Development of ultrasonography for the detection of prostate cancer.

Magnetic resonance imaging (MRI) has become an essential tool for localizing intraprostatic tumors and detecting clinically significant prostate cancer (csPC). However, limitations related to cost, availability, and the presence of MRI-invisible lesions have driven interest in alternative imaging modalities. Transrectal ultrasound (TRUS), routinely performed by urologists, has evolved substantially with the development of advanced ultrasound technologies. Conventional gray-scale TRUS enables real-time assessment of prostate morphology and provides guidance for biopsy; however, its sensitivity for detecting csPC remains limited. Recent advances, including 29-MHz micro-ultrasound, color and power Doppler imaging, contrast-enhanced ultrasound, superb microvascular imaging (SMI), and elastography, have significantly expanded the diagnostic capability of ultrasound. Micro-ultrasound offers high-resolution visualization of ductal architecture and lesion morphology, and it has demonstrated diagnostic performance comparable to multiparametric MRI (mpMRI) in several prospective studies. Doppler-based techniques and SMI enable assessment of tumor-associated vascularity, while elastography provides quantitative assessment of tissue stiffness, which correlates with tumor aggressiveness. The integration of multiple ultrasound modalities, known as multiparametric ultrasound (mpUS), has shown promising diagnostic accuracy for csPC detection. Recent studies suggest that mpUS can identify clinically significant cancers missed by mpMRI and may serve as a complementary or alternative imaging strategy, particularly when MRI is unavailable or impractical.