CT理论与应用研究

A New Calculation Method of Rock Elastic Modulus Based on Kuster-Toksöz Model

MU Xing, HAN Yongliang, SONG Jianguo

2019, 28(3): 279-290. doi: 10.15953/j.1004-4140.2019.28.03.01

Abstract(285) PDF(3)

Abstract:
In the process of combining the Kuster-Toksöz (KT) model with the differential effective medium theory (DEM), the rock elastic modulus of the porous medium is finally obtained by continuously replacing the matrix with the pore inclusions. The pore volume that is replaced each time is constant in the existing method. While the matrix volume is decreasing, the calculated rock elastic modulus is greatly deviated from the Xu-White model. In this paper, it is by improving the pore volume calculation formula for each replacement so that the replacement volume is gradually decreased with the increase of the number of iterations. And it keeps the ratio of the replacement volume to the matrix volume constant. When the number of iterations is large enough, The ratio is sufficiently small. The requirements of the KT calculation formula are satisfied and the calculation result is closer to the theoretical value. The test results show that with the increase of porosity, the equivalent elastic modulus of rock gradually converges to the elastic modulus of the pore inclusions, indicating that the method accords with the physical understanding; compared with the existing KT iterative model, the calculation results using this method are closer to the Xu-White model. The new method proposed that the calculation formulas of the actual volume and the calculated volume of pore inclusions are more in line with the pore segmentation process of KT model.

Effect of Different Concentrations of Iodine Contrast Agent on MSCT Hepatic Artery Enhancement under the Guidance of Body Surface Area

XIA Zhenying, DING Jinli, YIN Yue, SUN Hanchen, LI Hongjun

2019, 28(3): 291-298. doi: 10.15953/j.1004-4140.2019.28.03.02

Abstract(377) PDF(6)

Abstract:
To evaluate the effects of different concentrations of iodine contrast agent on MSCT hepatic artery enhancement. Methods: A total of 328 patients who underwent enhanced CT scan of the upper abdomen were selected as study subjects. According to different concentrations of contrast agents, they were divided into study group and control group. The study group received 400mgI/mL contrast agent, while the control group received 370mgI/mL contrast agent. The injection flow rate of the contrast agent was 2.5mL/s. All patients underwent three-phase enhanced scan of the liver and reconstruction of the hepatic artery. The enhancement value of abdominal aorta at different levels, the display rate of various branches of hepatic artery and the image quality of hepatic artery were compared between the two groups. Results: The enhancement values of hepatic portal level, peritoneal trunk level and renal artery level in the study group were significantly higher than those in the control group. There was no significant difference in the rate of hepatic arterial branches between the study group and the control group. There were statistically significant differences in the image quality scores of the study group and the control group. The image quality of the hepatic artery in the 400 group was more clear and sharp than that of the control group. Conclusion: The dose of contrast agent is determined by body surface area, which is beneficial to individual use of contrast agent. The use of 400mgI/mL contrast agent can reduce the dose of contrast agent, improve the strengthening efficiency of abdominal aorta and optimize the image quality of liver artery, which is worthy of clinical promotion.

Prediction of Terrestrial Gas Hydrate Accumulation Based on Support Vector Regression

PENG Yan, ZHANG Xueqiang, LU Peng, FU Kangwei

2019, 28(3): 299-310. doi: 10.15953/j.1004-4140.2019.28.03.03

Abstract(237) PDF(8)

Abstract:
Natural gas hydrate, commonly known as "combustible ice", had been extensively surveyed. Since the discovery of natural gas hydrate in Muli area of Qinghai province for the first time. However, the geological structure in this area was complex and gas hydrate accumulation rule is unclear. It's difficult for a single geophysics method to make full use of information to effectively find gas hydrate anomalies. In this paper, the features which were favorable for gas hydrate accumulation were extracted from geology, geophysics and geochemistry data In Muli area, and the corresponding transformation rules were proposed. Support vector regression was used to carry out the study of gas hydrate prediction, and the results were evaluated. The results showed that the drilling with hydrates and the drilling without hydrates were consistent with the prediction. The algorithm was effective and practical, and it could offer the guide for future exploration.

Algebraic Reconstruction Method Physical Model Ultrasonic Image Reconstruction

HE Tian, SHAN Tianshu, KONG Dehui, WANG Yakun, WANG Chengyong, WU Faen, CHEN Licheng

2019, 28(3): 311-321. doi: 10.15953/j.1004-4140.2019.28.03.04

Abstract(227) PDF(9)

Abstract:
Use the "DC4 Ultrasonic Detector" to detect the aluminum plate embedded with gypsum, with an unknown distribution of the velocity of the longitudinal wave, and collect "arrival time" data along each ray. Radon transform (line integral) is done on rays along the unknown digital image, with the same ray arrangement each ray's integral step is constant, thus easy to set up a linear algebraic equations of the unknown digital image. Use "Algebraic Reconstruction Technique" addition modified iteration to compile R program, with this program to handle the "arrival time vector" data and reconstruct the unknown digital image. The necessary and sufficient conditions, the test conditions and the inspection method for identifying the gypsum hole are proposed to identify the location of the gypsum hole on the aluminum plate mode based on the reconstructed digital image. In addition, the "Three-plate plane model" was tested and analyzed according to the same treatment method for the aluminum plate mode. The results of image reconstruction in this paper have reference value for understanding CT imaging methods and contribute to the popularization and application of CT imaging technology.

Applicative Research of 3 Different Intestinal Preparation Methods in CT Enterography

MA Zhoupeng, CHEN Bingye, FU Qitian, FU Wenbing, LIN Guansheng

2019, 28(3): 323-330. doi: 10.15953/j.1004-4140.2019.28.03.05

Abstract(474) PDF(4)

Abstract:
Objective: To explore the applicative value of 3 different intestinal preparation methods in CT enterography (CTE). Methods: A prospective study was conducted in 156 patients which were suspected of small intestinal lesions and underwent CTE. 156 cases were randomly divided into group A, B and C with 52 cases in each group. The intestinal contrast agents were taken orally all. Group A and B ate semi-liquid diet 16 hours before scanning, and took 6g of senna leaf for catharsis. They fasted for 12 hours before scanning, and Group A tried to take isotonic mannitol every 15 minutes from 1 hour before scanning, Group B tried to take drinking water as much as possible by the same way. Group C fasted for 6 hours before scanning and tried to take drinking water every 15 minutes from 1 hour before scanning. CTE was performed in all three groups 10 minutes after oral administration of contrast agent. The filling effect of small intestine and the diagnostic value for small intestinal lesions in 3 groups were compared respectively. Results: The filling effect of small intestinal in group A was the best, followed by group B, and group C was the worst. The diagnostic results of small intestinal lesions showed that group A had significant diagnostic value for all segments of small intestine lesions; group B had obvious diagnostic value for duodenal and jejunal lesions, but the diagnostic effect for small lesions of distal ileal was poor; group C had satisfactive diagnosticeffect for duodenal and upper jejunal lesions, but was not conducive to reveal small lesions of distal ileal. Conclusion: Full intestinal preparation is the important technical factor of CTE, and take isotonic mannitol filling intestine as much as possible is conducive to reveal intestinal lesions, which is a safe, reliable, cheap and convenient intestinal preparation method.

Study of Conventional Quantitative CT in the Identification of Urinary Tract Stones

ZHOU Zhenyuan, ZHANG Junwen, LIU Zhifeng, CAI Jinhui, RUAN Yaoqin, GUO Donghua, LIU Qingyu, XU Jinge

2019, 28(3): 331-338. doi: 10.15953/j.1004-4140.2019.28.03.06

Abstract(276) PDF(4)

Abstract:
Objective: The aim of this study is to assess the value of spiral CT parameters in differenting stone composition of urinary tract. Methods: Preoperative CT data of 112 patients with urinary calculi in our hospital from May 2016 to March 2018 were collected. All images were reviewed using abdomen windows to evaluate the following data of stone: the diameter (d), mean CT value (HUm), standard deviation of the mean CT value (HUsd), and the ratio of average CT value/diameter (HUd). The the differences of various stone components were compared for the above factors with statistical methods. Diagnostic performance of the d, Hum, HUsd and HUd for different stone components were measured by receiver operating characteristic curve (ROC curve). Results: There were 21 cases of uric acid stones, 49 cases of calcium oxalate monohydrate, 10 cases of carbonate apatite and 27 cases of mixed stones. The HUm, HUsd and HUd values of uric acid stones were significantly lower than other types of stones, and the difference were statistically significant between uric acid stones and non-uric acid stones (n calcium oxalate stone, carbonate apatite and mixed stones) in HUm, HUsd and HUd values (P<0.05). There were no significant difference in HUm, HUsd and HUd values between non-uric stones (P>0.05). There was no significant difference in the d value of various stones (P>0.05). The area under the ROC curve of d, HUm, HUsd and HUd to identify the stone components were 0.444, 0.915, 0.972 and 0.858, respectively. Conclusion: The HUm, HUsd and HUd values of spiral CT can identify uric acid stones and non-uric acid stones. Among them, HUsd has the best identification efficiency, but it cannot distinguish all types of non-uric acid stones.

Correlation of Image Quality and Angiographic Parameters in Two Groups of Angiocatheter by Hepatocellular Carcinoma DSA

LIU Min, LIN Yisheng, WANG Fangjun, LI Weihao, LIU Qiong, BAI Chenhui

2019, 28(3): 339-346. doi: 10.15953/j.1004-4140.2019.28.03.07

Abstract(302) PDF(6)

Abstract:
Objective: To discuss the image quality of HCC based on the angiographic parameters of two types of angiocatheter, i.e. COOK MEDICAL RH angiocatheter and TERUMO MEDICAL RH angiocatheter. Methods: 40 cases (23 males, 17 females) of TACE in the First Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine from June 2018 to January 2019 were selected. Patients ranged from 30 to 75 years with an average age of 56.3 and were all diagnosed with HCC. The actual imaging pressure of celiac trunk and superior mesenteric artery angiography in two groups of patients was analyzed and the image quality was evaluated under the same parameter settings, machinery and image post processing software with 20 cases using COOK MEDICAL RH angiocatheter (the COOK group) and 20 cases using TERUMO MEDICAL RH angiocatheter (the TERUMO group). Results: Among 340 angiography images of 40 cases, 36 cases showed good image quality with 16 from the COOK group and 20 from the TERUMO group, 4 cases showed poor image quality with all from the COOK group. The data was processed and analyzed with SPSS 25.0 software. The mean value of actual pressure of celiac trunk angiography was 107.6 PSI in the COOK group and 93.1 PSI in the TERUMO group, the difference was statistically significant (P<0.05), while that of the superior mesenteric artery angiography was 101.4 PSI in the COOK group and 88.9 PSI in the TERUMO group, the difference was statistically significant (P<0.05). Conclusion: Appropriate pressure should be chosen according to different angiocatheters in the selection of angiographic parameters. Lower pressure is advised in the case of TERUMO MEDICAL RH angiocatheter for good image quality.

Application Value of Dual-source Dual-energy CT Iodine Determination for Preoperative T Staging of Gastric Cancer

YUAN Weibiao, LU Dajun, CUI Lei, QI Rongxing, GAO Hui

2019, 28(3): 347-354. doi: 10.15953/j.1004-4140.2019.28.03.08

Abstract(317) PDF(7)

Abstract:
To study and analyze the value of dual-source dual-energy CT iodine determination in preoperative T staging of gastric cancer. Methods: A total of 110 patients with gastric cancer who underwent dual-source dual-energy CT examination in our hospital from January 2015 to December 2017 and confirmed by surgical pathology were enrolled. The T1 and T2-3 phases were calculated. Normalized iodine concentration (NIC) in the inner and outer layers of the gastric wall and the normal stomach wall during arterial and venous phases, and objective and subjective indicators of image quality at 40keV, 60keV, and 120keV. Results: There was a statistically significant difference between the inner and outer layers of the gastric wall and the normal stomach wall in the T-stage of the lower and middle venous stages (P<0.05). There was no significant difference between the outer layer of the gastric wall and the normal stomach wall during the arteriovenous period (P>0.05). The objective values of CT value, image noise, SNR and CNR image quality in the 120keV group were lower than those in the 60keV group and the 40keV group (P<0.05). The objective quality indicators of the 60keV group were lower than the 40keV group (P<0.05). The overall image quality score of the 60keV group was higher than that of the 40keV group and the 120keV group (P<0.05). There were no significant differences in the significant scores of the three groups (P>0.05). Conclusion: The dual-source dual-energy CT iodine value method is of great value for the differential diagnosis of T1 and T2-3 gastric cancer, and can improve the image quality, which is of great significance for enhancing the accuracy of preoperative T staging of gastric cancer. Has a good clinical application value.

CT Findings of Ovarian Thecoma-fibroma

XING Chunhua, WANG Liping

2019, 28(3): 355-362. doi: 10.15953/j.1004-4140.2019.28.03.09

Abstract(255) PDF(6)

Abstract:
Objective: To investigate characteristic CT manifestations of the ovarian thecoma-fibroma and improve the level of preoperative diagnosis. Methods: Clinical data, CT manifestations and pathological features of 18 cases of ovarian thecoma-fibroma were analyzed retrospectively, and the diagnoses were confirmed by pathology after surgery. Results: Our findings included: 18 patients were all unilateral; 10 lesions were located in the left side of ovary, while 8 lesions were in the right side. Of the 18 lesions, the largest diameters of tumor ranged from 1.5 to 18mm with the mean value of 8.7mm. 13 patients were accompanied by ascites, of which 4 cases were combined with pleural effusion. The shape of 13 lesions appeared round or elliptic, and 1 lesion with lobulation, 4 lesions were irregular. All the tumors had well-defined or mostly well-defined borders. The tumors showed solid density in 7 cases, cystic solid density was observed in 11 cases. No enhancement was found in the cystic part after enhancement. The solid part of solid mass or cystic solid mass showed no obvious enhancement in the arterial phase after injection of the contrast medium, while in venous phase and delayed phase presented continuous and asymptotic slight enhancement. The CT value of the solid part increased by 2~18HU in the delayed phase after enhancement compared with plain CT scan, and did not exceed 20HU. Conclusions: The characteristic CT manifestations of the ovarian thecoma-fibroma were often unilateral solid mass with the shape of oval and well defined border; slight enhancement; accompanied by ascites.

CT and MRI Imaging Findings of Solid Pseudopapillary Tumor of Pancreas

WANG Yuebo, CHEN Guangwen, PU Hong

2019, 28(3): 363-369. doi: 10.15953/j.1004-4140.2019.28.03.10

Abstract(252) PDF(5)

Abstract:
Objective: To investigate the CT and MRI imaging manifestation of solid-pseudopapillary tumor of pancreas (SPTP) and to improve the diagnostic accuracy of the lesion. Methods: A retrospective analysis was performed on the comprehensive manifestations of CT, MRI and clinical information of 18 cases of SPTP confirmed by pathology and surgery. Results: 13 cases were examined with CT, 8 cases were examined with MRI and 4 cases were examined with both CT and MRI. The patients included 3 male and 15 females with mean age of 33 years (range 17~63). The mean diameter of tumor was 6.0cm. The lesions were located in the pancreatic head in 5 cases, in the pancreatic tail in 13 cases. The tumors had regular shape in 13 cases, irregular shape in 5 cases. 15 cases of plain and enhanced CT scan showed cystic-solid tumors, the solid part of SPTP was mildly enhanced during arterial phase, and it was progressively filled during portal venous phase and equilibrium phase. The cystic part was not enhanced. The capsule of 5 cases was incomplete. 5 cases presented as granular calcification. 8 cases were examined by plain and enhanced MRI and presented cystic-solid tumors. 4 cases appeared hemorrhage with incomplete capsule in 3 cases. 1 case located in the pancreatic head leading to the secondary ducts dilatations. Conclusion: There are some characteristics in the CT and MRI manifestations of SPTP and the comprehensives analysis of imaging manifestations of the lesion has very important valuable for accurate diagnosis and differential diagnosis.

Analysis of the Value of Three-dimensional CT and X-ray Examination in Calcaneal Fractures

SUN Guangjiang, YAO Xiaosheng, YANG Dongxiang

2019, 28(3): 371-376. doi: 10.15953/j.1004-4140.2019.28.03.11

Abstract(225) PDF(7)

Abstract:
objective: to study the accuracy and utility of 3D CT and X-ray in evaluating calcaneal fracture injury. Methods: 32 cases of calcaneal fracture from January 2017 to January 2018 were selected. 3D CT and X-ray films were used to analyze the degree and location of calcaneal injury. The accuracy of the results was judged (based on the results of operation). The accuracy of the results was compared with McNemar test. Results: 3D CT reconstruction of calcaneal fracture was superior to X-ray in the diagnosis of articular surface. The description has higher clinical application value. Conclusion: 3D CT reconstruction of calcaneal fracture can effectively improve the accuracy and utility of evaluation of fracture injury, and has clear significance for clinical diagnosis and treatment.

The Value of Dual-phase Enhanced Multi-slice Spiral CT on Diagnosis of Parathyroid Adenoma

YUAN Hui, DUAN Yongli, CHEN Xiaobai, WEN Tingguo, WANG Rengui

2019, 28(3): 377-384. doi: 10.15953/j.1004-4140.2019.28.03.12

Abstract(265) PDF(5)

Abstract:
Objective: to investigate the characteristics of parathyroid adenoma on multi-slice spiral CT (MSCT) and 3 dimension (3D) reformatted images, evaluate this technique in diagnosing parathyroid adenoma preoperatively. Materials and Methods: CT findings were retrospectively analyzed in 63 patients with pathologically conformed parathyroid adenoma (PTA). Results: 62 (98.4%) cases of PTA were solitary, 1 (1.6%) case with multiple nodules, there were 64 lesions altogether, 45 (70.3%) of which located in the trachea-esophageal sulcus at the thyroid lower pole, 15 (23.4%) of which located in the trachea-esophageal sulcus at the thyroid upper pole, 4 (6.3%) lesions were ectopic adenoma. On plain CT scan, all lesions showed homogeneous or heterogeneous soft tissue density, 33 (51.6%) lesions of which displayed the "short-line sign". In the early phase of contrast enhanced CT, significant enhancement was found in all lesions, in the later phase, the density difference between the tumor and surrounding tissues became lesser. However, there was less change in the "short-line sign" after administration of contrast enhancement. Conclusion: MSCT and 3D reformation can demonstrate the location, size, shape and texture of PTA, as well as the relationship between the tumor and adjacent structures. There would be important for the qualitative diagnosis and localization in patient with PTA. 3D reformatted images showed long axis of 53 (82.8%) lesions parallel to the long axis of the body, 3D reformation can display the relationship between lesions and the surrounding tissue.

CT Feature Analysis of Metanephric Adenoma

HUANG Jieling, LI Yuanzhang, LIN Bingquan, QIU Ya

2019, 28(3): 385-392. doi: 10.15953/j.1004-4140.2019.28.03.13

Abstract(205) PDF(4)

Abstract:
Objective: to analyze CT features and pathological features of metanephric adenoma in order to improve the preoperative diagnostic accuracy of MA. Data and methods: CT imaging data and pathological features of 5 patients with MA confirmed by surgical pathology was retrospectively analyzed, and MSCT manifestations and pathological features of MA were summarized in combination with literature. Results: all the 5 patients were female, aged 35-58 years, with an average age of 48 years. The lesions were almost round in shape with an average diameter of about 7.5cm. In 5 cases, the lesion protruded into the renal collecting system or/or the renal extrorenal system, and the surrounding structures were compressed and pushed, without local invasion or metastasis. The density of the lesions on plain scan was similar to that of renal parenchyma, but the density was not uniform. There was no bleeding, calcification or capsule in the lesions. In 5 cases, progressive heterogeneous enhancement was observed in the lesion on enhanced scan, mild enhancement was observed in the cortical phase, mild to moderate enhancement was observed in the parenchymal phase, and moderate enhancement was observed in the excretory phase. Low-density scar was observed in 2 cases. Pathology showed that the MA range and shape tended to be consistent with the section of the gross specimen, and was clearly demarcated from the surrounding renal tissue. MA cells were arranged in small glandular tubules with few cytoplasm and small nuclei. No mitotic figure and necrosis were observed. Immunohistochemical ki-67 (+, < 5%), -catenim (+), CK (+) and CK7 (+) were detected. Conclusion: the CT manifestations of MA have certain characteristics, combined with the occurrence of erythrocythemia in female patients, which is helpful to improve the preoperative diagnosis accuracy of MA.

Research Progress of Low Dose CT Imaging Based on Feature Learning

LIU Jin, ZHAO Qianlong, YIN Xiangrui, GU Yunbo, KANG Jihuai, CHEN Yang

2019, 28(3): 393-406. doi: 10.15953/j.1004-4140.2019.28.03.14

Abstract(374) PDF(35)

Abstract:
The continuous development and extensive use of CT in modern medical practice has raised a public concern over the associated radiation dose to the patient. Hence, extensive efforts have been made to design better image reconstruction or image processing methods for low-dose CT over the past years. The recent explosive development of learning type algorithm suggests new thinking and huge potential for the CT imaging field under the imaging big data environment. This paper summarizes the development and implementation of low dose CT scans from the following aspects: sparse learning and deep learning. The research status of low dose CT technology and feature learning models are also summarized. Finally, both the current research focus and the future research prospect are discussed and analyzed.

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2019 Vol. 28, No. 3