CT理论与应用研究

Influence of the Size of Regions of Interest on CT Value and Material Decomposition Measurement in Water Phantom by Single-source Dual Energy CT

LIU Ze-qun, SUN Mei-yu, LIU Ai-lian, HAN Zheng

2016, 25(2): 129-134. doi: 10.15953/j.1004-4140.2016.25.02.01

Abstract(672)

Abstract:
Objective: To investigate the effect of different size of Region of interest(ROI) on CT value and material decomposition measurement in the standard water phantom using single-source dual-energy CT. Methods: The standard water phantom provided by GE company was scanned by single-source dual-energy CT machine(Discovery CT 750 HD, America GE Company). The image processing was performed on GSI Viewer browser to acquire and record CT value(HU), the concentration value of water-iodine(mg/cm³). The scanning parameters were as follows: scanning visual field: medium, rotating speed of 0.8 seconds/rotation, pitch 0.984, detector width 40 mm, current: 550 m A. The two drawn ROIs were round, located in the central part of the water phantom. Their areas were(600 ± 30) mm² and(3 000 ± 30) mm², and then recorded as ROI1 and ROI2 respectively. Paired sample t test was used for statistical analysis. Results: ROI1 CT value was(2.45 ± 1.83) HU, ROI2 CT value was(2.55 ± 1.68) HU, there was no statistical significance between CT value of ROI1 and ROI2(P = 0.06); The water-iodine value was(1 001.22 ± 0.86) mg/cm³ in ROI1, and that of ROI2 was(1 001.31 ± 0.84) mg/cm³, there was no statistical significance between water iodine value of ROI1 and ROI2(P = 0.135). Conclusions: Different ROI size will have no effect on the measurement of CT value and the concentration of water-iodine from single-source dual energy CT.

The Value of CT Imaging Spectroscopy Quantitative Analysis in the Differential Diagnosis of Peripheral Lung Cancer and Pneumonia Mass

YU Hua-yan

2016, 25(2): 135-140. doi: 10.15953/j.1004-4140.2016.25.02.02

Abstract(540)

Abstract:
Objective: To research CT imaging spectroscopy quantitative analysis of value in the differential diagnosis of peripheral lung cancer and pneumonia in the mass. Methods: Retrospective analysis in July 2011 to February 2015 to our hospital for treatment of patients with solitary pulmonary mass total 84 cases as of this study will be divided into around 38 cases of lung cancer patients and 46 patients with pneumonia mass cases of patients with CT imaging spectroscopy quantitative analysis, observed in patients with test results, analyze its diagnostic value. Results: vein CT values of peripheral lung cancer patients in different ke V pneumonia were significantly higher than mass group, the two groups have significant difference(P<0.05), peripheral artery CT values in patients with lung cancer were significantly different ke V higher than pneumonia mass group, the two groups have significant difference(P<0.05), iodine concentration and the slope of the energy spectrum of patients with peripheral lung cancer and pneumonia in arteriovenous mass of patients had significant differences(P<0.05), and water There was no significant difference(P>0.05) concentrations. Conclusions: CT imaging spectroscopy for quantitative analysis of high peripheral lung cancer and pneumonia mass differential diagnosis accuracy, a good clinical value.

Study of Displacement Characteristics of CO2 in Tight Sandstone Reservoir by Nuclear Magnetic Resonance

LANG Dong-jiang, LUN Zeng-min, LV Cheng-yuan, WANG Hai-tao, PAN Wei-yi

2016, 25(2): 141-147. doi: 10.15953/j.1004-4140.2016.25.02.03

Abstract(770)

Abstract:
The displacement oil characteristics of different pressure of carbon dioxide(CO2) in cores of different permeability and core with fracture of tight sandstone reservoir are studied by nuclear magnetic resonance(NMR) technology. This paper briefly describes the principle of nuclear magnetic resonance(NMR) and the experimental method. The results show that the tight sandstone reservoir, low and ultra-low permeability core in the initial CO2 displacement pressure,core capillary pores rang and micro capillary pores rang of oil is produced different degree,with CO2 displacement pressure increased, oil recovery degree of core capillary pores rang is increase and cumulative recovery degree is different. Tight sandstone reservoir core with fractures,oil of fractures and the part of oil in capillary pores range in the initial CO2 displacement pressure is displacement, with CO2 displacement pressure increased, oil recovery degree and cumulative recovery degree is smaller in core capillary pores rang and micro capillary pores rang. When CO2 displacement pressure increased, the part of oil of core capillary pores range is proportional to the increase into micro capillary pores rang in tight sandstone reservoir, low and ultra-low permeability cores and fracture tight sandstone reservoir core and change the distribution of residual oil. Thus it is concluded that the nuclear magnetic resonance(NMR) technology can further study of oil recovery degree and the distribution of residual oil under different displacement pressure of CO in capillary pores rang and micro capillary pores rang of tight sandstone reservoir, for the tight sandstone reservoir microscopic oil displacement mechanism is of important value.

Metal Artifacts Correction Method Research about Liquid Metal Angiography

CHAI Jia-bin, LI Gong-ping, WEI Cun-feng, WEI Long, YU Yang, WANG Qian, LIU Bao-dong

2016, 25(2): 149-157. doi: 10.15953/j.1004-4140.2016.25.02.04

Abstract(497)

Abstract:
Computed Tomography(CT) can be used in the visualization on the anatomical vessel networks. Liquid metal angiography can enhance the vessel networks. Because the liquid metal contrast agent has high linear attenuation coefficient, the reconstructed images usually have radial metal artifacts, which will cause the inaccurate edges of the vessels. To solve this problem, a new correction method based on bone beam-hardening correction is developed. The experiment results show that it can reduce the metal artifacts in isolated pig kidney liquid metal angiography image and improve the image quality.

CT and MRI Findings under the Act and Act on Indoor Central Nervous Cell Tumor

WU Yan-chun, WU Dong-qing, HU Jun

2016, 25(2): 159-167. doi: 10.15953/j.1004-4140.2016.25.02.05

Abstract(725)

Abstract:
Objective: To study under the act and act on the brain MRI findings of central nervous cell tumor. Methods: From August 2010 to June 2015, 39 patients with central nervous cell tumor of our hospital, using GE Highspeed CT/I, for all patients with CT scan, and the use of GE signa Twinspeed 1.5 T superconducting MRI scanner, an MRI scan on all of the patients of 39 patients with central nervous cell tumor were detected in the ventricle under the act and act on tumor location, size, shape; And the performance of the contrast CT scan and MRI. Results: In 39 patients with central nervous cell tumor, 13 cases located in the right lateral ventricle, 9 cases located in the left lateral ventricle, 11 cases of patients with bilateral lateral ventricle is the tumor, the other 6 cases with bilateral lateral ventricle and the third ventricle tumor. 39 patients with tumor size for an average of 52 mm; 36 cases showed irregular, lobulated 3 cases of tumor boundary vague. Part has different degree of tumor calcification phenomenon. Conclusion: The imaging findings of central nervous cell tumor site and was typical characteristic, by CT scans and MRI scanning, can effective detection of the central nervous cell tumor, and MRI imaging examination, can effectively improve the diagnostic accuracy rate of the central nervous cell tumor, the inspection result is superior to CT examination.

128-MSCT Angiography Combined with Color Doppler Flow Image in the Assessment of Carotid Artery Stenosis

LIANG Hui-qing, ZHANG Sheng-lin, TANG Kan-hua, YUAN Guo-qi, LIU Hai-ming, LIU Rui-hong

2016, 25(2): 169-174. doi: 10.15953/j.1004-4140.2016.25.02.06

Abstract(529)

Abstract:
Objective: To assess the value of 128-slice CT angiography(MSCTA) combined with color Doppler flow image in the assessment of carotid artery stenosis(CAS). Methods: fifty-eight patients with extracranial carotid stenosis including 116 segments were examined by MSCTA and CDFI within one week, the results of DSA were used as a golden standard. The results of MSCTA and CDFI were comparatively analyzed. Results: The consistent rates in diagnosis on s light-stenosis, mild-stenosis, moderate-stenosis, severe-stenosis and complete occlusion with MSCTA and CDFI was 84.6%, 79.5%, 86.7%, 92.8% and 82.6%, 76.7%, 85.1%, 91.2. The consistency were excellent between MSCTA and CDFI(χ²= 265.261, ν = 16, P<0.001, Kappa =0.870). Conclusions: MSCTA compared with CDFI had excellent consistency with DSA in diagnosis of carotid artery stenosis. MSCTA unite CDFI can be used early screen in artery stonosis. which can be used as an important basis for carotid stenosis screening in primary hospital.

CT Features of Pulmonary Tuberculosis Complicated by Low Immune Function Patients

YU Hong-sheng, SHEN You-li, LIU Meng-lei, DUAN Pan-feng

2016, 25(2): 175-182. doi: 10.15953/j.1004-4140.2016.25.02.07

Abstract(484)

Abstract:
objective: To analyze CT features of pulmonary tuberculosis complicated by low immunefunction patients. Methods:38 cases of confirmed CT images of pulmonary tuberculosis in immunocompromised patients were collected, anglicizing from the lesion types, distribution, size, configurations of focus, property and lymphatic pathological changes, etc. Results : the most of CT images of pulmonary tuberculosis in immunocompromised patients caught infiltrative pulmonary tuberculosis, the lesions distributed widely, the consolidation(38/38, 100%), nodules(21/38, 55%), cavitations(16/38, 42.1%), lymphatic pathological changes(11/38, 28.9%) were typical manifestation, which accompanied emphysema, hardening and calcified fibrous bands, the stenosis and dilatation of bronchus and pleural changes, etc. Conclusion: the CT images of pulmonary tuberculosis complicated by low immune function patients are complex and changeable, the features of which include that the pathogenic location and CT symptom are both atypical, the extent of disease is wide, the multi-character focus coexist and spread easily, the lung is damaged seriously and the prognosis is poor. CT diagnosis with medical history and clinical material attach positive significance to clear diagnosis.

The Diagnosis Value of Solitay Plasmacytoma in Spine Using Multi-slice Computed Tomography

XU Guan-zhen, TONG Cheng-wen, LAN Shan, WANG Lin-lin, LIU Yuan-yuan, LUO Xiao-qin, ZHANG Zi-li, ZOU Wen-yuan

2016, 25(2): 183-188. doi: 10.15953/j.1004-4140.2016.25.02.08

Abstract(456)

Abstract:
Objective: To discuss appearance of solitay plasmacytoma of spine(SPS) using Multi-slice computed tomography(MSCT) and promote the cognition of this disease. Methods: Combination with literature, one case with pathologically proved SPS and clinical data as well as the image features of MSCT was retrospective reviewed. Results: The imaging features of SPS is that residual crest bone with linear, wedge and irregular-shaped in centrum bone destruction area. This case show fractured vertebral endplate with multiple crack sample and one side accessories involved, vertebral body and accessories display expansion bone destruction, and soft tissue mass adjacent to vertebral body. MSCT can visually display imaging features of SPS lesions. Conclusion: MSCT can clear display imaging features of SPS lesions and higher diagnostic value to SPS.

Comparative Study of Vertebral-basilar Artery Stenosis Diagnosed by 3D-TOP-MRA and DSA to Patients with Posterior Circulation Ischemia

XIE Hui, TAN Chuan, LV Fa-jin, WANG Yi, DENG Xiao-lin, ZHANG Li-juan, HU Jian-gang, YANG Jun-xiao, RONG Tian, SHI Wu-fei, QU Ya-lin, ZHOU Bang-jian, ZHOU Qin, FANG Xiang-yong

2016, 25(2): 189-195. doi: 10.15953/j.1004-4140.2016.25.02.09

Abstract(497)

Abstract:
Objective: To the diagnostic value of magnetic resonance angiography(3D-TOP-MRA) in detecting the posterior circulation ischemia(PCI), and utilize digital subtraction angiography(DSA) as the gold standard. Methods: 80 PCI patients' vertebral-basilar artery was examined both by DSA and 3D-TOP-MRA. And the sensitivity, specificity of 3D-TOP-MRA was compared with DSA. Results: 3D-TOP-MRA had a pooled sensitivity of 88.23% for artery stenosis, and the sensitivity of mild, moderate, severe stenosis and occlusion were 57.89%, 96.30%, 85.71% and 100%, respectively;3D-TOP-MRA had a pooled specificity of 66.67%, and the specificity of mild, moderate, severe stenosis and occlusion were 100%, 96.23%, 92.42% and 100%, respectively. The overall accuracy of 3D-TOP-MRA was 85.00%, and the accuracy of mild, moderate, severe stenosis and occlusion were 90.00%, 96.25%, 91.25% and 100%. Conclusion: 3D-TOP-MRA showed high accuracy and sensitivity for the detection of high-grade PCI stenosis and occlusions.

The Patient's Clinical Practical Value of Elbow Fixed Splint Applied to Enhanced CT Examination

WANG Ling-sheng, WANG Ling-cheng, WU De-hong, WU Lei, CHEN Yi-jia, FU Chuan-ming

2016, 25(2): 197-202. doi: 10.15953/j.1004-4140.2016.25.02.10

Abstract(525)

Abstract:
Objective: To investigate the patient's clinical practical value of elbow fixed splint applied to enhanced CT examination. Methods: Pre-do enhanced CT examinations of 120 patients were randomly divided into control group(60 cases) and observation group(60 cases). All patients in the control group before performing enhanced CT examination did not use the elbow fixed splints; the observation group before performing enhanced CT examination used the elbow fixed splints, compared the two groups of the incidence of iodine contrast agent leakage and nursing service satisfaction. Results: In the control group, 10 of 60 cases occurred iodine contrast agent leakage, the incidence rate was 16.7%; the nursing service satisfaction rate was 80%. In the observation group, 2 of 60 cases occurred iodine contrast agent leakage, the incidence rate was 3.3%; the nursing service satisfaction was 95%. The incidence of iodine contrast agent leakage in the observation group was significantly lower than that in the control group, while the satisfaction of nursing service was better than that of the control group, and the difference between the two groups was statistically significant(P <0.05). Conclusions: When elbow fixed splint applied to enhanced CT patients, the incidence of iodine contrast agent leakage reduced apparently, and the nursing service satisfaction rate improved a lot. So it is easy for the patients to accept and worth promoting in clinic.

Imaging Features of Atypical Oligodendroglial Tumor

CAI Han-shou, XIAO Shu-kai, ZHANG Yue, ZHANG Jun

2016, 25(2): 203-210. doi: 10.15953/j.1004-4140.2016.25.02.11

Abstract(482)

Abstract:
Objective: To explore the Imaging features of atypical oligodendroglial tumors(OG) in order to improve the diagnostic abilities. Method: The CT, MRI findings of 12 patients pathologically confirmed OG was retrospectively studied. Results: 13 lesions were found in 12 cases(7 lesions were situated in deeply and 5 were superficial), ranged in age from 23 to 60 years. 10 patients are older than 40 years(83.3%). 9 cases showed solid masses with a ill-defined border, manifested as slight low signal on T1 WI and high singal on T2 WI. Among them, the leision was uniformity signal in 1 case, and heterogeneous signal in 8 cases accompany hemorrhage or necrosis. After contrast scanning, th leision had a patched mild to moderate in 7 cases, a ring-shaped enhancement in 1 case, which solid part showed high singal on DWI, and no enhancement in 1 case, respectively. 3 cases manifested as cystic leision, with thick walls and unclear boundaries. The cyst fluid showed long T1 and long T2 signal intensity. The cyst wall showed isointense signal on T1 WI and slight hyperintense on T2 WI, one of which showed high signal on DWI. All of the leision had no enhancement after contrast administration. Calcification was seen on CT in 3 cases. Serious peritumoral edema was seen in 2 cases. 2 lesions crossed the mildline and 1 lesion infiltrated the adjacent basal ganglion and thalamus. Conclusion: Atypical MRI manifestation of OG included occuring in middle-aged and old people, multiple lesion, deep site, serious peritumoral edema, crossing the mildline, infiltrated into deep tissue, circular enhancement, restricted diffusion on DWI, cystic mass. It still has relative features on imaging, and comprehensive analysis can elevate the accuracy of diagnosis.

The Diagnostic Value of CT Lymphangiography about Chylothorax of Lymphangioleiomyomatosis

ZHANG Qi-jin, WANG Ren-gui, ZHANG Chun-yan, SHEN Wen-bin, SUN Ying-shi, LI Xiao-ting, CAO Kun

2016, 25(2): 211-217. doi: 10.15953/j.1004-4140.2016.25.02.12

Abstract(540)

Abstract:
Objective: To explore the diagnosis value of CT lymphangiography(CTL) about chylothorax of lymphangioleiomyomatosis(LAM). Methods: A retrospective review of the clinical and radiological data of 38 LAM and 172 non-LAM-chylothorax patients. The distribution and pattern of chylothorax and in CTL were analyzed by 2 doctors. Results: 36 LAM accompanied with chylothorax. There is no difference between LAM and primary chylothorax about the distribution of chylothorax. There is difference between LAM and secondary chylothorax about the distribution of chylothorax. Secondary chylothorax is usually bilateral. The common pleura pattern of LAM chylothorax is no-manifestation, whereas visceral pleura pattern is common in primary and secondary chylothorax. Conclusions: CTL can display the pattern of chylothorax for LAM, which suggests that abnormality of thoracic duct extremity or high pressure of abdominal lymphatic vessel maybe the etiopathogenisis of chylothorax for LAM, which provides information to therapy chylothorax of LAM.

CT Diagnosis and Follow-up Analysis of Lung Cancer as Ground-glass Opacity

BAO Ya-hong, CHENG Gang

2016, 25(2): 219-225. doi: 10.15953/j.1004-4140.2016.25.02.13

Abstract(504)

Abstract:
Purpose: To analyze CT manifestations of fGGO for improving diagnosis of early lung cancer. Methods: Retrospective analyze lung cancer cases presenting as fGGO confirmed by operation and pathology with complete clinical CT data, observe its size, shape, margin, density and other lung cancer signs, as well as imaging diversity during follow-up CT scan. Result: 34 cases included 7 pGGO and 27 mGGO, showed well-defined interface, lobulated border and spiculated margin vacuole sign and air bronchogram, surrounding with pleural indentation sign and blood vessel cluster sign. In follow up, larger size and higher percent of solid component were seen in fGGO, with more solid lesions in pGGO, larger size in mGGO, lobulated border and spiculated margin, pleural indentation sign and blood vessel cluster sign. Conclusion: CT manifestations of lung cancer as ground-glass opacity have certain characteristics, CT follow-up has high value to the identification between benign and malignant fGGO.

Value of CT and MRI for diagnosing Central Pontine Myelinolysis

HU Li, WU De-hong, YU Gang, CHEN Xue-qiang, CHEN Ping-you

2016, 25(2): 227-233. doi: 10.15953/j.1004-4140.2016.25.02.14

Abstract(539)

Abstract:
Objective: To analyze the CT and MRI features of central pontine myelinolysis(CPM) to improve diagnostic level and determine the value of CT and MRI in the diagnosis and follow-up of CPM. Methods: Retrospectively analyzed the clinical and imaging features of 8 patients with confirmed CPM and summarized the imaging features. Results: 4 patients underwent CT examination, 2 patients' CT scan testing revealed abnormal results:the low density lesions were found at pontine, bilateral cerebral peduncle and right cerebellum in one patient,the other one showed low density lesions at pontine. The remaining 2 patients had normal CT scan results. 8 patients underwent MRI scan has a positive findings which revealed pontine lesions in all cases. It showed symmetrical distribution, clear edge, round, oval or butterfly. 4 of which accompanied extrapontine lesions include hemisphaerium cerebelli, caudex cerebri,thalami,basal ganglia and radiate infarction.The lesions showed iso/hypointensity in T1 WI, hyperintensity in T2 WI, T2 FLAIR,markedly hyperintensity in DWI sequence, with no edema around the lesion and no enhancement. Conclusion: The diagnostic value of MRI in the diagnosis of CPM was significantly better than CT, especially in T2 FLAIR and DWI sequence. It has great value in diagnosis early,guideline of clinical therapy and estimation prognosis diagnosis.

The Review of Scatter Suppression Methods in Cone Beam CT

RONG Jun-yan, LIU Wen-lei, GAO Peng, LIAO Qi-mei, LU Hong-bing

2016, 25(2): 235-250. doi: 10.15953/j.1004-4140.2016.25.02.15

Abstract(505)

Abstract:
Scatter artifacts in cone beam CT(CBCT) degrades image quality seriously, which limits the development and application of CBCT. Researchers have reviewed scatter suppression or correction methods at home and abroad. However, a few new technologies have appeared along with the advancement of scatter suppression methods. This paper analyses the effects of X-ray scattering to CT imaging and summarizes general scatter suppression methods. Also, the scatter correction framework is combed, in which the projection compensation technique and common scatter estimation methods are introduced particularly. Problems in scatter correction are concluded, in which the magnification of noises in scatter correction is emphasized. It provides use for reference to the research and development in scatter suppression.

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2016 Vol. 25, No. 2