MULTIPARAMETRIC ULTRASOUND IN THE ASSESSMENT OF POLYCYSTIC OVARY SYNDROME IN INFERTILE WOMEN: A NARRATIVE REVIEW OF MORPHOLOGICAL, HAEMODYNAMIC AND ELASTOGRAPHIC MARKERS

Polycystic ovary syndrome (PCOS), renamed in 2026 as polyendocrine metabolic ovarian syndrome (PMOS), is the leading cause of anovulatory infertility, yet its ultrasound definition has changed repeatedly over four decades. Conventional two-dimensional (2D) transvaginal sonography remains the first-line imaging tool, but follicle counting is operator-dependent, thresholds depend on transducer resolution, and the ovarian stroma, the compartment most closely linked to hyperandrogenism, is assessed only subjectively. This narrative review summarises the evidence on the individual components of multiparametric ultrasound in PCOS: 2D morphometry and the stroma-to-ovarian area ratio, three-dimensional (3D) volumetry with automated follicle counting, spectral and 3D power Doppler indices of stromal perfusion, and strain and shear wave elastography. Published data show that automated 3D counting shortens examination time and detects more follicles than 2D scanning; that stromal flow in PCOS is characterised by lower resistance and higher vascularisation indices, although individual studies disagree; and that ovarian stiffness is higher in PCOS in most, but not all, elastography studies, with a pooled standardised mean difference of 1.86 for shear wave techniques. None of these parameters is yet validated as a stand-alone diagnostic criterion. We outline a stepwise framework that combines morphological, haemodynamic and elastographic data with the endocrine profile, and we identify the methodological gaps (standardised acquisition, cycle timing, phenotype-specific reference values) that prospective studies must close before multiparametric ultrasound can be recommended for routine infertility work-up.