Christoph Engelke MD, Presenter: Nothing to Disclose

Stefan Schmidt, Abstract Co-Author: Nothing to Disclose

Florian Auer, Abstract Co-Author: Nothing to Disclose

Ernst Josef Rummeny MD, Abstract Co-Author: Nothing to Disclose

Annemarie Bakai PhD, Abstract Co-Author: Employee, Siemens AG

Katharina Marten, Abstract Co-Author: Nothing to Disclose

To assess the value of a computer-aided detection tool(CAD) as second reader in combination with experienced and inexperienced radiologists for diagnosis of acute pulmonary embolism (PE).

PE-positive CT-angiographies (0.6 mm collimation; 61.4 mm/rot table feed) of 56 consecutive patients were analysed by 2 experienced (readers 1,2) and 2 inexperienced (readers 3,4) observers for presence and distribution of PE using a five-point confidence scale, and by CAD. Results were compared to an independent reference standard. Interobserver agreement was calculated by kappa, confidence assessed by ROC analysis.

A total of 1116 emboli were included. CAD made 551 detections with 4.07±3.32 false-positives/patient. CAD was false-negative in 6 patients (10.7%). The CAD-specificity was high (spec≥.90), however, sensitivity was fair(sens=.21-.41). Interobserver agreement was good between readers 1 and 2 (k=.84) and readers 3 and 4(k=.79), moderate between experienced and inexpereinced readers(k=.60-.62), but was enhanced by consensus with CAD(k=.69-.72;p<.05). CAD performance was best in segmental and subsegmental arteries (Az=.64). Overall reader agreement in these branches was enhanced after consensus with CAD(k=.56-.70;p<.05). The overall performances of readers 3 and 4 were improved by consensus with CAD(Az=.86 and Az=.89, for unassisted and consensus readings, respectively, p<.05) while readers 1 and 2 improved their segmental artery performances and their overall sensitivities(p<.05). The average radiologists PE severity score (Ssc) was substantially higher after consensus with CAD data (Ssc= 21.5±12.3 and 34.7±14.5 before and after CAD consensus, respectively; p<.05).

CAD significantly enhances overall performances of inexperienced, and performances of experienced radiologists in segmental pulmonary arteries. CAD increases the average PE severity score and is therefore recommended as second reader in CT diagnosis of acute PE.

CAD-systems for detection of pulmonary ermboli are at an early stage. CAD increases the PE-severity score and may thus lead to stratifying individual patients to more agressive treatment.

Engelke, C, Schmidt, S, Auer, F, Rummeny, E, Bakai, A, Marten, K, Computer-assisted Detection of Pulmonary Emboli: Performance Evaluation in Consensus with Experienced and Inexperienced Chest Radiologists.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5001538.html