VAI TRÒ CỦA SIÊU ÂM VI MẠCH TRONG CHẨN ĐOÁN VÀ ĐÁNH GIÁ ĐÁP ỨNG ĐIỀU TRỊ TÂN BỔ TRỢ BỆNH LÝ UNG THƯ VÚ

Abstract

Objective: To present an overview of microvascular ultrasound (MVUS), including principles, imaging features, and applications in the diagnosis and follow-up after neoadjuvant therapy of breast cancer. Methods: Narrative review, collecting and analyzing recent studies on MVUS. Sources were retrieved from PubMed, Google Scholar, and related medical literature. Results: MVUS allows visualization of very small vessels (<0.1 mm) and slow flow that are difficult to detect with conventional Doppler. Qualitative vascular features on MVUS include: presence or absence of vessels, vascular morphologies (linear, dendritic, root-like, crab-claw). Quantitative index includes the vascular index (VI), calculated as the ratio of pixels with vascular signal to the total number of pixels of the lesion, helping to distinguish benign tumors from breast cancer. Contrast-enhanced MVUS (CEUS) further evaluates perfusion; malignant tumors often show heterogeneous hyperenhancement, perfusion defects, rapid enhancement, etc. Main applications of MVUS include: (1) Differentiating benign and malignant tumors: breast cancers usually show mixed central and peripheral vascular distribution, tortuous vessels, irregular branching, penetrating vessels, uneven diameters; benign tumors often have few vessels, peripheral distribution, straight vessels, regular branching… A high VI generally suggests malignancy, with thresholds reported in the literature around 3–9%. (2) Monitoring neoadjuvant chemotherapy (NAC): reduction in VI, vessel number, diameter, and tortuosity appears early, with potential to predict treatment response or detect drug resistance. MVUS is a non-invasive, repeatable, low-cost method that adds diagnostic value to B-mode ultrasound; however, it still depends on vendor-specific microvascular detection software, and consensus on VI cutoff thresholds is lacking. Conclusion: MVUS is a promising technique, becoming an important component of multiparametric breast ultrasound. Identifying vascular patterns and VI in breast lesions aids differential diagnosis, supports biopsy decisions or follow-up. In NAC monitoring, MVUS contributes to personalized assessment of breast cancer treatment.