The undescended testicle (cryptorchidism) may be intra-abdominal or what is termed cannilicular in nature. Cannilicular describes those testicles along the normal pathway of descent, that are both outside of the abdominal cavity, but not in the scrotum.
Ultrasound is the first line investigation, as a large percentage of undescended testicles (80%) are within the inguinal canal and therefore can be identified.
MRI has a role, especially in identifying those within the abdomen, when ultrasound has not a cannilicular type. It is usually of greater use in the late-presenter, that is older children or young adults, due the difficulties in cooperation with small children and infants.
The undescended testicle is also often smaller as in this case (3.5 cm vs 2.4 cm).
T1 and T2 weighted axial and coronal sequences, especially with a small field of view (FOV) are advisable as well as diffusion weighted imaging. The testicle is typically low signal on T1 and high signal on T2. The normal testicle exhibits intense diffusion restriction, and these sequences can aid confident identification.