What type of ultrasound is best for a 39-year-old patient with left testicular pain, US scrotum or US duplex scrotum complete?

Ultrasound for Testicular Pain: Duplex Doppler Scrotum Complete is the Optimal Choice

For a 39-year-old patient with left testicular pain for 3 weeks, US duplex Doppler scrotum complete is the best ultrasound choice as it provides comprehensive evaluation of testicular perfusion and anatomical structures, which is essential for accurate diagnosis and optimal patient outcomes. 1

Why Duplex Doppler is Superior

Duplex Doppler ultrasound combines several critical components:

• Grayscale imaging: Identifies structural abnormalities, masses, and inflammation
• Color Doppler: Visualizes blood flow patterns and perfusion
• Spectral Doppler: Provides quantitative assessment of blood flow velocity and resistance

The American College of Radiology (ACR) Appropriateness Criteria specifically recommends duplex Doppler ultrasound for evaluating acute scrotal pain, as it allows for:

1. Assessment of testicular perfusion with high sensitivity (96-100%) and specificity (84-95%) 1
2. Identification of the "whirlpool sign" in cases of testicular torsion 1
3. Differentiation between various causes of scrotal pain including:
   • Epididymo-orchitis (most common cause in adults)
   • Testicular torsion
   • Segmental testicular infarction
   • Acute idiopathic scrotal edema

Technical Considerations

For optimal imaging quality:

• Use high-frequency linear transducer (>10 MHz)
• Set low pulse repetition frequency (<4 cm/s)
• Use low wall filter (<100 Hz)
• Apply adequate gain 2
• Always compare with the unaffected contralateral testis

Diagnostic Algorithm for Testicular Pain

1. Assess testicular perfusion using color and power Doppler:

   • Normal or increased flow: Suggests inflammatory process
   • Decreased or absent flow: Concerning for torsion or infarction

2. Evaluate grayscale findings:

   • Enlarged, heterogeneous epididymis with increased flow: Epididymitis
   • Enlarged testis with inhomogeneous echotexture and reduced flow: Possible torsion
   • Focal hypoechoic area with absent flow: Segmental infarction
   • Scrotal wall thickening with striated appearance: Acute idiopathic scrotal edema

3. Examine the spermatic cord from inguinal ring to testis:

   • "Whirlpool sign" is 96% sensitive and 99% specific for testicular torsion 1

Clinical Implications

The 3-week duration of pain in this 39-year-old patient makes acute testicular torsion less likely but doesn't exclude intermittent torsion or other serious conditions. Epididymo-orchitis is the most common cause of acute scrotal pain in adults 1, but other possibilities include:

• Varicocele
• Testicular tumor (10% are found incidentally during trauma evaluation) 3
• Hydrocele
• Chronic torsion

Pitfalls to Avoid

• Don't rely solely on standard ultrasound: Basic grayscale imaging without Doppler assessment may miss critical vascular findings
• Don't delay imaging: While 3 weeks of pain suggests a non-emergent condition, underlying pathology could worsen without proper diagnosis
• Don't forget to examine the entire scrotal contents: Include epididymis, spermatic cord, and scrotal wall in the evaluation

The ACR explicitly states that US duplex Doppler scrotum is equivalent to standard US scrotum for initial evaluation 1, but the addition of spectral Doppler analysis provides crucial quantitative data about organ perfusion that can help distinguish partial torsion from other conditions 1, making it the superior choice for comprehensive evaluation.