This case demonstrates global testicular infarction as a potential consequence of untreated severe epididymitis. Inflammatory edema restricts venous drainage of the testes which exacerbates the increased pressure on the vascular supply eventually restricting arterial inflow. Testicular torsion is unlikely in this case since there is robust hypervascular flow to the ipsilateral epididymis which would not be seen in torsion. 

The epidydimal tail was the most engorged and hypervascular part of the epididymis. This is consistent with the pathophysiology of this condition. The patient had a background of poorly controlled diabetes and a UTI prior to onset of symptoms. The bacteria would have translocated in a retrograde fashion from the urethra into the tail of the epididymis.