Objective Toexploreasimpleandaccuratemethodfordeterminingthequantitativeevaluationandthevolumedegree divisionofpleuraleffusionbyMDCTtissuesegmentationtechnology.Methods Thevolumeofwaterinjectedintothreecontainersof differentshapeswasmeasuredby MDCTtissuesegmentationtechnique,andwerefurthercomparedwiththevolumeoftheactual waterinjection.Byusingthesamemethod,theliquidvolumeofpleuraleffusionbeforeandafterpumpingfrompatientswasmeasured andthedifferencebetweentheanteriorandtheposteriorwascalculated.Thenthedifferencebeforeandafterthepumpingwascomparedwiththe actualvolumeofclinicalfluidpumping.Atthesametime,thespecificmethodtodeterminethedegreedivisionofpleuraleffusionwas established.Results Forcontainersofdifferentshapes,theresultfromtheCTscanningliquidmeasurementwasthesameasactualwater injection,andhadahighcorrelation.Thedifferencebetweenbeforeandafterfluidextractionandclinicalactualfluidextractionwas linearcorrelated(positivecorrelation,r=0.986,P<0.001).Accordingtothemethodfordegreedivisionofadulthemothorax,MDCT tissuesegmentationtechnologydividedthevolumeofpleuraleffusionbeforethepumpingintosmall,mediumandlargeamounts.There were44caseswithsmallpleuraleffusion,11caseswithmoderatepleuraleffusionand7caseswithlargepleuraleffusion.Conclusion The volumeofpleuraleffusion measuredby MDCTtissuesegmentationtechnologycanreflecttheactualvolumeofpleuraleffusionin clinictoacertainextent,and MDCTtissuesegmentationtechnologycanbeusedtodividethevolumedegreeofpleuraleffusion.