Evaluation of the need for CT venography in pulmonary embolism imaging in the emergency department; a prospective, observational study

Pulmonary embolism (PE) and deep vein thrombosis (DVT) are emergency conditions assoicated with high morbidity and mortality. This study aimed to evaluate the clinical of Compression Ultrasonography (CU) in diagnosing DVT and to investigate the necessity of CT venography by comparing CU findings with CT venography with suspected acute PE in the emergency department. This study was a prospective observational study. Patients evaluated for suspected PE at the Emergency Department of Eskisehir Osmangazi University Healt, Practice and Research Hospital between May 15 and August 8, 2023, and who unerwent TTE, CU, CTPA, and CT venography imaging, were incluted. Prior to the study, emergency physicians received training in compression ultrasonography. A total of 687 volunteers were enrolled, of whom 348 (50.66%) were female. Among patients with DVT findings on CT Venography, the presence of DVT sings on physical examination-including swelling, redness, a positive Homans's test, diameter discrepancy, elevated D-Dimer levels, and DVT detection via CU- were significantly higher than in those without DVT findings (p<0.001, p<0.001, p<0.005, respectively). CU demonstrated high specificity in diagnosing DVT [99.7%, (CI: 98.92% - 99.96%)] although its sensitivity was limited [57.69% (CI: 36.92% - 76.65%)]. The positive likelihood ratio was 191.83 (95% CI: 46.26 - 795.55), and a negative likelihood ratio was 0.42 (95% CI: 0.27 - 0.66). The positive predictive value (PPV) and the negative predictive value (NPV) was of CU for detecting DVT were 88.24% (95% CI: 64.39% - 96.89%) and 98.37% (95% CI: 97.47% - 98.95%) respectively. Overall accuracy was determined to be 98.12% (95% CI: 96.8% - 98.99%). Our findings suggest that CU is an effective method for diagnosing DVT; hoewer, negative results should be interpreted with caution. Additionally, other clinical parameters used in DVT diagnosis were found to have lower predictive value. This study supports the potential role of CU as an alternative to more invasive and radiation-based imaging techniques, such as CT venography. Key Words:Emergency Department, Deep Vein Thrombosis, CT Venography, Compression Ultrasonography, Pulmonary Thromboembolism