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Objective:To explore the application value of CT pulmonary function imaging in patients with Coronavirus Disease 2019 (COVID-19) in the convalescent phase.Methods:The COVID-19 patients who were clinically cured and discharged from Union Hospital, Tongji Medical College, Huazhong University of Science and Technology were prospectively collected from January to April 2020. Clinical pulmonary function tests (PFTs) and CT pulmonary function imaging were performed 3 months after discharge. The Philips IntelliSpace Portal image post-processing workstation was used to obtain the paired inspiratory-expiratory CT quantitative indexes of the whole lung, left lung, right lung and five lobes. The patients were divided into two groups according to whether residual lesions remain in inspiratory CT images: non-residual lesion group and residual lesion group. The chi-square test was used to compare the differences in the PFT results between groups; the Mann-Whitney U test was used to compare the differences in PFT indexes [forced expiratory volume in the first second as percentage of predicted value (FEV 1%), FEV 1/forced vital capacity (FEV 1/FVC), total lung capacity as percentage of predicted value (TLC%), FVC%] and the differences in quantitative CT indexes [lung volume (LV), mean lung density (MLD), volume change in inspiratory phase and expiratory phase (?LV)] between groups. Multiple linear regression was used to analyze the relationship between CT pulmonary function imaging and PFT indexes of convalescent COVID-19 patients. Results:Of the 90 patients with COVID-19, 35 were males and 55 were females; 45 were included in the non-residual lesion group and 45 were included in the residual lesion group. Fifty-three patients had clinical pulmonary dysfunction 3 months after discharge, including 22 patients in the non-residual lesion group and 31 patients in the residual lesion group. In patients with residual disease, left lower lobe and right lower lobe LV, left lower lobe and right lower lobe ?LV in the inspiratory and expiratory phase were smaller than those without residual disease; whole lung, left lung, right lung, left upper lobe, left lower lobe and right lower lobe MLD in the inspiratory phase and left lower lobe and right lower lobe MLD in the expiratory phase were greater than those without residual disease ( P<0.05). Since there was no significant difference in FEV 1/FVC and FVC% between residual and non-residual lesion groups ( P>0.05), FEV 1/FVC and FVC% of two groups were combined. Multiple linear regression analysis showed FEV 1/FVC=91.765-0.016×LV in-right middle lobe+0.014×MLD ex-left lower lobe ( R2=0.200, P<0.001), FVC%=-184.122-0.358×MLD in-right lung-0.024×?LV left upper lobe ( R2=0.261, P<0.001). There was significant difference in TLC% between residual and non-residual lesion groups ( P<0.05), so multiple linear regression analysis was performed both in the two groups. In the non-residual lesion group, TLC%=80.645+0.031×LV ex-right lower lobe ( R2=0.132, P<0.001); In the residual lesion group, TLC%=-110.237-0.163×MLD in-right upper lobe-0.098×MLD ex-left upper lobe -0.025×LV ex-right lower lobe ( R2=0.473, P<0.001). Conclusion:CT pulmonary function imaging can quantitatively analyze the whole lung, unilateral lung and lobulated lung, thus reflecting the regional pulmonary function, providing more valuable diagnostic information for the assessment of pulmonary function in convalescent patients with COVID-19.
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Objective:To investigate the optimal monoenergetic level of virtual monoenergetic images (VMI) in transplanted renal artery on a dual-layer spectral detector CT.Methods:A retrospective study was performed on 16 renal transplant patients who underwent transplanted renal angiography on a dual-layer spectral detector CT in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from June 2020 to April 2021. Conventional 120 kVp polyenergetic images (PI) were reconstructed, and virtual monoenergetic images (VMIs) in range of 40-200 keV with interval of 10 keV were reconstructed, too. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of 120 kVp PI and VMIs were measured. Meanwhile, the subjective scores of the display of transplanted renal artery were performed on volume rendering images of 120 kVp PI and VMIs. Spearman correlation analysis was used to explore the correlation between energy levels and SNR or CNR. Rank sum tests were performed to compare the parameters of image quality between the VMI which had the highest SNR and CNR, and the other VMIs, or 120 kVp PI.Results:Among the VMIs, SNR or CNR was negatively correlated with energy levels ( r =-0.86 and -0.88, all P<0.001). The SNR [22.80(18.57, 34.16)] and CNR [35.38(25.97, 39.01)] of 40 keV VMI were the highest, and significantly higher than that of 120 kVp PI and 50-200 keV VMIs, all the differences were statistically significant (all P<0.05). The subjective scores of 40 keV VMI and 120 kVp PI were 5 (5, 5) and 4 (3, 5), respectively. The score of 40 keV VMI was significantly higher than that of 120 kVp PI ( Z=-2.60, P=0.009). There were no significant differences in subjective scores between 40 keV VMI and 50-70 keV VMIs ( Z=-1.00, -1.41, -1.73, P=0.317, 0.157, 0.083), but the subjective score of 40 keV VMI was higher than that of 80-200 keV VMIs and the differences were statistically significant (all P<0.05). Conclusions:As for the images of transplanted renal angiography on a dual-layer spectral detector CT, the image quality of 40 keV VMI was best, thus 40 keV was the optimal monoenergetic level.
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Objective:To study the feasibility that using size-specific dose estimation (SSDE) to estimate organ dose and effective dose in coronary CT angiography (CTA).Methods:Totally 421 consecutive patients with coronary artery CTA were included and retrospectively analized. All patients were scanned using the 3rd generation dual-source Force CT with prospectively ECG gated axis scan mode. The size specific dose estimation(SSDE) for each patient was conducted by calculate water equivalent diameters with Radimetrics. The organ doses of heart, lung, liver and breast, were estimated with Monte Carlo method. Patient-specific effective dose was calculated as a weighted sum of simulated organ doses with the coefficients from ICRP 103. Linear correlation analysis was used to validate the relationship between SSDE and organ doses as well as effective dose, and to derive coefficients for patient specific dose estimation. The mean error rate was used to evaluate estimation accuracy.Results:The CTDI vol, SSDE and effective dose were (16.8±8.7)mGy, (20.8±8.8)mGy and (4.4±2.9)mSv, respectively. The linear fitting formula for estimating organ dose based on SSDE were: Y=1.2 X-6.4 ( R2=0.91, P<0.05, mean error 0.1%) for heart, Y=1.4 X-7.4 ( R2=0.91, P<0.05, mean error 7.9%) for breast, Y=0.89 X-4.6 ( R2=0.86, P<0.05, mean error 8.3%) for lung, and Y=0.36 X-1.8 ( R2=0.64, P<0.05, mean error -17.9%) for liver. The linear fitting formula for estimating the individual effective dose based on SSDE were: Y=0.21 X-1.2 ( R2=0.92, P<0.05, mean error 0.2%) for men, Y=0.39 X-2.2 ( R2=0.93, P<0.05, mean error 1.7%) for women. Conclusions:In coronary artery CTA, the absorbed dose of the organs and patient specific effective dose could be estimated with SSDE and the corresponding conversion coefficients, which will help to achieve personalized assessment and precise management of patient radiation dose and risk in clinical practice.
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Objective To evaluate the diagnose value of nonenhanced electrocardiogram (ECG)?gated quiescent?interval single?shot MR angiography (QISS MRA) in lower extremity arterial stenosis. Methods A retrospective analysis of 30 patients with lower extremity ischemic manifestations and concurrent lower extremity arterial CTA and QISS MRA was performed from April to December 2017 at the Union Hospital of Tongji Medical College, Huazhong University of Science and Technology. All patients underwent CTA and ECG?gated non?contrast?enhanced QISS MRA. The entire lower extremity arteries were divided into 19 segments (lower abdominal aorta, common iliac artery, internal iliac artery, external iliac artery, superficial femoral artery, deep femoral artery, radial artery, anterior tibialis anterior tibial artery, posterior tibial artery, radial artery). Two radiologists scored QISS MRA and CTA image quality using a 4?point scale and assessed the severity of arterial stenosis. Kappa analysis was used to evaluate the degree of stenosis of different examination methods in the same patient and the consistency of the scores of different radiologsts in the same patient. Result A total of 570 vessel segments were collected from 30 patients. The image quality of 560/570 (98.2%) and 548/570 (96.1%) of radiologist 1 was rated as excellent or good by CTA and QISS?MRA (grades 3 and 4), and 561/570 (98.4% of radiologist 2) The image quality of the segment and the 544/570 (95.4%) segment were rated as excellent or good by CTA and QISS?MRA, respectively. The image quality scores of radiologist 1 to CTA and QISS MRA were (3.87±0.38) and (3.70± 0.53), respectively, and radiologist 2 were (3.86±0.40) and (3.68±0.54) respectively. On the QISS?MRA, only 7 of the 570 segments (1.2%, 7/570) obtained images that could not satisfy the diagnostic image quality. The two radiologists used CTA and QISS MRA to evaluate the consistency of different degrees of vascular stenosis. The radiologist 1 evaluated the Kappa value of CTA and QISS MRA between 0.714 and 0.939 for different degrees of vascular stenosis. Radiologist 2 had a Kappa value of 0.603 to 0.939. QISS MRA was used to evaluate the consistency of vascular stenosis in different segments between the two radiologists. The Kappa value ranged from 0.813 to 0.933. Conclusion QISS?MRA is of great value in the diagnosis of lower extremity arterial stenosis.