Ultrasound of the Scrotum Vikram Dogra, M.D. Professor of Radiology, Urology & BME Department of Imaging Sciences University Of Rochester Medical Center
Etiologies of Acute Scrotal Pain Epididymitis/Orchitis Testicular Torsion Trauma Hernia, Scrotal Infection Tumor Infarct, Thrombosis, Torsed appendices
Doppler Evaluation of Testis Describe the normal blood flow pattern to testis Understand the spectral Doppler patterns Describe the technique of optimization of Color flow Doppler in testes Understand various patterns of spectral and color flow Doppler in testicular torsion, partial torsion and its mimics.
Technique Transducer frequency Grayscale 7-12 MHz Doppler 4-9Mhz, depending on penetration and options given by manufacturer Patient position Supine with towel supporting the scrotum Warm gel
Sonographic Technique Testicular perfusion is evaluated with color, power, and spectral Doppler ultrasound. If flow is difficult to obtain, scanning parameters should be optimized for detecting slow flow. Direct comparison with a portion of both testes in one transverse field of view should be obtained in gray scale and color flow Doppler (CFD) modes. While an asymmetry of findings is helpful to establish a diagnosis, one should keep in mind that testicular torsion may be bilateral in 2% of all patients with testicular torsion.
Vascular Anatomy The arterial supply to the epididymis and the testis is supplied by the: Epididymal artery, a branch of the testicular artery Deferential artery, a branch of the superior vesicle artery Cremasteric artery, a branch of the inferior epigastric artery The venous drainage is via the pampiniform plexus and continues as the testicular vein through the deep inguinal ring. Dogra et al Vascular Anatomy of the Epididymis and Testis
Sonographic Anatomy 1. The spectral waveform of the intratesticular arteries has low resistance pattern. 2. Mean resistive index 0.62 (range,0.48-0.75). Middleton WD et al., AJR, 1989 Siegel MJ, Radiol Clin North Am, 1997
Color flow Doppler: Technique Color box Small results in frame rate and better color resolution. Doppler gain Just below the noise level. Gate size (sample volume) Usually 2/3rd of the vessel lumen. Color scale (PRF) Low PRF is more sensitive to low flows but may lead to aliasing. Beam steering Adjust to obtain satisfactory vessel angle. Wall filter Keep the filter at 50-100 Hz. Focal zone Optimized at focal zone.
Scrotal Anatomy Tunica Vaginalis- Bell clapper deformity It completely encircles the epididymis, distal spermatic cord and the testis rather than attaching to the posterolateral aspect of the scrotal wall. Its bilateral in most cases A 12% incidence was found in one autopsy series Caesar RE et al, Urology1994
Bell- Clapper Deformity Dogra et al Ultrasound Clinics, (Vol)1:1 January 2006
Testicular Torsion How do these patients present? Acute onset of scrotal pain Anorexia, nausea and/or vomiting Lack of urinary symptoms or fever As many as 35-50% of patients experience gradual onset suits are more of pain, similar to epididymitis. Lawcommon in patients with atypical presentation.
Testicular Torsion What do you find on Physical examination? Horizontal position of the testis. Absent cremasteric reflex And Negative Prehn s sign.
Testicular Torsion: Gray scale Color flow Doppler of the right testis in the longitudinal plane reveals absent color flow with normal gray-scale echotexture, Suggestive of early testicular torsion.
Testicular Torsion: Gray scale Enlarged and hypoechoic testis Enlarged and hypoechoic epididymis Commonest Absent blood flow in testis and epididymis finding at 4-6 hours
Testicular Torsion:Time Line Time from onset of symptoms to surgery associated with salvage rate:* 5-6 hours, 80-100% 6-12 hours 70% After 12 hours 20% If non salvageable, the necrotic testis is removed to decrease risk of autoimmune reaction to the residual testis. Surgery is required within 6 hours of onset of symptoms. Donohue RE, Utley WL. Urology 1978 11:33
Testicular Torsion: Grayscale Patterns Acute torsion with viable testis: normal Acute torsion with infarction: hypoechoic pattern which may be total, or partial in the case of a partial infarct. Acute torsion with hemorrhagic infarction: hyperechoic and heterogeneous pattern. Chronic: hypoechoic with small testis. Dogra et al Ultrasound Clinics, (Vol)1:1 January 2006
Testicular Torsion: Doppler Patterns Absent arterial and venous flow Increased Resistive Index on affected side (diminished or reversed diastolic flow) Decreased flow velocity on symptomatic side
What is your diagnosis? A B
Follow up after 24 hours A B
Where is the left Testis? A Cryptorchid testis10 times more prone to torsion than normal. B C
Partial Torsion Dogra et al J Clin Ultrasound; 2001
Partial Torsion A 16 year-old male presented with 10 hrs. of severe pain, nausea and vomiting. At surgery he had a 360o torsion. Dogra et al J Clin Ultrasound; 2001
Partial Torsion
Partial Torsion
Partial Torsion Whirlpool Sign S. Boopathy. J. Ultrasound Med. 2006
Partial Torsion Presence of blood flow does not exclude torsion
Abnormal Blood Supply
Torsion/Detorsion Classic history of intermittent symptoms If scanned when asymptomatic or after detorsed, will see increased flow in the affected testis, which may suggest epididymitis. Testis may be enlarged, and focal infarcts may or may not be present.
Torsion With Increased Flow? 2 hours symptoms. Left testis detorsed just before US.
Torsion/Detorsion Missed diagnosis is most common cause of liability
Torsion/Detorsion 45-yr-old with intermittent testicular pain for 6 months. No h/o lymphoma or radiation.
Torsion/Detorsion
Testicular Torsion Mimics 48 hours of increasing right sided pain
Testicular Torsion Mimics Note reversed diastolic flow on the symptomatic side.
Normal Flow Re-established
Testicular Torsion mimics 22-yr-old male with epididymo-orchitis on antibiotics Reversal of diastolic flow indicating a high arterial resistance. Patient was lost to follow-up and presented after 3 months. At that time he was found to have atrophic testis.
Testicular Torsion Mimics Right 12-27-2002 Left
Testicular Torsion Mimics Scan done on 12-29-02 Patient is s/p Lt orchectomy and S/P Rt Orchiopexy
Testicular Torsion Mimics 40X 200X
Torsed Appendages Twisting of testicular or epididymal appendages produces focal tenderness at upper pole of the testis. Most common ages 7-12 Palpable nodule on superior testis with bluish discoloration- Blue Dot Sign Pain usually resolves in two to three days. Requires no intervention. Role of ultrasound to exclude torsion and epididymitis
Torsed Appendix Testis
Torsed Appendix Testis
Conclusions US is the primary imaging modality to evaluate the acute scrotum. It is important to optimize the scan parameters. Absence of color flow Doppler is not always testicular torsion. Presence of color flow does not testicular torsion- think partial torsion or torsion- detorsion syndrome.