In recent years, the consumption of diagnostic imaging, including computed tomography (CT) and ultrasonography (US) has increased dramatically with approximate doubling of CT and US examinations over a 10-year period ^1-3_.

Venous thromboembolism (VTE) is a frequent disease, affecting nearly 10 million people worldwide. VTE includes deep vein thrombosis (DVT) and pulmonary embolism (PE), and untreated these conditions have a considerable morbidity and mortality ⁴.

Lower extremity venous duplex ultrasonography (LEVDUS) and computed tomography pulmonary angiography (CTPA) are the primary diagnostic imaging methods for VTE ^5,6:

1. LEVDUS: high accuracy and low cost, with an overall sensitivity and specificity of 78 and 82% ⁷.
2. CTPA: widely available, quick and accurate, with a sensitivity and specificity of 74 and 90% ^7,8.

In radiology, the justification of diagnostic imaging is a key performance indicator. Both the American College of Radiology and the European Society of Radiology define justification of a radiological procedure by the evidence-based advantages of the risk–benefit ratio ^9,10. The referral letter is a key document for communication between the referring physician and the radiologist ¹¹. The referral is the basis for radiologists’ assessment of modality, protocol and urgency, and insufficient information may threaten patient safety ¹².

The main aim of this study is to assess the completeness of referrals for LEVDUS with suspicion DVT and to CTPA with suspicion of PE. Additionally, we wanted to investigate associations between the provided clinical information in the referrals and positive findings of DVT and PE.