Diagnostic and therapeutic impact of ultrasound tomography in lower extremity varicose veins: protocol for a paired accuracy study and randomised controlled trial in a tertiary hospital in China.

Background: Chronic venous disease, particularly lower extremity varicose veins (VVs) and incompetent perforating veins (IPVs), is a prevalent condition associated with significant morbidity, including venous ulcers and post-surgical recurrence. Current diagnostic modalities for IPVs-such as digital subtraction angiography, CT venography, magnetic resonance venography and conventional ultrasound-are limited by ionising radiation, operator dependency or inadequate spatial resolution. Ultrasound tomography (UT), an emerging automated 3D imaging technology, offers comparable resolution, wider field of view and reduced operator bias compared with conventional ultrasound. Preliminary studies suggest UT improves IPV detection rates, yet its diagnostic accuracy and clinical utility remain unvalidated in large-scale trials. This study aims to evaluate UT's diagnostic performance and its impact on surgical outcomes in a paired-design and randomised controlled trial (RCT), addressing a critical gap in non-invasive venous assessment.

Methods: This study combines a paired diagnostic trial and a prospective, triple-blind RCT. In the paired trial (n=84), patients with VVs (Clinical-Etiological-Anatomical-Pathophysiological C2-C5) receive both conventional ultrasound and UT combined with Doppler examination to compare IPV detection sensitivity against surgical findings. The RCT (n=264) randomises patients to conventional ultrasound group (control group) or conventional ultrasound＋UT group (intervention group). After examination, all patients undergo standardised treatment (radiofrequency ablation with sclerotherapy and selective IPV ligation), with follow-up extending to 5 years. The primary endpoint is 1-year recurrence rates and secondary endpoints, including 3-month, 3-year and 5-year recurrence rates, as well as Venous Clinical Severity Scores, quality of life and Aberdeen Varicose Vein Questionnaire scores.

Ethics and dissemination: The study has been approved by the Ethics Committee of Shanghai Sixth People's Hospital (approval number: 2024-132). Written informed consent will be obtained from each participant, and final results will be published in peer-reviewed journals.

Trial registration number: The study has been registered on Chinese Clinical Trial Registry (http://www.chictr.org.cn), identifier: ChiCTR2500097289.