although ultrasound with color doppler is the most commonly used imaging modality , torsion of undescended non neoplastic testis in an adult may be identified using non contrast computed tomography ( ct ) using the  inguinoscrotal whirlpool sign on ct . a 30-year - old male with acute abdominal and left groin pain for 2 days was referred for ct scan with a clinical diagnosis of ureteric colic . an ovoid hypodense structure measuring 3.8 cm  2.5 cm  2.6 cm was noted in the left inguinal region with serpentine twisting soft tissue density structures proximal to it [ figures 1 , 2 , and video 1 ] , prompting the diagnosis of torsion of the undescended left testis . axial non contrast computed tomography shows cryptorchid left testis in the left inguinal canal ( long white arrow ) and adjacent proximal soft tissue representing twisted cord ( short white arrow ) ( a ) coronal reformat of non contrast computed tomography shows cryptorchid left testis in the left inguinal canal ( white arrow ) . ( b and c ) serpentine twisting soft tissue density structures proximal to it representing twisted spermatic cord ( white arrows ) cryptorchidism , failure of intra - abdominal testes to descend into scrotal sac , has an incidence of 3.7% at birth and declines to about 1% by 1 year . torsion of undescended testis classically occurs during the perinatal period and is considered unlikely after infancy . although the incidence of torsion is higher in cryptorchid testis , there are only isolated reports of torsion of undescended testicle . ultrasound with color doppler is the most commonly used imaging modality in suspected testicular torsion . scintigraphy and magnetic resonance imaging ( mri ) may be helpful , but are not widely used . testicular salvage is more likely if treated within 6 hours of torsion onset . in our case , torsion was diagnosed based on the twisting appearance of serpentine soft tissue density structures in the inguinal canal , just before the cryptorchid testis , which may be called this is based on the direct extension of  real - time whirlpool sign  on color doppler described as the most definitive sign of torsion with 100% specificity and sensitivity . soft tissue edema and altered density are seen in inflammatory testicular conditions also , but whirlpool appearance is absent . it is essential for the radiologists to recognize  inguinoscrotal whirlpool sign on ct  which clinches the diagnosis of testicular torsion . this case also emphasizes the importance of examining scrotum and groin in all patients with acute abdomen pain .
non contrast helical computed tomography ( ct ) study of the abdomen is frequently performed in evaluation of suspected ureteric colic . 
 we present ct images of a young adult male patient who had torsion of an undescended , non - neoplastic testis and describe the 
 inguinoscrotal whirlpool sign on ct  .