The feasibility and accuracy of enhanced MR pulmonary perfusion imaging in evaluating therapeutic effect of pulmonary embolism

Abstract

Objective To investigate the feasibility and accuracy of enhanced magnetic resonance pulmonary perfusion imaging(MRPP) in the diagnosis and follow-up of pulmonary embolism(PE). Methods Sixty patients suspected of PE underwent MRPP. Twenty-seven patients also underwent radionuclide perfusion imaging. 22 patients repeated MRPP examination after 3 day to 1 month anticoagulation or thrombolytic therapy. The feasibility and accuracy of MRPP in the diagnosis and follow-up of PE were evaluated according to the transformation rate of signal (TROS), time-signal curve and some parameters of main pulmonary artery(such as peak value of flow,mean flow velocity and flow rate). The t test and rank sum test were used for the statistics. Results MRPP showed a high agreement with radionuclide perfusion imaging. TROS was (2. 86 ± 2. 48 ) vs ( 6. 72 ± 2. 54) ( t = 3. 370, P ＜ 0. 01 ), the peak time was ( 13.98 ±5.60) vs ( 12. 33 ± 3.63 ) s ( t = 3. 930, P ＜ 0. 01 ), the peak value of main pulmonary blood flow was (60.39 ± 15. 17) vs (69.93±13.22) cm/s(t=2.930, P＜0. 01) and mean flow velocity (11.68±5.46) vs ( 13.54 ± 4. 18 ) cm/s ( t = 2. 380, P ＜ 0. 05 ) before and after anticoagulation or thrombolytic therapy. The flow rate per unit was (80. 57 ± 24. 87) vs ( 85.48 ± 11.81 ) ml/s ( t = 0. 86,P ＞ 0. 05 ) . Conclusion MRPP shows a high agreement with radionuclide perfusion imaging and is a useful method for the diagnosis and follow-up of PE. Key words: Pulmonary embolism; Magnetic resonance angiography; Radionuclide imaging