This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Male comes with acute scrotal pain. To differentiate between testicular torsion and epididymo-orchitis which is the best way 
Select and explain. 
A. Angel sign, B. Prehn sign, C. Color Doppler, D. MRI
C: Color Doppler
Answer: C: Color Doppler 
Explanation: Angel sign and prehn sign are not reliable.color Doppler is investigation of choice