CT理论与应用研究

A Review of Dual Energy CT: Principles, Applications, and Future Outlook

Adam S. WANG, Scott S. HSIEH, Norbert J. PELC

2012, 21(3): 367-386.

Abstract(1288) PDF(24)

Abstract:
The contrast properties of computed tomography (CT) depend significantly on the X-ray energy spectrum used to measure the object. Conventional CT uses only a single energy spectrum and at times suffers from ambiguity so that two different materials can appear identical. Dual energy CT (DECT) uses two different energy spectra that can be used to remove this ambiguity. Although the basic concept of DECT is not new, its popularity has recently skyrocketed because of the availability of commercial implementations. We review the basic principles of DECT physics and estimation, as well as the technologies that have enabled DECT to enter modern clinical imaging. Applications of DECT abound, and we familiarize the reader with a selection of the most common clinical applications. Finally, we conclude by touching on two areas of current technical development: photon-counting detectors and synthetic CT.

3D Display System for Exploration Cardiovascular DSCT Volume

SONG Wei, DU A-an, YANG Xin, XUE Hai-hong, SUN Kun

2012, 21(3): 387-399.

Abstract(927) PDF(1)

Abstract:
In order to visualize and analyze the complicated intra-cardiac anatomy,this paper presents a 3D display system from cardiovascular Dual Source Computed Tomography(DSCT) data.In combination of virtual endoscopy(VE) and cross-sectional views for routine clinical inspection,it supplies two different modes to virtually navigate inside the intra-cardiac structures: automatic and interactive,respectively.For automatic mode,the part enhanced by the contrast agent is skeletonized based on 3D Euclidean distance to obtain the flythrough path.The raycasting algorithm is implemented using Euclidean distance to skip empty space to reduce the rendering computational consumption.For interactive mode,to improve the efficiency of diagnosis and fit cardiologists' style,the four-chamber plane that is essential for standard clinical examination can be automatically detected.Meanwhile,users can switch from VE navigation conveniently to an arbitrary cross-sectional view for comprehensive analysis.The Experiments demonstrate that our system can efficiently realize volume rendering with CUDA(Compute Unified Device Architecture) programming to investigate intra-cardiac structures intuitively and facilitate the assessment of heart disease accordingly.

An Automatic Image Sorting Algorithm for 4D CT Based on Spatial Continuity

LI Chen, LIU Jie

2012, 21(3): 401-411.

Abstract(1236) PDF(1)

Abstract:
4D CT imaging technology,which could track the movement of the tumor in the entire respiratory cycle and reduce motion artifacts effectively,has been widely used in radiation therapy for tumors.The current 4D CT methods require external surrogates of respiratory motion obtained from extra instrument.In the paper we propose a novel automatic 4D CT sorting algorithm that completes 4D imaging without these external surrogates.The first step of the algorithm is to collect the image data within a cine scan protocol.Beginning with the first couch position,images from the adjacent couch position are selected out according to spatial continuity.The process is continued until images from all couch positions are selected for the entire 3D volume is produced.The algorithm is verified by respiratory phantom data and clinical image data are used to verify the algorithm.The primary test results show that the 4D CT images created by our algorithms have eliminated the motion artifacts effectively and clearly demonstrated the movement of tumor and organ in the breath period.

The Application Effect of Geophysical Prospecting Method to the Evaluation of Liulin Uranium

SHI Jian-feng, SHI Jun-sheng

2012, 21(3): 413-422.

Abstract(921) PDF(1)

Abstract:
For further research geological structure and the position development situation of LiuLin uranium area,geophysical methods include radioactive geophysical prospecting and electrical prospecting were used successively.To interpret the data and proof results,analyses the relationship geophysical anomalies and the space distribution of uranium,has achieved the anticipated target.The results show that: high radiation,high polarization and have a certain rule of uranium and thorium,potassium radionuclide secondary halos abnormalities is uranium prospecting marks.

Geometrical Form of Fault Zones in the Crustal Interior in Xichang Region Determined by Seismic Travel-time Tomography

FAN Ji-chang, WANG Fu-yun, ZHANG Xian-kang, DUAN Yong-hong, ZHAO Jin-ren, ZHANG Cheng-ke, LIU Bao-feng, LIU Qi-yuan, HAI Yan

2012, 21(3): 423-432.

Abstract(1177) PDF(2)

Abstract:
The geometry of the fault and spatial relations between faults are the basis for studying the crustal deformation,dynamics,their surface response,and for modeling the relations between fault movement and strong earthquake.To fully understand the relation between strong earthquake and deep crustal faults,Anninghe fault,Zemuhe fault and Jinhe fault,we apply the algorithms on seismic ray tracing and travel-time modeling to first arrival Pg wave and reflection wave from the fault for Yanyuan-Xichang-Leibo high-resolution seismic profile,and the direct information on the velocity and fault from three faults mentioned above has been obtained.The results show that: Anninghe fault and Zemuhe fault incline towards east with dip of 32~35 degree,and their velocity structures present low velocity zone of tongue-like shape;those two faults extend downwards to the crystalline basement at large scale and control most strong earthquake activities in this region.Jinhe fault inclines towards east with dip of 30 degree,and extends downwards at least 5 km.

Application of X-ray 3D CT Technology on Electrocomponent Failure Analysis

LU Hao-tian, LU Xiao-qing, ZHANG Xiang-chun, CAI Liang-xu, WU Qiong, ZHANG Hui

2012, 21(3): 433-441.

Abstract(1050) PDF(1)

Abstract:
Through comparing the functional characteristics of X-ray,traditional CT and SAM,the advantage of X-ray 3D CT technology was analyzed.With the analysis of solder voids,micro switch and different package components,research on the application of 3D CT technology in electronic component failure analysis was conducted.In addition,according to the feature of X-ray 3D CT imaging,the prospect of this technology was discussed.

The Implementation of a Conveying System Based on Synchronous Belt Drive in CT Security Equipment

HUO Mei-chun, LI Hao, ZHANG Yan-ming, WU Jian-yi, MO Yang, CAO Qin-qin

2012, 21(3): 443-448.

Abstract(871) PDF(1)

Abstract:
Computed tomography security inspection equipment for luggage and package is aimed at spiral scan and spot scan test for luggage and package.The conveying system is an important part of the equipment.The operation stability and accuracy of the conveying system will affect the quality of scanning image and image acquisition of contraband.The need to research and develop a specific conveying system for computed tomography security equipment and several technical difficulties to be solved are described.A new type of conveying system with a built-in servo motor,a synchronous belt to drive,a controlled feed speed,a high positioning accuracy and the modular design method,which is designed to solve the difficulties mentioned above,is discussed briefly.The conveying system supports the integral design of the CT security inspection instrument well and ensures the smooth realization of the entire system function.

The Research on Test and Evaluation of CT Security Inspection Equipment for Civil Aviation

ZHAO Yue, CHEN Xi, NIU Yi-jie

2012, 21(3): 449-456.

Abstract(1263) PDF(7)

Abstract:
With the ever-changing domestic and international security situations and development of scientific technology,more and more X-ray Computed Tomography security inspection equipments are used in civil aviation.Therefore,it's practically crucial to develop the test and evaluation method for this kind of security inspection equipment.Based on the characteristics of civil aviation passenger's baggage checking,this paper analyzed and calculated the parameters of Computed Tomography security inspection equipment,and described the test methods and evaluation.Such efforts should be made to promote and expedite the development of security equipments for security check.

Application of 64 Multi-detector Helical CT in Evaluation of the Tibial Plateau Occult Fracture

LIU Hai-ping, ZHANG Li-li, WU Ge, MENG Hua-wei, CENG Qing-yu

2012, 21(3): 457-463.

Abstract(966) PDF(2)

Abstract:
Objective: To evaluate the diagnostic value of 64 multi-detector helical CT of the tibial plateau occult fracture.Methods: MDCT scans were performed in 21 patients who were suspected fracture of tibial plateau but negative(12 cases) or probable positive(9 cases) on X-ray film(including CR and DR).The data's was transmitted to ADW4.3 workstation,and reconstructed by MPR,MIP,VR and generally analyzed with original axial images.Results: MDCT 3D demonstrated Schatzker type Ⅰ 10 cases;type Ⅱ 4 cases;type Ⅲ 3 cases;Ⅳ 2 cases;type Ⅳ 1 case and type Ⅴ 1 case.Conclusion: 21 cases fracture of tibial plateau were demonstrated clearly by 64-MDCT,and it can reveal the location,types,level and complication of fracture change,it is reliable and accurate in evaluating occult fracture of tibial plateau,gradually become necessary modality examination in patients after trauma of knee joint and therefore should be applied to clinically suspicious cases.

The Application Value of Spiral CT in Psoas Lesions

DING Chang-qing, SUN Ying-ying, SHI Zhi-wei, XIE Guang-tong

2012, 21(3): 465-470.

Abstract(793) PDF(0)

Abstract:
Objective: To investigate the application value of spiral CT in psoas lesions.Methods: A retrospective analysis of spiral CT data of 110 cases of psoas lesions confirmed by surgical pathology or clinical.Results: Psoas hematoma in 37 cases(acute hematoma in 30 cases,chronic hematoma in 7 cases),the acute hematoma manifesting as psoas fascia thickening,enlargement volume,inhomogeneous high density,all with the transverse process fracture,follow-up CT showing the thin volume and the reduced density.In the chronic phase,the liquefied hematoma presenting watery density.The psoas involved by infection in 28 cases(tuberculosis in 21 cases,the other infections in 7 cases),CT showing the psoas muscle swelling,fuzzy contour,bands and effusion in the peritoneal fat clearance,follow-up CT could change due to the outcome of lesion,tuberculosis may be associated with the vertebral and accessories destruction;Psoas tumors in 45 cases,15 cases of them were direct invasion from abdominal malignant tumor,metastasis in 30 cases(the simple psoas metastasis in 3 cases,the spine metastasis simultaneously in 27 cases),CT showing an enlargement of the psoas and a significantly enhancement of the tumor.Conclusion: It is crucial significance for the diagnosis to understand the CT features of psoas lesions.

Optimizing Study of 64 Slices CT Examination Workflow with Lean Six Sigma

HAO Guang-yuan, CHEN Jun, WEI Cong-quan, XU Shi-li, WANG Li, LIU Wen-ting, KONG Que

2012, 21(3): 471-478.

Abstract(1069) PDF(0)

Abstract:
Objective: To study the process of 64-slices detectors CT examination in patients by the implement of Lean Six Sigma methods: In order to reduce the patients' invalid waiting time so as to raise the patient's flux.Methods Five-step method in Lean Six Sigma management system was performed and implemented.According to such segments as the time of registration,waiting for CT examination,CT examination,films printing,films collecting,CT image interpretation,taking diagnostic report,160 patients were randomly selected to analyze the times of each segment to find the key factor of resulting in extending the whole CT examination time.Refining methods to aim directly at the factors of resulting in the whole CT examination time were prolonged were proposed to improve the conventional CT examination process.And these methods were retained to be modified and optimized to increase the performed CT scan's patients in each segment.Then,another 160 patients were randomly selected to be compared with the fore 160 patients for the total time of CT examination after the refining methods were performed.Results: The average invalid waiting time of the patients were dropped from 88.50 min to 52.30 min with statistically difference(P<0.01).The Six Sigma value(Z value) was increased from —0.54 to 5.12.Conclusion: The implementing of Lean Six Sigma in the 64-slices CT examination process can shorten the patient's invalid waiting time significantly and improve the patient's flux of single 64-slices CT scanner in each work-day.

16-Slice CT Diagnostic Value in Adult Nontraumatic Abdominal Wall Hernia

DING Chang-qing, SUN Ying-ying, SHI Zhi-wei, WANG Wen-sheng, XIE Guang-tong

2012, 21(3): 479-484.

Abstract(721) PDF(0)

Abstract:
Objective: To investigate 16 layer spiral CT diagnosis value in adult non traumatic abdominal wall hernia.Methods: A retrospective analysis of 37 cases data of adult non traumatic abdominal wall hernia confirmed by operation or clinical follow-up with 16 slice spiral CT.Results: Abdominal wall incisional hernia in 13 cases,inguinal indirect hernia in 10 cases,lumbar hernia in 4 cases,spigelian hernia in 3 cases,abdominal wall stoma hernia in 3 cases,white line hernia in 2 cases,umbilical hernia in 2 cases.Hernia sac diameter less than 5cm in 23 cases,6~10cm in 11 cases,greater than 10cm in 3 cases.The hernial contents are the greater omentum,bowel and adjacent organs.Conclusion: It is a better diagnosis method with multi-layer CT and post-processing for non traumatic abdominal wall hernia,which could provide a reliable basis for further treatment.

The Application Value of Nursing Intervention in the Coronary Atery CTA Check

ZHAO Yun, FU Chuan-ming, CHEN Lun-gang, XU Lin, GONG Xiao-hong, CAI Ke-tao, WANG Kai-hua

2012, 21(3): 485-491.

Abstract(852) PDF(0)

Abstract:
Objective: To study the application value of nursing intervention in the coronary artery MSCTA check.Materials and Methods: 80 patients who were ready to received cornary artery MSCTA examinations,were randomly divided into control group(n=40) and the nursing intervention groups(n=40).Care in the control group only to oral metoprololg decreas heart rate,no other intervention measures,Care in the nursing intervention group,to take a series of nursing intervention measures,effectively reduce the heart rate(HR<70 bpm) and control of heart rate stability.Results: The control group: success in 25 cases,failure in 15 cases,the success rate is 62.50%(25/40),of which image quality was excellent in 13 cases,good in 5 cases,basically meet the needs of diagnosis in 7 cases,the excellent and good rate was 72%(18/25);the nursing intervention group: success in 38 cases,failure in 2 cases,the success rate is 95%(38/40),of which the image quality was excellent in 30 cases,good in 5 cases,basically meet the needs of diagnosis in 3 cases,the excellent and good rate was 92.11%(35/38).The success rate in two groups was significant difference(P<0.01),the image of good quality rate also had statistical significance(P<0.05).Conclusion: It can significantly improve the success rate;ensure the image quality and diagnostic excellent rate to take the nursing intervention before coronary CTA check.

The Study of CT Dynamic Changes and Clinical Comparison in Neonatal Hypoxic-ischemic Encephalopathy Treated by Hyperbaric Oxygen

ZHANG Hai-bo, FU Chuan-ming, ZHAO Yun, CHEN Lun-gang, XU Lin, WANG Kai-hua

2012, 21(3): 493-499.

Abstract(942) PDF(0)

Abstract:
Objective: For neonatal hypoxic ischemic encephalopathy(HIE) of hyperbaric oxygen(HBO) therapy,brain CT showed dynamic changes and clinical effect comparison.Methods: A retrospective analysis of 85 cases of HIE neonatal clinical data and CT before treatment,according to CT findings of the brain is divided into light,medium,heavy type 3,HBO and conventional adjuvant therapy in 1,2,3 respectively after a course of brain CT review,on 3 type CT prognosis and clinical comparison analysis.Results: 85 cases of children with HBO before treatment CT examination,in which mild HIE in 20 cases,moderate HIE in 42 cases,severe HIE complicated with cerebral hemorrhage of 23 cases;HBO and conventional adjuvant treatment after 1 courses of treatment review of CT in 9 cases,mild HIE negative,symptoms returned to normal,and 11 cases of mild and moderate,severe HIE before treatment with CT examination results slightly better,alleviation of clinical symptoms,CT total turnover rate was 11.12%(9/85);HBO and conventional adjuvant treatment after 2 courses of treatment review of CT,mild in 20 patients with HIE all negative,moderate HIE in 30 patients were negative,CT turnover rate of 58.82%(50/85),of which 12 cases of moderate and severe in 23 patients before treatment with CT examination results improved significantly,the clinical symptoms were also significantly reduced;HBO and conventional adjuvant treatment after 3 courses of treatment review of CT,mild and moderate HIE all negative,severe HIE in 12 patients were negative,CT turnover rate of 87.06%(74/85),in which severe HIE with intracerebral hemorrhage in 11 cases,CT shows hemorrhage absorbed,leaving encephalomalacia,clinical symptoms improved markedly.Conclusion: Application of CT display neonatal brain dynamic change on HBO treatment HIE have important guiding value.

An Analysis of the CT Features of Ovarian Thecoma

ZHONG Wen-xin, SHEN Bi-xian, SUN Zhi-wei, MING Jian-zhong, ZENG Zhi-bin, CHU Er-wei

2012, 21(3): 501-506.

Abstract(1021) PDF(1)

Abstract:
Objective: To analyze CT features of ovarian thecoma to enhance the understanding and the correct diagnosis of that disease.Methods: A retrospective analysis of clinical data and CT manifestations is performed in 12 cases of ovarian thecoma sufferers which have been confirmed through surgery and pathology.CT manifestations are analyzed in terms of the location,size,shape and boundary,plain scan density and intensity extent,whether or not focus of infection having cystic change and ascites.The characteristic of density is subject to myometrium for reference.Results: A total of 12 patients ranging from 23 to 66 years old with a mean age of 38 are enrolled in the clinical study.Of the 12 patients,two suffer from amalgamative uterine myoma,one suffer from amalgamative uterine gland muscle disease,one suffer from amalgamative cervical carcinoma.The tumors of the 12 cases are all unilateral,the shape of most tumors are predominantly round or orbicular-ovate.The small tumors are 1.5cm×2.0cm and the big ones are 5.5cm×7.0cm,average 2.8cm×3.0cm.CT plain scan demonstrates the solid mass in seven cases,cystic-solid mass in four cases,and cystic mass in one case.No ascites is observed in eight cases and mininal ascites in four cases.CT enhancement showed the solid part of tumor with unobvious enhancement at the arterial phase,and inhomogeneous mild enhancement is chief manifestation at the equilibrium phase.The enhancement of cystic part is not observed.Conclusion: The benign morphological characteristic of ovarian thecoma on CT,especially the mild contrast enhancement of its slight blood supply is conducive to the diagnosis and differential diagnosis of the tumor.

The Imaging Diagnosis of Avulsion Fracture of Tibial Tuberosity in Adolescents

HUANG Yu-jian, FANG Ting-song, ZENG Xue-wei, HE Wei-hong

2012, 21(3): 507-513.

Abstract(950) PDF(1)

Abstract:
Objective: To investigate the diagnostic value of X-ray,CT and MRI in acute avulsion fracture of tibial tuberosity in adolescents.Method: 6 cases(all male) of acute avulsion fracture of tibial tuberosity in adolescents confirmed by operation were analyzed retrospectively.Of them,2 cases and 4 cases were right side and left side,respectively.5 cases were caused by sport injury and 1 case was tumble injury.6 cases all received X-ray examination,2 cases underwent plain CT scans and 3 cases underwent conventional MRI scans.Results: According to Ogden's classification,the case of type ⅠB,ⅡA,ⅡB,ⅢA,ⅢB were 1,1,2,1,1 respectively on X-ray film.The sign of patella on the shift was found in all cases.CT scanning showed displacement of bone fragmenets and patella on the shift in 2 cases of type ⅡB,and 1 case was complicated with old fracture of patella.3 cases were complicated with patellar tendon ruptures.In 1 case of type ⅡB complicated with patellar tendon ruptures,CT and MRI showed that patellar tendon was swollen and twisted,and was high signal intensity on T1WI and T2WI.Conclusion: X-ray was the first choice for imaging diagnosis in acute avulsion fracture of tibial tuberosity and CT is helpful for the fracture classification.MRI has an important value in diagnosis and guiding treatment when suspected that complicated with soft tissue injuries,such as patellar tendon,meniscus tear and so on.

Low-dose CT Coronary Angiography with Status Quo of Tube Current and Voltage Parameters Optimization

LI Ruo-mei, WANG Si-wei, JIN Dan-dan

2012, 21(3): 515-520.

Abstract(1225) PDF(0)

Abstract:
With the rapid development of the 64-row multi-slice spiral CT(MSCT) and dual-source CT(DSCT),CT coronary angiography(CTCA) for its non-invasive,convenient,low-risk and low-cost superiority in clinicalhas has been more widely used.But more complex cardiovascular imaging,often accompanied by higher radiation doses,which greatly increases the chance of suffering from malignant tumors.In recent years,CTCA radiation problem has been the concern of many scholars,the study of how low-dose CTCA done a lot of tube current and tube voltage regulation plays an important role in the CT low-dose coronary angiography,this paper reviews the current overall condition of the tube current and tube voltage parameter optimization applications,and that under the premise of ensuring the CTCA image quality for normal body mass index,heart rate and stable coronary artery calcification score in patients less than 100 AU,the use of lower tube voltage scan significantly reduce the radiation dose,if more combined ECG modulation current exposure technology will further reduce the radiation dose.However,higher obesity,weight,cardiac arrhythmia and calcification do not apply to low-dose CTCA check.

CT Diagnosis of Tracheobronchial Tuber-culosis in Aged Patients

ZHOU Xiao-yong, DONG Yun-xu, XIE Die-lai, YANG Hong-zhi, LAN Yong

2012, 21(3): 521-526.

Abstract(747) PDF(0)

Abstract:
Objective: To study the CT features and increase the diagnostic capability in aged patients with tracheobronchial tuberculosis(tTB).Methods: Forty-six aged patients with tTB underwent CT were reviewed retrospectively.Among which,15cases were confirmed by biopsy,5 cases were confirmed by bacteriology and 26 cases were confirmed by clinical follow up findings.Results: (1) There were 98 lesions in 46 cases,40 of 98 lesons were found in upper lobes of the bronchi(40.8%).69.6% of the cases had multiple involvement of 2 or more bronchi.(2) To demonstrate thickening of the bronchial wall or intraluminal tubercle and irregular or smooth stenosis or obstruction were the main direct signs of tTB.(3) The indirect signs of tTB were lungparenchymal TB,collapsed and(or) consolidated lung segment or lobe and enlarged hilar or mediastinal lymph nodes.Conclusions: CT is a valuable diagnostic procedure to reveal tTB.

The Imaging Analysis of Warthin Tumor of Parotid Gland

DUAN Fu-hong, QIU Shi-jun, JIANG Jian-wei

2012, 21(3): 527-533.

Abstract(844) PDF(0)

Abstract:
Objective: To investigate the findings of the CT and MRI of the warthin tumor of parotid gland,in order to improve its knowledge.Methods: The CT and MRI findings of 37 patients(32 males and 5 female,the age ranged from 27~80 years with average of 59 years) proved pathologically were retrospectively analyzed.30 cases had history of smoking(81%).Results: 56 lesions were found among 37 cases,with unilateral single tumors in 28 cases(28 lesions),unilateral multiple lesions in 4 cases(12 lesions),and bilateral multiple lesions in 5 cases(16 lesions).The maximal diameter of the lesions ranged between 0.5cm and 4.8cm.The lesions were round or oval,and well-demarcated soft tissue mass.The parenchyma of the tumors appeared as homogeneous or heterogeneous density or signal intensity.The parenchyma of the lesions demonstrated early significant enhancement on postcontrast CT,and non-uniform enhancement on postcontrast MRI scans.Conclusion: There are some characteristic clinical and CT and MRI features in the warthin tumor,its diagnostic accurate rate can be improved combined with the patient's age,gender and the long duration of clinical symptoms.

The Value of 256iCT Angiography in Lower Extremity Arteriosclerotic Occlusive Disease

SUN Xiao-li, WANG Ren-gui, ZHANG Fu-xian, YANG Lei, LI Hai-lei, DUAN Yong-li, ZHAO Jun, FU Yan

2012, 21(3): 535-541.

Abstract(1008) PDF(0)

Abstract:
Objective: To assess the clinical value of 256i CT angiography in the arteriosclerotic occlusive disease(ASO) of lower extremity.Methods: A total of 119 patients with symptomatic arteriosclerotic occlusive disease of lower extremity underwent 256i CT angiography.The scan ranged from the celiac to thenar artery.Original axial images were transferred to EBW workstation and 3D reconstruction images were performed.75 patients underwent digital subtraction angiography(DSA) between 0 and 14 days after CT angiography.The manifestations of 256i CT angiography were compared with those of DSA.Results: Of 1575 segments of arteries,1505 were displayed on both DSA and CTA.DSA images as the gold standard,the sensitivity,specificity and accuracy of 256i CTA were 100.0%,98.8%,99.7% in displaying the segments occluded and 99.3%,97.8%,98.2% in detecting the segments that had more than moderate stenosis.Therefore,there was excellent agreement between 256i CT angiographic and DSA findings in the assessment of ASO(k=0.945).Of 975 segments,905 were found atherosclerotic plaques,12 were simple mural thrombus.Conclusion: The diagnostic performance of 256i CT angiography is excellent in patients with clinical symptoms of the arteriosclerotic occlusive disease of lower extremity.The results can be used to effectively guide therapeutic decision making in these patients.

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2012 Vol. 21, No. 3