What is the recommended diagnostic approach for a patient presenting with left upper quadrant (LUQ) abdominal pain?

CT Abdomen and Pelvis with Contrast is the Recommended Diagnostic Approach for Left Upper Quadrant Abdominal Pain

For patients presenting with left upper quadrant (LUQ) abdominal pain, CT of the abdomen and pelvis with contrast media is the recommended first-line imaging modality due to its high diagnostic accuracy and ability to detect a wide range of pathologies. 1

Rationale for CT as First-Line Imaging

• CT provides superior diagnostic yield compared to other imaging modalities for LUQ pain, with the ability to change the leading diagnosis in up to 51% of patients and management decisions in 25% of patients 1
• CT with IV contrast improves characterization and detection of subtle bowel wall abnormalities and complications such as abscesses 2
• CT has high sensitivity for detecting common causes of LUQ pain including splenic pathology, pancreatitis, renal disease, and gastrointestinal conditions 1
• CT can effectively evaluate disease extent and identify complications that may require surgical or interventional management 2

Special Populations and Considerations

• For premenopausal women when gynecologic pathology is suspected, transvaginal ultrasound is recommended as the initial imaging modality 2, 1
• In pregnant patients or young patients where radiation exposure is a concern, ultrasound should be considered as the initial imaging approach 1
• When IV contrast is contraindicated (e.g., severe renal impairment, contrast allergy), unenhanced CT remains valuable and is preferred over other imaging modalities 1
• In elderly patients (≥75 years), unenhanced CT has similar accuracy to contrast-enhanced CT for acute abdominal pain 1

Imaging Modalities to Avoid

• Plain radiography has limited diagnostic value in the assessment of LUQ pain due to low sensitivity, though it may occasionally detect pneumoperitoneum or bowel obstruction 2, 1
• Fluoroscopic contrast enema is not recommended as initial imaging for LUQ pain as it will not show extraluminal abnormalities and increases the risk of perforation in certain conditions 2, 1
• MRI is generally not recommended for initial evaluation of acute LUQ pain due to longer acquisition time, decreased sensitivity for extraluminal air, and increased susceptibility to motion artifacts in symptomatic patients 2, 1

CT Protocol Considerations

• IV contrast significantly improves visualization of vascular structures, inflammatory changes, and abscesses 2
• Oral contrast may not be necessary in many cases of acute abdominal pain, as studies show no significant difference in diagnostic accuracy between CT with and without oral contrast 3, 4
• Low-dose CT techniques can achieve radiation dose reduction of 75-90% compared to standard-dose protocols while maintaining similar sensitivity and specificity 2

Common Pitfalls to Avoid

• Relying solely on clinical assessment for diagnosis, which can lead to misdiagnosis rates of 34-68% for conditions like diverticulitis 2
• Waiting for the classic triad of symptoms (pain, fever, and leukocytosis) before imaging, as this combination is present in only approximately 25% of patients with conditions like diverticulitis 5
• Using ultrasound as the primary imaging modality for LUQ pain outside of specific populations (pregnant patients, young patients, suspected gynecologic pathology), as CT provides more comprehensive evaluation 1

By following these evidence-based recommendations, clinicians can ensure appropriate diagnostic imaging for patients with LUQ abdominal pain, leading to accurate diagnosis and optimal management.