ABSTRACT
BackgroundThe corona-virus disease 2019 (COVID-19) pandemic has caused a serious public health risk. Compared with conventional high-resolution CT (C-HRCT, matrix 512), ultra-high resolution CT (U-HRCT, matrix 1024) can increase the effective pixel per unit volume by about 4 times. Our study is to evaluate the value of target reconstruction of U-HRCT in the accurate diagnosis of COVID-19. MethodsA total of 13 COVID-19 cases, 44 cases of other pneumonias, and 6 cases of ground-glass nodules were retrospectively analyzed. The data were categorized into groups A (C-HRCT) and B (U-HRCT), following which iDose4-3 and iDose4-5 were used for target reconstruction, respectively. CT value, noise, and signal-to-noise ratio (SNR) in different reconstructed images were measured. Two senior imaging doctors scored the image quality and the structure of the lesions on a 5-point scale. Chi-square test, variance analysis, and binarylogistic regression analysis were used for statistical analysis. ResultsU-HRCT image can reduce noise and improve SNR with an increase of the iterative reconstruction level. The SNR of U-HRCT image was lower than that of the C-HRCT image of the same iDose4level, and the noise of U-HRCT was higher than that of C-HRCT image; the difference was statistically significant (P< 0.05). Logistic regression analysis showed thatperipleural distribution, thickening of blood vessels and interlobular septum, and crazy-paving pattern were independent indictors of the COVID-19 on U-HRCT. U-HRCT was superior to C-HRCT in showing the blood vessels, bronchial wall, and interlobular septum in the ground-glass opacities; the difference was statistically significant (P < 0.05). ConclusionsPeripleural distribution, thickening of blood vessels and interlobular septum, and crazy-paving pattern on U-HRCT are favorable signs for COVID-19. U-HRCT is superior to C-HRCT in displaying the blood vessels, bronchial walls, and interlobular septum for evaluating COVID-19.
ABSTRACT
BackgroundAn ongoing outbreak of mystery pneumonia in Wuhan was caused by coronavirus disease 2019 (COVID-19). The infectious disease has spread globally and become a major threat to public health. PurposeWe aim to investigate the ultra-high-resolution CT (UHR-CT) findings of imported COVID-19 related pneumonia from the initial diagnosis to early-phase follow-up. MethodsThis retrospective study included confirmed cases with early-stage COVID-19 related pneumonia imported from the epicenter. Initial and early-phase follow-up UHR-CT scans (within 5 days) were reviewed for characterizing the radiological findings. The normalized total volumes of ground-glass opacities (GGOs) and consolidations were calculated and compared during the radiological follow-up by artificial-intelligence-based methods. ResultsEleven patients (3 males and 8 females, aged 32-74 years) with confirmed COVID-19 were evaluated. Subpleural GGOs with inter/intralobular septal thickening were typical imaging findings. Other diagnostic CT features included distinct margins (8/11, 73%), pleural retraction or thickening (7/11, 64%), intralesional vasodilatation (6/11, 55%). Normalized volumes of pulmonary GGOs (p=0.003) and consolidations (p=0.003) significantly increased during the CT follow-up. ConclusionsThe abnormalities of GGOs with peripleural distribution, consolidated areas, septal thickening, pleural involvement and intralesional vasodilatation on UHR-CT indicate the diagnosis of COVID-19. COVID-19 cases could manifest significantly progressed GGOs and consolidations with increased volume during the early-phase CT follow-up.
ABSTRACT
BACKGROUND:The hemodynamics changes of aneurysm provide the basis for aneurysm treatment and ruptured aneurysm prevention, while finite element analysis is a good technical means. OBJECTIVE:To construct the two-way flow-solid coupling model of internal carotid artery aneurysm, and thus simulate its flows. METHODS:CT angiography data of internal carotid artery aneurysm were recorded with GE Lightspeed 64 spiral CT scanning, and the corresponding three-dimension model was constructed with mimics10.01 software. Then the fluid-solid coupled flow simulations were done depending on Ansys+Fluent software. RESULTS AND CONCLUSION:The two-way flow-solid coupling model of internal carotid artery aneurysm was built, with the same morphology and anatomy as the three-dimensional CT imaging. In the whole cardiac cycle, the blood flow of aneurysm body was swirl typed and its velocity was slower than that of the aneurysm neck;the deformation, wal shear stress, pressure and von Mises stress of aneurysm wal were the maximum at the neck, and the minimum at the top. Their highest value was at the 0.16 s (rapid ejection period), and their lowest value at the 0.74 s (relaxation period). On the basis of CT angiography data, to construct the two-way flow-solid coupling model of internal carotid artery aneurysm is a simple and practical method. The blood flow simulation of aneurysm is close to the human physiological conditions, and the results wil provide new theoretical basis for the study on the occurrence and development of aneurysm.
