Objective:To investigate the accuracy and application value of color Doppler flow imaging (CDFI) in diagnosis of carotid artery stenosis.Methods:A retrospective analysis was performed on the clinical data of 172 patients with cerebral infarction or transient ischemic attack (TIA) underwent both CDFI and cerebral digital subtraction angiography (DSA) in our hospital from January 2013 to July 2019. The carotid arteries from these patients were classified into 6 categories: normal type, mild stenosis (stenosis degree<30%), moderate stenosis (stenosis degree: 30%-69%), severe stenosis (stenosis degree: 70%-94%), subtotal occlusion (stenosis degree: 95%-99%), and total occlusion (stenosis degree: 100%). The detection rates of carotid artery stenosis by CDFI and DSA were compared; and using DSA result as the gold standard, the accuracy of CDFI in diagnosing carotid artery stenosis was discussed. Kappa analysis was used to evaluate the consistency of the two detection methods.Results:A total of 344 carotid arteries were detected in the 172 patients. CDFI examinations showed that 179 were normal, 15 were with mild stenosis, 66 were with moderate stenosis, 61 were with severe stenosis, 13 were with subtotal occlusion, and 10 were with total occlusion. DSA showed that 160 were normal, 32 were with mild stenosis, 84 were with moderate stenosis, 45 were with severe stenosis, 14 were with subtotal occlusion, and 9 were with total occlusion. The vascular stenosis detection rate of DSA was 53.5% (184/344), and that of CDFI was 48.0% (165/344), without significant difference ( P>0.05). Using DSA result as the gold standard, the accuracy, sensitivity and specificity of CDFI in diagnosing carotid stenosis were 94.5%, 89.7% and 100% respectively. Consistency analysis showed that Kappa was 0.846, and the consistency of DSA and CDFI detection results was high. Conclusions:CDFI is a non-invasive and cost-effective method for diagnosing carotid artery stenosis, enjoying high consistency with DSA. CDFI can be used as the first choice for preoperative screening and postoperative follow-up of carotid artery stenosis.

Umbilical cord mesenchymal stem cells (UC-MSCs) have been widely used in regenerative medicine, but there is limited research on the stability of UC-MSCs formulation during production. This study aims to assess the stability of the cell stock solution and intermediate product throughout the production process, as well as the final product following reconstitution, in order to offer guidance for the manufacturing process and serve as a reference for formulation reconstitution methods. Three batches of cell formulation were produced and stored under low temperature (2-8 ℃) and room temperature (20-26 ℃) during cell stock solution and intermediate product stages. The storage time intervals for cell stock solution were 0, 2, 4, and 6 h, while for intermediate products, the intervals were 0, 1, 2, and 3 h. The evaluation items included visual inspection, viable cell concentration, cell viability, cell surface markers, lymphocyte proliferation inhibition rate, and sterility. Additionally, dilution and culture stability studies were performed after reconstitution of the cell product. The reconstitution diluents included 0.9% sodium chloride injection, 0.9% sodium chloride injection + 1% human serum albumin, and 0.9% sodium chloride injection + 2% human serum albumin, with dilution ratios of 10-fold and 40-fold. The storage time intervals after dilution were 0, 1, 2, 3, and 4 h. The reconstitution culture media included DMEM medium, DMEM + 2% platelet lysate, 0.9% sodium chloride injection, and 0.9% sodium chloride injection + 1% human serum albumin, and the culture duration was 24 h. The evaluation items were viable cell concentration and cell viability. The results showed that the cell stock solution remained stable for up to 6 h under both low temperature (2-8 ℃) and room temperature (20-26 ℃) conditions, while the intermediate product remained stable for up to 3 h under the same conditions. After formulation reconstitution, using sodium chloride injection diluted with 1% or 2% human serum albumin maintained a viability of over 80% within 4 h. It was observed that different dilution factors had an impact on cell viability. After formulation reconstitution, cultivation in medium with 2% platelet lysate resulted in a cell viability of over 80% after 24 h. In conclusion, the stability of cell stock solution within 6 h and intermediate product within 3 h meets the requirements. The addition of 1% or 2% human serum albumin in the reconstitution diluent can better protect the post-reconstitution cell viability.