Impact of CT venography added to CT pulmonary angiography for the detection of deep venous thrombosis and relevant incidental CT findings

Objectives: To assess the additional diagnostic value of CT venography (CTV) simultaneously performed with CT pulmonary angiography (CTPA) in the context of thmmboembolic disease for the detection of deep venous thrombosis (DVT) and other relevant incidental CT findings. Materials and Methods: Retrospectively and consecutively, we included all patients referred to our emergency department within the last 24 months for suspected pulmonary embolism (PE) who underwent CTPA combined with CTV. Two radiologists blinded to clinical information and results independently analysed CTV images in the context of DVT of the lower extremities and other, unsuspected abdominal/pelvic findings. These latter were classified as relevant with therapeutic consequences or irrelevant. One radiologist reviewed patient clinical records. Inter-observer agreement for DVT detection was calculated. Results: Of 696 patients, 119 had PE (17.1%) and 54 had DVT (7.8%), 16 (2.3%) of them without concomitant PE. Inter-observer agreement between the two readers was substantial (kappa = 0.78). CTV examinations led to diagnosis of relevant incidental abdominal/pelvic findings in 40 (5.7%) patients, including 11 with new malignant tumours, and 8 with progressive metastatic disease. The evaluated clinical and biological risk factors were not significantly associated with the presence of relevant incidental findings. CTV changed therapeutic management in 29 patients (4.3%): 15 had DVTs without PE, and 14 had abdominal/pelvic findings with therapeutic consequences. Conclusion: CTV simultaneously performed with CTPA offers limited incremental value for detecting DVT. It may reveal other relevant findings leading to therapeutic changes, but the low rate does not justify screening patients with suspected PE.