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Objective:To investigate the application value of dual-energy CT in the differential diagnosis of lung metastases and benign nodules in breast cancer.Methods:The data of 96 patients with pathology-confirmed breast cancer at the Fifth Affiliated Hospital of Wenzhou Medical University from March 2017 to June 2021 were analyzed retrospectively. All patients received dual-energy chest CT scans within 2 weeks before surgery. All 96 patients were female, aged 31-84 (56±12) years. A total of 207 pulmonary nodules from 96 patients were classified into 81 lung metastases and 126 benign nodules according to pathological findings. Conventional CT features [longest diameter, boundary, location and CT value difference between arterial and venous phases (ΔCT) of nodules] and dual-energy CT parameters [standardized iodine concentration (NIC), slope of energy spectrum (λ HU) and normalized effective atomic number (nZ eff) in arterial and venous phases] were analyzed and measured. The χ 2 test, independent samples t test and Kruskal-Wallis rank-sum test were used to analyze the differences of conventional CT features and dual-energy CT parameters between lung metastases and benign nodules. First, the least shrinkage and selection operator (LASSO) regression method was used to screen conventional CT features and dual-energy CT parameters, and then logistic regression analysis was performed to screen out independent risk factors for lung metastases. Receiver operating characteristic (ROC) curves were used to evaluate the efficacy of CT parameters alone and logistic model in differentiating lung metastases from benign lung nodules. Results:There were statistically significant differences between lung metastases and benign nodules in longest diameter, ?CT, NIC, λ HU and nZ eff in arterial and venous phases (all P<0.05). LASSO regression and binary logistic regression analysis showed that the venous phase λ HU (OR=59.413, 95%CI 14.233-248.002, P<0.001) and the venous phase nZ eff (OR=4.508, 95%CI 2.787-7.290, P<0.001) were independent risk factors for predicting lung metastases. Among them, the venous phase λ HU had the highest diagnostic efficiency, with an area under curve (AUC) of 0.794 and an accuracy of 74.88%. The AUC of the logistic model constructed by combining the venous phase λ HU and the venous phase nZ eff could reach 0.958, and the accuracy was improved to 92.27%, which was significantly higher than the efficacy of the two alone ( Z=6.02, 9.54, all P<0.001). Conclusion:Dual-energy CT has great application value in the identification of lung metastases and benign nodules in patients with breast cancer, especially when combined with venous phase λ HU and venous phase nZ eff, the diagnostic efficiency is further improved.
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Objective:To evaluate image quality and radiation dosage of CT cerebral perfusion (CTP) imaging of 70 kV with different tube current and scanning passes and its diagnostic value for hyperacute cerebral infarction.Methods:A total of 190 patients with suspected hyperacute cerebral infarction in Lishui Central Hospital of Zhejiang Province from December 2017 to February 2019 were selected prospectively, and all patients were divided into 4 groups according to random number table and received non-contrast CT examination and dual-source CT cerebral perfusion imaging with 70 kV protocol simultaneously within 6 hours after the onset of symptoms: group A, 120 mA, 21 scanning time points; group B, 100 mA, 21 scanning time points; group C, 100 mA, 17 scanning time points; group D, 80 mA, 21 scanning time points. The values of perfusion parameters such as cerebral blood flow (CBF), crerbral blood volume (CBV), mean transit time (MTT), time to peak (TTP) were acquired. Image quality was evaluated and effective dose (ED) was recorded. The quantitative variables of image quality and radiation dosage were compared between four groups using one-way analysis of variance test.Results:There was no differences between groups on the CBF, CBV, MTT, TTP maps for all CTP values ( P>0.05), and all images could meet the diagnostic requirements. The subjective image quality score of vessel sharpness and overall image quality of both internal carotid artery and middle cerebral artery and the degree of noise of internal carotid in artery in group A was higher than that in group D ( P<0.05). The score of vessel sharpness of internal carotid in artery ingroup A was higher than those in both groups B and C ( P<0.05). The scores of vessel sharpness of both internal carotid artery and middle cerebral artery internal carotid in artery ingroups B and C were higher than that in group A ( P<0.05). The mean EDs of non-contrast CT in group A, B, C, D were 1.10, 2.11, 1.76, 1.42, 1.40 mSv; compared to group A, ED was reduced approximately 16.6% (0.35/2.11), 32.7% (0.69/2.11) and 33.6% (0.71/2.11), respectively ( P<0.05). The diagnostic accuracy of low dose dual source CTP for detecting hyperacute cerebral infarction was 93.5% (172/184), while that of non-contrast CT was 52.2% (96/184);for detecting hyperacutelacunar cerebral infarction, it was 72.1% (31/43) and 16.3% (7/43) respectively ( P<0.05). Conclusion:Appropriate reduction of tube current (100 mA) and scanning passes (17 scanning time points) can reduce the radiation dosage and acquire comparable image quality for 70 kV protocol CTP. Compared with non-contrast CT, low dose dual-source CTP is more sensitive to hyperacute cerebral infarction, especially hyperacute lacunar cerebral infarction.
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Objective@#To evaluate image quality and radiation dosage of CT cerebral perfusion (CTP) imaging of 70 kV with different tube current and scanning passes and its diagnostic value for hyperacute cerebral infarction.@*Methods@#A total of 190 patients with suspected hyperacute cerebral infarction in Lishui Central Hospital of Zhejiang Province from December 2017 to February 2019 were selected prospectively, and all patients were divided into 4 groups according to random number table and received non-contrast CT examination and dual-source CT cerebral perfusion imaging with 70 kV protocol simultaneously within 6 hours after the onset of symptoms: group A, 120 mA, 21 scanning time points; group B, 100 mA, 21 scanning time points; group C, 100 mA, 17 scanning time points; group D, 80 mA, 21 scanning time points. The values of perfusion parameters such as cerebral blood flow (CBF), crerbral blood volume (CBV), mean transit time (MTT), time to peak (TTP) were acquired. Image quality was evaluated and effective dose (ED) was recorded. The quantitative variables of image quality and radiation dosage were compared between four groups using one-way analysis of variance test.@*Results@#There was no differences between groups on the CBF, CBV, MTT, TTP maps for all CTP values (P>0.05), and all images could meet the diagnostic requirements. The subjective image quality score of vessel sharpness and overall image quality of both internal carotid artery and middle cerebral artery and the degree of noise of internal carotid in artery in group A was higher than that in group D (P<0.05). The score of vessel sharpness of internal carotid in artery ingroup A was higher than those in both groups B and C (P<0.05). The scores of vessel sharpness of both internal carotid artery and middle cerebral artery internal carotid in artery ingroups B and C were higher than that in group A (P<0.05). The mean EDs of non-contrast CT in group A, B, C, D were 1.10, 2.11, 1.76, 1.42, 1.40 mSv; compared to group A, ED was reduced approximately 16.6% (0.35/2.11), 32.7% (0.69/2.11) and 33.6% (0.71/2.11), respectively (P<0.05). The diagnostic accuracy of low dose dual source CTP for detecting hyperacute cerebral infarction was 93.5% (172/184), while that of non-contrast CT was 52.2% (96/184);for detecting hyperacutelacunar cerebral infarction, it was 72.1% (31/43) and 16.3% (7/43) respectively (P<0.05).@*Conclusion@#Appropriate reduction of tube current (100 mA) and scanning passes (17 scanning time points) can reduce the radiation dosage and acquire comparable image quality for 70 kV protocol CTP. Compared with non-contrast CT, low dose dual-source CTP is more sensitive to hyperacute cerebral infarction, especially hyperacute lacunar cerebral infarction.