What is the imaging study of choice for a patient with epigastric and lower right abdominal pain, accompanied by nausea and malaise?

Imaging of Choice for Epigastric and Right Lower Quadrant Pain with Nausea and Malaise

CT abdomen and pelvis with IV contrast (without oral contrast) is the imaging of choice for this clinical presentation, as it effectively evaluates both the epigastric pathology (peptic ulcer disease, gastritis, perforation) and right lower quadrant pathology (appendicitis), which are the leading diagnostic considerations given this symptom constellation. 1

Rationale for CT as First-Line Imaging

The combination of epigastric pain extending to the right lower quadrant with nausea and malaise creates a diagnostic challenge requiring imaging that can evaluate multiple potential etiologies simultaneously:

• CT abdomen and pelvis with IV contrast achieves sensitivities of 85.7-100% and specificities of 94.8-100% for appendicitis, the most critical diagnosis to exclude given the right lower quadrant involvement 1

• For upper gastrointestinal pathology including peptic ulcer disease and gastritis, CT can detect wall thickening, mucosal hyperenhancement, perforation with free air, and ulcer craters 1

• CT without oral contrast is preferred because it avoids delays in diagnosis and treatment while maintaining diagnostic accuracy, with studies showing no compromise in clinical efficacy for patients with BMI >25 2

• The negative appendectomy rate with preoperative CT ranges from only 1.7-7.7%, compared to 14.7% historically without imaging 1

Technical Specifications

Perform CT abdomen and pelvis with IV contrast only—oral contrast is unnecessary and delays care:

• IV contrast is essential for detecting mucosal hyperenhancement, nodular wall thickening, and inflammatory changes 1

• Oral contrast provides minimal additional diagnostic value (helpful in only 3.4-4.6% of cases) and significantly delays imaging 3

• Studies of 1,922 patients with acute abdominal pain showed 100% sensitivity for appendicitis using IV contrast alone without oral contrast 1, 2

Alternative Diagnoses This Approach Captures

This imaging strategy simultaneously evaluates multiple life-threatening conditions:

• Perforated peptic ulcer: CT detects extraluminal gas (97%), focal wall defect (84%), and fluid/fat stranding (89%) 1

• Appendicitis with perforation: Identifies periappendiceal abscess, free fluid, and inflammatory changes 1

• Gastric outlet obstruction: Evaluates for malignancy or chronic inflammatory changes 1

• Diverticulitis: Though less likely with epigastric pain, CT has high sensitivity if symptoms are atypical 1

When Ultrasound is NOT Appropriate Here

Ultrasound should be avoided as initial imaging in this clinical scenario:

• Ultrasound sensitivity for appendicitis is only 51.8-81.7% with specificity of 53.9-81.4%, substantially lower than CT 1

• The appendix is not visualized in 27.7-45% of ultrasound examinations 1

• Ultrasound cannot adequately evaluate for peptic ulcer perforation or free air 1

• For epigastric pathology, endoscopy—not ultrasound—is the standard when upper GI disease is strongly suspected 1

Critical Pitfalls to Avoid

Do not order fluoroscopic upper GI series as initial imaging:

• While upper GI series can detect hiatal hernia and some ulcers, it cannot evaluate for appendicitis or perforation complications 1

• The clinical presentation demands evaluation of the right lower quadrant, making fluoroscopy inadequate 1

Do not perform CT without IV contrast:

• Non-contrast CT has lower sensitivity (85.7%) compared to contrast-enhanced CT (90-100%) for appendicitis 1

• IV contrast is essential for detecting inflammatory changes and mucosal abnormalities in peptic ulcer disease 1

Do not delay imaging for oral contrast administration:

• Oral contrast delays diagnosis by 2-4 hours without improving diagnostic accuracy 3

• In peptic ulcer perforation, mortality reaches 30%, making rapid diagnosis critical 1

Special Populations

For pregnant patients with this presentation:

• MRI abdomen and pelvis without contrast is preferred, with sensitivity and specificity of 96% for appendicitis 4

• Ultrasound can be attempted first in pregnancy, but if non-diagnostic, proceed directly to MRI rather than CT 1

For pediatric patients:

• Ultrasound with graded compression is reasonable as initial imaging in children, given radiation concerns 1

• However, if ultrasound is non-diagnostic or the appendix is not visualized, proceed immediately to CT rather than repeating ultrasound 1