RESUMO
Objective To investigate the correlation between the blood flow characteristics of contrastenhanced ultrasound (CEUS) and malignancy of patients with ovarian tumor.Methods 60 cases with ovarian tumors treated by surgery and confirmed by pathology were selected,including 28 cases of ovarian cancer and 32 cases of benign ovarian tumor.The time of arrival (AT),peak time (TTP) and intensity of enhancement (EI) were determined by CEUS,and microvessel density (MVD) of tumor tissue was detected by immunohistochemistry.The correlation of the above parameters with MVD and tumor staging was analyzed.Results AT,TTP of the malignant tumor group (10.8±2.1,25.3±10.5) was significantly lower than those of the benign tumor group (15.4±2.7,59.4±11.2).EI of the malignant tumor group (28.6±2.9) was significantly higher than that of the benign tumor group (14.9±2.6),with statistical significance (P＜0.05).MVD of the malignant tumor group (62.8± 13.6) was significantly higher than that of the benign tumor group (21.5±11.4),with significant difference (P＜0.05).AT and TTP were negatively correlated with MVD and FIGO staging (r=-0.562,r=-0.504,r=-0.636,r=-0.623),while EI was positively correlated with MVD and FIGO staging (r=0.839 and r=0.785),with statistical difference (P＜0.05).Conclusions Blood flow characteristics of CEUS are closely related to the malignancy of ovarian tumors.CEUS can accurately evaluate angiogenesis,blood perfusion and malignancy of ovarian tumors.
RESUMO
Objective To study the flow characteristics of the upper airway and force dynamics of the soft palate and uvula in a representative male OSAHS (obstructive sleep apnea hypopnea syndrome) patient during normal respiration. Methods A CT image-based reliable geometry model of the upper airway was established. Numerical simulation boundary conditions were determined by clinical data of sleep monitoring, and the low-Reynolds number turbulence model was adopted to calculate the flow movement during a complete respiration period. Results The flow characteristics of the upper airway were obviously different in the breathing process of OSAHS patient. During inspiration, the maximum velocity of airflow in the upper airway reached 9.808 m/s, and the maximum negative pressure of airflow reached -78.856 Pa. Backflow districts were found at top of the nasal cavity. The maximum pressure on the soft palate was -10.884 Pa, and that on the uvula was -51.946 Pa. The maximum shear stress on the soft palate and uvula was 78 and 311 mPa, respectively. During expiration, the maximum velocity of airflow in the upper airway was 10.330 m/s, and the maximum negative pressure was -51.921 Pa. Backflow was observed to appear both at the oropharynx and top of the nasal cavity. Specifically, clockwise backflow was remarkable at the oropharynx. The maximum pressure on the soft palate was 2.603 Pa, and that on the uvula was -18.222 Pa. The maximum shear stress on the soft palate and uvula was 51 and 508 mPa, respectively. Conclusions Oropharynx is most likely to collapse in the upper airway. Numerical simulation on the respiratory cycle can capture the salient backflow features of the flow field in the upper airway. The backflow in the upper airway directly affects the forces on the soft palate and uvula and the breathing fluency of OSAHS patients.