Multiparametric Ultrasound of Nonpalpable Focal Testicular Lesions

Ultrasonography of the scrotum: Revisiting a classic technique

Conventional US is the primary imaging modality for the evaluation of the scrotum, due to its high resolution, availability, cost-effectiveness and absence of ionizing radiation. Grayscale and color Doppler US provide a comprehensive assessment of scrotal diseases. The technique represents the mainstay for imaging of acute scrotum. US is highly accurate in the detection, localization and characterization of scrotal masses. Multiparametric US, including conventional US, contrast-enhanced US and tissue elastography has improved the diagnostic performance of the technique in the assessment of testicular diseases. MRI represents a valuable supplemental imaging tool for the investigation of scrotal pathology, mainly recommended in cases of indeterminate US findings. Recommendations recently issued by the European Society of Urogenital Radiology Scrotal and Penile Imaging Working Group (ESUR-SPIWG) refer to the use of scrotal sonography for the evaluation of pathologic entities, including testicular microlithiasis, small, non-palpable incidentally detected testicular masses, varicocele and scrotal trauma. In this review, the technical specifications for scrotal US and the normal sonographic findings are presented. Grayscale and color Doppler US findings of common acute scrotal diseases and scrotal masses are discussed. The complimentary role of multiparametric US and scrotal MRI is addressed. ESUR-SPIWG's guidelines are also reviewed.

When to ask for an MRI of the scrotum

Background

Multiparametric MRI (mpMRI) of the scrotum has been established as a useful second‐line diagnostic tool for the investigation of scrotal diseases. Recently, recommendations on clinical indications for scrotal MRI were issued by the Scrotal and Penile Imaging Working Group of the European Society of Urogenital Radiology.

Objective

To update current research on when to ask for an MRI of the scrotum.

Methods

PubMed database was searched for original articles and reviews published during 2010–2021.

Results

Eighty‐three articles fulfilled the search criteria. Scrotal MRI is mainly recommended after inconclusive US findings or inconsistent with the clinical examination and should be asked in the following cases: differentiation between intratesticular and paratesticular lesions (in rare cases of uncertain US findings), characterization of paratesticular and intratesticular lesions (when US findings are indeterminate), discrimination between germ cell and sex cord‐stromal testicular tumors, local staging of testicular malignancies (in patients planned for testis‐sparing surgery), differentiation between seminomas and non‐seminomatous tumors (when immediate chemotherapy is planned and orchiectomy is delayed), assessment of acute scrotum and scrotal trauma (rarely needed, in cases of non‐diagnostic US findings) and detection and localization of undescended testes (in cases of inconlusive US findings). Although preliminary data show promising results in the evaluation of male infertility, no established role for mpMRI still exists.

Conclusion

Multiparametric MRI of the scrotum, by assessing morphologic and functional data represents a valuable problem‐solving tool, helping to improve our understanding on the nature of scrotal pathology and the process of spermatogenesis. The technique may improve patient care and reduce the number of unnecessary surgical procedures.