Cryptorchidism

Ultrasound examination (ultrasound)

Ultrasound traditionally serves as the first-line imaging modality in the search for an undescended organ, although today the rationale for its routine use is questioned by surgeons. The problem is that ultrasound results rarely change the overall patient management strategy, which will require surgical intervention regardless.

Optimal visualization is achieved in the transverse plane. The physician needs to perform a very thorough search, as the undescended testis is often atrophic and reduced in size. On sonograms, testes may be visualized within the inguinal canal, where they are surrounded by suprapubic fat, or at the level of the superior pubic rami (which is particularly characteristic of bilateral cryptorchidism).

Diagnostic performance metrics of ultrasound strongly depend on the depth of the organ's location:

The overall specificity of ultrasound in localizing non-palpable testes is approximately 75–80%. The method shows high efficacy if the organ is located in the inguinal canal, near the anterior abdominal wall, or adjacent to the urinary bladder. However, a deep intra-abdominal location is visualized significantly worse.

In addition, ultrasound allows the detection of associated scrotal pathologies, such as a hydrocele or cystic dysplasia of the rete testis (rete testis). It is important to remember that cystic dysplasia can mimic a neoplastic process and is often associated with multicystic dysplastic kidney (MCDK).

Magnetic resonance imaging (MRI)

MRI significantly outperforms ultrasound in searching for non-palpable testes, especially if their structure is close to normal. It is the method of choice for disorders of sex development (ambiguous genitalia) or the presence of hypospadias.

MRI semiotics of an undescended testis:

• On T1-weighted images (T1WI), testicular tissue demonstrates low signal intensity.
• On T2-weighted images (T2WI), a hyperintense (high) signal is noted.
• For targeted detection of intra-abdominal testes, T2WI with fat suppression are most useful.

The introduction of diffusion-weighted imaging (DWI) has significantly improved diagnostics. The addition of DWI increases the sensitivity of MRI for detecting non-palpable testes from 85% to 90%, while the specificity of the method approaches 100%.

Despite high accuracy, MRI has a number of serious limitations. First, there is the high cost of the study and the need for sedation in young children. Second, small and deeply dysplastic testes may be practically indistinguishable from non-specific lymph nodes (the typical MRI pattern in hypoplasia is low signal on T2WI, which makes differentiation difficult).

Computed tomography and laparoscopy

Computed tomography (CT) is sometimes used to visualize the retroperitoneal space in cases where the testis cannot be detected in the inguinal region. Five specific patterns of CT findings in cryptorchidism have been described in the literature. However, in infants, the use of CT is associated with significant difficulties: detecting a small testis is severely hindered by the superposition of bowel loops and the critically small amount of retroperitoneal adipose tissue, which serves as natural contrast in adults.

Diagnostic laparoscopy in modern practice is considered the definitive method of examination for non-palpable forms of cryptorchidism. The main advantage of the endoscopic approach is the ability to transition from diagnostics to treatment: the surgeon can simultaneously perform a biopsy of a suspicious formation or execute surgical correction (orchidopexy).

Note on the fertility issue: cryptorchidism remains one of the frequent causes of male subfertility and infertility even after successful orchidopexy. In the comprehensive evaluation of such patients at an older age, the role of imaging is reduced to searching for basic structural anomalies (after excluding endocrine and chromosomal disorders).

What else to study on this topic

• Acute scrotum syndrome: differential diagnosis and the role of ultrasound
• Testicular torsion: whirlpool sign on color Doppler and bell-clapper deformity
• Diagnostic imaging of male infertility: evaluation of the epididymis and testicular atrophy
• Congenital anomalies of the kidneys and urinary tract (CAKUT)

Other topics in the section "Diagnostic Radiology of the Abdominal Organs"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.