What are the indications for ordering a testicular ultrasound in a male patient?

Indications for Testicular Ultrasound

Testicular ultrasound with Doppler is the first-line imaging modality for virtually all scrotal pathology, and should be ordered liberally given its high sensitivity (98%) and specificity (99.8%) for detecting testicular malignancy, even in patients presenting with seemingly benign conditions. 1, 2

Acute Scrotal Pain (Non-Traumatic)

Order ultrasound with Duplex Doppler immediately for any acute scrotal pain to differentiate testicular torsion from epididymitis/orchitis. 1

• Testicular torsion presents with abrupt pain onset, while epididymitis has gradual onset, but clinical overlap is substantial and imaging is essential in equivocal cases 1
• Look for the "whirlpool sign" (twisted spermatic cord) on grayscale imaging, which has 96% sensitivity for torsion 1
• Color Doppler showing absent or decreased testicular blood flow indicates torsion, though normal flow does not exclude it in early or intermittent torsion 1
• In pediatric patients (3 months-18 years), those with low or intermediate TWIST scores benefit from Doppler ultrasound, while high TWIST scores should proceed directly to surgical exploration 1
• Ultrasound can prevent unnecessary surgery by identifying alternative diagnoses like epididymitis, appendix testis torsion, or orchitis 1

Palpable Scrotal Abnormality

Any palpable testicular mass or change in testicular texture warrants immediate ultrasound, as 90% of intratesticular masses are malignant. 1, 3

Critical distinction: Intratesticular vs. Extratesticular

• Ultrasound is nearly 100% sensitive for detecting intratesticular masses and 98-100% accurate for distinguishing intratesticular from extratesticular processes 1
• Intratesticular solid or mixed cystic lesions require surgical exploration, as ultrasound cannot reliably differentiate benign from malignant lesions 1
• Extratesticular masses (epididymal cysts, spermatoceles) are usually benign but still require ultrasound confirmation 3

Specific scenarios requiring urgent ultrasound:

• Non-painful testicular enlargement or change in shape/texture 3
• Painful or tender intratesticular mass not suggestive of infection 3
• Patients aged 20-40 with hydrocele (to exclude underlying tumor) 3
• Uncertainty whether mass is intratesticular or extratesticular on physical exam 3
• Testis cannot be fully palpated due to large hydrocele or scrotal wall thickening 4, 3

Testicular Size Abnormalities

Order ultrasound when testicular volume appears <12 mL or when there is >20% size discrepancy between testes. 4, 5

• Testicular volumes <12 mL are definitively atrophic and associated with impaired spermatogenesis and increased risk of intratubular germ cell neoplasia (TIN) 4, 6
• In men under 30-40 years with volume <12 mL, there is >34% risk of TIN in the contralateral testis if testicular cancer is present 4
• Size discrepancy >2 mL or 20% between testes warrants ultrasound to exclude pathology regardless of absolute volume 4, 5
• Ultrasound is recommended for small testis with large epididymis, inguinal testis, or epididymal enlargement/fibrosis 4

Infertility Evaluation

Ultrasound is indicated in infertile men to assess testicular volume, detect varicoceles, and exclude structural abnormalities. 4, 7

• Testicular volume strongly correlates with total sperm count and sperm concentration 4
• Ultrasound can detect varicoceles, especially subclinical ones not apparent on physical examination 7
• Volumes of 15-18 mL are associated with normal spermatogenesis and adequate fertility potential 4

High-Risk Surveillance

Order ultrasound for surveillance in patients with cryptorchidism history, testicular microlithiasis, or contralateral testicular cancer. 6, 7

• Men with testicular atrophy have an 11.9-fold higher cancer risk, particularly with cryptorchidism or family history 6
• Cryptorchidism with marked contralateral testicular atrophy warrants consideration of testicular biopsy to exclude TIN 6
• Testicular microlithiasis requires ultrasound follow-up, though microcalcifications without other abnormalities can be observed 5
• Hypoechoic masses or macrocalcifications require further evaluation with tumor markers and consideration of orchiectomy 5

Scrotal Trauma

Ultrasound is essential following scrotal trauma to detect testicular rupture, which requires urgent surgical exploration. 7, 8

• Ultrasound can differentiate testicular disruption (requiring surgery) from hematocele or contusion (managed conservatively) 7
• Can differentiate solid masses from mass-like hematomas, which will be avascular on Doppler 1

Clinical Presentation Mimicking Epididymal Disease

Order ultrasound in all patients with scrotal symptoms, even when epididymitis seems clinically obvious, as 1.3% harbor unsuspected testicular tumors. 2

• In a prospective study of 610 patients with clear clinical diagnosis of epididymal disease and no clinical suspicion of malignancy, ultrasound detected unsuspected testicular tumors in 8 patients (7 malignant, 1 benign) 2
• Ultrasound sensitivity and specificity for testicular malignancy are 98% and 99.8% respectively 2

Technical Considerations

• Use high-frequency linear array transducer (12-17 MHz) for optimal anatomic detail 8
• Always include both grayscale and color/power Doppler evaluation 1
• Power Doppler is more sensitive for detecting low-flow states 5
• Perform spectral Doppler analysis in upper, mid, and lower poles of each testicle 5
• Use contralateral asymptomatic testicle as internal control 5

Critical Pitfall to Avoid

Never dismiss scrotal asymmetry or symptoms as normal without Doppler evaluation, as significant pathology may be present despite normal grayscale appearance. 5 Even in the setting of acute pain with apparent blood flow on initial Doppler, testicular torsion cannot be excluded and requires urgent evaluation. 5

budget:budget_used 10934 10502 432 0.1638