Comparison of Colour Doppler Ultrasonography and Indirect Computer Tomography Venography for the Diagnosis of Deep Venous Thrombosis in Patients with Suspected Pulmonary Thromboembolism at a Tertiary Care Centre in Chennai, Tamil Nadu, India

Abstract

Introduction: Pulmonary Thromboembolism (PTE) and Venous Thromboembolism (VTE) are prevalent conditions with a high mortality rate and need immediate medical attention. The initial and standard imaging techniques are Computed Tomography Pulmonary Angiography (CTPA) for the diagnosis of PTE and Colour Doppler Ultrasonography (CDUS) for Deep Vein Thrombosis (DVT). However, there can be some issues when using these two different approaches, like the requirement for a separate area and more time. With the so-called indirect Computed Tomography Venography (CTV) approach, thrombi in the deep venous system that may cause PTE can be examined right after pulmonary CT Angiography (CTA) without the need for additional contrast agent. Aim: To determine the accuracy of indirect CTV for the diagnosis of deep venous thrombosis in patients with suspected PTE. Materials and Methods: This cross-sectional study was conducted in the Department of Radiology in Government Stanley Medical College, Chennai, Tamil Nadu, India, India from June 2021 to May 2022. A total of 50 patients with a probable diagnosis of PTE and was established with CTA were included. All 50 patients underwent indirect CTV and CDU on the same day. For indirect CTV lower extremities between the iliac crest and the popliteal region were scanned without administration of extra contrast medium. Colour Doppler Ultrasound (CDUS) was considered as Gold standard. To find the efficacy of CTV in determining DVT the Receiver Operating Characteristics curve (ROC) was used. Results: Of the total 50 patients, who were enrolled in the study, 21 (42%) patients were females and 29 (58%) patients were males. The mean age of the study subjects was 43.5±12.1 years. Among these DVT was detected in 25/50 patients (50.0%) by Doppler Sonography, Similarly DVT was detected in 23/50 patients (46%) by CTV. The sensitivity of CTV was 76% and the specificity was 84%, Positive Predictive Value (PPV) of 82.6%, Negative Predictive Values (NPV) of 77.8%. The p-value and kappa value between CTV and CDUS was calculated as 0.0005 and 0.600, respectively. Conclusion: According to the results of the present study, a combined CTA indirect CTV method can determine the DVT with a moderate level of sensitivity and specificity