Charles William Bowkley MD, Presenter: Nothing to Disclose

Thomas K. Egglin MD, Abstract Co-Author: Nothing to Disclose

Michael Kemal Atalay MD, PhD, Abstract Co-Author: Nothing to Disclose

William W. Mayo-Smith MD, Abstract Co-Author: Nothing to Disclose

To determine if the reduced field of view used for coronary artery evaluation on CT angiography can be used to reliably exclude pulmonary emboli.

One hundred consecutive pulmonary embolism studies initially read as positive were reviewed. All studies were obtained in our emergency department using the same 16-detector emergency department scanner over a 15-month period. One board certified radiologist with extensive experience in CT reviewed each exam at full field of view to confirm the presence of pulmonary emboli and to verify the cases were technical adequacy. This reader concluded that 8 studies did not have PE and they were excluded from this series. The remaining 92 cases were reviewed independently by two board certified radiologists using a 25 cm cardiac field of view, with z-axis coverage from the inferior aspect of the aortic arch to 2cm below the heart. Studies were rated using a 5-point confidence scale as: 1 = definitely no PE, 2 = probably no PE, 3 = indeterminate, 4 = probably PE and 5 = definitely PE.

One radiologist diagnosed emboli (rating 4 or 5) in 85/92 exams, while the second radiologist identified emboli in 88/92 exams. Using the full field of view over-read as a gold-standard, the sensitivity of the readers was 92% and 96%, respectively. In 91/92 cases (99%) both readers identified the abnormalities interpreted as pulmonary emboli by the full field reader even if they did not rate them as “probably” or “definitely” being emboli.

CT retains a very high sensitivity for the diagnosis of PE even using a focused cardiac field of view. Only 1/92 emboli was situated in a part of the lungs outside the field of view we use for cardiac CT.

IV contrast chest CT permits the confident exclusion of pulmonary embolism as an etiology of chest pain when the field of view is optimized for coronary artery evaluation.

Bowkley, C, Egglin, T, Atalay, M, Mayo-Smith, W, Can a Cardiac CT Field of View Be Used to Exclude Pulmonary Emboli?.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4431199.html