and magnetic resonance imaging(MRI) findings of patients with venous cerebral embolism. Methods: The clinical data of 8 patients(12 lesions) diagnosed by clinical and imaging combined examination was retrospectively analyzed. Among them, 6 patients underwent MRI enhanced scan and some patients underwent surgical treatment. The results of CT scan and MRI sequence examination were analyzed before and after treatment, and their imaging findings were evaluated. Results: Among the 8 diagnosed patients, 6 cases were diagnosed with superficial venous thrombosis(5 cases were unilateral and 1 case was bilateral). The clinical manifestations were headache, nausea, vomiting, focal neurological deficits or seizures; there were 2 cases with deep central venous thrombosis(unilateral/bilateral thalamus venous infarction in basal ganglia in 1 case respectively). The clinical manifestations were mild and the progression of pathogenic condition was slow. The prognosis was ideal. CT plain scan of 12 lesions showed low density shadow; T1 WI image showed low signal while DWI image showed high signal. T2 WI image showed high signal in 9 and mixed signal in 3; The 8 lesions in 6 cases undergoing enhanced MRI scan showed enhanced ring and thickness was homogeneous, irregular. Conclusions: Compared with CT examination, MRI can help doctors to understand the information of lesions in patients with venous cerebral embolism more directly and clearly, which has positive effect on the development of targeted therapy and the accurate assessment of prognosis.

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2016 Vol. 25, No. 5