The clinical utility of a diagnostic imaging algorithm incorporating low-dose perfusion scans in the evaluation of pregnant patients with clinically suspected pulmonary embolism.

PURPOSE OF THE REPORT: The aim of this study was to determine the proportion of pregnant patients with a clinical suspicion of pulmonary embolism and a normal chest radiograph who require further evaluation with perfusion scintigraphy alone compared with both perfusion scintigraphy and computed tomography (CT).

PATIENTS AND METHODS: All patients who had a low-dose perfusion lung scan as part of a clinical imaging algorithm to assess for clinically suspected pulmonary embolism in pregnant patients at 3 regional hospitals from September 2009 to February 2011 were retrospectively reviewed. The proportion of patients requiring a low-dose perfusion-only lung scan was compared with the proportion requiring further evaluation with both a low-dose perfusion scan and a CT scan to complete the algorithm.

RESULTS: Seventy-four (74) patients were included. Sixty-one (61/74; 82.4%) patients had a normal low-dose perfusion-only scan and did not require further imaging. Thirteen (13/74; 17.6%) patients demonstrated an abnormal perfusion scan and required further imaging with a CT scan. One patient (1/74; 1.4%) was diagnosed with pulmonary embolism.

CONCLUSIONS: Our results suggest that for pregnant patients with a normal chest radiograph, pulmonary embolism can be excluded in 82.4% of patients with a low-dose perfusion scan alone.