The ultrasound appearance of varicocele consists of multiple, hypoechoic, serpiginous, tubular structures of varying size larger than 2–3 mm in diameter that are usually best visualized superior and/or lateral to the testis. When large, a varicocele can extend posteriorly and inferiorly to the testis [6, 13]. The size of dilated veins usually increases in the upright position and with a Valsalva maneuver. Low-level internal echoes are often detected in the dilated veins (Fig. 42.1), consistent with slow flow [13, 14]. Echoes are mobile during respiratory movements, during manual compression, and with a Valsalva maneuver.

Different threshold values of venous size are used for the diagnosis of varicocele. Most authors consider a cutoff value of 3 mm, but Gonda et al. reported a 95 % sensitivity with a cutoff of 2 mm [15]. Therefore, a diagnosis based only on the diameter of the vessels is characterized by a high number of false positives and negatives. Moreover, variability makes it difficult to compare the results of diagnostic modalities and treatments.

Besides evaluation of varices, gray-scale ultrasound allows assessment of the testis as well. Accurate and objective measurement of testicular volume can be obtained more accurately than with physical examination or using an orchidometer.

A strong association between clinical varicoceles and testicular damage was found, as reflected by testicular size [16–18]. According to Sigman et al., testicular hypotrophy is associated with a significantly decreased total motile sperm count and higher-grade varicoceles [19]. Zini et al. showed that also left subclinical varicocele may be associated with decreased left testicular volume [20]. Finally, Marks et al. showed that in patients with varicocele, a lack of testicular hypotrophy results in a higher postoperative pregnancy rate [18].

Other studies, however, did not found a close relationship between testicular volume and subclinical varicocele [17], nor a correlation between testicular hypotrophy and clinical grading [21].

At present, color Doppler ultrasound is the imaging modality of choice for detection and grading varicocele [11, 12, 22–27]; it is more sensitive than clinical examination and can detect up to 93 % of the reflux subsequently confirmed by spermatic venography [28].

In order to obtain a suitable evaluation of flow changes in the spermatic veins, ultrasound should be performed in the supine and then the upright positions, with and without a Valsalva maneuver.

Diagnosis is reached in case of prolonged venous flow augmentation or reflux. This must be differentiated from the mild and transient flow augmentation that can be seen with a Valsalva maneuver in normal men, lasting less than 1 s. According to Sarteschi and to the majority of investigators, we believe that in order to make a correct diagnosis of varicocele, it is necessary to detect a prolonged reflux that must be longer than 2 s. Other authors, however, use a threshold value of 1 s to distinguish between physiological reflux and varicocele [17].

Several classifications have been used for grading varicocele. We use the score system introduced by Sarteschi in 1993 [11] which divides varicocele into five grades according to the characteristics of the reflux, to its length, and to changes during Valsalva maneuver.

According to Sarteschi, grade 1 varicocele is characterized by the detection of a prolonged reflux in vessels in the inguinal channel only during Valsalva maneuver, while scrotal varicosity is not evident in the previous gray-scale study. Grade 2 is characterized by a small varicosity that reaches the superior pole of the testis and whose diameter increases during Valsalva maneuver. Color Doppler interrogation clearly demonstrates the presence of a venous reflux in the supratesticular region only during Valsalva (Fig. 42.2). Grade 3 is characterized by vessels that appear enlarged to the inferior pole of the testis when the patient is evaluated in a standing position. Color Doppler ultrasound demonstrates a clear reflux only during Valsalva maneuver (Fig. 42.3, Video 42.1). Grade 4 is diagnosed if vessels appear enlarged, even if the patient is studied in a supine position; dilatation increases in an upright position and during Valsalva maneuver (Fig. 42.4). Enhancement of the venous reflux during Valsalva maneuver is the criterion that allows the distinction between this grade from the previous and the next one. Hypotrophy of the testis is common at this stage. Grade 5 is characterized by an evident venous ectasia even in the supine position. Color Doppler interrogation demonstrates basal venous reflux that does not change substantially while standing and during Valsalva maneuver (Fig. 42.5).

The Sarteschi’s classification for varicocele is the most commonly used in Europe. Other authors, however, suggested different score systems. Hoekstra [29] and Hirsh [30], for instance, suggested two similar classifications, which score varicocele in 4 and 3°, respectively (Tables 42.4 and 42.5). Oyen [31] scores 3° for varicocele mainly based on the length of reflux at pulsed Doppler interrogation (Table 42.6).

Precise duration of the reflux can be only measured at pulsed Doppler interrogation [7, 32]. Brief reflux lasting less than a second is physiological. Permanent reflux is not palpable in only 20 % of cases, lasts more than 2 s, and has a plateau aspect throughout the abdominal strain (Fig. 42.6). It does not correlate with the diameter of the spermatic vein [32]. Intermediate reflux is never palpable and lasts 1–2 s in most cases. It keeps decreasing during the Valsalva maneuver and stops before the end of the maneuver. It has been suggested that, in the absence of palpable varicocele, only permanent reflux should be termed subclinical varicoceles, because the Doppler features and changes after treatment are identical to those of palpable varicocele [32]. Iosa and Lazzarini focused their attention on venous reflux and they proposed a new hemodynamic classification. In this classification, continuous venous reflux indicates complete valvular incompetence at the level of the spermatic cord; intermittent reflux indicates early-stage valve failure; and reflux lasting more than 1 s that occurs only during the Valsalva maneuver indicates that the valve is incontinent only when abdominal pressure is increased [33].

A correct ultrasound evaluation of patients with varicocele must integrate findings at gray-scale, color Doppler, and pulsed Doppler analysis. Regardless of the classification used, a series of gray-scale, color Doppler, and spectral Doppler parameters should be included in the medical report: