Diagnostic Accuracy of Doppler Ultrasound in Detecting Deep Vein Thrombosis: Clinical Evaluation Study

Abstract

Background: Deep vein thrombosis (DVT) is a serious vascular condition where blood clots form in the deep veins, most often in the lower limbs. It's crucial to diagnose DVT early due to risks like pulmonary embolism (PE) and post-thrombotic syndrome. While clinical assessments using scoring systems like Wells' criteria help in initial risk assessment, accurate diagnosis requires objective imaging. Doppler ultrasound is a non-invasive tool for detecting DVT, valued for its sensitivity, specificity, ease of use, and real-time evaluation. This study examines Doppler ultrasound's effectiveness in diagnosing DVT by comparing its accuracy with clinical scoring and laboratory markers, including D-dimer levels. Objectives: The study's main aim is to evaluate Doppler ultrasound's diagnostic accuracy for DVT. It seeks to determine the tool's sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) relative to clinical risk scores and D-dimer levels. The study also explores DVT's anatomical distribution, common risk factors, and ultrasound characteristics indicative of thrombosis severity. Subjects and Methods: This observational study was conducted at a tertiary care hospital in India, involving 100 patients suspected of having DVT based on clinical evaluation and Wells criteria. Participants underwent Doppler ultrasound imaging of the lower limbs to assess vein compressibility, flow dynamics, spectral waveform changes, and thrombus echogenicity. D-dimer tests were also performed, with positive results identified at levels above 500 ng/mL. The gold standard for DVT confirmation included serial Doppler imaging or clinical follow-up in uncertain cases. Sensitivity, specificity, PPV, and NPV of Doppler ultrasound were calculated and compared to clinical scoring models. Results: Doppler ultrasound identified DVT in 54 out of 100 patients (54%), while 71 patients (71%) had elevated D-dimer levels. Most DVT cases were proximal (femoral and popliteal veins, 65%), with 35% being distal. Doppler ultrasound demonstrated a sensitivity of 91.5%, specificity of 88.3%, PPV of 89.1%, and NPV of 90.8% compared to final clinical diagnoses. In high-probability cases (Wells score ?3), Doppler ultrasound confirmed DVT in 82% of patients, underscoring its importance as a primary diagnostic tool. Conclusion: Doppler ultrasound is highly accurate in diagnosing DVT, making it a vital first-line imaging tool in suspected cases. The study supports its extensive use in clinical practice due to its strong correlation with clinical probability scores and D-dimer levels. However, serial imaging remains necessary for uncertain cases or suspected distal thrombosis. Given its non-invasive nature and high reliability, Doppler ultrasound should be the cornerstone of DVT diagnosis to ensure early treatment and prevent complications like pulmonary embolism.