Imaging characteristics of abnormal chest air accumulation after allogeneic hematopoietic stem cell transplantation in children with hematopathy

LI Lianbo; SHI Yuzhu; LI Li; QIU Ke

doi:10.20258/j.cnki.1006-9011.2025.07.014

Abstract：Objective To investigate the imaging manifestations of abnormal chest air accumulation after allogeneic hemato-poietic stem cell transplantation(allo-HSCT)in children with hematopathy.Methods Imaging findings of 19 children with allo-HSCT complicated with abnormal chest air accumulation were retrospectively analyzed,including 7 cases of acute lympho-blastic leukemia(ALL),7 cases of acute myeloid leukemia(AML),1 case of T-lymphoblastic lymphoma(T-LBL),3 cases of aplastic anemia(AA),and 1 case of Shwachman-Diamond syndrome.Of those 19 patients,2 patients were found to pneumatosis intestinalis(PI)and then underwent abdominal CT plain scan.Those cases were divided into 2 groups according to the different causes of air leakage,namely,BOS group and non-BOS group.11 cases in BOS group were all caused by air leakage,and 8 cases in non-BOS group were caused by air leakage,including 2 cases of pneumatosis intestinalis(PI),2 cases of pulmonary in-fection,1 case of oropharyngeal infection,and 3 cases with unknown causes of air leakage.The imaging manifestations included pneumomediastinum(PM),pulmonary interstitial emphysema(PIE),pulmonary balloon,pneumothorax,air accumulation in the extrapleural space,pneumorrhachis,and subcutaneous emphysema.Those with one imaging manifestation were classified as single air leak,and those with at least two imaging manifestations were classified as mixed air leak.SPSS 22.0 software was used for data analysis.P<0.05 was considered to be statistically significant.Results BOS mainly manifested as bilateral lung air trapping sign,multiple bronchial cysts,columnar dilation and thickening of the lumen wall,etc.Among the 11 patients,all were of mixed type air leakage,and all were accompanied by mediastinal emphysema,among which 5 cases were accompanied by subcutaneous emphysema.7 cases were accompanied by PIE,4 cases were of peripheral type PIE around bronchovascular bundles,3 cases were of peripheral type PIE beside the lobar septa,5 cases had unilateral pneumothorax,and the imaging manifestations were strip-like gas shadows in the thoracic cavity,with compression of adjacent lung tissue.5 cases had extrapleu-ral air accumulation,and the imaging manifestations were arc-shaped band-like gas shadows in the pleural fat space,with local small septa,among which 1 case(1/5)was accompanied by intraspinal air accumulation,manifested as strip-like gas shadows in the spinal canal.In the non-BOS group,2 cases were of mixed type air leakage,6 cases were of single type air leakage.Among them,2 cases of PIE had multiple cystic gas shadows around the colon wall and multiple free gas shadows in the abdominal cav-ity.Among the 2 cases of pulmonary infection patients,1 case had a small amount of mediastinal emphysema,and the other 1 case had unilateral pneumothorax.Among the 3 cases of unknown cause of air leakage,1 case was of mixed type air leakage,presenting multiple manifestations such as mediastinal emphysema,interstitial emphysema,pneumothorax and intraspinal air accumulation,and the other 2 cases only had a small amount of mediastinal emphysema.1 case of mediastinal emphysema originated MRI plain scan and enhanced scan showed cystic long T1WI and long T2WI signals in the upper mediastinum,and small patchy high signals after enhancement,and the lesion showed ring-like enhancement after enhancement.In the non-BOS group,no pulmonary air cysts or extrapleural air accumulation were found.In the BOS group,7 cases had PIE,and in the non-BOS group,1 case had PIE.The difference between the two groups was statistically significant(P<0.05).In the BOS group,5 cases had extrapleural air accumulation,and no such sign was found in the non-BOS group,and the difference was statistically significant(P<0.05).In the BOS group,11 cases were of mixed type air leakage,and 2 cases were of mixed type air leakage in the non-BOS group.The difference between the two groups was statistically significant(P<0.05).There was no statistically significant difference in mediastinal emphysema,pulmonary air cysts,pneumothorax,intraspinal air accumulation and subcutaneous emphysema between the two groups(P>0.05).Conclusion Abnormal chest air accumulation after allo-HSCT in children may be due to various causes.Compared with other causes,the air leakage manifestations of BOS compli-cated with ALS are more diverse,and interstitial emphysema and air accumulation in the extrapleural space can better indicate the occurrence of BOS.