ISSN 1004-4140
CN 11-3017/P

2010 Vol. 19, No. 4

Display Method:
CT Theory
Automatic Method of Rotation Center Determination with Hough Transform and Thin Cylinder Phantom
WANG Xian-gang, ZHANG Chao-zong, GUO Zhi-ping
2010, 19(4): 1-6.
Rotation Center Determination is one of the basic problems in CT system integration.This paper proposed an automatic method to decide rotation center by Hough Transform with thin cylinder phantom.Hough Transform can provide position and radius of cylinder and also the difference of actual radius of cylinder,the radius of the cylinder,and the difference of the actual radius of the cylinder.With this difference,we can determine the rotation center of CT system.
Proof of Exact Computing Formula for Lambda Tomography
WANG Wei-dong, BAO Shang-lian
2010, 19(4): 7-10.
This paper re-proves the theorem for exact computing formula of lambda tomography in reference [6].The lambda tomography is a class of technology reconstructing from few scanning data,which can reduce the radiation dose of the scanned objects and improve the speed of image reconstruction.Reference [6] proved an exact reconstruction formula of lambda tomography in the case of fan beam scanning geometry.This paper provides an alternative simplified proof of the theorem in [6].
A Local Reconstruction Algorithm of CT Based on Improved Reconstruction Filter
LI Bao-lei, ZHANG Yao-jun
2010, 19(4): 11-17.
According to the requirement of practical engineering application,the image reconstruction based on truncated projection is one important problem in X-ray CT.The current local reconstruction algorithms are described and their advantages and disadvantages are analyzed.One local reconstruction algorithm based on improved reconstruction filter is proposed.Via the improvement of the filter,the energy of the filter function is centralized on the center position and its side band falls down quickly to make the filter function have local reconstruction feature.In addition,the improved filter,suppresses the low-frequency information and enhances high-frequency information,can enhance the imaging spatial resolution.While the proposed algorithm enlarges the noise of CT image more or less.The feasibility of the proposed algorithm is validated by the practical experiment data.
Study on Acceleration of Cone-beam CT Image Reconstruction Based on DSP
WANG Chao, LI Jian-xin, WANG Da-hui, YAN Bin, LI Lei
2010, 19(4): 19-26.
With the development of CT technology,reconstruction speed has become an important indicator of CT systems,and the research of acceleration image reconstruction has become a hotspot in CT.For the Harvard architecture,dedicated hardware multiplier and the extensive use of pipelining,etc.,DSP has been applied to acceleration image reconstruction.In this paper,the method of acceleration three-dimensional cone-beam CT image reconstruction using DSP is researched.Firstly,the situation that DSP is used in image reconstruction is introduced.Secondly,an acceleration CT image reconstruction technique based on DSP is presented though the decomposition of the typical three-dimensional reconstruction algorithm-FDK,combined with the characteristics of the hardware structure of DSP.The hardware architecture and soft pipelining are fully utilized with C optimization,assembler optimization and compiler optimization.Finally,the acceleration computing of CT image reconstruction is achieved with TMS320C6455 chip.The experimental results show that the method achieved higher speedup.
Study on Building Geomaterial Numerical Model Method Based on CT Image
MAO Ling-tao, BI Yu-jie, ZUO Jian-min, HAO Li-na, WANG Huan
2010, 19(4): 27-34.
Building numerical model based on actual mesostructure is a hot research field of rock-soil mechanics.According to the different inter structure,equivalence graph and edge vectorization methods are introduced.Taking the pore geomaterial made by ourselves and concrete CT images as examples,the steps of building model are shown.Analyses prove that it is easy to segment character areas when the image histogram has two or more peaks.When the image histogram has only one peak,top-hat mathematical morphology method can be used to enhance image,which make the segment easier.Equicalence circle or ellipse are placed for pore strucure in numerical model,while edge vectorization is applied to characterize the complicated structure.The results provide a method to build numerical model based on actual mesostructure.
A Novel Method of CT Reconstruction Filter Function Design
SHI Ben-yi, WANG Cheng, CHEN Si-hai, BI Kun
2010, 19(4): 35-43.
The design of filter function is very important in the CT reconstruction.In order to improve the image quality,a new method of filter function design was presented based on the FBP theory.Based on the simulated data of Shepp-Logan and the projection data of conch,the compared result of CT reconstruction using R-L filter function,S-L filter function and a new filter function based on the new design method was given.The reconstruction result of the new design filter function was the best in overall performance.In local areas,the density resolution had increased.So this paper provided a novel method for filter function designing in CT reconstruction.
Simulation Study on Coded Excitation in Rock Property Ultrasound Imaging
WU He-zhen, HE Tai-ming
2010, 19(4): 45-52.
The succeed application of the digital encoded technology in the radar,the medical aspects make it possible to use this technology in the seismic detection.In order to introduce the digital encoded technology to seismic detection,the simulation study on coded excitation in rock property imaging carried out.Firstly,we introduce the principles of coded ultrasound imaging and the characteristics on the coded technology.Secondly,through the excitation of Golay codes,ultrasound imaging of the rock property testing has been completed using Field Ⅱ package and compared the simulation result.The results proved that encoded technology is the effective method improving the image quality.The results can be used to guide the seismic detection in the field.
Industrical CT
Simulation Study of Positron Emission Tomography Based on GATE
XU Jing-hua, ZHOU Ming, LIU Zhen
2010, 19(4): 53-59.
To discuss utilizing the Geant4 Application for Tomographic Emission(GATE) software to simulate the imaging process of Positron Emission Tomography(PET),as well as the related image reconstruction.The configuration and calculation of script parameters for several important components in the GATE simulation are introduced,which includes the structure configuration of a PET scanner,the setting of the object's the spatial structure and activity distribution,as well as the determination of detector performance parameters for γ photon detections.The generation of sinogram data from photon counts and the following image reconstruction are also described.As an example,the imaging process of Inveon micro PET for small animals produced by Siemens is simulated and desirable images are obtained.
The Projection Ordering Scheme of Three-dimensional Cone-beam for ART
WU Kun, PAN Jin-xiao
2010, 19(4): 61-70.
The order of the applied projections in Algebraic Reconstruction Technique(ART) has a great effect on speed of convergence and accuracy in reconstructed image.In 3D cone-beam ART,some schemes of the sort of the projection sequence are compared in the paper.The schemes are listed below:Sequence Access(SAS),Multilevel(MLS),Prime Number Decomposition(PND),and Weighted Distance(WDS).The experiment results got by simulation experiment show that the speed of convergence on which reconstructed image by MLS,PND and WDS is more quick than by SAS,and the WDS is the best one in three sort schemes.
Medical CT
The Value of 64-slice CTA in the Etiological Diagnosis of Spontaneous Subarachnoid Hemorrhage
LIU Chao, ZOU Jian-hua, CHEN Lun-gang, CHEN Yi-jia
2010, 19(4): 71-78.
Objective:To investigate the value of CT angiography(CTA) in the etiological diagnosis of spontaneous subarachnoid hemorrhage(SAH) with 64-slice CT.Methods:from January to December 2009,97 patients with spontaneous subarachnoid hemorrhage underwent CTA with 64-slice CT,post-processing techniques such as volume rendering(VR),maximum intensity projection(MIP),curved planar reformation(CPR),multiplanar reformation(MPR) were used to show blood vessels with a clear cause.Results:CTA diagnosis of 12 cases of normal,one case of carotid cavernous fistula,nine cases of arterioven- ous malformation,75 cases of aneurysm,all patients were confirmed with digital subtraction angiography(DSA) and or surgery,12 normal cases diagnosed by DSA,64-slice CTA missed one case,but the overall sensitivity of 98.7 % and specificity of 100%.Conclusion:64 slice CT angiography is a simple,rapid,minim-ally invasive,safe and economical method in the diagnosis of the cause of spontaneous subarachn-oid hemorrhage with a high accuracy,it can be used as a preferred method in the early etiological diagnosis of spontaneous subarachnoid hemorrhage.
MSCT Diagnosis of Pedunculated Hepatocellular Carcinoma
ZHAO Lin, CHEN You-san, SUN Zhi-qiang, YANG Yu-heng, SONG Jia, SHEN Gui-ping, LIU Xin, TIAN Long-hai, CHEN Xin-jian
2010, 19(4): 79-84.
Objective:To invetigate the MSCT features of pedunculated hepatocellular carcinoma.Methods:12 cases of pedunculated hepatocellular carcinoma proved by angiography were collected,including 8 males and 4 female aged from 19 to 56 years old,the average age is 37.5 years old.All patients had underwented CT scan,enhance and three-dimensional reconstruction.To analysis of three-dimensional reconstruction of MSCT for diagnosis of pedunculated hepatocellular carcinoma.Result:In this group of 12 cases of pedunculated hepatocellular carcinoma,8 cases showed cirrhosis of the liver tumor is located beside the left lobe of lver in 6 cases,right lobe of liver adjacent to 5 cases,1 case next to the caudate lobe;5 cases with cystic mass in the main,7 cases with solid part of the main rare cystic;Arterial phase MSCTA showed 6 cases of blood from the right hepatic artery,4 cases of blood from the left hepatic artery,1 case from the right gastric artery,1 case from the stomach and duodenum artery.12 patients in this group were no portal vein tumor thrombus formation.Conclusion:Three-dimensional reconstruction of MSCT can show feeding arters of liver cancer,which has important diagnosis value of pedunculated hepatocellular carcinoma.
CT Diagnosis of Intraductal Papillary Mucinous Neoplasm of Pancreas
ZHAN Yong, XIANG Zi-yun, WANG Jing-bo, ZHU Yu-hui, YANG Xue
2010, 19(4): 85-90.
Objective:To evaluate the CT findings and diagnostic value of intraductal papillary mucinous neoplasms(IPMN) of pancreas.Methods:16 cases of IPMN proved by pathohistological evidence and examined with plain and enhanced CT scans were retrospectively analyzed with literature reviewed.Results:Of 16 cases of IPMN,three cases of main-duct type pancreatic IPMN demonstrated dilation of pancreatic main duct with nodule on the wall of the duct.Five cases of branch-duct type pancreatic IPMN showed solitary or multiplecystic lesion with septa or nodule in the duct.6 cases of mixed type pancreatic IPMN displayed dilation of pancreatic main duct combined with cystic lesion.Conclusion:The CT findings of pancreatic IPMN are of certain characteristics,which is helpful to diagnose the disease correctly.
CT-guided Biopsy of Thoracic Lesions Using 20-gauge Cutting Needle
CHEN Xiang-meng, LIU Xue-guo, LIANG Ming-zhu, WANG Guo-jie, ZHANG Li-jing, QIN Pei-xin, CHEN Kai, HE Yan-li, DING Xiang-lian, YI Xian-ping
2010, 19(4): 91-98.
Purpose:To evaluate the diagnostic value and complications of CT-guided biopsy of thoracic lesions using 20-gauge(20G) cutting needle.Materials and Methods:We retrospectively analyze the diagnostic outcome of 72 cases of CT-guided biopsy of thoracic lesions using 20G coaxial cutting needles:5 cases with mediastinal lesions,5 cases with plural lesions,other 62 cases with pulmonary lesions.Sensitivity,specificity,and diagnostic accuracy were calculated,complications and the relative factors were evaluated.Results:Biopsy diagnosis:58 cases were malignant,8 cases were benign,6 cases were non-specific.All cases were finally proved by surgical operation and clinical follow-up.The diagnostic accuracy was 95.8%(66/72).The diagnostic sensitivity of malignant lesions was 95.1%(58/61),specificity was 100%(11/11),no false-positive result was found.6 cases(8.3%) had complications.Pneumothorax occurred in 4 cases(5.5%),pulmonary alveolar hemorrhage occurred in 1 cases(1.4%),hemoptysis occurred in 1 cases(1.4%).Conclusions:CT-guided biopsy using 20G cutting needles is a useful technique for the diagnosis of thoracic lesion with high accuracy and low complications.
Multi-slice CT Urography Imaging in Children Congenital Kidney and Ureter Development Abnormal of Clinical Value
DAI Yan-zeng, ZHANG Qiao-quan, XIE Li-ping, LIU Zhong-hou
2010, 19(4): 99-110.
objective:To investigate the melamine milk powder incident by ultrasound screening for kidney and ureter due to unexplained expansion of water,by multi-slice CT urography after inspection found water reasons,come to imaging diagnosis conclusion.Methods:Ultrasound screening of urinary tract stones were not defected,but the kidney and ureter due to unexplained expansion of water,all cases were done by multi-slice CT urography in imaging diagnosis was confirmed by surgery in 15 cases.Results:The multi-slice CT urography imaging diagnosis of 60 cases of congenital kidney and ureter in children is mainly caused by renal dysplasia and the side of renal agenesis and ectopia.Analysis of CT performance and multi-slice CT urography on the diagnosis of urinary tract abnormalities was 98.3% acurafe(59/60) and superior to IVP and ultrasound(p<0.05).Conclusion:Ultrasound examination should be used as a screening tool for congenital urinary system,but multi-slice CT urography of congenital urinary system is an important inspection method.Multi-slice CT urography is rapid,noninvasive,high resolution and combined with a variety of image processing technique,can be intuitive,three-dimensional display the whole process of the urinary system is the diagnosis of urinary congenital abnormalities of the ideal method with high clinical value.
2010, 19(4): 110-119.