Do preliminary chest x-ray findings define the optimum role of pulmonary scintigraphy in suspected pulmonary embolism?

AIM: To investigate if preliminary chest radiograph (CXR) findings can define the optimum role of lung scintigraphy in subjects investigated for pulmonary embolism (PE). MATERIALS AND METHODS: The CXR and scintigraphy findings from 613 consecutive subjects investigated for suspected PE were retrieved from a radiological database, Of 393 patients with abnormal CXRs, a subgroup of 238 was examined and individual radiographic abnormalities were characterized. CXR findings were related to the scintigraphy result. RESULTS: Scintigraphy was normal in 286 subjects (47%), non-diagnostic in 207 (34%) and high probability for PE in 120 (20%). In 393 subjects (64%) the preliminary CXR was abnormal and 188 (48%) of scintigrams in this group were non-diagnostic. Individual radiographic abnormalities were not associated with significantly different scintigraphic outcomes, If the preliminary CXR was normal (36%), the proportion of non-diagnostic scintigrams decreased to 9% (19 of 220 subjects) (P < 0.05). CONCLUSION: In subjects investigated for PE, an abnormal CXR increases the prevalence of nondiagnostic scintigrams, A normal pre-test CXR is more often associated with a definitive (normal or high probability) scintigram result. The chest radiograph may be useful in deciding the optimum sequence of investigations. (C) 2001 The Royal College of Radiologists.