Clinical Evaluation of Pulmonary Embolism with Radiopharmaceuticals for Lung Perfusion and Ventilation Scan

Pulmonary embolism (PE) is a common fatal disease; therefore, the accurate and prompt diagnosis is very important. The aim of this study was to evaluate lung perfusion-ventilation scan with radiodrugs including 99mTc-MAA and radio aerosols in diagnosis of the PE. In this study, 149 patients with respiratory problems referred to the nuclear medicine department of Tabriz Imam Hospital, from October 2005 to November 2006, were studied. The perfusion scans were performed after intravenous injection of 99mTc-MAA, and the ventilation scans after inhalation of 99mTc-DTPA aerosol on the routine views of lungs. The resulting images were evaluated regarding the probability of the PE. Association between gender, age, clinical presentations, risk factors, previous cardio-pulmonary disorders, chest X-rays, and probability of the PE were evaluated. In the present study, the number of involved men with PE was higher than women (P<0.005). The highest incidence of PE was noted in patients >50 years old (P=0.005). There was a direct association between the probability of PE and the related clinical presentations (P=0.005). It was also apparent that the existence of cardio-pulmonary disorders, having an abnormal CXR and the lack of a risk factor, were all accompanied with low probability of PE, but the presence or absence of risk factors showed no meaningful difference for the high probability of PE (P=0.232). The lung perfusion-ventilation scan is recommended as an acceptable method in the early diagnosis of PE and also evaluation of prevalence and affecting factors of the disease.