Comparative study of the diagnostic value using ultrasound, CT and their combination in constrictive pericarditis ABSTRACT Objective: To investigate the diagnostic value in constrictive pericarditis (CP)by transthoracic echocardiography (TTE ),CT and their combination . Methods: Seventy-four suspected CP patients by Clinical manifestation (including 54 patients with CP which confirmed by surgery and pathology ) in our hospital and Nanchong city center hospital from February 2010 to September 2017 were retrospectively analyzed . Two experienced TTE physicians and two experienced CT physicians analyzed the imaging findings of TTE 、CT respectively，and analyzed their combination together using Five-level diagnosis criterion.The ROC curves of CP were drawn by TTE, CT and their combination. The area under the ROC curve was calculated, and the area under the curve was tested.Using χ2 to analysis the imaging parameters of the patients diagnosed with CP.Results: According to the ROC curve, the area under the curve of TTE、CT and their combination are 0.948，0.912and 0.981, respectively.The area under the curve of TTE and CT has no statistical difference (P>0.05). The differience between their combination and the area under the TTE curve or the CT curve is statistically significant (P < 0.05).Conclusions: There is no difference in diagnostic efficiency between TTE and CT. TTE can be used as the first choice for screening and diagnosis. CT can be used as a deficiency in the diagnosis of TTE and provides important information for the formulation of surgical procedures,but their combination can provide more reliable basis for the diagnosis and treatment of CP. KEY WORDS Constrictive pericarditis; Echocardiography ; CT