Varicocele is defined as the dilatation and tortousity of the pampiniform plexus of veins and the internal spermatic vein. This can cause retrograde flow of venous blood, which may impair the process of spermatogenesis resulting in male infertility. This entity can be clinically diagnosed by physical palpation of the scrotum when it is in the advanced form. Most studies mention a palpable internal spermatic vein at 3 mm or larger diameter. However, varicocele may present in a subclinical form, in which case imaging modalities need to be used to arrive at a diagnosis. A left varicocele is more common than the right and is due to various reasons:
1. The acute angle formed by the left testicular vein and the left renal vein.
2. The lack of antireflux mechanism at the above junction.
3. The increased pressure transmitted to the left testicular vein via the renal vein which is compressed between the superior mesenteric artery and aorta [nutcracker effect].
Therefore, a sudden appearance of a right sided varicocele should warranty a complete evaluation of the right renal system to rule out any secondary cause of the varicocele.
Ultrasound with color Doppler is diagnostic in nearly all cases of varicocele and is the imaging technique of choice. Dilated tortuous veins are seen on gray scale ultrasound. The venous diameter may increase with valsalva maneuver. A significant clinically silent subclinical varicocele may have an internal spermatic vein diameter ranging from 2-3 mm. However in cases where the varicocele is very small or subclinical, the diameter of the veins cannot be reliably used to diagnose the condition, but may be used only to document and quantify the pathology. Color Doppler serves to assess the hemodynamic changes that accompany this condition, which can be diagnostic if the venous diameter is small. Retrograde flow/ reflux in these veins is often demonstrated either during quite respiration, with standing position or with valsalva maneuver [is seen as change in the color of flow]. On spectral analysis, various flow patterns have been described in these dilated veins, however the diagnostic and most specific of all these patterns is the one in which venous flow is directed to the testis and which augments on increasing the abdominal pressure.
A study by Chiou, et al reported the use of a scoring system to diagnose varicoceles which collectively includes the individual findings discussed above and assigns a score to each finding. This was proposed to be more specific than the physical examination findings. The Doppler study is also important in the postoperative period to assess the therapeutic effectiveness of the surgery and to follow up for recurrences. Microsurgical repair of varicocele is often done and studies report the usefulness of color Doppler in delineating the anatomy and depicting the flow patterns of the microsurgical anastomosis.
Thus, ultrasound with color Doppler of the scrotum is usually recommended for the diagnosis and follow up of varicoceles.