Objective To observe the value of the ratio of cerebral hyperdensities(PCHD)/venous sinus maximum density for predicting hemorrhagic transformation(HT)after endovascular treatment(EVT)in patients with acute ischemic stroke(AIS).Methods Data of 79 AIS patients with PCHD immediately after EVT were retrospectively analyzed.The patients were divided into HT group(n=41)or non-HT group(n=38)based on the presence of HT or not.Clinical data and CT parameters were compared between groups.The value of the ratio of PCHD/venous sinus maximum density for predicting HT was evaluated.Results The maximum density of PCHD and the ratio of PCHD/venous sinus maximum density in HT group were both higher than those in non-HT group(both P＜0.001).Taken 87 HU as the best cut-off value of the maximum density of PCHD,the sensitivity,specificity and area under the curve(AUC)for predicting HT after EVT in AIS patients was 90.24%,71.05%and 0.79,respectively.Taken 0.94 as the best cut-off value of the ratio of PCHD/venous sinus maximum density,the sensitivity,specificity and AUC was 97.56%,71.05%and 0.81,respectively.No significant difference of AUC was found between the former and the latter(P＞0.05).Conclusion The ratio of PCHD/venous sinus maximum density immediately after EVT could be used to predict HT in AIS patients.

Efficient treatment of hematopoietic system radiation injuries that occur in medical and military settings is a real problem that has attracted increasing attention.However,current treatments for hematopoietic system radiation injury are lacking.Mesenchymal stem cells(MSCs)are one of the important components of the bone marrow microenvironment.The role of infusion of exogenous MSCs or their exosomes in promoting hematopoietic system radiation damage repair has been extensively reported.However,there have been relatively few studies on the responses of MSCs in situ in bone marrow after radiation injury.This review focuses on the in situ bone marrow MSC populations that are potentially involved in hematopoietic system radiation injury repair and on the heterogeneity of these MSCs.