Contrast-enhanced CT for detecting pleural malignancy at a large district general hospital

Introduction: Contrast CT is an initial investigation in the work up of exudative pleural effusions and can differentiate between benign and malignant pleural disease. Specificity for malignant disease approaches 100% but sensitivity is low at 36-56%1. Findings from study populations do not always transfer to clinic populations. We compared the diagnostic utility of CT for pleural malignancy as reported by radiologists at our centre to study populations.Method: We retrospectively reviewed CT reports of all patients who subsequently underwent medical thoracoscopy for investigation of pleural effusion from January 2012- July 2013 at Queen Alexandra hospital. 47 patient records were reviewed at 1 year to confirm diagnosis. A 2x2 contingency table analysed CT specificity, sensitivity and positive predictive value (PPV) for pleural malignancy.Results: Radiologists at our district general hospital (DGH) reported features suggestive of pleural malignancy in 68% of cases. The specificity for pleural malignancy was 71.4% with a sensitivity of 75%. The PPV was 93.8% [figure 1].[figure 1]Discussion: The sensitivity was higher which may be due to restricting the analysis to patients undergoing thoracoscopy. Specificity and PPV were lower than quoted in the literature. Many DGHu0027s may not have specialist thoracic radiologists to report scans relying instead on generalists. Our results may be better representative of the true value of contrast CT to differentiate malignant from benign pleural features in clinical practice.Reference 1. Hooper C, Lee YCG, Maskell N. Investigation of a unilateral pleural effusion in adults: British Thoracic Society pleural disease guideline 2010. Thorax. 2010;65(Suppl 2):ii4-ii17.