Ultrasound is of minimal value in localizing the position or existence of testes that cannot be felt through physical examination. Studies have shown that there remained a significant chance that testes were present even after a negative ultrasound result. The likelihood of locating testes is low when using ultrasound.
Sources:
Tasian G et al. Diagnostic performance of ultrasound in Nonpalpable Cryptorchidism: A systematic review and meta-analysis. Pediatrics. 2011 Jan;127(1):119-28. PMID: 21149435.
National Advisory Committee on Blood and Blood Products (NAC). Prothrombin Complex Concentrates [Internet]. 2014 May [cited 2017 May 5].
Scottish Intercollegiate Guidelines Network (SIGN). Sign 129: Antithrombotics: Indications and Management [Internet]. 2013 Jun [cited 2017 May 5].