The accuracy of duplex studies compared with angiography in the assessment of extracranial vascular disease depends on the method of angiographic determination of carotid stenosis. Vascular laboratories should validate the duplex criteria they use against a standard method of angiographic assessment of carotid artery stenosis, with special reference to the recently reported studies noting the significance of a stenosis greater than 70% in patients with symptoms.

To compare a non‐invasive technique with contrast venography in the diagnosis of lower limb deep venous thrombosis (DVT), 355 patients (380 limbs) were examined over 15 months, using Duplex ultrasound. During this period, ascending venograms were performed in 53 of these patients (56 limbs) and the results were compared. Duplex detection of intraluminal thrombus was based on venous compressibility, Doppler‐derived flow spectra, and visualization of thrombus within the lumen. Venography was designated the ‘gold standard’. Duplex scanning had a sensitivity of 90.9%, and specificity of 91.3% in diagnosing DVT anywhere in the lower limb. Sensitivity, specificity, and accuracy were best in the femoral segment (95.2%, 100%, 98.2%, respectively), and fell slightly in the more distal limb: popliteal segment (90.4%, 97.1% and 94.6%), and calf veins (88.8%, 92.0% and 90.4%). These results indicate that duplex scanning produces sufficiently accurate data in the diagnosis of lower limb DVT to warrant its clinical use. It provides both the facility for diagnosis without the risks of contrast venography, and permits repeated imaging to follow the immediate progression of disease and efficacy of treatment.

Introduction Classification of endoleak is determined by the mechanism by which the endograft fails to exclude the aneurysm. In some instances, the endoleak may be very subtle or not visible; yet, the aneurysm continues to expand. This report presents our experience in identifying unstable abdominal aortic aneurysm sacs associated with endoleaks or endotension in early and late monitoring using color duplex ultrasound (CDU) in a series of more than 1000 endograft patients. Aims We sought to (1) describe ultrasound features of atypical endoleaks and endoleaks from unusual sources and (2) characterize other CDU features that may be associated with endotension. Methods Philips HDI 5000 and IU22 machines were used during routine post-endograft surveillance scans of the abdominal aorta. Color, spectral, and power Doppler analysis were also performed to identify evidence of perigraft flow, graft stenosis, thrombus, kink, or migration. Secondary diagnostic maneuvers were conducted in the presence of perigraft flow to characterize the type of endoleak. Particular attention was also paid to the abdominal aortic aneurysm sac contents, size, and pulsatility. Correlation was made to angiography and computed tomography imaging in a series of 22 patients who underwent secondary endograft procedures or open conversion. Results Technically satisfactory studies were achieved in approximately 90% of patients. We detected type II endoleaks in 10% of patients assessed and graft migration in 12 cases. Endotension was characterized by sac enlargement and/or shape change without identifiable perigraft flow and correlated highly with device migration. Suggestive features of graft/sac instability included increased sac pulsatility, prominent areas of echolucency within the sac, and occasional low-amplitude atypical color signals within the sac thrombus close to the graft wall. Conclusion Reliable CDU assessment for late endograft follow-up requires careful scrutiny of the aneurysm sac contents and wall, as well as the graft device. Endoleak may not always be obvious yet CDU features can assist in identifying the source of endoleak or the presence of endotension. There are suspicious ultrasound features that may alert one to graft/sac instability and potentially dangerous outcome.