CT理论与应用研究

Value of Advanced Virtual Monoenergetic Images in Evaluating Early Gastric Cancer

SHI Cen, ZHANG Huan, YAN Jing, LIU Huan-huan, PAN Zi-lai, YAN Fu-hua

2014, 23(4): 535-540.

Abstract(571) PDF(1)

Abstract:
Objective: To evaluate the impact of advanced monoenergetic dual-energy computed tomography(DECT) datasets on detection rate and CNR of early gastric cancer(EGC). Method: Total of 29 cases of EGC who underwent two phases DECT scan were retrospectively enrolled in this study. CT findings were compared with surgical and histopathologic results. Advanced monoenergetic images(AMEIs) at 40 keV, 60 keV and 80 keV were calculated from the 100 and Sn 140 kV DE image data respectively using a monoenergetic software application(Dual energy Mono+, syngo IPIPE,Siemens). Differences in detection rates of EGC and CNR numbers were compared between different AMEIs and conventionally reconstructed polyenergetic images(PEIs) at 120 kVp. Results: AMEIs at 40 keV showed the highest detection rate(86.21%) for EGC which showed no significant difference with PEIs(P = 0.062). AMEIs at 40 keV revealed statistical higher CNR-AP and CNR-PP compared to other AMEIs and PEIs(all P〈 0.05). Conclusion: Virtual 40 keV image datasets of advanced image-based calculated monoenergetic significantly increase the CNR of early gastric cancer which was helpful to detect EGCs.

Study on the Value of Dual Source CT Assessment of Smoking and Coronary Plaque Correlation

ZHAO Yue, SHEN Bi-xian, TAN Si-ping, YANG Chun-yu, CHEN Sheng-ji, HUANG An-rong

2014, 23(4): 541-550.

Abstract(579) PDF(1)

Abstract:
Objective: To investigate the correlation between smoking and coronary atherosclerotic plaque in DSCT angiography. Methods: The patients underwent DSCT coronary angiography, based on questionnaire packet basis, were divided into smoking group and non-smoking group first, then to eliminate high risk family history or diabetes, hypertension, hyperlipidemia and other factors, the rest of 200 cases of smoking group and 200 cases of non-smoking group were used for the experiment. Two groups were observed and compared the incidence rate of plaque, distribution characteristics and types. Results: The incidence rate of 3 coronary artery vascular lesions is 23.0% in smoking group and 7.0% in non smoking group; Incidence rate of diffuse lesions is 46.0% in smoking group, 14.5% in non smoking group, The difference between the two groups were statistically significant(P〈0.05). Comparison of the degree of vascular stenosis: Severe stenosis was 27.5% and occlusion was 6.7% in smoking group; those were 17.1% and 3.7% respectively in non smoking. Plaque types: occurrence rate of mixed plaque is 44.7% in smoking group and 21.9% in non smoking group. The incidence of non calcified plaque was 38.7% in smoking group, 67.9% in non-smoking group, the difference between the two groups were statistically significant(P〈0.05). The Logistic fitting multivariate regression models adjusted for age, sex and body mass index, smoking is an independent risk factor for mixed plaque. Mixed plaque was increased with the smoking index increasing through statistical analysis. Conclusion: DSCTCA can evaluate difference of coronary atherosclerotic plaque accurately between smokers and no-smokers. Incidence rate of mixed plaque in smokers is higher than no-smokers and having more risk prone to cardiovascular events.

CT Reconstruction from Few Views Based on Extrapolation in Frequency Domain

TONG Li, JIN Zhao, YAN Bin, LI Lei, ZHANG Han-ming

2014, 23(4): 551-560.

Abstract(592) PDF(2)

Abstract:
In CT reconstruction, challenge of few-view projections is always the focus and difficulty. At present, the method based on spatial iterative reconstruction is primary solution. However, due to high computational complexity of projection and back projection, spatial iterative reconstruction has some problems, such as time-consuming, great demand for hardware resources and other issues. In this paper, a CT reconstruction algorithm which is named INNG-TV based on extrapolation in frequency is proposed to improve the performance. We first convert data, which is sampled from parallel beam, into frequency-domain by Fourier transform and spline interpolation. In the following process of iteration, the known data of projection in Fourier space keep constant, whereas the unknown data are estimated by INNG extrapolation. At the same time, prior knowledge and constrained optimization, such as non-negativity constraint and minimum total variation, are introduced to image reconstruction in image space.

On Implementation and Stability Analysis of Two Types of Finite Hilbert Transforms Used in Backprojection Filtration Algorithms

QIAO Zhi-wei

2014, 23(4): 561-568.

Abstract(577) PDF(6)

Abstract:
Backprojection filtration(BPF) algorithms are important analytical reconstruction algorithms in Computed Tomography(CT), Magnetic Resonance Imaging(MRI) and Electron Paramagnetic Resonance Imaging(EPRI). An important step in the BPF algorithm is the finite Hilbert transform(FHT), which allows recovery of a compactly supported function from its inverse Hilbert transform using only a finite interval. Two simple and practical implementation methods were proposed to serve for CT and EPRI, respectively. Numerical experiments were made on three classical functions to verify the two implementation methods. The boundary stability analysis was given by numerical experiments on a parabola function. The results show that the two methods can get enough exact results using an appropriate interval bigger than the supporting interval of the compactly supported function and that the method not including definite integration is not stable and is sensitive to the change of the interval. However the method including definite integration is very stable and can get an exact result just using a small interval that is a little bigger than the supporting interval. The method including definite integration is fit for CT and the method not including definite integration is fit for MRI and EPRI.

The MRS Response of 3D Model in Uniformity Medium

WANG Peng

2014, 23(4): 569-578.

Abstract(605) PDF(1)

Abstract:
MRS forward calculation of 3D water-contained medium involves two difficulties. First is to calculate expression of exciting field, which is an integration including two Bessel functions' product. The integration is divided into two integral intervals. In the first interval, Hankel expression of Bessel functions and the latter asymptotic properties of large volume are used, the double Bessel integration is converted into Fourier sine(cosine) transformations and fast calculation to the transformations is adopted to finish the integration in this interval. Traditional calculation method can achieve high accuracy in the second interval. The second difficulty is the space discretization of the 3D water-contained medium. Discretization methods in both cylindrical and rectangular coordinates system are introduced. The cubic grids in rectangular coordinates system can construct 3D water-contained bodies of any shape. Based on what mentioned above, forward calculations are done for several common 3D water-contained bodies. By analyzing the magnitude responses, the following disciplines were found:(1) All the magnitude response curves were similar to responses of horizontal layered medium;(2) The pulse moment corresponding to the maximum of the magnitude increased as the model depth increased;(3) For bodies containing the same quantity of water, the bigger the scale was, the larger the maximum of the magnitude was;(4) If the scale of the model is too small, it cannot be detected by current instruments;(5) The 3D pattern of the water-contained body cannot be defined if the signal is received by the same loop that excites the field.

Method and Experiments on Slice Reconstruction of Plate-like Component Based on X-ray Laminography

CHEN Zhong, LIANG Jia-hui, ZHANG Xian-min

2014, 23(4): 579-589.

Abstract(643) PDF(3)

Abstract:
In order to realize slice reconstruction and defect detection for plate-like component, an X-ray slice reconstruction system is established and its imaging method, imaging precision and reconstruction algorithm are investigated. First, the method of acquiring multiple X-ray images in special way and the theory of slice reconstruction based on laminography are presented. Reconstruction precision is analyzed and mechanical errors of the system are calibrated. Then the section of a shape-known workpiece is reconstructed according to the algorithm and calibration result. Finally, based on the experiment result, simulation is carried out and the reconstruction algorithm is improved. Experimental results indicate that, reducing the step angle of the detector to 0.5° and the use of S-L filter can reduce artifacts and improve the contrast of the profile. The method is able to reconstruct the information within the maximum incidence angle of X-ray. The real section image can be reconstructed if the incidence angle is large enough and the detection is appropriately rotated.

Small Airway Parameters of Chronic Obstructive Pulmonary Disease: Correlation between Quantitative CT and Pulmonary Functional Tests

XIA Ting-ting, GUAN Yu-bao, LI Jing-xu, WAN Qi, ZHOU Jia-xuan, LI Hong, SUN Shen-shen, KANG Yan

2014, 23(4): 591-599.

Abstract(599) PDF(1)

Abstract:
Objective: To evaluate the correlation between COPD quantitative CT pulmonary function parameters and PFT parameters. Methods: 28 cases of COPD patients, using the maximal inspiratory and maximum expiratory phase spiral CT scanning to analysis the correlation between quantitative CT parameters and pulmonary function test(PFT) parameters. Results: The correlation between COPD quantitative CT pulmonary function parameters of inspiratory phase average lung density, expiratory phase average lung density, inspiratory phase emphysema volume, expiratory phase emphysema volume, inspiratory phase emphysema pixel index, expiratory phase emphysema pixel index and pulmonary function of FEV1/FVC is best(r value respectively 0.44, 0.64, 0.50,0.66, 0.57, 0.64, P〈0.01). The correlation between maximum expiratory phase lung volume and lung function FEV1%(P) is best(r = 0.48, P〈0.01). The correlation between expiratory phase average lung density and lung function PEF(% P) is best(r = 0.40, P〈0.05). The correlation between maximum expiratory phase lung volume, expiratory phase average lung volume density, expiratory phase emphysema and pulmonary function best FEF25% FVC%(P) is best(r value respectively 0.40, 0.44, 0.44, P〈0.05). The correlation between expiratory phase average lung density, expiratory phase emphysema pixel index and pulmonary function MMEF is best(r value respectively-0.57, 0.50, P〈0.01). Conclusion: The quantitative parameters with maximal inspiratory phase and maximum expiratory phase helical CT scanning have a correlation with small airway PFT parameters, and expiratory phase is better than that of inspiratory phase.

Study of CT and MRI Diagnosis for the Pancreatic Lipomas

LI Xiao-qiang, JIN Er-hu, ZHANG Bin-bin, ZHENG Xin

2014, 23(4): 601-610.

Abstract(564) PDF(2)

Abstract:
Objective: The purpose of this study was to investigate the value of CT and MRI in diagnosing pancreatic lipomas. Materials and Methods: A retrospective study was carried out in 9 patients with pancreatic lipomas. CT scanner was Lightspeed multi-slice device, MRI system was Signa Excite HD 3.0T superconducting unit. The patients included four male and five female, their ages ranged from 35 to 75 years old, mean 51 years old. Two experienced doctors analyzed CT and MRI findings of the lipomas, including morphology, density and enhancing appearance on CT(n = 7), as well as MR signal intensity in various pulse sequence and enhancing appearance in T1 WI following administration of Gd-DTPA on MRI(n = 2). Results: The size of the lipomas in the nine cases ranged from 0.7 cm × 0.7 cm to 3.37 cm × 4.2 cm, mean size was 1.57 cm × 2.3 cm in the axial imaging plane. The lesions located in the pancreatic head in 5, pancreatic body in 3, pancreatic tail in 1 case, and they appeared as round shape in 2, oval shape in 5 and irregularity in 2 cases. CT revealed well-circumscribed masseswith fatty density in the pancreas, the measured CT value was between-74 Hu and-108 Hu, mean value was-91 Hu ± 3.01 Hu. Obvious enhancement was not observed on post-contrast CT following iodine contrast administration, the CT value was between-66 Hu and-98 Hu, mean value was-87 Hu ± 2.15 Hu, a slight rise was noted somehow by comparing with the pre-contrast CT scans. No statistically significant difference was found between mean CT value of pre- and post-contrast CT scan(P ＞ 0.05). A few scattered shadows indicating vessels and/or septa may be seen within larger lipomas. On MRI examinations, the lipomas showed high signal intensity on conventional T1 WI and T2 WI, but low signal intensity on fat-suppressed T1 WI and T2 WI, the alterations of the MR signal intensity are consistent with those of the fatty tissue around the pancreas. Conclusion: CT and MRI examinations were definitely diagnostic for lipomas of the pancreas.

Clinical Application and Study of CT Colonography in the Evaluation of Colorectal Cancer

BAI Zhi-gang, YANG Xiao-guang, ZHAO Lei, ZHAO Sheng, LIU Ai-shi

2014, 23(4): 611-619.

Abstract(605) PDF(3)

Abstract:
Objective: To evaluate the accuracy of the staging of the colorectal cancer, T, N by describing the evaluation of contrast-enhanced CTC, comparing the clinical pathological staging and clarify its clinical application value. Methods: In the study, 40 patients are selected, contracting non metastatic colorectal cancer, who were performed the scan of contrast-enhanced CTC, the tube voltage is 120 kV and the tube current is 300 mA. Evaluate the clinical staging, make comparison with the pathological staging, calculate the coincidence of T and N staging and conduct consistency test, only to draw a conclusion that there is statistical significance(P〈0.05). Results: The coincidence rate of T staging is 77.5%, which is favorable(k = 0.665, P = 0.000), and the coincidence rate of N staging is 82.5%, which is more favorable,(k = 0.734, P = 0.000), and the total coincidence rate is 67.5%. Conclusion: The contrast-enhanced CTC can be applied in the evolution of colorectal cancer before surgery, especially can help the clinical staging accurately, and have some important clinical values in determining therapeutic methods and evaluating the prognosis of the patients.

The Value of Multislice CT Enterography in Diagnosis of Gastrointestinal Bleeding Diseases

YU Yang, JIANG Tao, WANG Yan, LIU Jian, TANG Hong-bin, YANG Shu-lan, ZHANG Hong-pei, LI Min, LIANG Lu

2014, 23(4): 621-630.

Abstract(530) PDF(3)

Abstract:
Objective: To evaluate the diagnostic value of multislice CT enterography for gastrointestinal bleeding diseases. Methods: 16 patients with clinically suspected gastrointestinal bleeding diseases were all examined using multislice CT enterography after bowel preparation. The patients were initially performed with 0.62 mm slice thickness plain scans and a bolus-tracking software and then three phase enhanced scan using multi-modal reorganization such as multiplanar reconstruction, maximum intensity projection, and volume rendering. Results were compared with those from a reference standard(surgery or endoscopy) and clinical follow-up. Results: In 16 clinically suspected cases of gastrointestinal bleeding disorders, multislice CT enterography and final diagnosis findings were in agreement in 8 cases. Sites of hemorrhage depicted by multislice CT enterography were as follows: 3 cases of jejunal hemorrhage, 2 cases of ileal hemorrhage, 1 case of ileocecal hemorrhage, 1 case of ascending colon hemorrhage, 1 case of internal hemorrhoid. One of 8 patients with positive multislice CT enterography results had an active bleeding. The reason of the hemorrhagic lesions was diverticulitis in 1 cases(confirmed at endoscopy), gastrointestinal stromal tumor in 1 cases(confirmed at surgery), lymphoma in 1 cases(confirmed at surgery), internal hemorrhoid in 1 case. In one case, multislice CT enterography and final diagnosis results were both positive but were not in agreement on the bleeding source. In one case, both mulitislice CT enterography and final diagnosis findings were negative. The results of mulitislice CT enterography were negative in six of 16 patients with positive findings of final diagnosis. Conclusion: Mulitislice CT enterography with relative reconstruction techniques has high value for detecting the site of hemorrhage and detecting the cause of gastrointestinal bleeding.

The Imaging Diagnosis of Traumatic Diaphragm Rupture

LUO Qing-hua, JIANG Jun-jun, FU Chuan-ming

2014, 23(4): 631-636.

Abstract(631) PDF(3)

Abstract:
Objective: To analyze imaging manifestation of traumatic diaphragm rupture, and provide effective imaging diagnostic basis for clinical surgery. Methods: The imaging findings of 15 patients with diaphragmatic rupture and surgical treatment from January 2011 to January 2013 were retrospectively reviewed. Results: The results of chest plain film and abdominal spiral CT of 15 patients clearly showed the location of the diaphragm rupture, the size of fracture, the formation of diaphragmatic hernia and the contents of hernia sac, among of results, the CT examination could clearly show the characteristic signs of diaphragmatic muscle interruption and contracture. Conclusion: Spiral CT performance of diaphragm rupture has characteristic, can provide effective basis for clinical surgery in combination with plain radiographs, and has a high diagnostic value in diaphragm rupture.

Imaging Findings and Diagnosis of Intradiploic Meningioma

WU Lei, CHEN Wen, GUO Juan, LIU Chao, CHEN Yi-jia

2014, 23(4): 637-642.

Abstract(735) PDF(1)

Abstract:
Objective: To assess the imaging finding of CT and MRI in intradiploic meningioma of skull. Methods: The clinical symptoms, pathological type and imaging finding of two cases were analyzed. Results: One of the intradiploic meningioma was located in the frontal temporal bone and the pathological type was clear cell meningioma. Its imaging finding of CT showed osteogenic destruction and the skull was thicken, edge is coarse. Another was located in parietal bone and the pathological type was Epithelial type. Its imageology was lytic bone destruction and T1 WI showed low signal or equisignal intensity, T2 WI was equisignal intensity. The signal of enhance scan improved significantly. Conclusion: CT and MRI can play an important role in diagnosing intradiploic meningioma. The size and surroundings of tumor can show by them accurately.

CT Imaging Characterization of Central Airway Primary Tumors

WANG Rui, CENG Qing-yu, ZU De-gui

2014, 23(4): 643-654.

Abstract(550) PDF(3)

Abstract:
Objective: To study the CT characterize of central airway tumors, improve the CT diagnosis of the disease. Methods: Review of basic clinical data and CT findings of 189 cases of the central airway pathological confirmed primary tumor patients, Analyses include: sex, age, growth site, tumor size, shape, density, edge, degree of enhancement, mediastinal lymph node and lung conditions. Results: male: 138, female: 51; age among 3 to 84(average age 56.3 ± 17.7), 165 cases is malignant, 24 is benign. The tumor diameter 3-67 mm, average(25 ± 18.6) mm. Mass in 73 cases of trachea, and 8 cases in carina, left main bronchus in 37 cases, right main bronchus in 28 cases, 12 cases of middle bronchus. The mass was found intracanalicular type in 35 cases, walltype in 29 cases, extraluminal in 6 cases, 88 cases of mixed type. lesion in 40 cases of smooth surface, non smooth in 118 cases, 138 cases of wide basal, narrow base in 20 cases. 37 cases of tumor necrosis, 3 cases of tumor with calcification; 47 cases of mediastinal and hilar lymph nodes, 12 cases with lung metastasis, 8 cases with pleural effusion, 75 cases with pulmonary atelectasis and obstructive pneumo. Conclusion: Different types of central airway tumors have certain features in CT images.

Correlation of CTCA Stenosis Associated with Regional Myocardial Dysfunction and Major Adverse Cardiac Events

CHEN Yi-jia, WANG Wei-min, LI Fu-yan, PEI Zhi-jun

2014, 23(4): 655-661.

Abstract(552) PDF(1)

Abstract:
Objectives: To determine the prognostic value of coronary stenosis associated with regional ventricular motion abnormality by cardiac CT for predicting MACE(Major Adverse Cardiac Events, MACE) in patients with acute chest pain. Methods: 294 patients with acute chest pain were prospectively studied with a follow-up of 2 year for MACE, CT was assessed for the presence of plaque, stenosis(≥ 50% luminal narrowing), and RWMA(Left Ventricular Regional Wall Motion Abnormalities, RWMA). Kaplan-Meier method and COX risk models were made to evaluate the correlation between coronary artery stenosis(≥ 50%), left ventricular dysfunction and MACE. Results: MACE rate of patients with stenosis was 14 fold of those without. There was evident difference of MACE rate between patients with RWMA positive and those negative. The rate of MACE in patients without evident stenosis(＜ 50%) was 0.9%(RWMA negative) and 12.5%(RWMA positive), and 8.1%(RWMA negative) and 39.4%(RWMA positive) in those with stenosis(≥ 50). Conclusion: Besides providing coronary anatomical and functional information, CTCA can also predict the occurrence of MACE, with good clinical prognosis value in patients with acute chest pain.

The Classification Diagnosis of CT and its Imaging Features in Infantile Hepatic Hemangioendothelioma

WU Meng-nan, PENG Zhen-peng, HU Xiao-shu, DONG Zhi, LUO Yan-ji, FENG Shi-ting, YANG Xu-feng

2014, 23(4): 663-668.

Abstract(545) PDF(1)

Abstract:
Objective: to summarize the image features of Infantile Hepatic Hemangioendothelioma(IHH) base on Computed Tomography, in order to improve the diagnostic capacity. Methods: 11 cases of IHH which were confirmed by pathological examination were recruited to explore their CT features, All patients had undergone enhanced scan, and 6 received delayed scan. Results: 11 cases of IHH included massive type(6),(diameter, 5-10 cm); nodular type(3),(diameter,＜ 5 cm); diffuse type(2). In plain scan, all the cases show round low-density focus, massive type appear to be uneven density, with multiple calcifications, lower-density focus shows in central region in 4 cases, hemorrhagic focus shows in central region in 1 case. Nodular type appear to be uneven density, and calcifications is found in 1 case; diffuse type appear to be uniform density; massive type are lobulated, with clear border or unclear border; nodular type and diffuse type are lobeless, nodular type have unclear border, and diffuse type have clear border; in enhanced scan arterial phase, floral pattern of contrast enhancement are seen in massive type(5), nodular type(3), diffuse type(1), nodular of contrast enhancement is seen in massive type(1), Peripheral of contrast enhancement is seen in diffuse type(1), centripetal cord-like contrast enhancement were seen in massive type(3) and nodular type(1), the tumor enhancement was isodense relative to the abdominal aorta; all cases showed progressive enhancement in the portal venous phase and delayed phase, 4 cases of massive type show no enhancement in central region, enhancement of the entire tumor are found in all cases of nodular type and diffuse type. Conclusions: CT appearance of IHH mainly presented as centrality enhancement and delayed enhancement, but different kinds of which is characteristic.

Clinical Application of 64 Multi-detector Helical CT in Evaluation of Stable Pelvic Fracture

LIU Hai-ping, ZHANG Li-li, WU Ge, ZENG Qing-yu

2014, 23(4): 669-676.

Abstract(779) PDF(3)

Abstract:
Objective: To evaluate the diagnostic value of 64 multi-detector helical CT in stable pelvic fracture. Methods: 44 cases of stable pelvic fracture were performed with 64-MDCT. The data was transmitted to ADW4.3 workstation, and reconstructed by MPR, MIP, VR and generally analyzed with original axial images. Results: All the 44 cases are Tile A classification, including 16 cases of Tile A1 and 28 cases of A2. All fractures were demonstrated clearly by MDCT, and it can reveal the location, types, level and complication of fracture change. Conclusion: 64-MDCT is reliable and accurate in evaluating stable pelvic fractures, gradually becomes necessary modality examination in patients after trauma of pelvis.

The CTA Examinational Value of Vascular Lesions in Ischemic Cerebrovascular Disease

WANG Zhi-ping, ZHAO Hai-ling, YANG Zhi-hui, SUN Jian

2014, 23(4): 677-685.

Abstract(562) PDF(3)

Abstract:
Purpose: To investigate the CTA examinational value of the vascular lesions caused by ischemic cerebrovascular disease. Methods: Use Philips Brilliance's 16-slices helical CT, Philips Extended Brilliance TM Workspace or GE AW4.4 Image post-processing workstations, mainly by MIP and CPR, supplied by VR, to do some analysis of neck and cranial artery, then observe the morphologic changes of the vascular lesions in ischemic cerebrovascular disease. Results: 90 of the 102 ischemic cerebrovascular diseases have been found vascular lesions(88.24%), in the 90 vascular lesions, there were 57 pure cerebral artery diseases(63.33%), 12 pure carotid artery stenosis and plaques(13.33%), 21 combined lesions of cerebral arteries and carotid arteries(23.33%). The CTA performance of vascular lesions: from the 78 detected cases of cerebral artery disease, 24 were showed of atherosclerotic changes, 38 were showed of clearer limited hemal stricture, 6 cases of which could be seen patches, 16 were showed of vascular occlusion, all happened in the middle cerebral artery. In the 33 detected cases of carotid artery disease, those were showed of hemal stricture, plaque formation and hemal wall calcification, all located in the carotid arterial bifurcation and the initial part of internal carotid artery. The relationship of varieties of the ischemic cerebrovascular diseases and the vascular lesions: 48 cases of cerebral infarction, 29 have been found responsible vessels; 26 TIA, 22 have been found vascular; 19 cases of lacunar cerebral infarction,16 of which could see different levels of carotid artery and cerebral artery diseases. 9 cases had clinical manifestations but were found normal through CT and(or) MRI, 6 showed of cerebral and carotid artery diseases. Conclusion: CTA can be the routine examination method of ischemic cerebrovascular diseases, so as to evaluate the morphologic changes of the vascular lesions in ischemic cerebrovascular diseases.

Review of the Study on Crustal Anisotropy by Shear Wave Splitting Analysis

SUN Chang-qing, LEI Jian-she, ZHU De-fu

2014, 23(4): 687-697.

Abstract(670) PDF(1)

Abstract:
Shear wave splitting analysis is one of the most commonly used techniques in crust and mantle deformation. In this paper, we show the derivation process of theoretical equations of the split wave, introduce several shear wave splitting analysis methods, and then summarize the progress of research on crustal anisotropy using shear wave splitting analysis. Although the shear wave splitting analysis method is widely used in the study on crustal anisotropy, it also has some inherent limitations. A reliable method and procedure of data processing to accurately obtain shear wave splitting parameters was expected in future.

Current Status and Prospects of Simulation Studies of Time of Flight PET

LIU Xing, CAO Xue-xiang, LI Gong-ping, WEI Long, YUN Ming-kai

2014, 23(4): 699-706.

Abstract(544) PDF(4)

Abstract:
A brief introduction of the principles of time of flight(TOF) positron emission tomography(PET) and simulation toolkits of simulation software Geant4, GATE, DETECT2000 commonly used for TOF-PET detector simulation. A brief review of documents relating to the various studies of Monte Carlo towards TOF-PET simulation studies are introduced and the various factors impacting the time resolution of LSO/LYSO TOF-PET and the TOF-PET simulation studies of the future development prospects are presented.

Advancement of Clinical Application Based on Multi-mode Molecular Imaging

TONG Zheng-hao, WANG Rong-fu

2014, 23(4): 707-714.

Abstract(571) PDF(5)

Abstract:
Since mankind has entered the 20 th, PET, PET/CT, PET/MRI, SPECT, SPECT/CT have aroused the interest of scholars and researchers in succession. Giving a better clarity on imaging modalities, they have gained prominence in the diagnosis and treatment. The aim of the article is to introduce the advancement of clinical application based on multi-mode molecular.

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2014 Vol. 23, No. 4