MRPP In Diagnosing Follow-up Pulmonary Embolism: The Feasibility And Accuration Of Estimating Therapeutic Effect

ObjectiveThis study was designed to investigate the feasibility of Enhanced magnetic resonance pulmonary perfusion imaging(MRPP) in diagnosing pulmonary embolism(PE),then to evaluate the diagnostic value in follow-up visit.MethodsThis study has been approved by hospital ethics committee,and all patients gave written informed consent. Between November 2007 and June 2008 ,Sixty patients suspected of PE, were underwent MRPP. Twenty-seven patients took the examination of MRPP and Radionuclide perfusion imaging at the same time .Besides,22 patients were examined MRPP again after 3 day to 1 month in 60 patients. Through analyzing prior and posterior treatment change in MRPpP of transformation rate of signa(lTROS),time-signal curve and some parameters of main pulmonary artery(such as peak value of blood,mean glow velocity,flow rate).to evaluate the feasibility of MRPP in diagnosing PE and evaluate the diagnostic value in follow-up visit. The t test and rank sum test were used for statistics.MR scanning method:All of the patients were went the examination of Haste,2D FLASH,ECG-cine sequence to observe the morphous and Thromboembolus of the main pulmonary artery;utilized the PC MRI to observe the dynamic change of the main pulmonary artery,such as flow volume,average velocity,peak velocity and so on. Applied IR turbo FLASH sequence completed lung parenchyma perfusion imaging.ResulesMRPP showed a high agreement with Radionuclide perfusion imaging(kappa value per examination 0.705,and 0.7632,0.8280 and 0.7344 for lobar ,segmental subsegment perfusion defects, respectively( p< 0.001)).12 patients were definitely diagnosed as PE, the relative enhancement of normal parenchyma was (7.3±2.8)fold,peak time,peak value ,mean glow velocity ,and flow rate of main pulmonary blood were (9.50±1.58)s,(67.44±13.11)cm/s(,20.49±7.92)cm/s(,127. 84±44.26)ml/s, respectively. pulmonary embolism perfusion defect were (4.65±2.44)fold,(16.9±7.12)s ,(62.97±14.24) cm/s,(12.83±7.48)cm/s,(82.15±26.6) ml/s, respectively. After treatment enhancement of normal parenchyma(2.86±2.48vs6.72±2.54fold,respectively ,t=3.370,P=0.001),peak time(13.98±5.60vs12.33±3.63s , respectively , t=3.930 , P<0.001) , peak value(60.39±15.17vs69.93±13.22 cm/s,respectively ,t=2.930,P=0.010) and mean glow velocity(11.68±5.46vs13.54±4.18cm/s , respectively , t=2.380,P=0.031) of main pulmonary blood have statistics discrepancy , but the flow rate per unit(80.57±24.87vs85.48±11.81ml/s ,respectively,t=0.86,P=0.40) don't have.ConclusionMRPP showed a high agreement with Radionuclide perfusion imaging. MRPP have higher spatial resolution and time resolution, It can semiquantitative analysis pulmonary blood. In addition to this, MRI can estimate pulmonary hypertension roughly. So it have a crucial clinical significance to diagnose and evaluate the diagnostic value in follow-up visit of PE.