CT理论与应用研究

Geometric Correction Method for Double-plane “Multi-use” Nuclear Medical Imaging System

SHANG Lei-min, TIAN Li-xia, YUAN Ming-kai, DAI Chao-cheng, LI Lin, HUANG Xian-chao, WEI Cun-feng

2017, 26(2): 129-138. doi: 10.15953/j.1004-4140.2017.26.02.01

Abstract(502) PDF(4)

Abstract:
Double-plane multi-function nuclear medical imaging system can support both Positron Emission Tomography Imaging(PET) and Single Photon Emission Imaging(Gamma camera). It is a "multi-use" device which can switch operating mode between double plane PET and γ camera using tractable collimators. Considering the requirements of this special operating mode and the accuracy of the mechanical assembly, it is particularly important to process a series of geometric calibration before data acquisition. After that the calibration factors can be used in data correction or image reconstruction. In this paper, we studied the influence of system geometry offset on image quality and established a set of calibration and correction methods based on the parametric representation of these factors. The performance of correction accuracy was evaluated based on the Monte Carlo simulation data. The results showed that the method is effective, feasible and simple.

The Prediction Method of Diffracted Wave Attribute on Buried Hill Fractured Reservoir

SHU Meng-cheng

2017, 26(2): 139-146. doi: 10.15953/j.1004-4140.2017.26.02.02

Abstract(431) PDF(4)

Abstract:
The prediction of fracture-developed area is one of the most important missions for exploration of reservoir of fractured buried hill. A fracture predicted flow based on diffracted wave attribute is proposed, and the principal component analysis algorithm is used to extract diffraction information from seismic field. Meanwhile, via forward modeling, it is the practicability that the flow prove and it's indicate that diffraction attributes can descript the fracture distribution effectively. Finally, the fracture predicted flow is proved feasibility and accuracy to descript the character of fractured reservoir in practice.

The Control Study of Dual Source CT Dual Energy Lung Perfusion Imaging and CTPA with Experimental Acute Pulmonary Embolism Model

ZHANG Xiao-qin, LIAO Jian, WANG Min, ZHANG Kai, DONG Yu-qing, YUN Feng

2017, 26(2): 147-156. doi: 10.15953/j.1004-4140.2017.26.02.03

Abstract(457) PDF(6)

Abstract:
Objective: Study the diagnosis value of CTPA combined with dual energy CT lung perfusion imaging(DEPI) in acute pulmonary embolism, and the sensitivity of the DEPI to diagnosis the acute pulmonary embolism. Methods: The experimental group with 20 New Zealand rabbits. Acute pulmonary embolism models of rabbits were established by injection of gelatin sponge through the ear vein. The control group 2 New Zealand rabbits injected saline via the same path. The CTPA scan and dual energy CT lung perfusion imaging were collected successively after 2 hours then kill all rabbits. Observe the rabbit lung tissue with the gross anatomy and microscope. With the pathology as the gold standard to evaluate the accuracy of CTPA combined with DEPI in the diagnosis of acute pulmonary embolism. Results: In the control group, the CTPA show pulmonary artery patency, no filling defect, DEPI images show a substantially uniform yellow and red color. Experimental group after embolization of CTPA show visible ground-glass attenuation, lung tissue lung texture sparse and Mosaic change in part of pulmonary artery corresponding lung tissue in New Zealand rabbits, and embolism regional perfusion images displayed in blue or black perfusion defects or uneven perfusion. Pathological examination revealed small pulmonary embolus occurs, CTPA found no vascular filling defect, and DEPI show is slightly uneven image with normal perfusion regional color. The sensitivity, specificity, positive predictive value and negative predictive value of CTPA and DEPI in the diagnosis of pulmonary embolism were 97.22%, 98.65%, 97.22%98.65%; 97.37%, 95.83%, 92.50%, 98.57%. Conclusion: DEPI with a high sensitivity for the detection of acute pulmonary embolism; CTPA combined with DEPI can improve the diagnostic rate of acute pulmonary embolism.

The Application of Capacitively-coupled Resistivity Method to Archaeological Exploration of Urban Site

BIE Kang, SHI Zhan-jie, TIAN Gang, CHEN Ran, ZHAO Wen-ke

2017, 26(2): 157-164. doi: 10.15953/j.1004-4140.2017.26.02.04

Abstract(501) PDF(3)

Abstract:
The dense asphalt road and hardened cement floor bring much difficulty to the archaeological exploration of underground urban site, while the traditional high-density resistivity method need to interpose electrodes, so it cannot be used to the urban environment. The capacitively-coupled resistivity method don't have to invade in the earth, through the special electrode consist a capacitor with the earth so that produces current, therefore, it's suitable for the conditions of urban hard surface particularly. In order to test the effect of capacitively-coupled resistivity method in archaeological exploration of urban site, we conducted the capacitively-coupled resistivity exploration in Wuyue seawall which located in Hangzhou main city area, and collected the electrical data contain multiple transmitter and receiver distance, then use the data for the inversion processing, finally, compared and analyzed the results of inversion and archaeological excavations. Indicating that the inferred results of resistivity images are consistent with the archaeological excavation results. The capacitively-coupled resistivity method is effective for archaeological exploration of urban sites and has broad application prospects.

Application of Parabolic Radon Transform in the Suppression of Multiple Seismic Wave

GONG Shu, REN Qin-qin, WANG Min-ling

2017, 26(2): 165-176. doi: 10.15953/j.1004-4140.2017.26.02.05

Abstract(414) PDF(3)

Abstract:
The existence of multiple waves will reduce the signal to noise ratio of seismic data, and effect quality of seismic data processing and the subsequent geological interpretation accuracy, so the suppression of multiple wave interference is an important work in the processing of seismic data. Author modeled seismic wave field of several typical geological model through using the finite difference method, After NMO correction, then transformed the reflected wave and multiple wave in the t-x domain to the τ-q domain through the method of parabolic Radon transform. Energy convergence is obtained in the τ-q domain, because of the velocity differences between the reflected wave and the multiple wave, the reflection wave and the multiple wave energy were apart from each other in the τ-q domain, so we can get rid of multiple wave energy in the Radon domain and retain the reflected wave information effectively, then reached the suppression of multiple wave effect, improved the signal-to-noise ratio. The suppression of multiple waves were further verified by the results of the parabolic Radon transform of the real seismic data.

Noise Reduction for Low-dose CT Sinogram Based on PDE

WU Wen-shu, WANG Zhe, SHI Yi-fan, ZHAO Zhan-shan, WEI Cun-feng, WEI Long

2017, 26(2): 177-188. doi: 10.15953/j.1004-4140.2017.26.02.06

Abstract(410) PDF(11)

Abstract:
With the wide application of medical imaging technology,the low-dose CT has become an inevitable tendency in medical CT because of the gradual awareness of scan dose.However,the reconstruction image degradation in low-dose CT will affect the medical diagnostic accuracy.In order to solve the problem above,a4-neighborhood partial differential equation based on anisotropic diffusion equation sinogram noise reduction is proposed.To get more effective at noise smoothing and features preserving,novel model defined a weight normalized gradient according to the control rate of relevant pixel values.Additionally,a time-varied diffusion function based on the regular rule of image feature is provided to be adaptive for the balance between noise removal and edge preservation.Numerical results and scan data of the breast model reveal that the novel method can achieve better reconstruction image quality.

Research on the Preparation and Performance of Tungsten-diamond Transmission Target for Microfoucs X-ray Source

MA Yu-tian, LIU Jun-biao, NIU Geng, ZHAO Wei-xia, HAN Li

2017, 26(2): 189-194. doi: 10.15953/j.1004-4140.2017.26.02.07

Abstract(485) PDF(8)

Abstract:
The present paper designed a basic structure of tungsten-diamond transmission target, according to the theoretical model of the end-window transmission target for micro-focus X-ray source. The tungsten-diamond transmission target is prepared by magnetron sputtering deposition technology. The microstructure of tungsten film is analyzed by scanning electron microscope. The performance of tungsten-diamond transmission target is carried out on the X-ray tube of YXLON, and the performance is compared to that of YXLON. The experimental results show that the surface morphology of homemade target is similar to that of YXLON. Under the same operating conditions, the X-ray emitting efficiency is slightly higher about one percent than that of YXLON and the corresponding X-ray production power of them is little difference, and the lifetime of homemade target is longer than that of YXLON. All the above mention results indicate that homemade target could be satisfied the application requirements of high quality target for micro-focus X-ray source.

A Study on High-resolution MRI and Double-contrast MRII Combined with DWI in the Preoperative Local Staging of Rectal Cancer

YANG Jie-yu, WANG Jie, LÜ Xing-long, XIE Zhao-yong

2017, 26(2): 195-202. doi: 10.15953/j.1004-4140.2017.26.02.08

Abstract(550) PDF(6)

Abstract:
Objective: This study aims to analyze the significance of MRI in the preoperative local staging of rectal cancer by high-resolution MRI Imaging and double-contrast MRI combined with diffusion-weighted imaging(DWI) imaging technique. Methods: A total of 250 patients clinically diagnosed with rectal cancer were enrolled into this study from January 2013 to January 2016.MRI-TN preoperative staging was used for rectal cancer lesions, based on all sequences. The mesorectal fascia and circumferential resection margin involvement was evaluated and comparatively analyzed through the pathological results of the operation. Results: The overall diagnostic accuracy of T staging was 88.8%(250/222). Diagnosis accuracy rate, specificity, sensibility, PPV and NPV of rectal carcinoma T-stage by MRI were consistent with postoperative pathological T staging(kappa = 0.712, P = 0.000). The overall diagnostic accuracy of N-stage was 75.6%(250/189). Diagnosis accuracy rate, specificity, sensibility, PPV and NPV of rectal cancer N staging by MRI were moderately consistent with postoperative pathological N-stage(kappa = 0.623, P = 0.000). The overall diagnostic accuracy of CRM involvement was 97.6%(58/52). In judging CRM involvement by MRI, accuracy rate was 97.6%, sensibility was 100%, specificity was 97.0%, PPV was 89.7%, and NPV was 100%. Conclusion:(1) high-resolution of thin-section MRI and double-contrast MRI combined with DWI can provide the accurate T staging of preoperative rectal cancer and provide a relatively accurate multi-parameter and multi-angle N staging.(2) MRI can accurately predict CRM involvement.(3) The sagittal view can accurately measure the distance from the lesion edges to the anus, which offer visual information for preoperatively deciding whether to keep the anus or not.

Imaging Features of Lung Focal Ground-glass Opacities on MDCT after Thin-section (1mm) Reconstruction

YAN Ying-nan, ZHANG Su-yan, YU Tie-feng, ZHAO Hong-xia, LIU Rong-hua

2017, 26(2): 203-210. doi: 10.15953/j.1004-4140.2017.26.02.09

Abstract(384) PDF(12)

Abstract:
Objective: Analyzing the performance of focal ground glass that under MDCT thin thickness reconstruction, and obtaining CT features of focal ground glass opacity from early stage lung cancer. Method: 53 clinically or pathologically confirmed f GGO were collected and analyzed clinical informations and imaging features including lesion location and size, shape, margin, interface, internal density, pleural indentation, vacuole, air bronchus-charging sign and blood vessel clustering. Statistical analyze the differences between the benign and malignant. Results: There were statistical differences between benign and malignant fGGOs in terms of margin(P = 0.001), interface(P = 0.000) and blood vessel clustering(P = 0.009) as well as gender(P = 0.120), age(P = 0.437), location(P = 0.565) size(benign 1.55 ±0.67) cm, malignant(1.54 ±0.85) cm,(P = 0.978), shape, vacuole(P = 0.100), air bronchus-charging sign(P = 0.211) and pleural indentation(P = 0.243) doesn't significantly found in malignant fGGOs. Conclusion: Margin, interface and blood vessel clustering can make contribute to early lung cancer diagnosis and differentiation of benign and malignant fGGOs.

Imaging Manifestation of Cerebral Cortical Laminar Necrosis

SUN Ying-ying, DING Zhang-qing, LUO Hui, DAI Lan-lan, WANG Wen-sheng, DING Ai-lan, WANG Xue-lu

2017, 26(2): 211-218. doi: 10.15953/j.1004-4140.2017.26.02.10

Abstract(507) PDF(7)

Abstract:
Objective: To analyze the imaging features of cerebral cortical laminar necrosis(CLN), and to improve the abilities of diagnosis and differential diagnosis. Methods: From January 2015 to November 2016, 77 patients with CLN diagnosed by follow-up CT and MRI in our department were enrolled. The clinic data were analyzed retrospectively, and the etiological and imaging features were summarized. Of all the 77 patients, 45 were male and 32 were female, aged from 24 to 88 years(mean(66.53 ±3.1) years). All the patients underwent MRI examination, 71 patients also underwent CT examination, and there were more than 3 times(mean 3.8 times) imaging examination information in all the cases. The imaging examination follow-up time was 20 d ~ 18 m(mean 2.3 m). Results: Of all the 77 cases, 58 cases were cerebral infarction, 9 cases were traumatic brain injury, 5 cases were spontaneous cerebral hemorrhage, 4 cases were post-operative brain tumor, 1 case was hypoxic ischemic encephalopathy. Bilateral cerebral hemisphere involved in 3 cases, unilateral cerebral hemisphere involved in 74 cases. Single lobe involved in 28 cases, double lobes involved in 35 cases, multiple lobes involved in 14 cases. A follow-up brain imaging's demonstrated diffuse or localized cortical atrophy, with 1inear or gyrate high density on plain CT scan and high signal on MRI T1 WI, along the cortex surface or along the gyrus, some of the lesions could reach the region of basal ganglia or hippocampus. Conclusion: The etiology of CLN is complicated and diverse, typical follow-up imaging's show 1inear or gyrate high density on plain CT scan and high signal on MRI T1 WI, combined with the clinical history can make an accurate diagnosis.

The Clinical Value of Contrast Analysis between 64-CT Coronary Artery Imaging and PET-CT Myocardial Perfusion Imaging

WANG Quan-yong, LIU Ai-shi, HAO Fen-e

2017, 26(2): 219-230. doi: 10.15953/j.1004-4140.2017.26.02.11

Abstract(379) PDF(4)

Abstract:
Objective: Comparison of CT coronary artery imaging(CTCA) and PET-CT myocardial perfusion imaging(MPI) for relevant coronary artery stenos is and pinpoints the value of the "criminal" blood vessels. Methods: A retrospective analysis of the Affiliated hospital of Inner Mongolia Medical University from March 2009 to December 2014,the clinical diagnosis and 59 patients with suspected CAD were used CTCA and MPI within four weeks. By two experienced imaging and nuclear medicine physician images and data analysis, according to the segmental coronary artery blood flow characteristics, analysis of coronary artery blood supply region and sarcomere corresponding relation we used the Spearman rank correlation and Pearson and Kappa test method. Results: According to the LAD, LCX, RCA three coronary artery myocardial part of dominion on 59 patients, total 177 vessels and coronary vascular level 0, 58 branch; 24 Ⅰ level; 33 the Ⅱ level; 40 Ⅲ level; 22 Ⅳ level. Perfusion 0, 63; 1 minute 30; 2 minutes and 45; 3 minutes and 27 teams; 4 points, 12.Three CTCA coronary arteries with MPI line of correlation analysis and alignment analysis respectively, both for the positive correlation, self-agreement is higher. LAD r = 0.764, P = 0.000; LCX r = 0.593, P = 0.000; RCA r = 0.831, P = 0.000. LAD k = 0.666, P = 0.000; LCX k = 0.601, P = 0.000; RCA k = 0.559, P = 0.000. Conclusion: CTCA anatomic information and MPI physiological functional combination, effective complementary, able to pinpoint a combination of CAD patients "criminals" blood vessels, greatly improve the CAD diagnosis accuracy, and provide powerful basis for clinical treatment and prognosis judgment.

Clinical Exploratory Development of Atypical Aortic Dissection Diagnosed by MSCT

YU Hong-sheng, JI Liu-zhou, SHEN You-li, ZHOU Quan, LIU Yi-kang

2017, 26(2): 231-240. doi: 10.15953/j.1004-4140.2017.26.02.12

Abstract(381) PDF(3)

Abstract:
Objective: Analyze and summarize the MSCT imaging features of atypical aortic dissection, to evaluate MSCT's clinical diagnosis value to the disease. Methods: Retrospectively analyses the MSCT plain scans and CAT signs of 13 AAD cases, diagnosed by referring to the Stanford types. Results: Stanford type A: 3 cases, type B: 10 cases. Their aortic walls showed the meniscus or annular incrassation and plain scans showed high density and increase with no enhancement and 5 cases of inward moving of the calcified inner wall. Including 2 cases of intima leakage, 9 cases of atherosclerosis; 1 case of pericardial effusion, 4 cases of pleural effusion. Conclusion: CT imaging manifestations of AAD have characteristic feature: aortic walls showed the meniscus or annular incrassation, with inward moving of the calcified inner wall, intima leakage, penetrating ulcer, the structure change of aorta, atherosclerosis and so on, which erupt simultaneously pericardial effusion and pleural effusion. The advantage of AAD to scan and diagnose before and after the enhancement is obvious, plain scans combining clinic could strongly suggests that AAD, CTA are of diagnostic values.

The Value of 64-MDCT Diagnosis of Intestinal Tumor

YANG Hong, YANG Ying, LI Dong-cheng, XIU Cheng-xiang

2017, 26(2): 241-246. doi: 10.15953/j.1004-4140.2017.26.02.13

Abstract(395) PDF(7)

Abstract:
Objective: To evaluate the value of 64-MSCT diagnosis of intestinal tumor. Methods: The imaging data of 39 patients with intestinal cancer were retrospectively analyzed in our hospital from july 2013 to may 2016, All the patients were examined with water imaging technique. Coronal plane and Sagittal plane imaging reconstruction was performed by work station multiplanar reconstruction(MPR), and sectional plane imaging was combined. CT findings of 39 patients of intestinal tumor were retrospectively analyzed. Results: In 39 cases of intestinal tumor.2 cases of small intestinal adenocarcinoma.1 case of malignant lymphoma. 2 cases of gastrointestinal stromal tumors. 3 cases of ileocecal junction tumor. 22 cases of hemicolon tumor. 9 cases of rectal tumor. Tumor complicated with intestinal obstruction in 2 cases, combined intussusception in 1 case, tumor perforation in 1 case. Tumor invasion and 28 cases of deep muscularis, break through the infringement of 16 cases of fat around the gap size film layer, around 10 cases of lymph node metastasis, liver metastasis in 1 case.Conculsion:64 layer spiral CT on gastrointestinal tumor detection rate is high, can accurately determine the patient's pathological changes, and help the tumor qualitative, has diagnostic value in intestinal tumor.

Diagnostic Value of Enhanced CT Scan in Emergency Patients with Trauma Emergency

MING Jian-zhong, LIU Tao, XIANG Cheng-xian, CHOU Rong, WU Jing-lan

2017, 26(2): 247-252. doi: 10.15953/j.1004-4140.2017.26.02.14

Abstract(590) PDF(6)

Abstract:
Objective: To analyze the diagnostic value of multi-slice CT in the diagnosis of trauma patients. Methods: A retrospective analysis was performed on 15 cases of emergency patients with critical disease after trauma, and the data of emergency plain and enhanced CT were retrospectively analyzed. Results: 15 cases of acute trauma patients, 8 cases of pelvic fractures(CT contrast-enhanced A. with arterial hemorrhage: 1 cases of left common iliac artery rupture, 5 cases with unilateral internal iliac artery branch bleeding, 2 cases of bilateral internal iliac artery branch bleeding; b. 2 cases with hepatic rupture and 3 cases with spleen rupture); small intestine and mesentery and multiple fracture 1 cases with rupture of liver and spleen; liver rupture in 1 cases; 4 cases of splenic rupture; left superior gluteal artery rupture in 1 cases. Enhanced CT can directly display the contrast extravasations and organ rupture injury changes. Conclusion: Multi slice spiral CT enhanced display with comparison of plain CT scan has important clinical application value of vascular rupture and organ hemorrhage location, the conditions of the hospital can be an active application.

Analysis of MSCT Diagnosis and Misdiagnosis of Early Central Type Lung Cancer

SHEN Chun-lin, WAN Zhe-jun, LIU Yue-jun, XU Xiao-hu

2017, 26(2): 253-258. doi: 10.15953/j.1004-4140.2017.26.02.15

Abstract(399) PDF(5)

Abstract:
Object: To investigate the MSCT signs, diagnosis and misdiagnosis causes of early central lung cancer in order to improve the MSCT diagnostic level of early central lung cancer. Methods: CT data of 29 cases of early central type lung cancer confirmed by pathology were analyzed and the main features, diagnosis and misdiagnosis factors of MSCT were analyzed. Results: CT diagnosis or diagnosis of central lung cancer in 24 cases, pneumonia in 1 case, bronchial dilatation with infection in 1 case, tuberculosis in 1 case, missed diagnosis in 2 cases, and analysis of the causes of misdiagnosis cases. In early stage, the main CT features of the central lung cancer include: the bronchial lumen, the thickening of the bronchial tube wall, the lumen of the stenosis, bronchial casts shadow, obstructive pneumonia and pulmonary stenosis, etc. Conclusion: Early central lung cancer with MSCT, multidimensional reconstruction and CI main signs to find the disease early and accurate diagnosis is of great significance, familiar with CT of bronchial anatomy structure, good read piece habits of observation, careful reconstruction is helpful to improve the diagnosis of early central lung cancer.

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2017 Vol. 26, No. 2