Objective To investigate the application value of diffusion-weighted imaging with background suppression (DWIBS) in lymph node metastasis of rectal cancer.Methods 30 patients with rectal cancer diagnosed by colonoscopy underwent routine MRI and DWIBS examinations.Metastatic and non-metastatic lymph nodes were confirmed by postoperative pathology.Apparent diffu-sion coefficient (ADC)values of the solid part of metastatic and non-metastatic lymph nodes were measured and compared.ROC curve analysis was used to define the threshold between the metastatic and non-metastatic lymph nodes.Results In all 73 lymph nodes,there were 52 metastatic lymph nodes and the other 21 were non-metastatic.ADC values of the solid part of metastatic and non-metastatic lymph nodes were (0.881 ± 0.094)× 10 -3 mm2/s and (1.072 ± 0.108)×10 -3 mm2/s respectively,the difference was statistically significant (P <0.05).With the threshold ADC value of 0.957×10 -3 mm2/s,the sensitivity and specificity for dif-ferentiating metastatic from non-metastatic lymph nodes were 90.5% and 80.8% respectively.The diagnostic value was excellent (Az value = 0.91 9,P <0.05).Conclusion ADC values may be used to differentiate lymph node metastasis of rectal cancer,and DWIBS has higher application value in assessing lymph node metastasis of rectal cancer.

Objective:To explore the recovery of bladder function in patients with short-term indwelling catheter after urinary dynamic monitor simulated the physiological function of normal filling and emptying of bladder.Methods:From May 2019 to July 2019, a total of 60 patients with short-term indwelling catheters after operation in Department of Urinary Surgery in Beijing Tiantan Hospital of Capital Medical University were selected. According to the method of random block, they were divided into the observation group and the control group, with 30 cases in each group. After the operation, urinary catheters of patients were connected to urinary dynamic monitors by nurses. The control group adopted the smooth drainage mode to continuously drain urine while the observation group adopted the timed mode to automatically open the urine tube once every 3 hours for 5 min each time. The time for first intention to urinate after catheter removal, the first urination time, the first urination volume, hospitalization expense, date of indwelling catheter, date of hospitalization, incidence of bladder spasm, incidence of symptomatic urinary tract infections, incidence of autonomic hyperreflexia and reintubation rate were compared between two groups to evaluate effects of clamping catheter on bladder function.Results:In the control group, time for first intention to urinate was (104.00±29.88) min, the first urination time was (135.90±29.76) min and the first urination volume was (250.17±60.18) ml. In the observation group, time for first intention to urinate was (122.10±37.18) min, the first urination time was (160.33±36.11) min and the first urination volume was (327.17±88.59) ml. The time for first intention to urinate and first urination time in the observation group were longer than those in the control group while the first urination volume was greater than that in the control group, and the differences were statistically significant ( P<0.05) . There was no significant difference between the two groups in hospitalization expense, date of indwelling catheter, date of hospitalization, incidence of bladder spasm and other indexes ( P>0.05) . No symptomatic urinary tract infection, autonomic hyperreflexia or reintubation due to urinary retention occurred in either group. Conclusions:It was effective and safe for maintaining the bladder function using urinary dynamic monitor to simulate filling and emptying of bladder during the short-term postoperative indwelling of the urinary catheter. For patients with short-term indwelling urinary catheter after urology surgery, the bladder can be trained with the timed clamping catheter mode.

Objective To investigate the value of high resolution CT (HRCT) in displaying the anatomic relationship between labyrinth segment of facial canal and cochlea.Methods Totally 110 patients (220 ears) who underwent HRCT were collected.The original images were transferred to workstation for image processing.MPR images were acquired.The anatomic relationship between labyrinth segment of facial canal and cochlea was observed in oblique coronal MPR images.The bony septum between labyrinth segment of facial canal and cochlea was assessed as definite defect (Type Ⅰ),doubtful defect (Type Ⅱ) or complete (Type Ⅲ),respectively.Results There were 71 ears (71/220,32.27％) of Type Ⅰ,diameters of bone fissure ranged from 0.3-1.3 mm (average diameters [0.64±0.26]mm),86 ears (86/220,39.09％) of Type Ⅱ and 63 ears (63/220,28.64％) of Type Ⅲ,with bony septum thickness ranged from 0.3-1.0 mm (average thickness [0.68±0.15]mm).No statistical difference of rates of the above three types was found between different genders,among age groups and between both side of ears (all P＞0.05).Conclusion HRCT is a reliable method to show the anatomic relationship between labyrinth segment of facial canal and cochlea.

In the past decades, people's work and life styles have dramatically changed during the rapid economic development and urbanization in China. A national survey reported that Chinese adults spend an average of 81% of daily time in indoor environment. Exposure to indoor air pollution plays key roles for human health but is likely to be neglected due on the relatively lower concentration levels and lower awareness among common people. Till now, published studies focus more on the pollution levels or the toxicological effects of indoor air pollutants but there is a lack of disease burden assessment attributable to indoor air pollution. In this review, several international studies were introduced on the disease burden estimation attributable to indoor air pollution, as well as the estimation methods. The current situation of national study was also reviewed. The strengths and limitations of the representative international studies were discussed. This review is helpful in providing data to guide the research on disease burden assessment attributable to indoor air pollution in China, and further helps to prioritize the indoor air pollution control based on disease burden ranking among pollutants and motivate public policies to protect the public health.

Objective:A residual false lumen progress risk prediction model was constructed based on computational fluid dynamics and biomechanical parameters were calculated to assess the factors affecting the long-term reintervention after the first operation.Methods:Patients with Stanford type A aortic dissection admitted to Fuwai hospital were retrospectively collected and divided into control group and thoracoabdominal aortic replacement group according to long-term prognosis or history of reintervention. The fluid parameters of the descending aorta were calculated based on the early CTA imaging data after first operation. The differences of parameters between the two groups were compared to explore the risk factors.Results:A total of 24 patients were included from January 2015 to May 2021. The average age was(47.88±9.84) years old, 21(87.5%) male, and 3 female. The balance position of luminal pressure difference in the descending aorta was closer to the opening of the left subclavicular artery[(22.00±3.91)cm vs.(36.00±1.77)cm, P<0.001], and the false lumen pressure was greater than the true lumen pressure in the thoracoabdominal aortic replacement group. Conclusion:The computational fluid dynamics method can simplify and visualize the complex human blood flow and postoperative structure based on the mathematical model. The lumen pressure balance point moving to the proximal are the risk factors for poor remodeling of the descending aorta and reintervention.

Objective To investigate the pathogenesis of type-B aortic dissection by using morphological analysis and computational fluid dynamics (CFD) method, so as to provide evidence for the effective prediction of type-B aortic dissection. Methods Six primary type-B dissection cases scanned by CT (dissection group) and six normal cases applied to black-blood MRI (control group) were included in this study and patient-specific three-dimensional (3D) models of aorta were established through image segmentation and 3D reconstruction. The pre-type-B dissection aortas were constructed by applying the scaling algorithm to shrink the dissection and then compared with subjects in control group. The differences between morphological parameters and hemodynamic parameters of the two groups were compared. Results Compared with the normal cases, the area of the descending aorta increased dramatically in dissection group ［(892.03±263.78) mm2 vs (523.67±64.10) mm2, P=0.036］. A significant decrease in angle of the left subclavian artery occurred (66.62°±20.11° vs 100.40°±15.35°, P=0.036). The tortuosity of the aorta also had an obvious increase (0.37°±0.07° vs 0.21°±0.51°, P=0.011). The time-averaged wall shear stress (TAWSS) in dissection group was obviously higher than that in control group; the flow in the dissection region was vortex flow at low speed and the oscillating shear index (OSI) was higher. Conclusions The results of this study can be used to provide guidance for the early diagnosis and treatment of type-B aortic dissection.