CT理论与应用研究

Research of Lung Segmentation Based on CT Image

ZHOU Mao, CENG Kai, YANG Kui, YU Tao, FENG Peng, WEI Biao

2018, 27(6): 683-691. doi: 10.15953/j.1004-4140.2018.27.06.01

Abstract(373) PDF(13)

Abstract:
The accurate segmentation of lung segmentation in CT image is the basis for the detection of pulmonary nodules, which is of great significance for diagnosis of clinical pulmonary diseases. Firstly, in this paper, the segmentation methods of lung segmentation based on CT image were reviewed. Then the main steps of the lung segmentation were detailed introduced, and discussed several typical algorithms of segmentation results, including the comparison of pulmonary parenchyma and pulmonary trachea. Finally, based on those methods, the paper integrated and improved several kinds of common segmentation method and algorithm, and proposes a practical and robust algorithm of lung segmentation.

Study on Low Contrast Agent Injection Adopted in 320-slice CT Coronary Angiography

WEN Zhi-qin, MO Xu-kai, SHI Zhang-zheng

2018, 27(6): 693-699. doi: 10.15953/j.1004-4140.2018.27.06.02

Abstract(296) PDF(9)

Abstract:
Objective: To investigate the feasibility of 39 mL low contrast agent injection adopted for 320-row CT coronary artery imaging. Methods: Sampling among 100 patients (52 males and 48 females) with 320-slice CT coronary angiography for consistent data collection. The patients were randomly divided into low contrast group and control group with 50 patients respectively. The low-contrast agent group adopts three-phase injection protocol with 39 mL contrast agent in total, while the control group receives 50 m L contrast agent injection protocol for two phases. Measure and compare CT values of main blood vessels, signal-to-noise ratios and contrast-to-noise ratios. Then the coronary arteries are evaluated and analyzed by two experienced doctors. Results: There is no statistical difference reflected from gender ratio, age, weight, BMI, average heart rate during exposure, aortic root noise, SNR, superior vena cava, CNR^RCA1, and CNR^LM between the two groups (P>0.05). Meanwhile, the comparison of CT values of arterial root, right atrium, right ventricle, RCA1, LM, and ventricular wall of the two groups reveals a statistical difference (P<0.05). Among 1217 coronary segments, 94.91% (1155/1217) segments meet the diagnostic image quality requirement. The image quality acceptability rates of the low contrast group and the control group were 95.4% (555/582) and 94.5% (600/635) respectively, which reflects few statistical difference (P>0.05). Conclusion: It's feasible to use a small-dose (39 mL) contrast agent injection in 320-slice CT coronary angiography with three-phase injection protocol, which is able to form qualified diagnosis images with less contrast agent injection.

Value of Ultra-low Dose Coronary CT Angiography for Classification and Quantification of Coronary Stenosis

CHEN An, JIE Xue-qian, WANG Zheng, LI Yuan, ZHANG Hao, LI Nian-yun, MENG Jie

2018, 27(6): 701-707. doi: 10.15953/j.1004-4140.2018.27.06.03

Abstract(323) PDF(7)

Abstract:
Objective: To investigate the agreement between 70 kV and 100 kV scan for classification and quantification of coronary artery stenosis, on wide-detector coronary computed tomography angiography (CCTA) examination. Methods: 70 patients of suspected or known coronary artery disease were included, who were suitable for CCTA. Single heartbeat CCTA was performed on 256-row wide-detector CT by using 70 kV and 100 kV tube voltage, respectively. Effective radiation dose and signal-to-noise ratio (SNR) were compared between these two groups. Nine coronary segments were evaluated, in which the stenosis degree was categorized as:normal (0%), mild (1%~49%), moderate (50%~69%) and severe (70%~100%). We recorded the number of consistent stenosis category between 70 kV and 100 kV scan. Bland-Altman analysis was used to evaluate coronary stenosis between 70 kV and 100 kV scan. Result: Effective radiation dose of 70 kV scan was significantly lower than that of 100 kV, which were (0.26±0.08) mSv and (1.07±0.05) mSv (P<0.01), respectively. SNR of 70 kV scan was significantly lower either, which were 16.53±5.87 and 18.19±6.07 (P<0.05), respectively. Stenosis degree of 630 coronary segments were evaluated, in which 608 (96.5%) were consistent between 70 kV and 100 kV scan. Bland-Altman analysis revealed a 95% confidence interval (CI) between 15% and 30% for coronary stenosis between the two groups. Conclusion: CCTA of 70 kV tube voltage significantly reduces radiation dose, while showing optimal consistent categorization for coronary stenosis to 100 kV scan. However, variability exists between 70 kV and 100 kV scans for precise quantification of coronary stenosis.

Cross-sectional Study on the Relationship Between Integral Cognitive Level and Gray Matter Volume in Patients with Alzheimer's Disease Based on VBM

CHEN Rui-sen, XIA Jun, CHEN Jian-liang, LI Ai-dong, LI Xiang

2018, 27(6): 709-717. doi: 10.15953/j.1004-4140.2018.27.06.04

Abstract(294) PDF(7)

Abstract:
Objective: To explore the relationship between integral cognitive level and gray matter volume in Alzheimer's disease (AD). Methods: 20 AD patients, 17 MCI patients and 12 healthy old persons were in this study.All subjects were examined by T1-3 D BRAVO (brain volume) sequence in 1.5 T magnetic resonance scanner. The volume of gray matter was measured with Voxel-based morphometry (VBM). All subjects were underwent MMSE and obtained the score of MMSE. The multiple regression analysis of gray matter volume were compared with MMSE score. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of gray matter volume in AD. Results: All of the subjects with reduced gray matter volume of brain, also reduce the MMSE score, gray matter volume decreased by 10 m L and MMSE score decreased by 0.56 points (P<0.01). The decline was more pronounced in men and in younger groups. The area under the curve (AUC) of the gray matter volume was 0.927. The optimum threshold was 538.49 m L, the specificity was 90.0% and the sensitivity was 84.6%. Conclusion: As the volume of gray matter decreased, the level of integral cognition also decreased. The gray matter volume in all patients and control group could reflect the integral cognitive level. The measurement of gray matter volume in the brain could provide valuable information for the diagnosis of AD.

Spectral CT with Optimal Monochromatic Energy to Improve CTA Image Quality of Head and Neck

DENG Xiao-lin, XIE Hui, QU Ya-lin, YANG Shao-wei, YANG Zheng-bin

2018, 27(6): 719-726. doi: 10.15953/j.1004-4140.2018.27.06.05

Abstract(360) PDF(8)

Abstract:
Objective: To evaluate the value of spectral CT with optimal monochromatic energy to improve the CTA image quality of head and neck. Methods: A total of 60 patients with suspected head and neck vascular diseases admitted to our hospital from February 2016 to December 2017 were selected for subtraction spectral CTA of neck and neck. Two subtraction images of the optimal monochromatic energy and conventional mixed energy were obtained, and arterial attenuation of the aortic arch, the end of the common carotid artery and the M1 segment of the middle cerebral artery were measured, and the two groups of signal to noise ratio (SNR) and contrast to noise ratio (CNR) were calculated; the subjective quality score of the two groups were evaluated; The differences between the two groups were compared. Results: The mean attenuation values of the optimal monochromatic energy group and the conventional mixed energy group were 445.25±105.45 and 283.88±71.96 in the aortic arch, and the mean attenuation values were 444.00±96.02 and 350.38±76.40 at the end of the common carotid artery, and the mean attenuation values were 375.00±73.78 and 280.00±55.12 in the M1 segment of the middle cerebral artery, and there were significant differences among the three of them. The SNR of the two groups were 62.01±39.56 and 31.36±17.35, and the CNR were 60.46±39.19 and 30.10±16.80, respectively; and there were significant differences among the two of them, and there were significant differences in the subjective quality score of the two groups of images. Conclusion: The spectral CT with optimal monochromatic energy subtraction CTA is better than the conventional mixed energy subtraction CTA. It has higher arterial attenuation, SNR, CNR, and subjective quality score, which can improve the image quality of head and neck angiography and optimize the display of arteries.

Application of Multi-azimuth Pseudo-3D Electrical Resistivity Tomography in the Investigation of Ancient Mausoleums

YU Tian-xiang, SHI Zhan-jie, LIU Jie, FANG Zi-yan, HUANG Hao-de

2018, 27(6): 727-738. doi: 10.15953/j.1004-4140.2018.27.06.06

Abstract(286) PDF(9)

Abstract:
2D electrical resistivity tomography is widely used in the exploration of ancient tombs, but the limitations of two-dimensional section interpretation are more and more prominent. The pseudo-3D electrical resistivity tomography based on 2D parallel or equi-angled radial lines can give three-dimensional information to a certain extent, but the requirements for surface conditions are higher and the flexibility is slightly worse.Detailed 3D information can be given by 3D electrical resistivity tomography, but the acquisition efficiency is low and it is difficult to adapt to complex surface environments. In order to solve the problem of detecting ancient mausoleums under complicated surface, a multi-azimuth pseudo-3D electrical resistivity tomography was proposed, which was applied in the detection of large ancient mausoleums in an intensive bamboo forest.According to the actual situation of the surface, 2D lines of multiple orientations can be laid out, and 2D inversion data of all orientations are merged into a pseudo 3D data volume, and 3D internal structure information is obtained by visual interpretation. The results show that the technology can adapt to the complex environment, and the pseudo-3D data can not only supplement the 2D interpretation of missing information, but also basically coincide with the drilling results.

Kirchhoff Integral Prestack Time Migration with Full Azimuth Angle Gathers Generation Method and its Implementation

OUYANG Min, LIU Shou-wei, LI Lie, WANG Da-wei

2018, 27(6): 739-747. doi: 10.15953/j.1004-4140.2018.27.06.07

Abstract(274) PDF(7)

Abstract:
The azimuth angle domain common image gathers can objectively reflect the velocity, anisotropy parameter anomaly and amplitude versus angle (AVA) and fracture information of the subsurface medium. The traditional Kirchhoff PSTM usually outputs offset domain common image gathers, which have many inconveniences for velocity analysis, anisotropy analysis, AVA analysis, and fracture identification. This paper proposes a Kirchhoff pre-stack time migration with full azimuth angle gathers output method based on travel timegradient and proposes an industrially feasible implementation. The wave field propagation direction vector is calculated by the travel time field gradient to form full azimuth angle gathers, which can reflect seismic acquisition parameters and wave fields propagation effect. In order to process large-scale seismic data, this paper gives a practical strategy, which bases on input-imaging point. Imaging subsurface inline-by-inline, which greatly reduces the total the pressure of the azimuth angle gather output on the computer memory, and greatly improves the feasibility of the Kirchhoff integral time migration with full azimuth angle gathers output. The three-dimensional SEG salt model data and real data test in a certain offshore dataset proves the correctness of the method.

Research on Focal Spot to Skin Distance of Small Mobile CT Scanner

DAI Qiu-sheng, YANG Lei, FAN Bo, XU Ru-xiang

2018, 27(6): 749-757. doi: 10.15953/j.1004-4140.2018.27.06.08

Abstract(462) PDF(7)

Abstract:
The minimum focal spot to skin distance is a critical parameter in the national standard to restrict the miniaturization of CT scanners. This paper introduces the physical meaning of focal spot to skin distance, analyzesthe similarities and differences between X-ray fluoroscopy imaging and X-ray computed tomography, and investigates the important effect of the filter on the absorbed dose distribution in the scanning hole in X-ray computed tomography. The experimental results show that, due to the effect of the filter, the absorbed dose distribution in the CT scanning holes of the large and small CT scanners is high in the central region and low in the inner wall region. The concept of minimum focal spot to skin distance from X-ray fluoroscopy imaging does not perform the same function in computed tomography, but it limits the development of miniaturization of CT scanners.

CT Imaging Findings Neuroendocrine Tumors of Pancreas

QIU Gan-bin, MA Li-heng, JI Ya-yun, LIANG Yu-ying, LIU Mou-yuan

2018, 27(6): 759-766. doi: 10.15953/j.1004-4140.2018.27.06.09

Abstract(299) PDF(5)

Abstract:
objective: To investigate the CT appearance and diagnostic value of pancreatic endocrine tumor (NETP).Methods: The CT manifestations of 19 patients with NETP confirmed by surgery and pathology were analyzed retrospectively, Fisher's exact test was used to compare the relationship between different grades, functional and non-functional tumors and lesion size. Results: 19 patients had a total of 23 lesions, including 4 functional NETPs and 15 non-functional NETPs. According to the WHO classification, there were 7 cases of G1, 10 of G2, and 2 of G3. CT scans consisted of 6 completely solid lesions, 17 solid cystic lesions, 0 complete cystic lesions, 4 calcifications, and 10 main pancreatic duct dilatation. Low-grade tumors were less than 3 cm 72.7% (8/11), high-grade tumors were greater than 3 cm 83.3% (10/12), and the two were significantly different (P<0.05), while functional tumors were less than 3 cm 66.% (4/6), non-functional tumors were greater than 3 cm 82.4% (14/17), and both were statistically significant (P<0.05). Conclusion: The CT findings of pancreatic endocrine tumors have certain characteristics. The maximum diameter of the tumor is helpful for the judgment of different grades and functional and non-functional tumors, and can guide the clinical development of treatment plans.

CT Diagnosis of Primary Pleura Tumor

MA Zhou-peng, YU Qian, LIN Guan-sheng, ZHU Jian-zhong

2018, 27(6): 767-774. doi: 10.15953/j.1004-4140.2018.27.06.10

Abstract(352) PDF(10)

Abstract:
Objective: To explore the CT findings of the primary pleural tumors and improve the understanding of these diseases. Methods: The CT of 24 cases of primary pleural tumors confirmed by pathology were analyzed retrospectively. Results: Among 24 cases, there were 9 cases of mesothelioma, 8 cases showed pleural diffuse thickening irregularly together with multiple nodules, and 1 cases showed localized thickening of the pleura, 3 cases showed obvious inhomogeneous enhancement, 6 cases showed mild to moderate enhancement inhomog eneously, 8 cases of accompanied with pleural effusion, 3 cases accompanied with lymph node metastasis, 1 case accompanied with intrahepatic metastas and 1 case accompanied with intrapulmonary metastas. Among 7 cases of solitary fibroma, 3 cases were fusiform masses, 4 cases showed hemispherical masses, and all 7 cases showed mild to obvious enhancement inhomogeneously, 5 cases showed "pleural tail" sign and 2 cases accompanied with pleural effusion. 5 cases of neurilemmoma all showed "pleural tail" sign, 1 case showed fusiform mass and 4 cases showed spherical mass, and all 5 cases showed mild to moderate enhancement inhomog eneously. 1 case adipofibroma showed fusiform mass with fatty density mainly and clear boundary, and a little fibes with mild enhancement.1 case synovial sarcoma showed huge irregular mass and with inhomogeneous enhancement, accompanied with metastasis of the left adrenal with circular enhancement. 1 case inflammatory myofibroblastoma showed spherical mass with equal and mild low density, and with inhomogeneous delayed enhancement obviously. Conclusion: Primary tumor of the pleura is rare in clinic but is varied in variety, the CT characteristics of different tumors are different, and CT show important value for the diagnosis and differential diagnosis.

Imaging Findings of Acute Infarction Caused by Basilar Artery Occlusion

CUI Zhi-hui, DING Zhang-qing, WANG Xue-lu, WANG Sheng-qian, LIU Wen, SUN Ying-ying

2018, 27(6): 775-782. doi: 10.15953/j.1004-4140.2018.27.06.11

Abstract(259) PDF(6)

Abstract:
Objective: To investigate the imaging features of acute infarction caused by basilar artery occlusion (BAO). Methods: The data of 26 patients with acute infarction caused by BAO in our hospital from January 2016 to May 2018 were retrospectively analyzed. All patients underwent plain CT scan, noncontrast MRI scan and 3D-TOF MRA examinations. The plain CT images signs, MRI T1WI, T2WI and T2FLAIR signs at the occlusion displayed on the 3 D-TOF were mostly analyzed. Results: The BAO in this group was clearly shown by MRA. The acute infarction in the responsible blood supply area showed high signal on DWI and low signal on ADC. 18 cases showed high density artery sign and 6 cases showed calcification sign at the occlusion on CT images. T1WI showed 20 cases with hyper intense vascular sign at the occlusion as well as T2WI and FLAIR showed the absence of flow void phenomenon in all the 26 cases. Conclusion: BAO and its induced acute infarction can be diagnosed by MRA and MRI. CT and MRI imaging have a high display rate of basilar arterial vasculature signs and recognition of these signs is helpful for early diagnosis.

Chest Pain Triad 128-slice Spiral CT Scanning Imaging Application

ZHANG Xiao-feng, YUAN Guo-qi, LIU Hai-ming, LI Qing-shui

2018, 27(6): 783-788. doi: 10.15953/j.1004-4140.2018.27.06.12

Abstract(488) PDF(7)

Abstract:
Objective: to analyze and optimize the application value of 128 slice spiral CT scanning in chest pain triad. Methods: 69 patients with highly suspected chest pain triad were examined by 128 slice spiral CTA, and all the original data were reconstructed with a variety of post-processing techniques such as maximum density projection (MIP), surface reconstruction (CPR), volume rendering (VR), and multiplane reconstruction (MPR).The methods were performed on the thoracic aorta and coronary artery respectively. The arteries and pulmonary arteries were analyzed at different angles. Results: the main branches of the thoracic aorta and bilateral pulmonary arteries (CT value of 200 HU) were clearly shown in 69 patients with acute chest pain, and the image quality of the coronary artery was superior to 63.7% (44/69), 30.4% (21/69) and 5.8% (4/69). Conclusion: the specificity of the 128 slice spiral CTA triple scan CTA examination in the diagnosis of coronary syndrome is 94.7% (36/38), the accuracy is 95.8% (69/72). The specificity and accuracy of the diagnosis of the pulmonary artery and the aortic disease is very high. Through this study, we can preliminarily conclude that 128 slice spiral CT triple scanning has important application value in the triplet of chest pain.

Clinical Application of Percutaneous Transforaminal Endoscopic Lumbar Discectomy under the CT Guided

SHAO Nan, DENG Mao-song, WANG Xu, JIN Guang-wei, YIN Xiao-ming, WU Ge, WANG Da-min

2018, 27(6): 789-796. doi: 10.15953/j.1004-4140.2018.27.06.13

Abstract(312) PDF(5)

Abstract:
Objective: To investigate the value of multi-slice spiral CT guided percutaneous transforaminal lumbar discectomy. Methods: Eighty patients with lumbar disc herniation were enrolled in this study. All of them underwent single disc intervertebral disc discectomy, all under the guidance of multi-slice spiral CT. Results: Compared with the conventional fluoroscopy, the operation under CT guidance is more convenient, which can predict the puncture site and puncture path angle and depth more accurately, shorten the operation time and reduce the occurrence of intraoperative tissue damage Probability, reduce complications. Conclusion: CT guided percutaneous transforaminal lumbar discectomy is safe and reliable, and can achieve better diagnosis and treatment effect, which can be vigorously promoted in clinic.

MDCT Findings of Strangulated Intestinal Obstruction

SHEN Chun-lin, WAN Zhe-jun, LYU Pin, LIU Gang

2018, 27(6): 797-804. doi: 10.15953/j.1004-4140.2018.27.06.14

Abstract(350) PDF(5)

Abstract:
Objective: To evaluate multi-detector row spiral CT (MDCT) in imaging the emergency patients with strangulated intestinal obstruction (SIO). Methods: Twenty-nine patients with SIO confirmed by surgery were included in this study. All patients' clinical data and MDCT data were analyzed. After multiplanar reconstruction and multi window position analysis, CT characteristics of bowel (intestinal cavity expansion, effusion, intestinal wall thickness and density change), CT characteristic changes of mesentery (fuzzy effusion, mesenteric rotation, portal vein changes), image changes within the abdominal cavity (ascites, pneumoperitoneum) and enhanced CT imaging changes (bowel wall enhancement, mesenteric vascular embolism) were analyzed. Results: Of all the 29 participants, 26 cases have luminal dilatation changes, density changes and wall thickening of bowel were found in 18 cases, abnormal air accumulation at intestinal wall and in the portal vein were found in 2 cases, omesentericeffusion were found in 19 cases, stranding sign were found in 11 cases, the whirlpool sign were found in 9 cases, beak sign were revealed in 5 cases, abdominal dropsy were found in 12 cases, 3 cases have mesenteric vascular embolization, intestinal wall enhancement in 5 cases were found after intravenous injection of contrast medium.Conclusion: Careful identification of imaging details of SIO patients using MDCT has a better application value to improve the diagnosis and differential diagnosis in SIO patients.

The Research Progress in Imaging Evaluation of Efficacy of Radiotherapy and Chemotherapy for Central Lung Cancer

LIU Li-juan, ZHAO Lei, LIU Ai-shi

2018, 27(6): 805-812. doi: 10.15953/j.1004-4140.2018.27.06.15

Abstract(322) PDF(10)

Abstract:
Central lung cancer is one of the big threat to human's health and life. It is highly invasive and has a high fatality rate.so, the treatments are mainly composed of radiotherapy and chemotherapy. Precision medicine demands accurate assessment of tumor response to therapies with the purpose of timely optimization or adjustment of the given treatment regimens. This paper mainly reviews the current clinical imaging methods to assess the efficacy of radiotherapy and chemotherapy in central lung cancer.

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2018 Vol. 27, No. 6