Colour flow duplex scanning in suspected acute deep vein thrombosis; experience with routine use

Current approaches to diagnosing deep vein thrombosis (DVT) rely on invasive imaging techniques like venography. Prior research has shown venography to be highly accurate but limited by its invasiveness and longer examination times. No prior work had resolved whether non-invasive alternatives could match venography’s diagnostic precision. This uncertainty drove the need for a comparative study using colour flow Duplex scanning (CFDS). Established knowledge indicates that DVT diagnosis remains a clinical challenge, especially in patients with normal veins but persistent symptoms. This paper’s contribution lies in evaluating CFDS’s diagnostic accuracy in both proximal and distal DVT cases. The study addresses a gap in understanding whether CFDS can replace venography in routine clinical settings. It also explores the diagnostic utility of CFDS in identifying alternative causes of leg symptoms when no DVT is detected.

The aim of this study was to assess the diagnostic accuracy of colour flow Duplex scanning (CFDS) in detecting deep vein thrombosis (DVT). The specific problem addressed was whether CFDS could serve as a reliable alternative to venography in diagnosing DVT. The motivation stemmed from the limitations of venography, including its invasive nature and longer examination time. The study sought to determine if CFDS could achieve comparable diagnostic accuracy in both proximal and distal DVT cases. It also aimed to evaluate CFDS’s ability to detect alternative causes of leg symptoms when no DVT was present. The researchers proposed that CFDS could offer a non-invasive, rapid, and accurate diagnostic tool for DVT. The study’s design aimed to compare CFDS results with venography findings in a clinical setting. The ultimate goal was to establish CFDS as a viable diagnostic method for routine use in suspected DVT cases.

The study employed a prospective open clinical design, conducted in vascular laboratory and radiology departments at a university hospital. The first part involved 112 limbs in 103 patients with suspected acute DVT or pulmonary embolism (PE), who underwent both CFDS and venography. The second part involved 328 legs in 304 patients with acute symptoms of DVT or PE, examined using CFDS alone. Venography served as the reference standard for DVT detection. The study evaluated CFDS’s sensitivity, specificity, and predictive values for both proximal and distal DVT. The diagnostic accuracy of CFDS was compared with venography findings. The study also assessed CFDS’s ability to identify alternative causes of leg symptoms in patients with normal veins. Examination times for CFDS were recorded and compared with venography durations.

CFDS demonstrated high diagnostic accuracy in detecting DVT. In the first part, venography identified DVT in 55 limbs: 23 proximal, 25 distal, and 7 with both proximal and distal thrombosis. CFDS was 100% sensitive and 98.8% specific for proximal DVT, with 87.5% sensitivity and 98.7% specificity for distal DVT. Positive and negative predictive values exceeded 95% for both limb segments. The overall accuracy for proximal DVT was 99.4%, and for distal DVT, 93.1%. In the second part, CFDS alone detected DVT in 156 limbs (47.6%): 82 proximal, 61 distal, and 13 with both. In 172 limbs, other causes of symptoms were identified in 34 (20%). The average CFDS examination time was 15–20 minutes, significantly shorter than venography. These findings suggest that CFDS is as accurate as venography when performed by experienced operators.

The authors concluded that CFDS is as accurate as venography in diagnosing DVT when performed by experienced operators. The study supports the use of CFDS as a non-invasive diagnostic alternative to venography in routine clinical practice. The high sensitivity and specificity of CFDS for both proximal and distal DVT suggest its reliability in detecting thrombosis. The study also found that CFDS can identify alternative causes of leg symptoms in around 20% of patients with normal veins. The average examination time of 15–20 minutes makes CFDS a more efficient diagnostic tool compared to venography. The authors propose that CFDS can be used confidently in suspected DVT cases without the need for venography. The findings suggest that CFDS is a valid and effective diagnostic method for DVT detection. The study does not claim that CFDS is superior to venography but rather that it is equally accurate and more practical in clinical settings.