Testicular Evaluation using Bedside Ultrasonography

Updated: Aug 12, 2015
  • Author: Badar Bin Bilal Shafi, MBBS, MRCP, FRCR, CCT, EBIR; Chief Editor: Gowthaman Gunabushanam, MD, FRCR  more...
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Overview

Overview

Testicular ultrasonography (also called scrotal ultrasonography) is the primary diagnostic modality for the evaluation of testicular and scrotal disease. Its nonionizing nature, along with continued advances in technology, render ultrasonography the imaging modality of choice.

Testicular ultrasonography is a useful noninvasive tool in both adult and pediatric patient groups. It serves as a good screening and diagnostic tool and helps dictate further management in the appropriate clinical setting. [1] Testicular ultrasonography has a wide range of applications, varying from acute scrotal pain to more chronic and nonspecific symptoms. [1, 2]

Guidelines on scrotal ultrasound examination have been published by the American Institute of Ultrasound in Medicine (in collaboration with the American College of Radiology, Society for Pediatric Radiology, and Society of Radiologists in Ultrasound). [3]  Indications include the following:

  • Evaluation of scrotal pain, including but not limited to testicular trauma, ischemia/torsion, and infectious or inflammatory scrotal disease.
  • Evaluation of palpable inguinal, intrascrotal, or testicular masses.
  • Evaluation of scrotal asymmetry, swelling, or enlargement.
  • Evaluation of potential intrascrotal hernias.
  • Detection/evaluation of varicoceles.
  • Evaluation of male infertility.
  • Follow-up of prior indeterminate scrotal ultrasound findings.
  • Localization of nonpalpable testes.
  • Detection of occult primary tumors in patients with metastatic germ cell tumors or unexplained retroperitoneal adenopathy.
  • Follow-up of patients with prior primary testicular neoplasms, leukemia, or lymphoma.
  • Evaluation of abnormalities noted on other imaging studies (including but not limited to CT, MRI, and positron emission tomography [PET]).
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Indications

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  • Evaluation of the acute scrotum
    • Ultrasonography is often indicated in the work-up of acute scrotal pain. It is particularly valuable in cases that are challenging to diagnose clinically or in patients whose conditions fail to respond to initial treatment. Ultrasonography is also helpful in patients who present with chronic nonspecific symptoms, in whom a definitive diagnosis is not easily made. [4]
    • Ultrasonography has been shown to decrease the number of emergency scrotal explorations and the length of hospital stay, and, thus, reduce the cost of management of the acute scrotum. [5]
    • In animal studies of acute testicular ischemia, pulse-wave spectral Doppler ultrasonography has been shown to assess perfusion better than conventional color flow Doppler or power Doppler methods. [6] While promising, use of pulse-wave spectral Doppler is not currently a part of the standard evaluation.
  • Evaluation of testicular swelling or masses [7]
  • Testicular trauma
  • Infertility [8]
  • Undescended testis (vanishing testes or impalpable testis in children [9] )
  • Male hypogonadism [10]
  • Testicular interventions (eg, ultrasound-guided aspiration, biopsy, epididymal ablation)
  • Postvasectomy pain
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Contraindications

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  • Ultrasonographic evaluation of the scrotum has no contraindications.
  • In the clinical setting of testicular torsion, ultrasonography should not delay manual or surgical reduction.
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Anesthesia

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  • Anesthesia is typically not required when performing ultrasonography of the scrotum.
  • In the clinical setting of acute scrotal pain, however, the patient may need oral or parenteral analgesics prior to ultrasound. This makes any manipulation less painful and allows for better diagnostic evaluation of the patient's symptoms.
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Equipment

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  • Ultrasound machine with color flow Doppler and power Doppler (Doppler settings are essential for proper assessment; typically, little depth or gain compensation is required.)
  • High-frequency (>7 MHz), high-resolution linear transducer
  • Acoustic coupling gel
  • Gloves
  • Appropriate materials to drape the patient
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Positioning

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  • Place the patient in a supine position. Take care to support the scrotum. Consider adducting the thighs or placing a towel or sheet under the scrotum. Propping the scrotum with a towel or sheet, however, can block inferior and coronal approaches to the testis. It may also redistribute physiologic amounts of fluid within the scrotal sac and make the imaging of small structures (eg, appendix testis) more challenging.
  • If the penis obstructs the scanning field, ask the patient to shift the penis superiorly toward the abdominal wall and then cover with a sheet.
  • In infants and young boys, the testes may need to be immobilized directly with the sonographer's finger, since the testes are very small and mobile at this age. A towel can also be wrapped around the patient's thighs to lend support and to relatively immobilize the scrotum. [11]
  • In terms of grading varicoceles, the diameter of the dominant vein in the upright position at the inguinal canal can be used. [12]
  • Ultrasonography of the scrotum should be performed with the patient's symptoms and privacy in mind. Be sure the drape covers the patient appropriately. [13]
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Technique

History and Clinical Examination

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  • A focused history and clinical examination should be performed prior to scrotal ultrasonography. Ultrasonographic findings should always be interpreted in the context of the patient's history and clinical examination. The history and clinical examination, however, are often not enough to discriminate between the possible etiologies for the patient's symptoms.
  • Ask the patient to identify the area of maximum tenderness or the location of any palpable findings. Doing so saves time by decreasing the amount of time spent searching with ultrasound. The presence of inflammation or obvious signs of ischemia or injury dictate subsequent steps in assessment and management.

Technique

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  • Wash hands and put on gloves.
  • Apply ultrasound gel.
  • Using direct contact, scan the scrotum and all of its contents as follows:
    • Begin with the asymptomatic side first and then proceed to the affected side. If possible, perform views that include both testes. Comparing both sides is essential to defining and characterizing any abnormalities (see image below).
      Bilateral view of the testes across the median rap Bilateral view of the testes across the median raphe allows for direct comparison. The right testicle demonstrates decreased echogenicity and is consistent with infection (orchitis).
    • Each part of the testis and epididymis are to be scanned in both longitudinal and transverse planes (see images below). The tail of the epididymis is often best visualized using a coronal view; obtaining such a view may require the patient to temporarily assume a frog-leg position.
      Longitudinal view of the testicle. Longitudinal view of the testicle.
      Transverse view of the testicle with color flow Do Transverse view of the testicle with color flow Doppler. A hydrocele is present.
  • The video below is a demonstration of a scrotal ultrasonographic examination.
    Scrotal evaluation. Video courtesy of Meghan Kelly Herbst, MD. Also courtesy of Yale School of Medicine, Emergency Medicine.
  • The videos below depict normal findings.
    Cine loop depicting a normal testicle. Video courtesy of Meghan Kelly Herbst, MD. Also courtesy of Yale School of Medicine, Emergency Medicine.
    Cine loop depicting a normal testicle with color flow, showing vasculature. This is a technique used to evaluate for orchitis (increased Doppler flow) or torsion (decreased Doppler flow). Video courtesy of Meghan Kelly Herbst, MD. Also courtesy of Yale School of Medicine, Emergency Medicine.

Sequence of examination

The mnemonic TESTIC(K)AL is a practical sequence and useful guide to the scrotal and testicular ultrasound examination.

  • T estis
  • E pididymis
  • S kin and soft tissues of scrotum
  • T unicae (vaginalis, albuginea)
  • I nternal blood supply
  • C ompare with the other testis
  • K idney
  • A ppendages
  • Don't L eave examination of both pampiniform plexus

Evaluation of the testes

Thoroughly interrogate each testis in both longitudinal and transverse planes. Be sure to compare with the contralateral side.

Echogenicity

  • Decreased
    • Orchitis, epididymo-orchitis: Diffuse decreased echogenicity suggests orchitis; the addition of epididymal findings suggests a diagnosis of epididymo-orchitis; early in infection, however, the echogenicity may be isoechoic. See images below.
      Transverse view of the testis and epididymis with Transverse view of the testis and epididymis with color flow Doppler. Decreased echogenicity of the testis and swelling of the epididymis are consistent with epididymo-orchitis.
      Longitudinal view with color flow Doppler demonstr Longitudinal view with color flow Doppler demonstrating the head of the epididymis. The swelling and increased vascularity of the epididymis is consistent with epididymo-orchitis.
    • Testicular tumors: Focal low echogenicity masses or nodules should raise suspicion; a complex cystic lesion within the testis may represent necrosis resulting from tumor.
    • Scrotal injury or hematoma: Hematomas may resemble tumors. See images below.
      Bilateral view of the testes across the median rap Bilateral view of the testes across the median raphe demonstrating a low-echogenicity mass on the right. This finding was in the context of trauma and represents a testicular hematoma.
      Longitudinal view of the right testis. The surroun Longitudinal view of the right testis. The surrounding edema, irregular appearance, and low echogenicity mass are all consistent with a testicular hematoma.
      Transverse view of the right testis with power Dop Transverse view of the right testis with power Doppler. The surrounding edema, irregular appearance, and low echogenicity mass are all consistent with a testicular hematoma.
    • Tunica albuginea: Irregular masses, in the context of trauma, may be associated with rupture of the tunica albuginea; prompt diagnosis followed by emergent surgery results in salvage of the testis in 80-90% of cases. [14]
    • Torsion: In the subacute stage of testicular torsion, the testis may demonstrate low echogenicity.
  • Increased
    • Testicular microlithiasis: Multiple small echogenic grainlike calcifications throughout the testicle are important to appreciate, as they may be associated with an increased risk of cancer.
    • Chronic atrophy: In the chronic stage of torsion, the testis may be small, atrophic, and echogenic.

Vascularity

  • Decreased
    • Torsion: Decreased perfusion of the testis on Doppler imaging is the single most important finding to suggest the diagnosis of testicular torsion.
  • Increased
    • Infection: Acute infection results in inflammatory hyperemia and increased vascularity within the testis.

Comparison

  • Directly comparing both testes may be the only manner in which a subtle abnormal finding (eg, mild decrease in echogenicity) can be appreciated.

Evaluation of epididymis

The shape of the epididymis varies from straight to C-shaped. Scan the epididymal head, body, and tail on both sides. Be sure to scan the epididymis in multiple planes (longitudinal, transverse, and coronal). The epididymis is usually isoechoic to the testis. Look carefully for the following:

  • Cysts: Cysts are a common finding in the epididymal head; when found, measure the size in both longitudinal and transverse directions.
  • Increased size: An enlarged and swollen epididymis is a finding seen in epididymo-orchitis.
  • Increased vascularity: Hyperemia and increased vascularity of the epididymis may be another finding of epididymo-orchitis.
  • Imaging the tail of the epididymis is important because infection is often most apparent at this location.

Evaluation of skin, soft tissues, and tunicae

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  • The scrotum is a cutaneous pouch with 2 lateral compartments divided by the median raphe. It is lined by the tunica vaginalis, which reflects over the exterior surface of each testicle.
  • Assess for swelling of the skin and soft tissues; edema and hyperemia within the skin and subcutaneous tissues of the scrotal sac may be seen in infection (scrotal cellulitis) and trauma. In scrotal cellulitis, the skin and subcutaneous tissues are affected, but the contents of the scrotum inside the tunica vaginalis are spared. Scrotal abscesses may result when testicular abscesses rupture through the tunica albuginea and into the scrotal sac.
  • Rupture, discontinuity, or irregular disruption of the tunica albuginea (the exterior capsule of the testicle) all suggest testicular rupture in the appropriate clinical setting; associated hematoma may exist within the testis or subcutaneous tissues; testicular fracture requires prompt surgical evaluation.
  • Hydrocele: Fluid located between the visceral and parietal layers of the tunica vaginalis is called a hydrocele. It may be idiopathic and asymptomatic. Reactive hydroceles are seen in association with infection, torsion, and trauma; infective processes can lead to complex hydroceles or pyoceles.
  • Fournier gangrene: This is a serious and life-threatening form of necrotizing scrotal cellulitis and also involves the tissues of the perineum and base of the penis. Unlike simple scrotal cellulitis, Fournier gangrene causes ischemia, so involved tissue does not have demonstrable inflammatory hyperemia, and may also produce gas, which results in bright echoes with dirty shadowing on ultrasound.

Evaluation of appendages

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  • Vestigial appendages are normal variants in the testis and epididymis and are usually of little significance. They typically have a thin, elongated, vermiform shape.
  • Torsion of the appendix testis or appendix epididymis can present similar to spermatic cord torsion.
  • The torsed appendix appears enlarged and often with an altered echotexture due to infarction with or without hemorrhage. The testis appears normal, and a reactive hydrocele may be present.
  • Typically, blood flow is not demonstrated in the normal appendix testis or appendix epididymis. As such, the absence of flow in a suspected torsed appendix has little diagnostic value.

Evaluation of the pampiniform plexus

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  • The pampiniform plexus (venous drainage of the testicle) should be assessed in both planes and with Doppler ultrasonography. The caliber of the vessels before and after the Valsalva maneuver is the mainstay of the diagnosis of varicocele.
  • A grading system categorizes varicoceles as small, medium, or large. The caliber of the largest vessel is measured at the groin while the patient is standing.
  • Varicoceles generally occur in the left scrotum because of the anatomic venous connection of the left testicular vein draining into the left renal vein.
  • Varicoceles are often asymptomatic but can present as a chronic ache or heaviness. They generally do not cause acute pain; due to slow flow, however, thrombosis can occur, and this may result in acute pain.
  • Depending upon the symptoms and the size of the varicocele, further ultrasound examinations may be needed. Varicoceles are associated with decreased fertility and require appropriate follow-up.

Evaluation of the kidneys

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  • If a varicocele is present, the kidneys must be assessed to rule out a renal mass as the cause for the varicocele. Renal lesions can impair drainage of the testicular veins into the renal vein or inferior vena cava; some advocate for the routine assessment of both kidneys in every testicular ultrasound examination.
  • Testicular symptoms can be referred from the urinary tract (eg, kidney stones often cause pain that radiates down into the groin and testicles).
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Pearls

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  • Multiple views (longitudinal, transverse, and coronal) of the structure of interest should be obtained and compared to the contralateral side. Each structure should be interrogated in terms of echogenicity and vascularity.
  • In the acute setting, an unremarkable ultrasound with the presence of central testicular blood flow does not always exclude testicular torsion. Testicular torsion is based on a critical deficiency in testicular blood flow and not on the absence of blood flow.
  • When torsion is highly suspected, ultrasonography should not delay definitive treatment such as manual reduction or surgical exploration.
  • Doppler ultrasonography should be performed in all patients with an acute scrotum. Optimize Doppler settings on the asymptomatic side first, prior to evaluating the symptomatic side.
  • Color flow Doppler and power Doppler imaging are valuable tools; they are the mainstays in the diagnosis of emergent conditions such as testicular torsion.
  • Ultrasonography can also be used to facilitate a testis-sparing procedure. The amount of normal residual parenchyma visible on ultrasound is difficult to determine, as tissue is compressed during evaluation; thus, its true presence can be underestimated. [15]
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Complications

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  • Typically, scrotal and testicular ultrasonography are not associated with any complications.
  • The patient may experience pain if the testis is acutely inflamed or torqued, particularly in the setting of trauma.
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3D Ultrasonography

Three-dimensional (3D) ultrasonography offers an improved way to depict anatomy and to assess for abnormalities. More studies are needed to establish its role and added utility. [16]

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