Diagnosis of pulmonary embolism with helical CT scan

Objective: To determine the role of helical C.T. scan in the diagnosis of pulmonary embolism.SETTING: Radiology department, Aga Khan University Hospital. One year prospective study May 2001 to May 2002.Methods: Sixty patients suspected of having pulmonary embolism were included in this study. Helical C.T. scan chest was performed from aortic arch to lung bases with intravenous contrast medium. Images were acquired in mediastinal and lung windows. Image interpretation was performed on the console and hard copies for main branch and segmental thrombus.Results: Fifteen patients were diagnosed of having pulmonary embolism on C.T. scan. Clinical correlation and follow up with pulmonary angiography and Doppler ultrasound of leg was carried out. Pulmonary angiography was performed in one patient with embolectomy done after confirmation of diagnosis. 8 patients had associated DVT confirmed on Doppler sonography. Sensitivity of helical C.T. is 93.75%, specificity 100% and positive predictive value 95.65%.CONCLUSION: Helical CT scan is a quick, easy and accurate imaging modality for diagnosing pulmonary embolism