What is the best imaging modality for a patient with right upper and lower quadrant abdominal pain?

Imaging for Right Upper and Lower Quadrant Abdominal Pain

For a patient with both right upper and lower quadrant abdominal pain, ultrasonography should be performed as the initial imaging study, followed by CT with contrast if the ultrasound is inconclusive or if appendicitis is suspected. 1, 2

Right Upper Quadrant Pain Evaluation

First-Line Imaging

• Ultrasonography is the recommended initial imaging modality for right upper quadrant pain 1, 2
  • High sensitivity (81%) and specificity (83%) for acute cholecystitis
  • 96% accuracy for detecting gallstones
  • No radiation exposure
  • Cost-effective

When to Consider Additional Imaging

• If ultrasound is negative or equivocal but gallbladder disease is still suspected:
  • Cholescintigraphy (HIDA scan) should be performed next 2
    • Highest sensitivity (97%) and specificity (90%) for acute cholecystitis
    • Particularly useful for suspected acalculous cholecystitis
  • MRI with MRCP for suspected biliary obstruction or choledocholithiasis 2
    • Superior for detecting small stones in gallbladder neck, cystic duct, or common bile duct
    • No radiation exposure

Common Pitfalls in RUQ Imaging

• CT has limited sensitivity (approximately 75%) for gallstones, meaning 25% may be missed 2
• CT without IV contrast cannot detect important features of gallbladder inflammation 2
• Non-distended gallbladder can lead to false-negative results 2
• Patient should fast for 6-8 hours prior to gallbladder ultrasound to ensure proper distention 2

Right Lower Quadrant Pain Evaluation

First-Line Imaging

• CT of abdomen and pelvis with contrast media is the recommended initial imaging for right lower quadrant pain 1
  • High sensitivity and specificity for appendicitis and other causes of RLQ pain
  • Can identify complications such as perforation or abscess

Special Considerations

• For women of reproductive age:
  • Beta human chorionic gonadotropin testing should be performed before imaging 1
  • If pregnancy is confirmed, ultrasonography is the preferred initial imaging modality 3
  • If ultrasound is inconclusive in pregnant patients, MRI is preferred over CT 3

Approach to Combined Right Upper and Lower Quadrant Pain

1. Start with ultrasonography of the abdomen to evaluate:

   • Gallbladder for stones, wall thickening, pericholecystic fluid
   • Liver for abnormalities
   • Right lower quadrant for appendicitis, if visualized
   • Kidneys for hydronephrosis or stones

2. If ultrasonography is inconclusive or negative despite high clinical suspicion:

   • For predominant RUQ symptoms: Consider HIDA scan 2
   • For predominant RLQ symptoms or if appendicitis is suspected: Proceed to CT with contrast 1

3. If both regions require further evaluation:

   • CT of abdomen and pelvis with contrast media is appropriate 1
   • This allows comprehensive evaluation of both quadrants

Laboratory Tests to Consider

• Complete blood count (CBC) to evaluate for leukocytosis
• Liver function tests (LFTs) for liver abnormalities
• Pancreatic enzymes
• Urinalysis to rule out urinary tract causes

Key Points to Remember

• Conventional radiography has limited diagnostic value in assessing acute abdominal pain 1
• Ultrasonography is highly operator-dependent; quality may vary based on technician experience
• CT exposes patients to ionizing radiation; use judiciously, especially in young patients
• MRI is an emerging technique for evaluation of abdominal pain that avoids radiation exposure 1
• Point-of-care ultrasonography can aid in prompt diagnosis of several causes of acute abdominal pain 3

By following this approach, you can efficiently diagnose the cause of right upper and lower quadrant pain while minimizing unnecessary radiation exposure and optimizing diagnostic accuracy.