What radiology testing should be ordered for a 14-year-old male with pelvic pain?

Diagnostic Imaging for Pelvic Pain in a 14-Year-Old Male

Ultrasound of the pelvis (transabdominal) should be the initial imaging modality for a 14-year-old male presenting with pelvic pain. 1

Initial Evaluation Approach

The approach to pelvic pain in adolescent males requires careful consideration of age-appropriate pathologies:

1. First-line imaging: Transabdominal ultrasound

   • Provides detailed evaluation of pelvic organs without radiation exposure
   • Can effectively visualize:
     • Testicular pathology (torsion, epididymitis, varicocele)
     • Bladder abnormalities
     • Appendicitis (sensitivity up to 90% with proper technique) 2
     • Free fluid in the pelvis
     • Enlarged lymph nodes

2. When to consider advanced imaging:

   • If ultrasound is non-diagnostic or equivocal
   • If clinical suspicion for specific pathology remains high

Potential Diagnoses and Appropriate Imaging

Suspected Appendicitis

• If suspected after ultrasound:
  • CT abdomen and pelvis with IV contrast (sensitivity 94%, specificity 94%) 1
  • MRI abdomen and pelvis without IV contrast if radiation exposure is a concern

Suspected Urinary Tract Pathology

• For suspected urolithiasis:
  • Non-contrast CT "stone protocol" (sensitivity 92-99%, specificity 86-93%) 1
• For suspected urinary tract infection with complications:
  • Ultrasound first to evaluate for hydronephrosis or abscess

Suspected Musculoskeletal Causes

• For suspected muscle strain or sports-related injury:
  • Imaging typically not indicated initially 3
  • MRI pelvis may be considered for persistent symptoms or suspected labral tear

Imaging Algorithm Based on Clinical Presentation

1. For localized pelvic pain:

   • Begin with transabdominal ultrasound
   • Progress to CT with contrast if ultrasound is non-diagnostic

2. For diffuse abdominal/pelvic pain with fever:

   • Transabdominal ultrasound first
   • If inconclusive, CT abdomen and pelvis with IV contrast 3

3. For suspected testicular pathology:

   • Scrotal ultrasound with Doppler is the gold standard

Common Pitfalls to Avoid

• Overlooking age-appropriate pathologies:

  • Testicular torsion requires immediate evaluation
  • Sports hernias may present with chronic pelvic pain in athletic adolescents

• Excessive radiation exposure:

  • Avoid unnecessary CT scans in pediatric patients
  • Consider MRI as an alternative when appropriate

• Incomplete evaluation:

  • Ensure visualization of both testicles on ultrasound
  • Consider both urologic and gastrointestinal causes

Key Considerations

• Ultrasound is the preferred initial imaging modality due to its lack of radiation, accessibility, and ability to visualize most common causes of pelvic pain in adolescent males 1, 4

• CT should be reserved for cases where ultrasound is non-diagnostic or specific pathology (like appendicitis) is highly suspected 3

• MRI provides excellent soft tissue contrast without radiation exposure but may require sedation in younger patients and is less readily available in emergency settings

By following this evidence-based approach, clinicians can efficiently diagnose the cause of pelvic pain in adolescent males while minimizing radiation exposure and unnecessary testing.