RESUMO
Objective To compare the conventional non-enhanced and virtual non-enhanced images of dual-energy computed tomography (CT) in evaluating solitary pulmonary nodules (SPNs).Methods Forty-seven patients with SPNs proved by pathology underwent conventional and enhanced thoracic DECT.The virtual non-enhanced CT images and iodine images were reconstructed based on the enhanced imaging data.The mean CT number,noise,signal to noise (SNR),nodual diameter of SPNs were compared between the true non-contrast CT(TNCT) and the virtual non-contrast CT (VNCT),with paired t test.The image quality and detectability of calcification were also compared.The diagnostic accuracy for malignant nodulesbased on the increased CT values and iodine-enhanced image were compared.The independent t test was used to compare the increased CT number of SPNs and iodine images.The single-phase radioation dose of the single energy,was compared with dual energy scan.Results No significant difference in the mean CT Number(t =1.556,P ＞ 0.05),noise (t =-0.357,P ＞ 0.05),SNR (t =0.767,P ＞ 0.05) on TNCT and VNCT.The mean CT Number,the noise,and SNR were (29.90 ± 12.43)vs (27.52 ± 16.67) HU,(9.60 ±3.74) vs (9.88 ± 2.90),and (3.07 ± 1.93) vs (2.76 ± 2.36),respectively.The increased CT number ofSPNs with TNCT and VNCT from baseline were(18.63 ± 8.03) and(20.45 ± 9.13) HU.The CT number of iodine image was(23.82 ± 9.20)HU.A significant difference was observed between the TNCT and iodineed image (t =-2.371,P ＜ 0.05).The quality scores of VNCT image wasslightly worse than TNCT image.The detectability rate of calcification on VNCT was 92.3％ (72/78).The iodine image carried the highest diagnostic sensitivity rate and accuracy rate,82.3％ (28/34)and 74.5％ (35/47),respectively.The highest specificity rate was 76.9％ (10/13) from the increased CT number with VNCT.No significant difference in single-phase radiation dose was observed between TNCT and VNCT,(5.68 ± 1.31) vs.(4.89 ± 1.27)mSv.Conclusions VNCT could be obtained with similar image quality as TNCT.This methods might favor a reduction in radiation exposure.
RESUMO
Objective To study the effects of acute hypervolemi c hemodilution (AHH) on the coagulation and cardiac function in elderly surgical p atients. Method Sixty surgical patients, aged 60 to70, ASA Ⅰ~ Ⅱ, were randomly divided into three groups (n=20 for each group). 6% HES 50 0~1000ml was infused in a rate of 20ml/min during vasodilation with isoflurane i nhalation (group 1), nitroglycerin (group 2), or nicardipine (group3) with the a id of an intravenous injection pump. The blood coagulation and cardiac functions were observed during hemodilution. Results No significant diff erence was found among the three groups on cardiac function and coagulation func tion during 500ml 6% HES infusion. When the volume of infusion was over 1000ml, the parameters of cardiac function increased and those of coagulation decrease d significantly (P