Computed tomographic pulmonary angiography: Utility in acute pulmonary embolism in providing additional information and making alternative clinical diagnosis.

ABSTRACT

Objective: To evaluate the role of computed tomographic (CT) pulmonary angiography (CT-PA) in detecting additional information that may help in making an alternative clinical diagnosis in patients referred to CT for a suspected acute pulmonary embolism (PE). Materials and Methods: 50 patients (34 males, 16 females) in the age group of 18-72 years (mean 42.3 years), having high clinical suspicion of PE, underwent CTPA over a 2 year period. Chest x-ray, arterial blood gas (ABG) analysis, echocardiography were done in all patients. All patients underwent at least one other imaging examination besides CTPA ventilation perfusion scan, Doppler ultrasound or compression ultrasound (for DVT). All patients were followed for 3 months after completion of the diagnostic work up at baseline. The final diagnosis was achieved by a combination of clinical, imaging, and laboratory analysis, after adequate imaging, laboratory tests, and follow up. Result: CTPA helped correctly identify 29 of 30 patients with PE. In the remaining 20 patients (with no evidence of PE), CT-PA provided additional information (that suggested or confirmed alternate clinical diagnosis) in 15 patients (75%) pleural effusion (n=8), mediastinal or hilar lymphadenopathy (6), pneumonia/airspace consolidation (5), atelectasis/collapse (2), aspergilloma (1), malignancy (1), and others (2). Conclusion: CT-PA is highly specific and sensitive for diagnosis of PE. In addition, in a majority of patients who do not have PE, it also provides important ancillary additional information and helps in making an alternative clinical diagnosis.