Introduction: An understanding of haemodynamic principles is fundamental to accurate interpretation in vascular ultrasound. These concepts, however, are often presented in complex theoretical terms, making it difficult to apply them to practical scanning decisions.
Methods: This presentation will provide an overview of key haemodynamic principles and the flow changes encountered during vascular ultrasound examinations. The primary focus will be on the complex flow changes that occur through a stenosis, with the aim of improving understanding of which flow regions provide the most accurate velocity measurements for stenosis grading.
Results and Conclusion: Complex haemodynamic changes occur across regions of arterial stenosis, producing multiple waveform types within a short segment. Understanding these changes enables sonographers to identify the most appropriate sampling locations, improving the accuracy and consistency of velocity measurements used for stenosis grading.

Introduction: Thoracic Outlet Syndrome (TOS) describes compression of neurovascular structures in the thoracic outlet. Dynamic ultrasound is valuable in evaluating vascular TOS using positional arm manoeuvres. In this presentation we outline key techniques, measurements, and important pitfalls outlined in the literature.
Methods: Ultrasound assessment typically uses colour and spectral Doppler to examine baseline flow and vessel calibre in rest position, then with arm abduction and provocative positions (military brace position) to reproduce symptoms that patients experience. The dynamic assessment allows for clinicians to observe changes in vessel diameter, flow pattern, narrowing of the venous and arterial vessels.
Results: These findings can suggest a diagnosis of vascular TOS when correlated with symptoms and arm manipulation. Dynamic imaging also helps to identify specific compression sites such as the costoclavicular space). Contrastingly, there are pitfalls to accurately diagnosing TOS. Provocative manipulation to arm can trigger findings of TOS in asymptomatic individuals, with studies showing significant arterial waveform changes in a substantial proportion of healthy subjects during provocative tests. Ultrasound is also operator dependent, which can contribute to false positives or false negatives. Finally, there are lack of universally standardised imaging protocols further complicates diagnosis.
Conclusion: Dynamic ultrasound remains a valuable diagnostic assessment to assess TOS when performed with technique and protocol outlined in the literature.

Endovascular AVF creation for the purpose of dialysis access is a minimally invasive, catheter based procedure whereby an arteriovenous fistula is created using radiofrequency energy. BD's WavelinQ system situates the AVF in the proximal forearm between the radial artery or ulnar artery and one of their concomitant veins. The creation site is near the perforator vein at the antecubital fossa to encourage the flow into the superficial venous system of the arm which can be cannulated for haemodialysis.

The sonographic challenges of endovascular AVF scanning include the appropriate assessment of patient anatomy as a successful endoAVF is heavily reliant on the perforator vein. Additionally, careful assessment of vessel diameters and depth for access and cannulation is crucial for successful and practical long-term dialysis. Finally, serial sonographic surveillance ensures thrombosis, needling injuries and evidence of failure can be evaluated promptly to provide comprehensive and patient-centred care.