CT理论与应用研究

Dual-source CT in the Diagnosis of Acute Pulmonary Embolism Rabbit Experimental Study

LIAO Jian, ZHANG Xiao-qin, WANG Min, ZHANG Kai, DONG Yu-qing, YUN Feng

2015, 24(6): 769-775. doi: 10.15953/j.1004-4140.2015.24.06.01

Abstract(710) PDF(3)

Abstract:
Study the feasibility of manufacturing the model of acute pulmonary embolism by injecting gelatin sponge from New Zealand rabbit ear margin vein by dual-source CT. Methods: 24 New Zealand rabbits divided into two groups: experimental group(n=22) and control group(n=2). In experimental group, we injected gelatin sponge into rabbit's ear margin vein, and divided them into 2houes, 1 day, 3 days, 7 days group. All proceed CTPA and lung perfusion examination before and after embolization. After the inspection, all rabbits put to death. Control group injected isotonic saline into rabbit's ear margin vein. After the inspection, all rabbits put to death. All groups put to pathological examination. Results: In the experimental group, 20 New Zealand rabbits molding success, 2 rabbits have not obtained data because of embolization excess and anesthesia excess, the success rate of 90%. Analysis on CT images of 100 lung lobes, In 2 hours group, there are 12 lung lobes texture sparse; in 1d and 3d groups there are 22 lung lobes in ground-glass attenuation; in 7d group there are 3 lung lobes consolidation. DEPI show low perfusion in experimental group. Pathological examination revealed: The lung tissue in 2 hours group was bright red, no structural damage and alveolar exudates; In 1 day group the lung tissue was edema, congestion, hemorrhage and inflammatory cell infiltration; The lung tissue in 3 day group was deep red, the alveolar interval broaden, a large number of inflammatory cells infiltration, some lung tissue necrosis; The lung tissue in 7 day group was dark red, lung tissue necrosis, the alveolar cavity is filled with exudates. The experimental group was found three New Zealand rabbit pulmonary artery lumen with gelatin sponge. Conclusions: Injection of gelatin sponge By the New Zealand rabbit ear margin vein production of acute pulmonary embolism animal model is simple operation, low cost, and high success rate. It is a experimental model which relatively easy to make in imaging studies of pulmonary embolism.

The Application Value of Spectral CT in Study of Correlation between the Size and the Blood Content of Malignant Lung Nodules

ZHANG Huai-rong, LI Shu, CHU Jin-gang, ZHANG Li-na, LI Yan-hui, ZHAO Yu, ZHAO Li

2015, 24(6): 777-784. doi: 10.15953/j.1004-4140.2015.24.06.02

Abstract(619) PDF(2)

Abstract:
objective: To investigate the relationship between nodules size and blood content in patients with lung tumors by spectral computed tomography and the gemstone spectral imaging(GSI) viewer. Methods: During the period from August 2014 to June 2015, 40 patients with 46 lung nodules were collected in the first hospital of China medical university. The were divided the 46 nodules into three groups based on maximum diameter(small,<2 cm, 16 cases; medium,>2 cm~≤3cm, 15 cases; large,>3 cm,15,cases). All patients received biphasic pulmonary enhanced CT scan with GSI mode on a MDCT(Discovery CT 750 HD, GE healthcare). The region-of-interest was placed on the tumor's maximum section, and the mean CT value, water density and iodine density were measured. The difference between the mean values of variables was assessed with one way ANVOA. Pearson's product-moment correlation coefficient(r) was used to study the relationship between the CT values and the material densities. Results: The mean value of iodine density was significantly lower in larger tumors. The mean iodine density in arterial phase and venous phase in tumors of ≤ 2 cm, 2~3cm, and>3 cm were(17.45 ±4.56),(12.05 ±4.89),(10.31 ±5.76)(100 μg/cm³),(18.32 ±3.59),(14.05 ±4.13),(12.82 ±4.58)(100 μg/cm³), respectively. Significant difference in average iodine density was noted between tumors of from 2~3 cm and ≤ 2cm(P<0.05), and between those of>3 cm and ≤ 2 cm(P<0.05). There were no statistically significant differences in mean CT value and water density among three groups. The average CT value and water density were obviously influenced by air, but the average iodine density was unaffected. The average CT value and water density of the GGO-type tumors and solid-type tumors in arterial phase were(-323.83 ±220.27),(43.63 ±15.02)(HU),(638.47 ±227.07),(1 017.27 ±15.23)(100 μg/cm³)(P<0.05), respectively. The average iodine density of the GGO-type tumors and solid-type tumors were(12.86 ±5.92),(12.70 ±4.28)(100 μg/cm³)(P>0.05), respectively. Conclusion: With the increasing of tumor size, iodine density decreases gradually; The average water density were significantly related with CT value, but the average iodine density and the average CT value were no correlation. So the average iodine density is more accurate to indicate the blood content of tumors than mean CT value.

The Application of CT Spectrum Imaging for Diagnosis of Squamous Cell Carcinoma and Adenoid Cystic Carcinoma in Central Airway

WANG Rui, HU Chan-chan, YIN Xiao-ming, CENG Qing-yu

2015, 24(6): 785-792. doi: 10.15953/j.1004-4140.2015.24.06.03

Abstract(689) PDF(4)

Abstract:
Objectives: To investigate the preliminary application of spectral CT on the differential diagnosis between squamous cell carcinoma(SCC) and adenoid cystic carcinoma(ACC) of the primary central airway tumors by spectral CT scan and multi-parameter quantitative measurement. Methods: Choose the patients who were found with central airway tumors and without any treatment to take the gemstone spectral CT examination. We choose the patients who can comply with the conditions of enhancement to take plain scan and enhancement scan in arterial phase on GSI mode. All the data was processed by GSI Viewer software. The lump substance composition was selected as region of interest, measuring iodine concentration, water concentration and corresponding CT value of 40 ke V, Then calculate the corresponding slope of spectral curve, 26 patients were divided into SCC group and ACC group. Independent samples t test was used to analysis whether the parameters of plain scanning and arterial phase scanning have statistical significance. Results: Plain scan: Corresponding CT value at 40 ke V, energy spectrum curve slope, calcium content of SCC group was higher than those of ACC group, the difference was statistically significant(P<0.05), there was no significant difference in the water content in the two groups(P>0.05). Arterial phase enhanced scan: CT value at 40 ke V, the slope of the energy spectrum curve, iodine content of SCC group were higher than those of ACC group, the difference was statistically significant(P<0.05), there was no significant difference between the water content(P>0.05). Conclusions: Spectrum CT imaging can provide more quantitative and qualitative information for central airway primary tumor diagnosis. It can be used as a new method for diagnosis, and has certain clinical application value.

Three-dimensional Imaging of Articular Cartilage in Human Using Synchrotron Radiation Micro-computer Tomography

LIU Cheng-lei, XI Yan, ZUO Hou-dong, YANG Chun-ming, YAO Wei-wu

2015, 24(6): 793-799. doi: 10.15953/j.1004-4140.2015.24.06.04

Abstract(629) PDF(3)

Abstract:
Objective: To investigate the feasibility of detecting microstructure in human articular cartilage with Synchrotron Radiation Micro-Computer Tomography. Methods: Three cylindrical cartilage-bone plugs with approximate 1mm in diameters and 4mm in heights were harvested from the joint of human knee. The three specimens were performed by SR-μCT after being soaked in 4% formalin solution. The original projection images of SR-μCT were processed by phase retrieval, slice and 3D reconstruction. Then we compared the size, shape, orientation of chondrocytes with pathologic pictures and analyzed the differences of orientation of collagen framework between normal and damaged cartilage. Results: The size, shape, distribution of chondrocytes and lacunas can be clearly demonstrated on reconstructed images of SR-μCT. The results were in accordance with pathological pictures. On Maximum intensity projection(MIP) images the orientation of collagen framework was revealed. Collagen fiber structure was in a vertical direction through the cartilage with arcade structure on surface in normal cartilage. And the collagen fibrils were deformed in the vertical direction with their axial low-grade collapse in mild cartilage damage. As to severe cartilage damage, the collagen framework was disordered and there was a severe collapse in axial direction. Conclusion: SR-μCT can demonstrate a true cellular resolution for human articular cartilage and clearly show the three-dimensional structure of collagen framework by selecting appropriate threshold value.

Tomography Inversion Velocity Model Building Method Research

XUE Hua, ZHANG Bao-jin, WEN Peng-fei

2015, 24(6): 801-807. doi: 10.15953/j.1004-4140.2015.24.06.05

Abstract(708) PDF(4)

Abstract:
In the paper, we propose an optimized tomography based velocity model building method for pre-stack depth migration. The flow of velocity model building method for pre-stack depth migration was described. Two different tomography velocity model building methods(model tomography and grid tomography) were discussed. Applications in the same seismic data indicate that: under the high S/N ratio areas and accurate interpretation layer information provided condition, Model tomography is more accurate and stable than grid tomography.

The Bayes Sparse Spike Inversion Based on Spatial Variable Impedance Coefficient

XIAO Kai-pan, ZHANG Da, ZHANG Fan-chang

2015, 24(6): 809-817. doi: 10.15953/j.1004-4140.2015.24.06.06

Abstract(600) PDF(1)

Abstract:
In the conventional sparse spike inversion which based on Bayesian theory, the Lagrange operator of the constraint term always been valued as a constant coefficient. After inversed the field data, we found that the impedance inversion profile can't match well with the oil and gas by drilling. Considering that the seismic trace data is different, the effect of the low frequency trend model should be different, so on the basis of conventional inversion, this text made some improvement and we assumed that impedance constraint coefficient which determined by the difference between the actual seismic data and the synthetic record is a spatial variable. The practical application shows that the improved inversion results are more stable and can reflect the underground impedance information more accurately.

Study of Spectral CT Based on a Photon Counting Detector

XU Pin, CHEN Shi, YUAN Gang, ZHANG Yin, ZHENG Jian, XING Xiao-man, SUN Ming-shan

2015, 24(6): 819-825. doi: 10.15953/j.1004-4140.2015.24.06.07

Abstract(963) PDF(10)

Abstract:
The purpose of this paper is to evaluate the performance of the photon counting detector in CT. We tested the performance of a photon counting detector based on CZT, and built a tabletop X-ray CT scanner. Firstly, in order to reduce non-uniformity of the detectors, calibration of the energy thresholds and dead pixel correction were performed. Then calibration of the energy thresholds was applied to determine the working energy threshold of the detector. In the end we acquired projection data with two energy bins(36 and 45 ke V). The ART-TV algorithm based on the compressed sensing was performed to reconstruct the incomplete projection data.

Comparative Study of Imaging in Diagnosis and Therapy of Intracranial Aneurysms

KANG Zhi-lei, SHI Xin-jing, ZHANG Zhao

2015, 24(6): 827-834. doi: 10.15953/j.1004-4140.2015.24.06.08

Abstract(612) PDF(2)

Abstract:
Objective: To evaluate the clinical value of CTA(CT Angiography, CTA) in the diagnosis and treatment of intracranial aneurysms. Methods: 97 cases of patients with clinically suspected of intracranial aneurysms were randomly detected by one of the non-invasive examination CTA and MRA first, and then underwent a DSA examination. Comparing with DSA and surgical diagnosis, we discussed the advantages and disadvantages of CTA, MRA and DSA. After acceptance of the appropriate treatment, patients underwent a CTA + DSA examination or a MRA + DSA examination, and evaluate of residual aneurysm case. Results:(1) 50 patients in CTA + DSA inspection group, 46 cases were confirmed as positive cases. The specificity, sensitivity and accuracy of CTA detection were: 66.67%, 100%, and 98%. Negative and positive predictive values were: 100%, 97.92%. The specificity, sensitivity and accuracy of DSA detection were: 66.67%, 95.74%, and 94%. Negative and positive predictive values were: 50%, 97.83%.(2) 47 patients in MRA + DSA inspection group, 45 cases were confirmed as positive cases. The specificity, sensitivity and accuracy of MRA detection were: 50%, 97.67%, and 93.62%. Negative and positive predictive values were: 66.67%, 95.45%. The specificity, sensitivity and accuracy of DSA detection were: 66.67%, 97.73%, and 95.74%. Negative and positive predictive values were: 66.67%, 97.73%.(3) 48 patients who underwent aneurysm clipping surgery detected by CTA + DSA examination, and DSA as the standard, CTA evaluation of residual aneurysm specificity, sensitivity and accuracy were: 97.73%, 100%, and 97.78%. 42 cases accepted relief coil therapy detected by MRA + DSA examination,and DSA as the standard, MRA evaluation of residual aneurysm specificity, sensitivity and accuracy were: 100%, 66.67%, and 97.5%. Conclusion: CTA diagnosis of intracranial aneurysms specificity, sensitivity and accuracy slightly better than DSA, MRA for the diagnosis of intracranial aneurysms is slightly lower than the DSA; while CTA and MRA can clearly show the three-dimensional structure of the aneurysm and spatial relationships; comprehensive comparison, we believe that CTA for the diagnosis and determine aneurysm surgery programs can provide more information. And CTA can be used as an ideal follow-up after imaging methods.

Application of Snapshot Segment Combined with Triphasic Bolus Injection Technique in “Triple Rule-out” 64-row CT Imaging for Double-low Scanning of Chest Pain

LIANG Shuang, HU Wei, YI Jiao-e, TAN Xian-hua, YUAN Xi

2015, 24(6): 835-841. doi: 10.15953/j.1004-4140.2015.24.06.09

Abstract(636) PDF(1)

Abstract:
Objective: To investigate the clinical value of Snapshot segment(or single sector reconstruction) combined with triphasic bolus injection in “Triple Rule-Out(TRO)" 64-row CT imaging for double-low scanning of chest pain. Methods: A total of 50 patients with acute chest pain who underwent 64-row CT imaging for TRO CT angiography(TRO-CTA) examination were randomly divided into two groups. All patients underwent retrospective ECG-gated chest TRO-CTA scanning. The heart rates ranged from 50 to 70 bmp. The body mass index(BMI) of the patients ranged from 18 to 28. Group A was identified as experimental group, which were underwent Snapshot segment reconstruction technique at the voltage of 100 kV, and received triphasic bolus contrast media injection at a volume of 60-70 mL. Patients in Group B were included as the control, which were underwent multi-sector reconstruction technique at the voltage of 120 kV, and received dualphasic bolus contrast media injection at a volume of 90-100 mL. The CT values and contrast noise ratio(CNR) of superior vena cava, pulmonary arteries, coronary arteries, and thoracic aorta between the two groups were compared. Besides, the image quality of pulmonary arteries and coronary arteries, and the radiation dose were compared. Results: There were significant differences in the CT values of superior vena cava, pulmonary arteries, coronary arteries, and thoracic aorta were detected between two groups with Student's test was used(P<0.05). There was statistical differences between the CT values of pulmonary arteries and veins in experimental group(P<0.05). No significant differences were found in the image quality, noise, or CNR between two groups(P>0.05), whereas the radiation dose in experimental group was significantly reduced by 40.19% when compared to that of in the control group(P<0.05). Conclusion: Snapshot segment combined with triphasic bolus injection technique could greatly reduce the contrast media and radiation dose as well as improved image quality, and it implied its great practicing value in the clinic.

The Application of Multi Slice Spiral CT Angiography in Coronary Heart Disease

HAN Hong-cheng

2015, 24(6): 843-848. doi: 10.15953/j.1004-4140.2015.24.06.10

Abstract(631) PDF(1)

Abstract:
Objective: With digital subtraction angiography(DSA) as the gold standard, comparative analysis of multi slice spiral CT coronary angiography(CTA) in the evaluation of coronary artery stenosis of the accuracy and sensitivity of CTA for the clinical value of the examination of coronary artery stenosis. Methods: 78 cases of patients with known or suspected coronary heart disease were selected who diagnosed in our hospital from April 2014 to April 2015, the CTA inspection, and check in a week before and after the adept DSA examination, comparing with the results of CTA and DSA examination analysis, at the same time the pathological changes of lumen stenosis degree and the detection sensitivity and specificity of the comparison. Results: A total of 78 patients, 580 vessels, CTA found 440 coronary artery stenosis; DSA found 446 coronary artery stenosis. On the basis of DSA, CTA check the accuracy of diagnosis of above moderate coronary artery stenosis was 94.96%. CTA in the left main, left anterior descending, left circumflex branch and right coronary artery four specific distribution area and distribution of DSA examination result has high consistency. CTA inspection caused by calcification plaques in the conformity degree of luminal stenosis of 88.20%, due to non calcified plaque conformity degree of luminal stenosis was 90.31%. Conclusion: Multi slice spiral CT coronary angiography can clearly display the coronary vessel wall thickening and stenosis of the arterial wall plaque and calcification of advantage, is an ideal on the diagnosis of coronary artery disease in non-invasive detection method.

Comparative Analysis of the Diagnosis Value Using Ultrasound and CT in Benign and Malignant of Thyroid Nodules

YU Bei, LI Ya-chao

2015, 24(6): 849-855. doi: 10.15953/j.1004-4140.2015.24.06.11

Abstract(585) PDF(4)

Abstract:
Objective: To compare and study the diagnosis value of ultrasound and CT in benign and malignant of thyroid nodules, and improve the diagnosis of benign and malignant thyroid nodules accuracy. Methods: A retrospective analysis of the complete medical records from January 2011 to December 2014 in our hospital 120 cases of thyroid nodules in patients was made, and all patients within two weeks had carried ultrasound and CT examination and retained a complete image inspection results, and surgery value evaluation after all confirmed by pathology ultrasound and CT in the diagnosis of benign and malignant thyroid nodules was compared. Results: The sensitivity, specificity and diagnostic accuracy of ultrasound combined with CT was 83.17%, 93.06%, 92.77% respectively, which was significantly higher than the ultrasound and CT, the rates of misdiagnosis and missed diagnosis rate was 9.03%, 15.62% respectively, which was significantly lower than the ultrasound and CT(P<0.05). Conclusion: Ultrasound should be the preferred method of diagnosis of benign and malignant thyroid nodules, but ultrasound and CT diagnostic also have advantages and disadvantages, the combination of ultrasound and CT should thyroid nodules qualitative to improve the diagnosis of benign and malignant thyroid nodules accuracy.

Analysis of Brain Damage and Cerebral Vasospasm in Patients with SAH by 256 Slice Spiral CT CTA

LIU Qun, LIU Li, QIAO Hong-yan, FU Tian-peng, JIANG Jian-wei, FAN Chang-yan

2015, 24(6): 857-863. doi: 10.15953/j.1004-4140.2015.24.06.12

Abstract(631) PDF(1)

Abstract:
Objective: To study the diagnostic effect of SAH(CT) in the diagnosis of primary subarachnoid hemorrhage(CTA) and to evaluate the effect of serum S-100 protein on brain damage and cerebral vasospasm in SAH patients. Methods: patients with CTA from 2013 April 2014 march in our hospital, according to Glasgow Coma Scale(GCS) coma score and hunt Hess grade divided into different groups, they were detected by 256 slice spiral CT head CTA examination and serum S-100 B protein levels. Results: In 77 patients with SAH by CT sports a CTA examination 59 aneurysm. GCS score 3~8 points of patients admitted to hospital after 1 d, 7 d S-100 B protein levels were(1.94 ±0.31) μg/L respectively,(1.93 ±0.28) μg/L was significantly higher than patients with GCS score 9~12 points 1d, d after admission S-100 B protein levels(1.13 ±0.21) of μg/L,(1.09 ±0.19) μg/L and GCS score 13~15 points, 1 d, 7 d after admission in patients with S-100 B protein levels(0.54 ±0.09) of μg/L, μg/L(0.52 ±0.06), statistically significant difference(P<0.05). Hunt and Hess grade I^II patients admitted to hospital after 1 d, 7 d S-100 B protein levels were(0.68 ±0.12) μg/L,(0.64 ±0.11) of μg/L significantly lower than Hunt-Hess level III patients admitted to hospital after 1 d, 7 d S~100B protein levels(1.15 ±0.18) μg/L,(0.98 ±0.12) μg/L and Hunt-Hess level IV patients admitted to hospital after 1 d, 7 d S~100B protein levels(2.08 ±0.25) of μg/L,(1.99 ±0.23) μg/L, statistically significant difference(P<0.05). Conclusion: 256 slice spiral CT head and neck CTA scan can be effective response to the peripheral vascular three-dimensional structure of patients with SAH, the SAH patients with S-100 B protein level detection, can effectively evaluate the degree of brain damage and vascular spasm in SAH patients.

Application Status and Research Trends of the Low-dose CT Perfusion Imaging of Pancreas

TAN Zheng-wu, REN Ke

2015, 24(6): 865-872. doi: 10.15953/j.1004-4140.2015.24.06.13

Abstract(620) PDF(2)

Abstract:
At present, imaging diagnosis of the pancreas is gradually changed from the single morphological diagnosis to combining of morphological and functional diagnosis in the CT perfusion; CT perfusion is a kind of functional imaging technology developed on the basis of conventional CT scan, which could earlier detect and diagnose the pancreatic diseases by observing the pancreas microcirculation changes using CT perfusion. It is a hotspot in the research field of the pancreas disease. Radiation dose was significantly increased using CT perfusion scanning with conventional scanning conditions. How to do low dose CT perfusion becomes the key direction of current discussion. This review deals with the application status and research trends of the technology in the low-dose CT perfusion imaging of pancreas.

Research Progress of CBCT on Airway Morphology

ZHENG Ying, CAI Xing-wei, YANG Yong-jin, HAO Li-jing

2015, 24(6): 873-880. doi: 10.15953/j.1004-4140.2015.24.06.14

Abstract(576) PDF(3)

Abstract:
Upper airway is an important component of the human body. With the application of various imaging methods, it has been known deeply. Previous research has its limitation and unreliability, and now CBCT is becoming an useful method to study airway morphology and size. The present research progress at home and abroad are summarized. A variety of airway division standards, a variety of analysis and measurement software method are introduced. they investigated the difference of the upper airway morphology between different skeletal patterns mainly by measuring projects such as the airway volume, length, area, anteroposterior and lateral dimensions of cross-section, so as to guide the treatment of micromaxillary deformity and airway disease.

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2015 Vol. 24, No. 6