A 21-year-old man presents with scrotal swelling and pain. What is the MOST likely diagnosis?

Findings: Heterogeneous echotexture of the testicle, with no flow within the testicle on power Doppler. A. The absence of flow on power Doppler is consistent with testicular torsion, but the presence of heterogeneity within the testicle is consistent with infarct, indicating the testicle is no longer ble. B. The absence of flow confirms torsion, with the heterogeneous appearance indicating infarction. C. With acute epididymo-orchitis, there would be abnormal increased flow within the testicle in the region of orchitis, not absent flow as in this case. D. Seminoma if this large would be hypervascular, not have absent flow as in this case.