Abstract 1600: Spiral CT Angiography for Pulmonary Embolism: Comparison of Cine and Film-based Viewing
AUTHORS:
P.V. Kavanagh, MD, K.M. Link, MD, S.L. Fernandez, MD, M. D'Amore, MD, J.W. Wu, MD, C. Chiles, MD.
ABSTRACT:
PURPOSE: To determine radiologists' ability to detect pulmonary emboli (PE) on spiral computed tomographic (CT) scans of the chest with both rapid sequential (cine) and conventional film-based viewing.
METHOD AND MATERIALS: 3 radioloigists searched for evidence of PE on spiral CT images (3 mm collimation reconstructed at 1 mm invervals, pitch 1.7) presented in two formats. Cine viewing was performed at a computer or PACS workstation. Sections were viewed at frame rates up to 10 frames/second. Film-based viewing of images from a laser printer was performed using a standard lightbox. CT scans from 40 patients were studied. 20 were consecutive cases obtained from our database in which PE had been unequivocally diagnosed by spiral CT. These were combined with 20 matched controls and presented to the viewing radiologist in a random fashion.
RESULTS: Overall, radiologists detected a higher fraction of emboli with the cine presentation than with film. However, results varied according to the location of the embolus. For central pulmonary emboli there was no statistically significant difference comparing cine presentation with film. In the cine group 2 false-positive diagnoses of main right pulmonary artery emboli were correctly diagnosed as hilar lymphoid tissue on film-based viewing. Detection rates for emboli in segmental and subsegmental pulmonary arteries did reach statistical significance. When cine viewing and film viewing detection rates were analyzed in the same observer, the combination of both techniques provided superior detection than with either method alone.
CONCLUSIONS: Cine viewing of spiral CT images of the chest improves radiologists' ability to detect emboli in the segmental and subsegmental pulmonary artery branches. Central emboli were more accurately diagnosed using a film-based technique. The combination of both cine- and film-based methods provided superior detection than with either method alone.
