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ABDOMINAL EMERGENCIES

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Role of US in Testicular and Scrotal Trauma1  CME FEATURE See accompanying test at http:// www.rsna.org /education /rg_cme.html

LEARNING OBJECTIVES FOR TEST 4 After reading this article and taking the test, the reader will be able to: ■■Discuss

the significance of color Doppler US for evaluating testicular trauma.

■■Describe

US features of testicular and extratesticular injuries from blunt, penetrating, and iatrogenic trauma.

Shweta Bhatt, MD • Vikram S. Dogra, MD High-frequency ultrasonography (US) with a linear-array transducer is the modality of choice for the initial evaluation of patients with acute scrotal pain after trauma. Testicular trauma is the third most common cause of acute scrotal pain. US is useful in the triage of patients for medical or surgical management because it reliably depicts tunica albuginea rupture, intra- and extratesticular hematomas, and testicular contusions. Color Doppler US allows direct evaluation of testicular perfusion and detection of uncommon conditions, such as testicular torsion, that may be associated with scrotal trauma. In addition, 10% of testicular tumors are found incidentally at US performed for the evaluation of trauma. If a conservative approach is adopted for the management of an intratesticular abnormality after trauma, follow-up US should be performed until the images show a complete resolution of the abnormality, so that a tumor will not be missed. ©

RSNA, 2008 • radiographics.rsnajnls.org

■■Identify

US findings suggestive of testicular rupture.

TEACHING POINTS See last page

RadioGraphics 2008; 28:1617–1629 • Published online 10.1148/rg.286085507 • Content Codes: 1 From the Department of Imaging Sciences, University of Rochester School of Medicine, 601 Elmwood Ave, Box 648, Rochester, NY 14642. Recipient of a Certificate of Merit award for an education exhibit at the 2007 RSNA Annual Meeting. Received February 4, 2008; revision requested March 16 and received March 31; accepted April 7. All authors have no financial relationships to disclose. Address correspondence to V.S.D. (e-mail: [email protected]).

©

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Introduction

Testicular trauma is the third most common cause of acute scrotal pain (1), and high-frequency ultrasonography (US) with a linear-array transducer is the modality of first choice for the evaluation of testicular trauma (2). The need for US is further underscored because the clinical manifestations are not always correlative to or reliably indicative of testicular injuries (3). US findings may vary from a small hematocele requiring conservative management to a testicular rupture demanding immediate surgical intervention (3). US therefore is helpful in the triage of patients for surgical or nonsurgical management. The article provides a descriptive overview of the grayscale and color Doppler US features that may be seen in scrotal trauma. High-frequency US performed with a lineararray transducer helps identify both the normal tunica albuginea and its rupture with greater ease (4). The amount of swelling and ecchymosis may vary, and the degree of hematoma does not necessarily correlate with the severity of testicular injury. The absence of external signs does not entirely rule out a testicular rupture; a contusion without a fracture of the tunica albuginea may be accompanied by significant bleeding that requires surgical intervention. Early surgical exploration is important in patients with negative US findings of testicular injury when there is a high risk or a high degree of suspicion—for example, in patients who have undergone trauma involving high-energy transfer mechanisms (5).

Anatomy of the Scrotum and Testes

Each hemiscrotum contains a testis with its coverings, epididymis, and spermatic cord. A normal testis measures 5 × 3 × 2 cm in size and has intermediate echogenicity. The tunica albuginea is a fibrous covering that protects the testis from external injuries. It overlies the tunica vasculosa, which is composed of capsular arteries. The posterior surface of the tunica albuginea is reflected into the interior of the testis, forming the incomplete septum known as the mediastinum of the testis. The mediastinum appears as an echogenic band along the longitudinal axis of the testis (Fig 1) and may be mistaken for an intratesticular lesion (6). The tunica albuginea, with its great tensile strength, plays a significant role in protecting the testis from trauma. It can sustain a force of as much as 50 kg without rupturing. The testicular

Figure 1.  Normal mediastinum testis. Longitudinal gray-scale US image of a normal testis shows a linear echogenic structure (arrow) along the long axis of the testis.

parenchyma consists of multiple lobules, each of which is composed of many seminiferous tubules that lead via the tubuli recti to dilated spaces, called the rete testis, within the mediastinum. The epididymis, which overlies the superolateral aspect of the testis, comprises a head, body, and tail. The tail of the epididymis continues as the vas deferens in the spermatic cord. The epididymal head is a 5–12-mm pyramidal structure situated atop the superior pole of the testis. At US, the head is nearly isoechoic to the testis. The body of the epididymis is 2–4 mm thick.

US Technique

Scrotal US is performed with the patient lying in a supine position and with the scrotum supported by a towel placed between the thighs. The use of a 7–14-MHz high-frequency linear-array transducer is preferred. After trauma, the scrotum is often tender to the touch, which makes scanning difficult. An attempt should be made to evaluate both testes and epididymides in their entirety and to identify any extratesticular collections. The testes are evaluated in longitudinal and transverse planes. The size and echogenicity of each testis and epididymis should be compared with those of the contralateral testis and epididymis. Transverse scrotal imaging to depict both the testes is extremely important, allowing a comparison of their gray-scale and color Doppler appearances. The asymptomatic side should be scanned first to set the gray-scale and color Doppler gains to allow optimal comparison with the affected side. Color Doppler and pulsed Doppler US should be optimized to depict low flow velocities, and blood flow in the testis and surrounding scrotal structures should be documented by acquiring Doppler spectra of the intratesticular

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The two most common complications of inguinal and scrotal surgery include nerve injury and infection (10,11). Another common complication is spermatic cord transection, which may lead to bleeding from the spermatic cord vessels and, eventually, to large scrotal hematomas and progressive scrotal swelling. Bilateral testicular injuries and ruptures are rarer; they are seen in approximately 1.5% of cases of blunt scrotal trauma. Penetrating injuries are more likely to be bilateral, with an incidence rate of about 30% (12,13). Figure 2.  Normal tunica albuginea. Longitudinal gray-scale US image of a normal testis depicts a thin echogenic line (arrow) around the testis.

arterial flow in both testes. Ideally, three spectral Doppler recordings should be obtained in each testicle (preferably, in upper, middle, and lower thirds). Power Doppler also may be used to visualize the intratesticular blood flow in patients with acute scrotal pain.

Mechanisms of Injury

Teaching Point

The testes are protected by their mobility within the scrotum, the laxity of the overlying skin, the contraction reflex of the cremasteric muscles, and the tunica albuginea. However, although the laxity of the genital skin may protect the underlying organs from blunt trauma by allowing them to slip away from the point of contact, excessive skin laxity may lead to severe injuries if the genital skin becomes entrapped in rotating machinery, with avulsion and rupture of one or both testes (7,8). Sporting activities account for more than half of all cases of testicular injury, and motor vehicle accidents account for another 9%–17% of testicular injuries (9). The three main categories of injury to the scrotum are blunt injuries, penetrating injuries, and iatrogenic injuries. Blunt injuries are noninvasive injuries from high energy transferred during contact with a solid object (eg, from a kick to the groin or the impact of a baseball or hockey stick). The main mechanism of injury in blunt trauma is crushing of the testis against the symphysis pubis or between the thighs. The right testis is more likely to be injured in this way than the left testis (5), presumably because it has an anatomic location slightly higher than that of the left testis in most men. Penetrating injuries include wounds from sharp objects and missiles (eg, knives, bullets) as well as animal bites and injuries from self-mutilation. Iatrogenic injuries to the scrotal contents often result from complications of inguinal herniorrhaphy or orchiectomy.

US Findings Testicular Rupture US plays a significant role in the early identification of a testicular rupture, allowing prompt surgical exploration and repair. Guichard et al demonstrated a sensitivity of 100% and specificity of 65% for US in the detection of testicular rupture in a series of 33 patients (3). More than 80% of ruptured testes can be salvaged, with a high success rate, if surgical repair is performed within 72 hours of testicular injury (14). Findings of a heterogeneous echotexture within the testis, testicular contour abnormality, and disruption of the tunica albuginea are considered very sensitive and specific for the diagnosis of testicular rupture (2,15,16). Buckley and McAninch, in their series of 65 patients with blunt scrotal trauma, demonstrated a sensitivity of 100% and a specificity of 93.5% for the diagnosis of testicular rupture on the basis of US findings of a heterogeneous echotexture and contour abnormality (15). In addition, an absence of normal vascularity within the testis may help characterize a rupture. The US characteristics of testicular rupture are considered in order of their importance in the next four sections. Disruption of the Tunica Albuginea.—At US, the normal tunica albuginea appears as two parallel hyperechoic layers outlining the testis (Fig 2). In our experience, the US finding of an intact tunica albuginea allows the confident exclusion of a testicular rupture. Among our 63 patients with testicular trauma, none of those with a normal tunica albuginea at US were found to have a testicular rupture (17). The demonstration at US of a discontinuity in the tunica albuginea in a patient with a clinical history of scrotal trauma supports a straightforward diagnosis of tunica albuginea disruption or

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Figures 3, 4.  Testicular rupture. (3a) Longitudinal gray-scale US image of the right testis in a patient with scrotal trauma shows localized disruption of the tunica albuginea (arrows) with associated contour abnormality (arrowheads) and heterogeneous echotexture of the testicular parenchyma (*). (3b) Color Doppler US image depicts an absence of vascularity in the extruded lower pole of the testis (*). Surgical débridement of the inferior pole was performed with salvage of the uninjured part of the testis. (4) Longitudinal color Doppler US image of the right testis in a patient with more severe scrotal trauma shows complete disruption of the tunica albuginea with testicular contour abnormality (arrowheads) and no vascularity. The contralateral testis (not shown) also was ruptured. A bilateral orchiectomy was performed.

Figure 5.  Intratesticular hematomas. (a) Longitudinal gray-scale US image obtained immediately after blunt scrotal trauma demonstrates a heterogeneous echotexture in the left testis, with an intact surrounding tunica albuginea. (b) Follow-up sagittal US image obtained 12 hours later shows multiple avascular hypoechoic lesions (arrowheads) within the testis. The hematomas were managed conservatively.

testicular rupture (Figs 3, 4). The presence of any of the associated findings described below helps confirm this diagnosis. However, in a patient with a large extratesticular hematocele, US may be of limited use for evaluating the tunica albuginea. Surgical exploration should be performed in such patients, irrespective of the presence or absence of definitive US signs of testicular rupture (18,19).

Contour Abnormality of the Testis.—Abnormality in the contour of the testis results from the extrusion of testicular parenchyma after disruption of the tunica albuginea (20,21). In the presence of a large extratesticular hematocele or large scrotal wall hematoma that may obscure a site of tunica disruption, an abnormality in the contour of the testis is considered indirect evidence of rupture. US has a low accuracy for the diagnosis of testicular rupture on the basis of a finding of tunica disruption alone, with a reported sensitivity of 50% and specificity of 76% (3). Additional findings of testicular contour deformity and heterogeneous echotexture have been reported to increase the sensitivity and specificity of US for diagnosis of testicular rupture to 100% and 93.5% (15) (Fig 4).

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Bhatt and Dogra  1621 Figures 6, 7.  Testicular rupture. (6) Longitudinal color Doppler US image of the left testis in a patient with scrotal trauma depicts tunica albuginea disruption (arrowhead) with a loss of vascularity in the ruptured portion of the testis (*). Débridement of the avascular portion was performed with salvage of uninjured parenchyma. (7) Transverse color Doppler US image of the left testis in another patient with scrotal trauma shows disruption of the tunica albuginea (arrow) and a heterogeneous echotexture with an almost complete loss of vascularity. This patient underwent an orchiectomy.

unless it is accompanied by an observed tunica albuginea disruption or testicular contour irregularity (23) (Fig 5).

Figure 8.  Intratesticular hematoma. Transverse color Doppler US image in a patient with scrotal trauma demonstrates an avascular hypoechoic area (arrow) within the testis. The hematoma was managed conservatively.

Heterogeneous Echotexture of the Testis.— A significant amount of force (about 50 kg) is required to rupture a normal tunica albuginea. When the tunica is ruptured, the underlying testicular parenchyma is almost always injured. This fact helps explain the heterogeneous echotexture and irregular testicular outline associated with a tunica rupture. A heterogeneous echotexture of the testicular parenchyma, along with a contour abnormality of the testis, is considered highly sensitive and specific for the diagnosis of a testicular rupture (15,16,22). However, a heterogeneous echotexture also may be seen in the presence of intratesticular hematomas without a tunica albuginea rupture; therefore, it should not be considered indicative of testicular rupture

Absence of V   ascularity in the Testis.—Color Doppler imaging is invaluable for the evaluation of traumatic injuries to the scrotum (24). Tunica albuginea rupture is almost always associated with a disruption of the tunica vasculosa because of the close apposition of the latter to the tunica albuginea. As a result, rupture of the testis results in a loss of vascularity to a portion or the entirety of the testis, depending on the grade of injury (2) (Figs 6, 7). This aspect of the US evaluation of scrotal trauma is extremely important because it may help determine the viability of the testicular parenchyma and the appropriate method of surgical management (22). The avascular, lacerated portion of the ruptured testis is usually debrided, and the vascular portions are left behind. The absence of vascularity in a focal area of the testis may be secondary to an intratesticular hematoma, which, if it is large, may require surgical evacuation (Fig 8).

Testicular Fracture Testicular fracture refers to a break or discontinuity in the normal testicular parenchyma. A testicular fracture line is identified at US as a linear hypoechoic and avascular area within the testis, a finding that may or may not be associated with a tunica albuginea rupture (Fig 9). A fracture line is rare and is seen in only about 17% of cases

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(6,20,25,26). Color Doppler imaging plays a significant role in guiding management in such cases. The presence of vascularity in the testicular parenchyma is indicative of its salvageability; often, only débridement along the line of fracture is required, while the vascular parenchyma is preserved (2).

Testicular Dislocation Testicular dislocation, which is more often unilateral than bilateral, most commonly results from impact against the fuel tank in motorcycle accidents (27,28). Patients with a wide external inguinal ring, an indirect inguinal hernia, or an atrophic testis are more vulnerable to testicular dislocation due to trauma (29,30). The possible sites of testicular dislocation include superficial inguinal (50%), pubic (18%), canalicular (8%), penile (8%), intraabdominal (6%), perineal (4%), and crural (2%) sites (31). In addition to US, computed tomography (CT) of the pelvis may be helpful for localizing a dislocated testis. Delayed diagnosis of a dislocated testis and its tardy repositioning may lead to irreversible changes within the testis (32) and predispose it to malignant degeneration (33). A high index of suspicion, combined with a careful physical examination and appropriate imaging, are essential to avoid a delay in diagnosis.

Testicular Torsion Scrotal trauma may result in testicular torsion with clinical manifestations and a US appearance similar to those of non-trauma-related testicular torsion. According to the published literature, 5%– 8% of cases of torsion of the spermatic cord are thought to be precipitated by trauma (20,34,35). The most common predisposing factor for testicular torsion is so-called bell clapper deformity (20). In bell clapper deformity, an abnormal insertion of the tunica vaginalis allows the testis wide mobility (36). Trauma may induce a sudden forceful contraction of the cremasteric muscle, which encloses the spermatic cord in a spiral fashion and rotates the testicle as a result of its contraction (35,37). US findings allow an early diagnosis and prompt surgical intervention to salvage the testis. Color Doppler imaging of testicular torsion demonstrates a complete absence of blood flow within the testis (Fig 10). A gray-scale US finding of a homogeneous testicular parenchyma without necrosis or infarction is indicative of salvageability of the testis (38).

Figure 9.  Testicular fracture. Longitudinal color Doppler US image in a patient with scrotal trauma depicts a hypoechoic avascular band (arrows) that crosses the testicular parenchyma. Surgical repair was performed with salvage of viable parenchyma. (Reprinted, with permission, from reference 20.)

Intratesticular Hematoma Intratesticular hematomas are a common occurrence in the traumatized scrotum and may manifest various features. They may occur singly or in multiples, may range in size from small to large, may range in age from hyperacute to chronic, and may or may not be associated with other testicular and extratesticular injuries. The US appearance of a hematoma depends on the time that has elapsed between the occurrence of trauma and the US evaluation. Hyperacute and acute hematomas are sometimes difficult to identify, as they may appear isoechoic to the surrounding testicular parenchyma or may have a diffusely heterogeneous echotexture. For this reason, suspected acute hematomas are reexamined within 12–24 hours after the initial US evaluation to allow observation of any changes in their echogenicity (21). Chronic hematomas appear more hypoechoic to anechoic and tend to decrease in size as they resolve. Color Doppler imaging helps differentiate such hematomas from tumors, which are included in the differential diagnosis of intratesticular focal lesions (21). Hematomas demonstrate an absence of internal vascularity, but, when infected, an increase in peripheral hyperemia (Fig 11). The most significant goal of US in such patients is to exclude a testicular rupture, because the management decision in most such patients largely depends on the US findings. Small hematomas without any direct or indirect evidence of a testicular rupture are treated conservatively with ice packs, nonsteroidal antiinflammatory drugs, and follow-up clinical testing and US evaluation. Follow-up US of all conservatively treated intratesticular hematomas until their resolution is essential because of the high incidence rate (as much as 40%) of infection and necrosis, which may necessitate an orchiectomy (20). Another

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Figure 10.  Testicular torsion. Transverse color Doppler US image of both testes in a patient with scrotal trauma shows a complete absence of blood flow in the left testis.

Figure 11.  Infected testicular hematoma. Longitudinal gray-scale (a) and power Doppler (b) US images of the testis in a patient 3 weeks after scrotal trauma show a hypoechoic area with a fluid-debris level in a and peripheral hyperemia in b. The diagnosis, based on clinical symptoms (pain and fever) and US findings, was an infected hematoma. The condition was managed conservatively with antibiotics.

reason for continued follow-up is the fact that testicular tumors are incidentally identified in 10%–15% of patients with scrotal trauma (20) and can be excluded if an intratesticular lesion shows progressive resolution. However, large intratesticular hematomas should be surgically explored and drained even in the absence of testis rupture, to prevent progressive pressure necrosis, atrophy, and resultant orchiectomy (13).

Intratesticular Pseudoaneurysm Figure 12.  Testicular pseudoaneurysm. Color Doppler US image of the right testis in a patient with scrotal trauma demonstrates a focal area with a mosaic of colors (arrow). (Reprinted, with permission, from reference 40.)

A pseudoaneurysm is a vascular leak that is surrounded and contained by a pseudocapsule. Intratesticular pseudoaneurysms are extremely rare (39) and may result from either blunt or penetrating trauma. Gray-scale US demonstrates an anechoic area within the testis, which is filled by a mosaic of colors (typically known as the yin-yang sign) indicative of a turbulent flow pattern at color Doppler imaging (Fig 12). Spectral

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Figures 13, 14.  Gunshot wounds to the testis. (13) Transverse grayscale US image in a patient with a gunshot wound to the thigh demonstrates multiple echogenic foci (arrowheads) representative of air in the testis. The testicular wound was treated with partial débridement. (14) Longitudinal gray-scale image in another patient with a gunshot wound shows a pellet outside the testis (arrow) with a posterior acoustic shadow (arrowhead). (Fig 14 courtesy of Stephen Tamarkin, MD.)

Doppler at the neck of the pseudoaneurysmal sac reveals a to-and-fro flow pattern that is diagnostic of a pseudoaneurysm. Rarely, a pseudoaneurysm may be secondary to orchitis; however, to our knowledge, such an occurrence is described in only one published case report (41).

Penetrating Injury The incidence of penetrating injuries to the scrotum has been on the rise over the years, paralleling an increase in the rates of overall crime and violence (42). Gunshot injuries are the most common cause of penetrating injuries to the scrotum. Other causes include stab wounds, human and animal bites, and missile injuries (eg, in military action) (43). Bilateral injuries are more common in penetrating trauma than in other trauma categories (12). Penetrating injuries range from a small insignificant hematocele to testicular rupture. The role of US in such cases is the same as in blunt trauma, which is to assess the severity of injuries in order to allow their appropriate management. Additional US findings expected in penetrating trauma are the presence of air within the scrotum (a finding that may be intra- or extratesticular), an intratesticular missile track, and the presence of one or more intra- or extratesticular foreign bodies (21,44) (Figs 13, 14). Air is identified as multiple echogenic foci with a reverberation artifact. An intratesticular missile track is often seen as an avascular hypoechoic linear area. Color Doppler imaging helps determine the viability of the testis: If color flow is present in the uninjured part of the testis, surgical débridement and closure of the holes may be the only repairs required (44). Foreign bodies are more likely to be seen

Figure 15.  Hematocele. Transverse gray-scale US image of the testis (T) depicts a complex loculated extratesticular fluid collection with low echogenicity and a fluid-debris level, findings suggestive of a chronic hematocele.

in pellet wounds than in bullet wounds at US, a fact believed to be related to the velocities of the missiles involved (44). Gunshot wounds to the scrotum are often associated with soft-tissue injuries in the thighs, perineum, and penis and with intraabdominal injuries (45). Penetrating injuries secondary to animal bites, although rare, are potentially worrisome because they are associated with high risks of bacterial infection, tetanus, and rabies (46).

Extratesticular Injuries Hematoma (Hematocele).—Extratesticular hematoceles, or collections of blood within the tunica vaginalis, are the most common finding in the scrotum after blunt injury. Such findings were observed in 11 of 15 patients in a study by

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Figure 16.  Hematoma after inguinal herniorrhaphy. (a) Longitudinal gray-scale US image, obtained 1 day after hernia repair, demonstrates a large complex extratesticular fluid collection (H) that displaces the testis (T). (b) Corresponding nonenhanced CT image obtained 1 day later, after placement of a drain (arrowhead), shows a moderatesized right extratesticular fluid collection (arrow) and diffuse scrotal wall edema. T = testis. Figure 17.  Scrotal wall hematoma. Transverse gray-scale US image depicts echogenic (arrowhead) and hypoechoic (arrow) areas in the scrotal wall after blunt trauma but shows no injury to the testis (T). The scrotal injury was managed conservatively.

Micallef et al (16). Unpublished data obtained at our institution in 63 patients with a history of scrotal trauma also support that conclusion; extratesticular hematoceles were present in 31 (49%) of our patients and were the most common scrotal finding. The US appearance of extratesticular hematoceles varies with their age, as is true of other hematomas. Acute hematoceles are echogenic in appearance, whereas chronic hematoceles tend to become anechoic over time and develop septa and loculations that may show internal fluid-fluid levels and faint echoes (21,47,48) (Fig 15). A chronic hematocele that does not resolve may become calcified and may mimic an extratesticular calcified mass at imaging (49). The acute onset of a large hematocele may result in reduced blood flow to the testes because of extrinsic pressure on the vessels and thus may mimic testicular torsion or partial torsion (50). Evacuation of the extratesticular hematoma results in restoration of normal intratesticular blood flow.

The presence of a large hematocele is an indication for surgical exploration irrespective of any US evidence of tunica albuginea rupture. This is mainly because of the limited capability of US to help identify a tunica rupture in the presence of surrounding complex fluid. In the pediatric population, hematoceles may be secondary to abdominal trauma (51–53). Extratesticular hematomas also may be iatrogenic. They may occur, for example, as a complication of orchiectomy or inguinal herniorrhaphy (2,54) (Fig 16). Scrotal Wall Hematoma.—Scrotal wall hematomas are commonly associated with blunt trauma. They may be identified at US as an echogenic focal wall thickening or as a complex fluid collection within the wall, depending on the time that has elapsed since trauma (Fig 17). Scrotal wall hematomas usually resolve spontaneously or with conservative management, but those that are very large may require surgical evacuation. Traumatic Epididymitis.—The observation of an enlarged epididymis with hyperemia at US is suggestive of epididymitis, which is most commonly caused by an infection with Escherichia coli or Proteus mirabilis. Epididymitis due to scrotal trauma may have a similar appearance at US, manifesting as a heterogeneous and enlarged epididymis with increased vascularity

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Figure 18.  Traumatic epididymitis. Transverse gray-scale (a) and color Doppler (b) US images obtained in a patient with scrotal trauma show an enlarged heterogeneous epididymis (E) with increased vascularity and a small amount of surrounding fluid. T = testis.

Figure 19.  Spermatic cord hematoma. Longitudinal gray-scale US image of the right testis in a patient after abdominal surgery in the right lower quadrant demonstrates a large complex mass (M) superior to the testis (T), a finding that represents a hematoma of the spermatic cord. The hematoma was managed conservatively.

(55) (Fig 18). Although these US findings mimic those of infectious epididymitis, the history of scrotal trauma helps differentiate posttraumatic epididymitis. Heterogeneity in the epididymis may be secondary to small hematomas or contusions from trauma (21). These findings may be focal or diffuse, depending on the degree of trauma. Epididymal Fracture and Rupture.— Epididymal injuries are usually seen in association with testicular injuries. The most commonly observed epididymal injury at US is traumatic epididymitis. Epididymal rupture is a rare occurrence that is even more rarely observed at US. It is usually diagnosed during surgical exploration for testicular rupture or large hematoceles. An ill-defined epididymis with a heterogeneous echotexture and absence of blood flow, in the presence of other intrascrotal injuries, should arouse a suspicion of epididymal injury (21).

Spermatic Cord Hematoma.—Because of the close proximity of the spermatic cord to the inguinal ligament, spermatic cord injuries are common in patients who undergo surgical repair of an inguinal hernia. A hematoma in the spermatic cord is usually secondary to injury of a spermatic cord vessel; rarely, it may result from the rupture of a varicocele secondary to blunt trauma (56). Spermatic cord hematomas also may be idiopathic, may be secondary to anticoagulation therapy, or may represent an extension of a retroperitoneal hemorrhage (57). A spermatic cord hematoma is enclosed by fascia and is depicted on US images as a heterogeneous, well-defined, avascular mass located superior to the testis (Fig 19).

Rare Testicular and Scrotal Injuries Some rare causes of testicular and scrotal trauma may result in unusual clinical presentations. The physical manifestations and clinical history in such cases mandate surgery without initial US. US sometimes may be necessary to evaluate the salvageability of the testis by demonstrating the presence or absence of blood flow.

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US Findings and Management of Testicular and Extratesticular Injuries from Scrotal Trauma Injury Type Blunt trauma Testicular   Rupture   Fracture   Hematoma   Dislocation   Torsion   Pseudoaneurysm Extratesticular   Hematocele   Scrotal wall hema  toma   Traumatic   epididymitis   Epididymal fracture   or rupture   Spermatic cord   hematoma Penetrating trauma

US Findings

Management

Tunica albuginea rupture, contour irregularity, heterogeneous echotexture of testis Linear, hypoechoic, avascular area within testis, with or without tunica albuginea rupture Variable appearance, depending on hematoma age: echogenic to anechoic or complex Testis absent from scrotum Blood flow absent from testis Yin-yang sign and to-and-fro flow pattern at color and spectral Doppler imaging Variable appearance, depending on hematocele age: echogenic (acute) to complex anechoic (chronic) Thickened scrotal wall with echogenic or hypoechoic areas Enlarged heterogeneous epididymis with hyperemia Fragmented or absent epididymis (diagnosis is usually postoperative) Mass with variable echogenicity (echogenic to complex anechoic) located superior to the testis Missile track, air inside or outside testicular parenchyma, presence of foreign bodies (eg, bullets)

Thermal, electrical, or chemical burn injuries to the scrotum often impair the functioning of the testis by affecting spermatogenesis (58). Such injuries usually are manifested by skin loss of varying degrees, with varying damage to the scrotal contents. Electrical injuries or burns are commonly associated with the presence of an entry and an exit wound and often result in testicular infarction (2). Chemical burns secondary to podophyllin use for treatment of genital warts rarely have been reported (59). The management of such burn injuries involves surgical reconstruction in almost all cases. Scrotal bites by humans and animals are another rare cause of testicular injury, and they are associated with several complications (60,61). Scrotal bites may lead to severe morbidity due to microbial infection, if appropriate prophylaxis and treatment are not provided.

Surgery Surgery Conservative if the hematoma is small; surgical exploration if it is very large Open surgical reduction Surgical detorsion or orchiectomy, depending on the salvageability of the testis Conservative or surgical management, depending on pseudoaneurysm size and symptom severity Conservative if the hematocele is small; surgical exploration if it is large Usually conservative; surgical drainage if the hematoma is large Conservative management Conservative or surgical, depending on the severity of symptoms Conservative if the hematoma is small; surgical exploration if it is large Conservative or surgical, depending on the severity of injury to the scrotal contents

Frequent bicycling over long distances may induce scrotal and other urogenital injuries (62). Last, degloving injuries, also referred to as avulsion injuries, may result in exposure of the scrotal contents.

Summary

Scrotal trauma calls for careful physical and imaging evaluations to determine the appropriate management of injuries. US is the modality of choice for imaging of scrotal trauma because it allows reliable identification of various testicular and extratesticular injuries. The management options, like the US findings, vary according to the type of injury (Table). Testicular rupture, the most severe testicular injury, requires immediate surgical intervention to salvage the testis.

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This article meets the criteria for 1.0 credit hour in category 1 of the AMA Physician’s Recognition Award. To obtain credit, see accompanying test at http://www.rsna.org/education/rg_cme.html.

RG

Volume 28 • Volume 6 • October 2008

Bhatt and Dogra

Role of US in Testicular and Scrotal Trauma Shweta Bhatt, MD, and Vikram S. Dogra, MD RadioGraphics 2008; 28:1617–1629 • Published online 10.1148/rg.286085507 • Content Codes:

Page 1619 Sporting activities account for more than half of all cases of testicular injury, and motor vehicle accidents account for another 9%–17% of testicular injuries. Page 1619 More than 80% of ruptured testes can be salvaged, with a high success rate, if surgical repair is performed within 72 hours of testicular injury. Page 1620 Abnormality in the contour of the testis results from the extrusion of testicular parenchyma after disruption of the tunica albuginea. Page 1622 Follow-up US of all conservatively treated intratesticular hematomas until their resolution is essential because of the high incidence rate (as much as 40%) of infection and necrosis, which may necessitate an orchiectomy. Page 1624 Extratesticular hematoceles, or collections of blood within the tunica vaginalis, are the most common finding in the scrotum after blunt injury.