Close
New

Medscape is available in 5 Language Editions – Choose your Edition here.

 

Epididymitis Imaging

  • Author: Vikram S Dogra, MD; Chief Editor: Eugene C Lin, MD  more...
 
Updated: Nov 19, 2015
 

Overview

Acute epididymitis is the most common condition that causes acute scrotal pain, although acute epididymitis, testicular torsion, and testicular tumors can have a common presentation of pain. Distinguishing between acute epididymitis and testicular torsion is important because their treatments differ significantly.[1, 2, 3]

Anatomy

Normal testes develop in the celom and begin to descend into the scrotum at 36 weeks' gestation, guided by the contractile, cordlike structure called the gubernaculum testis. The epididymis and ductus deferens develop from the wolffian ducts.

At sonography, a normal adult testis has medium-level echoes and measures 5 x 3 x 2 cm. Septa extend from the tunica albuginea into the testicle, dividing the testes into lobules. The posterior surface of the tunica albuginea is reflected into the interior of the gland to form the incomplete septum known as the mediastinum of the testis. Each lobule is composed of many seminiferous tubules that open, via tubules (tubuli recti), into dilated spaces called the rete testes in the mediastinum. These, in turn, communicate via efferent ductules in the epididymal head.

The epididymis is composed of a head, body, and tail, the ducts of which continue as the vas deferens in the spermatic cord. The epididymis lies superior and lateral, along the posterior aspect of the testis; the head of epididymis is the most cephalic part.

Four testicular appendages have been described; however, only 2 are clinically relevant: the appendix of the testis (müllerian duct remnant) and the appendix of the epididymis, a wolffian duct remnant. Sonographically, the head of the epididymis is better depicted in the longitudinal view than in others. It is an isoechoic or slightly hypoechoic structure with medium-level echoes. Usually, the body of the epididymis is not identified at sonography in healthy adults. Sometimes, the epididymal tail is seen.

Preferred examination

Radiography has no role in the evaluation of epididymitis. The preferred imaging examination is ultrasonography, which is very useful in the detection of the epididymitis and/or epididymo-orchitis (see the following images). Ultrasonography is helpful in excluding testicular torsion.[4, 5, 6, 7, 8, 9, 10, 11]

Transverse ultrasonogram of the testis shows an en Transverse ultrasonogram of the testis shows an enlarged and predominantly hypoechoic epididymis with a reactive hydrocele in a patient with acute epididymitis.
Color-flow ultrasonogram shows increased vasculari Color-flow ultrasonogram shows increased vascularity in the epididymis. An enlarged epididymis with increased vascularity in the appropriate clinical setting is diagnostic of acute epididymitis.
This ultrasonogram shows an enlarged epididymis wi This ultrasonogram shows an enlarged epididymis with heterogeneous echotexture in a case of acute epididymitis.

The following should be considered in the differential diagnosis: malignant testicular tumors, testicular trauma, and testicular torsion.

Next

Ultrasonography

Ultrasonographic findings considered diagnostic of acute epididymitis include an enlarged (>17 mm) epididymis with a hypoechoic, hyperechoic, or heterogeneous echotexture (gray-scale ultrasonography) and increased blood flow (color or power Doppler ultrasonography) (see the images below).[12, 13, 14, 15, 16, 17, 18, 19, 20, 9] Associated reactive hydrocele and scrotal wall thickening may be present. Blood flow can be seen in a normal epididymis; therefore, the mere presence of blood flow should not be considered the sine qua non of epididymitis. It is the asymmetrical increase (more in the affected epididymis) that is important.[21]

Transverse ultrasonogram of the testis shows an en Transverse ultrasonogram of the testis shows an enlarged and predominantly hypoechoic epididymis with a reactive hydrocele in a patient with acute epididymitis.
Color-flow ultrasonogram shows increased vasculari Color-flow ultrasonogram shows increased vascularity in the epididymis. An enlarged epididymis with increased vascularity in the appropriate clinical setting is diagnostic of acute epididymitis.
This ultrasonogram shows an enlarged epididymis wi This ultrasonogram shows an enlarged epididymis with heterogeneous echotexture in a case of acute epididymitis.

The epididymis is primarily involved in epididymo-orchitis, with orchitis developing in about 20-40% of cases by means of direct spread. Diffuse testicular involvement is confirmed with testicular enlargement and an inhomogeneous echotexture. These findings are nonspecific, but acute epididymo-orchitis is the most common disease with this pattern. This pattern of heterogeneous echotexture can also occur in patients with tumors, metastasis, and infarction. Therefore, patients with these conditions should be followed up with ultrasonography to demonstrate complete resolution.

The readily detectable intratesticular venous flow is highly suggestive of orchitis. Analysis of the spectral waveform also can provide useful information. In the testes of a healthy volunteer, the resistive index (RI) is rarely less than 0.5, but more than half of the patients with epididymo-orchitis have an RI of less than 0.5.

Degree of confidence

Ultrasonography is the first-line imaging modality for evaluating a patient with suspected acute epididymo-orchitis. The sensitivity of color Doppler ultrasonography in detecting scrotal inflammation is almost 100%.

False positives/negatives

Usually, no false-positive or false-negative findings occur. However, the epididymis may be involved in some patients with testicular torsion. Hence, in every case of epididymitis, intratesticular blood flow should be carefully evaluated to exclude the possibility of acute testicular torsion.

Previous
Next

Nuclear Imaging

Nuclear medicine study is an alternative method for evaluating epididymitis. However, because of the improved capability of color and power Doppler ultrasonography in the evaluation of testicular perfusion, this modality is no longer favored. The most common scenario in which epididymitis appears on scintigrams is in patients who undergo imaging for suspected torsion.

The radionuclide angiogram obtained with technetium-99m (99m Tc) pertechnetate reveals increased spermatic cord blood flow. Static images reveal increased radiotracer uptake, which may be focal (as in epididymitis) or diffuse (as in epididymo-orchitis), in the involved hemiscrotum. These findings should easily differentiate epididymitis from acute torsion. However, if an abscess or hydrocele formation is present, a photopenic area with a hypervascular rim (halo sign) can be apparent. This finding could potentially mimic late, missed torsion.

False positives/negatives

Nuclear medicine studies help in the differentiation of epididymo-orchitis from acute torsion. Increased radionuclide uptake may be present in the setting of trauma.

Previous
 
Contributor Information and Disclosures
Author

Vikram S Dogra, MD Professor of Diagnostic Radiology, Urology, and Biomedical Engineering, University of Rochester School of Medicine; Director, Division of Ultrasound, Associate Chair of Education and Research, Department of Imaging Sciences, University of Rochester Medical Center

Vikram S Dogra, MD is a member of the following medical societies: American College of Radiology, Association of Program Directors in Radiology, Society of Radiologists in Ultrasound, American Institute of Ultrasound in Medicine, American Roentgen Ray Society, Radiological Society of North America, Society of Abdominal Radiology

Disclosure: Nothing to disclose.

Specialty Editor Board

Bernard D Coombs, MB, ChB, PhD Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand

Disclosure: Nothing to disclose.

Chief Editor

Eugene C Lin, MD Attending Radiologist, Teaching Coordinator for Cardiac Imaging, Radiology Residency Program, Virginia Mason Medical Center; Clinical Assistant Professor of Radiology, University of Washington School of Medicine

Eugene C Lin, MD is a member of the following medical societies: American College of Nuclear Medicine, American College of Radiology, Radiological Society of North America, Society of Nuclear Medicine and Molecular Imaging

Disclosure: Nothing to disclose.

References
  1. Tracy CR, Steers WD, Costabile R. Diagnosis and management of epididymitis. Urol Clin North Am. 2008 Feb. 35(1):101-8; vii. [Medline].

  2. Tracy CR, Costabile RA. The evaluation and treatment of acute epididymitis in a large university based population: are CDC guidelines being followed?. World J Urol. 2009 Apr. 27(2):259-63. [Medline].

  3. Gkentzis A, Lee L. The aetiology and current management of prepubertal epididymitis. Ann R Coll Surg Engl. 2014 Apr. 96 (3):181-3. [Medline].

  4. Lee JC, Bhatt S, Dogra VS. Imaging of the epididymis. Ultrasound Q. 2008 Mar. 24(1):3-16. [Medline].

  5. Al-Taheini KM, Pike J, Leonard M. Acute epididymitis in children: the role of radiologic studies. Urology. 2008 May. 71(5):826-9; discussion 829. [Medline].

  6. Shebel HM, Farg HM, Kolokythas O, El-Diasty T. Cysts of the lower male genitourinary tract: embryologic and anatomic considerations and differential diagnosis. Radiographics. 2013 Jul-Aug. 33(4):1125-43. [Medline].

  7. Avery LL, Scheinfeld MH. Imaging of penile and scrotal emergencies. Radiographics. 2013 May. 33(3):721-40. [Medline].

  8. Yusuf G, Sellars ME, Kooiman GG, Diaz-Cano S, Sidhu PS. Global testicular infarction in the presence of epididymitis: clinical features, appearances on grayscale, color Doppler, and contrast-enhanced sonography, and histologic correlation. J Ultrasound Med. 2013 Jan. 32(1):175-80. [Medline].

  9. Lev M, Ramon J, Mor Y, Jacobson JM, Soudack M. Sonographic appearances of torsion of the appendix testis and appendix epididymis in children. J Clin Ultrasound. 2015 Oct. 43 (8):485-9. [Medline].

  10. Redshaw JD, Tran TL, Wallis MC, deVries CR. Epididymitis: a 21-year retrospective review of presentations to an outpatient urology clinic. J Urol. 2014 Oct. 192 (4):1203-7. [Medline].

  11. Smith RP, Tracy CR, Kavoussi PK, Witmer MT, Costabile RA. The impact of color Doppler ultrasound on treatment patterns of epididymitis in a university-based healthcare system. Indian J Urol. 2013 Jan. 29 (1):22-6. [Medline].

  12. Bree RL, Hoang DT. Scrotal ultrasound. Radiol Clin North Am. 1996 Nov. 34(6):1183-205. [Medline].

  13. Brown JM, Hammers LW, Barton JW. Quantitative Doppler assessment of acute scrotal inflammation. Radiology. 1995 Nov. 197(2):427-31. [Medline].

  14. Burks DD, Markey BJ, Burkhard TK. Suspected testicular torsion and ischemia: evaluation with color Doppler sonography. Radiology. 1990 Jun. 175(3):815-21. [Medline].

  15. Dogra VS, Gottlieb RH, Oka M. Sonography of the scrotum. Radiology. 2003 Apr. 227(1):18-36.

  16. Dogra VS, Rubens DJ, Gottlieb RH. Torsion and beyond: new twists in spectral Doppler evaluation of the scrotum. J Ultrasound Med. 2004 Aug. 23(8):1077-85.

  17. Gordon LM, Stein SM, Ralls PW. Traumatic epididymitis: evaluation with color Doppler sonography. AJR Am J Roentgenol. 1996 Jun. 166(6):1323-5. [Medline].

  18. Gronski M, Hollman AS. The acute paediatric scrotum: the role of colour doppler ultrasound. Eur J Radiol. 1998 Jan. 26(2):183-93. [Medline].

  19. Herbener TE. Ultrasound in the assessment of the acute scrotum. J Clin Ultrasound. 1996 Oct. 24(8):405-21. [Medline].

  20. Lerner RM, Mevorach RA, Hulbert WC. Color Doppler US in the evaluation of acute scrotal disease. Radiology. 1990 Aug. 176(2):355-8. [Medline].

  21. Pearl MS, Hill MC. Ultrasound of the scrotum. Semin Ultrasound CT MR. 2007 Aug. 28(4):225-48. [Medline].

  22. Dogra V, Bhatt S. Acute painful scrotum. Radiol Clin North Am. 2004 Mar. 42(2):349-63. [Medline].

  23. Dogra VS, Sessions A, Mevorach RA. Reversal of diastolic plateau in partial testicular torsion. J Clin Ultrasound. 2001 Feb. 29(2):105-8. [Medline].

  24. Horstman WG. Scrotal imaging. Urol Clin North Am. 1997 Aug. 24(3):653-71. [Medline].

  25. Karmazyn B, Kaefer M, Kauffman S, Jennings SG. Ultrasonography and clinical findings in children with epididymitis, with and without associated lower urinary tract abnormalities. Pediatr Radiol. 2009 Oct. 39(10):1054-8. [Medline].

  26. Mevorach RA, Lerner RM, Greenspan BS. Color Doppler ultrasound compared to a radionuclide scanning of spermatic cord torsion in a canine model. J Urol. 1991 Feb. 145(2):428-33. [Medline].

 
Previous
Next
 
Transverse ultrasonogram of the testis shows an enlarged and predominantly hypoechoic epididymis with a reactive hydrocele in a patient with acute epididymitis.
Color-flow ultrasonogram shows increased vascularity in the epididymis. An enlarged epididymis with increased vascularity in the appropriate clinical setting is diagnostic of acute epididymitis.
This ultrasonogram shows an enlarged epididymis with heterogeneous echotexture in a case of acute epididymitis.
 
 
 
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.