TESTICULAR ARTERIAL ANATOMY

The right and left testicular arteries originate from the aorta just below the renal arteries. They course through the deep inguinal ring to enter the spermatic cord, accompanied by the cremasteric and deferential arteries, which supply the soft tissues of the scrotum, epididymis and vas deferens. The testicular artery penetrates the tunica albuginea along the posterior aspect of the testis and gives off capsular branches which course through the tunica vasculosa. These capsular branches then give rise to the centripetal arteries which carry blood from the capsular surface, centrally towards the mediastinum along the septula (Figs 13-5 and 13-6). Branches of the centripetal arteries then course backward towards the capsular surface; these are known as recurrent rami. In about 50% of testes, a more robust artery can be seen passing directly from the testicular artery at the mediastinum into the parenchyma, known as the transtesticular artery (Fig. 13-7). It is occasionally accompanied by a vein. Small anastomoses do exist between the testicular artery, cremasteric, and differential arteries. Branches of the pudendal artery may also supply the scrotal wall.

TESTICULAR VENOUS ANATOMY

Testicular venous outflow courses mostly through the mediastinum testis, into the spermatic cord, and eventually up through the inguinal canal. As the veins exit the scrotum through the spermatic cord, they form a web-like network that surrounds the testicular artery, known as the pampiniform plexus (Fig. 13-8). This plexus functions as a heat exchange mechanism, pulling warmth away from the testicular arterial inflow, thereby helping to maintain spermatogenesis at a lower, more optimal temperature.

On the left side, the testicular vein usually drains into the left renal vein; on the right side, drainage is directly into the inferior vena cava just below the right renal vein. The testicular veins normally have valves that prevent retrograde flow of venous blood to the scrotum, but if they are absent or become incompetent; this predisposes to development of a varicocele. This results in compromise of the heat exchange mechanism and, therefore, is a frequent cause of infertility.¹

DOPPLER TECHNIQUE

Ultrasound examination of the scrotum is not complete without the application of colour Doppler. The procedure is a mandatory part of the imaging evaluation to confirm the presence (or absence) of uniform, symmetric vascular perfusion of the testes and epididymides (Fig. 13-9). The settings for colour Doppler scanning must be optimised for low-volume and low-velocity flow. If colour noise is excessive at low-flow settings and interferes with the examination, colour artefact can be decreased by properly adjusting gain and pulse repetition frequency settings. Temporal resolution can be improved by minimising the overall image size and zooming in to the area of interest. Additionally decreasing depth, limiting the number of focal zones and limiting the size of the colour box will also improve temporal resolution. Use of appropriate technical parameters should assure demonstration of intratesticular vascularity in all normal adult patients. In the prepubertal age group, intratesticular flow volume is less and therefore more difficult to identify. The application of power Doppler may be helpful. Spectral Doppler can assess arterial and venous waveforms and quantify velocities (Fig. 13-10), but its application in the scrotum is relatively limited, except for a few conditions such as partial torsion or extreme swelling secondary to inflammation predisposing to ischaemia. In those cases spectral Doppler can best identify the high resistance to arterial inflow caused by venous outflow compromise or parenchymal congestion.

Doppler sensitivity varies greatly between ultrasound systems and software levels. Therefore, the examiner must be familiar with normal flow perception on their equipment. A good ‘rule of thumb’ is to examine the contralateral side (provided it is normal) to establish a colour flow baseline which can then be used as the standard by which to judge the abnormal testis or epididymis. When comparing flow between sides, be sure to set imaging parameters to the non-affected side; then, without changing any settings, image the affected side. Some advanced ultrasound machines can adjust imaging parameters automatically as depth and position of colour box changes with scanning. If possible, override this software feature to avoid misperception of asymmetric colour flow.

NORMAL ULTRASOUND AND DOPPLER FINDINGS

A normal ultrasound examination of the scrotum reveals uniform, homogeneous echogenicity throughout both testes. The epididymis is usually isoechoic or slightly hypoechoic compared with the testes. The size and echogenicity of testes and epididymides should be relatively the same bilaterally.

Colour Doppler should reveal bilaterally symmetric and relatively uniform flow through both testes and epididymides (Fig. 13-9). A fan-like array of the centripetal arteries should be present through the testicles (Fig. 13-6). Spectral Doppler tracings of testicular arterial inflow demonstrate relatively low resistance (Fig. 13-10); this is in contrast to the cremasteric and deferential arteries which have relatively high resistance to flow. The normal testicular artery resistive indices in adults range from 0.46 to 0.78, with a mean of 0.64. Similar findings are reported in the intratesticular arteries of postpubescent boys, with resistive indices ranging from 0.48 to 0.75 (mean, 0.62). In prepubertal boys, however, resistance is higher to the point that diastolic arterial flow may not be detectable. Supratesticular arteries to the vas deferens or cremaster muscle, on the other hand, have higher impedance with low-diastolic flow and resistive indices ranging from 0.63 and 1.0, with a mean of 0.84.

Pulsed Doppler is relatively insensitive in detecting arterial flow in prepubescent patients. In contrast, power Doppler has been shown to reveal arterial flow in 92% of testes in pre-pubescent patients, while colour Doppler demonstrates flow in 83% of cases. In postpubescent patients, both Doppler imaging techniques demonstrated flow in 100% of cases.2,3

Venous flow velocities in the epididymides may fluctuate with respiration. Cardiac periodicity rarely manifests at the level of the scrotum.

INFLAMMATORY DISEASE

Acute epididymo-orchitis is the most common cause of acute scrotal pain in men over the age of 20, accounting for up to 80% of cases, but it is frequently clinically indistinguishable from spermatic cord torsion. Patients usually present with an acutely painful, tender, swollen scrotum, with associated erythema, urinary tract symptoms, fever and leukocytosis. Sometimes, however, the signs and symptoms may be less distinct, making clinical differentiation between infection and torsion extremely difficult. The process typically first manifests in the epididymis and then ascends to affect the testicle, but isolated epididymitis, orchitis, or even focal orchitis can be encountered.

The cause of the infection varies with age.⁴ In adult patients less than 35 years of age, Chlamydia trachomatis and Neisseria gonorrhoeae (sexually transmitted organisms) are the most common agents. In prepubertal boys and in men over 35 years of age, the disease is most frequently caused by Escherichia coli and Proteus mirabilis. Cytomegalovirus is the most common agent in the immunocompromised patient. In most normal paediatric patients, a bacterial pathogen is not isolated and the inflammation is presumed to be viral in nature. Those patients who have an underlying urogenital congenital anomaly are prone to infection from Gram-negative bacteria.⁵

The sonographic appearance of epididymo-orchitis varies depending on the stage of the process. The sensitivity of greyscale sonography for detecting epididymo-orchitis is reported to be about 80%. In the early, acute stage, the epididymis and/or testicle will be enlarged and hypoechoic. With the onset of tissue breakdown and haemorrhage, the echogenicity begins to increase. There may be reactive thickening of the scrotal wall. A hydrocele may be present and it may contain debris. If allowed to progress, microabscesses may develop and the appearance becomes more complex and variable. Further progression can lead to frank intra- or extratesticular abscess, ischaemia and eventually necrosis. Scarring associated with chronic orchitis typically results in a small hyperechoic testis.⁶ The diagnosis of infection and inflammation typically hinges on the identification of hyperaemia by colour Doppler – an asymmetric appearance with more robust flow (an increased number and prominence of discernible vessels) in association with an enlarged, painful, hypoechoic epididymis and/or testis (Fig. 13-11). Several studies have demonstrated sensitivity and specificity for the diagnosis of scrotal inflammatory disease by colour Doppler sonography approximating 100%. Early in the inflammatory process, vasodilatation and hyperemia results in a low-resistance flow pattern on spectral Doppler (Fig. 13-12).⁷

In cases of severe epididymitis, periepididymal swelling may obstruct testicular venous outflow, leading to testicular ischaemia or infarction. An enlarged, heterogeneous testicle with reduced or absent colour flow and a contiguous abnormal epididymis may be seen on greyscale imaging (Fig. 13-13). Hyperaemia of the epididymis helps to differentiate testicular ischaemia following inflammation from that caused by torsion. A high-resistance waveform, along with decreased or reversed diastolic flow, may be seen on the spectral Doppler tracing and suggests venous infarction⁸ (Fig. 13-14).

If left untreated, the process may progress to abscess formation (Fig. 13-15), which usually manifests as an enlarged testicle with a complex, septated collection of fluid/debris and tissue of mixed echogenicity. It may be difficult to distinguish from a testicular neoplasm, as both can present as complex cystic/solid masses. Older abscesses may have radiating echogenic septa separating hypoechoic spaces. Increased blood flow around the abscess cavity and no internal flow is present on colour Doppler. Surgical exploration may be necessary to rule out the presence of a tumour and débride the abscess.

Occasionally, testicular inflammation may be focal, even rounded, with areas of decreased echogenicity and swelling. Hyperaemia concentrated in the abnormal, tender area may suggest inflammation over neoplasm, but there is overlap in this appearance with neoplasm, especially lymphoma (Fig. 13-16).

An inflammatory process may be isolated to the spermatic cord. This is most often associated with a recent viral illness. The patient typically presents with a nagging ache that is difficult to localise within the scrotum. Imaging reveals an enlarged and oedematous and hyperaemic spermatic cord. (Fig. 13-17).

TORSION

Torsion is divided into two types – extravaginal which occurs exclusively in newborns and intravaginal. Extravaginal torsion occurs outside the tunica vaginalis when the testes are not yet fixed and are free to rotate.⁹ The testis is typically necrotic at birth. Ultrasound reveals an enlarged heterogeneous testis, a reactive hydrocele, skin thickening and no colour Doppler flow in the testis or spermatic cord. Intravaginal torsion occurs most frequent in adolescent boys. A bell-clapper deformity, in which the tunica vaginalis completely encircles the epididymis, distal spermatic cord, and testis, is the key predisposing factor. This deformity is usually bilateral and leaves the testis free to swing and rotate within the tunica vaginalis (Fig. 13-18).

The diagnosis of spermatic cord torsion must be established quickly to allow for prompt surgical intervention, since obstruction of blood flow may result in the loss of testicular viability within a few hours (typically four) of onset of symptoms. Clinical history and physical findings, however, overlap with those of inflammatory disease to such a degree that even an experienced urologist may have difficulty in differentiating the two conditions. Symptoms and signs include sudden pain in the scrotum, lower abdomen or inguinal area (frequently accompanied by nausea, vomiting and low-grade fever), a tender testicle with a transverse orientation, and a swollen, erythematous hemiscrotum. The false-positive rate of nearly 50% for clinical diagnosis of testicular torsion often results in unnecessary surgical exploration.¹⁰

Greyscale sonography by itself has a low sensitivity and specificity when evaluating patients for suspected torsion. Findings will depend on the length of time that torsion has been present. During the first few hours, testicular appearance is normal, but after about 4–6 h, as the veins are obstructed, there is vascular engorgement and the testis becomes enlarged and oedematous, with a hypoechoic appearance as compared to the contralateral testicle. After 24 h, vascular congestion, haemorrhage and infarction will cause the testis to appear heterogeneous. The epididymis may also be enlarged and hypoechoic because of prolonged vascular stasis.

The application of colour Doppler to the diagnosis of torsion increases sensitivity in adults to 90–100% with a high specificity. Unlike greyscale imaging, colour and spectral Doppler are almost always abnormal even during the early stages of torsion. Instrument settings should be optimised on the normal side to identify low-velocity flow before ascertaining that there is indeed decreased blood flow on the symptomatic side. If arterial flow cannot be detected in the symptomatic testicle but can in the contralateral testicle, the diagnosis of torsion is effectively established. The characteristic finding of ischaemia is a completely avascular testicle (Fig. 13-19). In the late stages of torsion, colour Doppler may reveal an increase in peritesticular blood flow because of inflammation in the surrounding soft tissues of the scrotum.

Evaluation of the small testicles of prepubescent boys, however, can be very difficult because of inherently low-velocity blood flow. In addition, if the patient has intermittent torsion, and by the time the patient arrives for the ultrasound examination the torsion spontaneously resolves, flow may appear normal on colour Doppler. Since absence of flow is demonstrated only if torsion is present at the time of sonographic examination, differentiating between normal testicles and testicles with intermittent torsion may be difficult to accomplish.

With full torsion (greater than 360ᵒ) the addition of spectral Doppler does little other than to confirm the obvious fact that there is no flow. It should identify very high resistance in the spermatic artery within the cord above the level of the twist. With partial torsion (between 180ᵒ and 360ᵒ) however, the spermatic cord twists only enough to occlude the venous outflow. Because the artery has a thicker wall, patency is maintained. The resultant spectral Doppler tracing reveals a high-resistance arterial waveform within the cord and the testicle (Fig. 13-20).^11,12

If the spermatic cord spontaneously untwists prior to the ultrasound examination, colour Doppler will likely reveal diffuse, reactive hyperaemia. Although this finding will mimic epididymo-orchitis, resolution of acute scrotal pain concurrent with increased blood flow is highly indicative of spontaneous detorsion. Colour Doppler ultrasound can also be used to monitor non-surgical detorsion of the testicle as the testis is manually rotated; if this manoeuvre is successful, blood flow is re-established to the testicle and can be detected on Doppler. This non-surgical approach, however, is only considered a temporising measure. It is not a substitute for surgical intervention, which is still necessary to correct the underlying anatomical deformity that predisposes to torsion.

Direct evaluation of the spermatic cord on its long axis may reveal a snail-shell-shaped mass at the point of the twist (Fig. 13-21). Running the transducer along the affected cord in the transverse projection may show a vortex-like spin of the cord ending at the point of obstruction.

The use of echo-enhancing agents has been studied for improving imaging of small testicles with low-velocity and low-volume flow. In an animal study by Brown et al.¹³ the authors examined induced testicular torsion with greyscale imaging, colour Doppler, power Doppler and spectral Doppler analysis. Injection of contrast media did not enhance greyscale images, but visualisation of all vessels in both normal and rotated testicles was significantly improved with both colour and power Doppler. Asymmetry of blood flow was more obvious. The authors concluded that diagnosis of testicular ischaemia could be made with greater confidence using an intravenous ultrasound contrast agent because of improved demonstration of altered perfusion patterns.

Hand-held continuous-wave Doppler has no role in the evaluation of testicular torsion because of its inability to provide range-gated information. Normal or increased blood flow within the scrotal wall detected by the continuous wave beam may lead the examiner to incorrectly conclude that intratesticular flow is preserved.

Although testicular torsion may be accurately diagnosed by sonography, this does not guarantee successful surgical salvage. Success depends on a timely diagnosis and the duration of ischaemia. Indeed, the more obvious the ultrasound diagnosis, the less likely the chance of salvage. The testicle devoid of colour flow but with an appropriate ultrasound appearance is much more likely to be salvaged at surgery. The testicle that presents with irregular echotexture is likely necrotic and needs to be removed (Fig. 13-22).^14,15

TORSION OF THE APPENDIX TESTIS

The appendix testis is a Müllerian duct remnant that is attached to the upper pole of the testis. Doppler ultrasound is rarely able to identify flow within the structure. Newer, more sensitive equipment can occasionally reveal the presence of flow within a tender appendix testis (Fig. 13-23). Patients who develop torsion of the appendix testis usually present with acute scrotal pain. Physical examination reveals a small firm, palpable, tender nodule. Ultrasound evaluation usually reveals a hyperechoic rounded structure attached to the testicle with a reactive hydrocele. The patient will usually confirm an increase in pain when the transducer is over the appendix testis, and that typically clinches the diagnosis. Colour Doppler may reveal increased flow around the twisted testicular appendage but more importantly it rules out testicular torsion or an acute inflammatory process. After torsion and necrosis the appendix testis may slough and become calcified, in which case it becomes known as a scrotal pearl. Twinkle artifact may be present on colour Doppler and should not be confused for true flow (Fig. 13-24).

TRAUMA

Testicular trauma typically results from an athletic injury, a direct blow or a straddle injury. Clinical examination of a traumatised, tender testicle can be difficult because of pain and swelling; however, ultrasound can visualise and confirm testicular integrity, or identify the presence of haematoma, haematocele, or rupture. Colour Doppler sonography provides excellent delineation of blood flow throughout the testis, differentiating hyperaemic, contused regions from devascularised or ischaemic areas (Fig. 13-25).

In the case of testicular rupture, sonographic identification is extremely important because prompt diagnosis and quick surgical intervention are required to successfully correct the condition. If surgery is performed within 72 h of the trauma, approximately 80% of ruptured testes can be salvaged. If rupture is present, ultrasound may demonstrate a disrupted tunica albuginea; a heterogeneous testicle with asymmetric, poorly defined margins; thickening of the wall of the scrotum; and/or a large haematocele. Perception of blood flow will be diminished or absent on colour or spectral Doppler examination (Fig. 13-26).

Unlike rupture, intratesticular fracture, small haematomas and haematoceles do not require surgery if the tunica albuginea has not been interrupted and Doppler imaging shows normal blood flow to the testicle. Sonographic findings associated with a testicular fracture include a linear hypoechoic band crossing the parenchyma of the testicle, a smooth well-defined testicular outline, an intact tunica albuginea, and often an associated haematocele. Normal Doppler signals indicate unimpaired blood flow and viable testicular tissue. If Doppler signals are absent, ischaemia is very likely and surgical intervention is called for. Acute haematomas are usually hyperechoic relative to adjacent testicular parenchyma. Older haematomas may have both hyper- and hypoechoic areas, and there may be associated thickening of the scrotal wall. On colour Doppler, the septa of haematomas are avascular. Acute haematoceles are relatively uniform and echogenic. As they mature, proteinaceous septations develop and again are nonvascular on colour Doppler.16,17

TESTICULAR NEOPLASM

Patients with testicular neoplasms usually present with a palpable scrotal mass or a dull aching sensation. For palpable scrotal masses, ultrasound is widely considered the imaging modality of choice. The principal role of ultrasound is to distinguish intra- from extratesticular lesions, because the majority of extratesticular masses are benign, whereas intratesticular masses are considered malignant until proven otherwise.¹⁸ Ultrasound can easily differentiate solid from cystic masses and confirm their intra- or extratesticular location. The main role of ultrasound is to identify those masses which require additional assessment and possible surgical intervention.

On greyscale images, testicular neoplasms usually appear as a discrete mass whose echo pattern differs from that of the normal testis. Most neoplasms have hypoechoic components although heterogeneity of echotexture is frequently observed (particularly with larger and non-seminomatous germ cell tumours). Sonographic differentiation of seminoma, embryonal cell carcinoma, teratoma and choriocarcinoma can be difficult, especially since 40–60% of testicular neoplasms have mixed histological elements.

Seminomas are the most common single-cell-type testicular tumour in adult males (40–50%). The ‘classic’ ultrasound appearance of seminomas has been described as a well-defined, uniformly hypoechoic lesion, with no evidence of calcification, haemorrhage, or cystic areas.¹⁹ But the larger the lesion, the less likely it maintains the classic appearance (Fig. 13-27).

Teratomas generally are very heterogeneous with well-defined margins. Dense echogenic foci caused by calcification, cartilage, immature bone, fibrosis, and non-calcified fibrous tissue are interspersed with areas of haemorrhage, cysts and necrosis.²⁰ Choriocarcinomas and embryonal cell tumours generally appear as small masses with haemorrhage and associated calcification.

The ultrasound appearance of mixed germ cell tumours is that of a heterogeneous, small mass with poorly defined margins, anechoic areas due to cystic necrosis, and echogenic foci of haemorrhage. If the tumour invades the tunica, the normal contour of the testicle may be distorted.⁸ Testicular neoplasms have mixed histological components in 40–60% of cases, with the most common combination being that of teratoma and embryonal carcinoma (teratocarcinoma). Ultrasound findings of mixed tumours will vary, depending on which cell lines are dominant and if there are no particular ultrasound findings that permit differentiation for possible preoperative planning.

Testicular carcinoid is extremely rare and usually presents as painless testicular enlargement or as a discrete mass. The tumour may be primary, associated with teratoma or metastatic. Primary testicular carcinoid is believed to arise from pluripotential germ cells or from the development of a simplified teratoma without other teratomatous elements. Very few (< 3%) have associated carcinoid syndrome.²¹ On ultrasound testicular carcinoid appears as a solid well-defined hypoechoic intratesticular mass with or without dense calcification. On Doppler it has increased vascularity similar to seminoma²² (Fig. 13-28).

Metastatic disease to the testicle is rare with prostate and kidney being the more common primary sites. Metastases are more common over the age of 50 and are typically hypoechoic. Colour Doppler enhances perception by typically revealing displacement of the normal vascular architecture around the expanding mass.

If a testicular mass is suspected of being a neoplasm, the rest of the scrotum should be examined carefully to exclude any invasion of the tunica albuginea or epididymis. Hydroceles are often associated with testicular neoplasm and that makes them more difficult to palpate. Because a hypoechoic appearance has also been reported with other testicular conditions (e.g. epididymo-orchitis, trauma, spermatic cord torsion, sarcoid), the additional extratesticular findings may help in the differential diagnosis.

Colour Doppler and spectral Doppler sonography are considered to be of minimal benefit in the evaluation and characterisation of adult testicular masses and the diagnosis of testicular neoplasm. This is because vascularity of these lesions is extremely variable Small lesions tend to be hypovascular while larger lesions tend toward hypervascular compared with normal testicular parenchyma (Fig. 13-29).

An infiltrative neoplasm of the testicle, such as leukaemia or lymphoma, typically presents as an enlarged hypoechoic area on greyscale imaging. Colour Doppler often demonstrates hyperaemia in the neoplasm. Since these are infiltrative tumours, the underlying vascular architecture is often preserved (Fig. 13-30), with an appearance quite similar to inflammation. The absence of pain, however, should make one lean towards infiltrative tumour and away from orchitis.

BENIGN TESTICULAR LESIONS

Benign intratesticular masses are rare, but recognition is important to avoid unnecessary biopsy, or worse orchiectomy. Almost all intratesticular cystic lesions are benign. The list includes cysts of the tunica albuginea, simple intratesticular cysts, epidermoid cyst (Fig. 13-31), tubular ectasia of the rete testis (Fig. 13-32), and intratesticular spermatocele. Colour Doppler ultrasound helps in confirming the benign nature of these since no alterations in blood flow are demonstrated.²³

Bilateral, eccentrically located, intratesticular adrenal rest tumours may be seen in patients with congenital adrenal hyperplasia and primary adrenal insufficiency. In most cases, they are hypoechoic oblong lesions peripherally located close to the mediastinum.²⁴ They are bilateral in 83–100% of cases.²⁵ They may undergo extensive fibrosis and eventually become hyperechoic with acoustic shadowing. Vascularity on colour Doppler is variable relative to the normal testicle. Vessels may be seen entering from the adjacent testis without change in course or calibre (Fig. 13-33). Some lesions may exhibit a spoke-like pattern of converging vessels. There are two theories for the origin of these lesions. One says they originate from hilar pluripotential cells, which proliferate as a result of the elevated level of adrenocorticotropic hormone. The other says they originate from aberrant adrenal cortical tissue that adheres to the testes and descends during prenatal life.²⁶ Whatever the origin, these should be recognised as benign lesions and first treated with adrenal suppression with dexamethasone.

VARICOCELE

Varicoceles are present in approximately 15% of men. Incompetent or absent valves in the internal testicular veins predispose to stasis or retrograde blood flow, resulting in dilatation of the pampiniform plexus. This is the cause of the majority of varicoceles. Varicoceles occur more commonly on the left; this is attributed to the longer course of the gonadal vein and its direct drainage into the left renal vein. Varicoceles are important clinically because of their association with infertility. Diagnosis of varicoceles is important, because treatment improves sperm quality in over half of cases.²⁷

On ultrasound a varicocele is seen to consist of dilated (> 2 mm diameter), serpiginous channels in the head of the epididymis and spermatic cord. Colour Doppler has been shown to be very accurate in detecting varicocele.¹ At rest and with normal respiration, colour will saturate the tubules at intervals related to respiratory pressure fluctuations. With more vigorous respiration, to-and-fro movement of blood may manifest as alternating colour in the same vessel, changing direction between inspiration and expiration. Colour Doppler identification of varicocele is enhanced by having the patient perform a Valsalva manoeuvre or by having the patient stand up. This increases the abdominal pressure and results in the reversal of blood flow into the pampiniform plexus, thereby causing further distension. When the Valsalva manoeuvre is performed, a brief burst of reversed flow is common (Fig. 13-34). This is due to the expulsion of the venous blood in the gonadal vein of the pelvis below the lowest competent valve. As soon as this volume of blood is expressed, then flow usually stops, waiting for the scrotal venous pressure to rise above that generated by the Valsalva. When the pressure is released as the patient relaxes, the direction of blood flow reverts to normal. With valvular incompetence however, when the Valsalva manoeuvre is performed, there is constant reversal of flow. The venous outflow from the left kidney finds the left gonadal vein as the path of least resistance. With the release of Valsalva flow reverts back to the normal direction (Fig. 13-35).

Whenever a varicocele is identified, obstruction by a retroperitoneal mass, such as a left renal malignancy invading the renal vein should be considered. A brief scan of the upper abdomen should be performed to assess for this possibility.

Varicoceles can extend into the testicle. They manifest as dilated intratesticular veins (greater than 2 mm) with a positive response to the Valsalva manoeuvre. Incidence is estimated at less than 1%. Typically these are associated with testicular atrophy (Fig. 13-36).²⁸

After successful surgical varicocelelectomy colour Doppler ultrasound can confirm a decrease in the diameter of the pampiniform plexus of veins.²⁹

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