May Case #2: Testicular Pain

22 y/o WM presents to the ED with acute onset of testicular pain X 2 h.  He denies F/C, N/V/D.  He is currently sexually active with 1 partner.  He denies dysuria, hematuria, penile discharge, lesions or pain.

PMHx:  none
PSHx:  none
Meds:  none
All: NKDA
SocHx:  +tob (ippd), +ETOH (6 pk/d), no drug use

PE:  BP 123/85, P 68, R 12, T 98.4 (o), Pox 99% (RA)
GEN:  WNW, WM, NAD
CHEST:  CTA B, nonlabored
CV:  RRR, no M/R/G
ABD: soft, NTND, +BS, DRE norm tone, heme -
GU:  no inguinal LAD, penis without lesions or discharge, testicles with normal lie, +TTP R testicle

Bedside US is performed:

 

 

What is the diagnosis?