What type of CT (Computed Tomography) scan is recommended for an adult patient with abdominal pain and no significant past medical history, such as kidney disease or allergy to contrast agents?

CT Abdomen and Pelvis with IV Contrast

For an adult patient with nonlocalized abdominal pain and no contraindications, order a CT of the abdomen and pelvis with intravenous contrast as a single postcontrast phase—this is the preferred initial imaging modality. 1, 2

Why CT with IV Contrast is the Standard

CT with IV contrast is the most appropriate imaging choice because it:

• Changes the leading diagnosis in 49% of patients with nontraumatic abdominal complaints 1, 2
• Alters management decisions in 42-49% of cases, including changing admission status in 24% and surgical plans in 25% 1, 2
• Increases the spectrum of detectable pathology compared to non-contrast CT, particularly for inflammatory conditions, vascular abnormalities, and solid organ pathology 1
• Provides comprehensive evaluation of all abdominal organs, lymph nodes, and vascular structures in a single examination 2

Technical Protocol Details

The standard protocol should include: 1

• Single postcontrast phase only—precontrast and delayed postcontrast images are not required for initial diagnosis
• Coverage from diaphragm through pelvis—always include the pelvis to evaluate distal ureters, bladder, gynecologic organs, and pelvic pathology
• IV contrast administration—essential for detecting abscesses, inflammatory processes, vascular complications, and enhancing solid organ visualization

Oral contrast is NOT routinely necessary because it delays scan acquisition and departmental throughput without clear diagnostic advantage in the acute setting 1

When to Consider Alternative Imaging

Use ultrasound first if: 1, 2

• Pain is localized to the right upper quadrant (suspected gallbladder disease)
• Patient is pregnant or of reproductive age with suspected gynecologic pathology
• Patient is a child or adolescent (ultrasound preferred to avoid radiation) 3

Use MRI instead of CT if: 1

• Patient is pregnant and ultrasound is non-diagnostic (MRI has 97-99% accuracy for appendicitis without radiation) 1
• Patient has severe contrast allergy or renal insufficiency precluding IV contrast use
• Institutional expertise and rapid MRI protocols are available 1

Common Pitfalls to Avoid

Do not order plain abdominal radiographs as the initial imaging—they have low sensitivity (49% for bowel obstruction, minimal for inflammatory conditions) and rarely change management 1, 2

Do not order CT without IV contrast unless there is a specific contraindication—non-contrast CT significantly reduces diagnostic accuracy for inflammatory, infectious, and vascular pathology 1

Do not forget to check pregnancy status in women of reproductive age before ordering CT to avoid unnecessary fetal radiation exposure 1, 2

Do not delay imaging in clinically deteriorating patients while pursuing less sensitive modalities 2

Specific Clinical Scenarios

If fever is present with abdominal pain: 1

• CT with IV contrast has the highest rating (8/9) from the ACR for detecting abscesses, which are present in a significant proportion of these patients
• CT changed abscess diagnosis by 19% and increased detection of cholecystitis/cholangitis by 100% in one prospective study 1

If the patient has a history of abdominal disease: 4

• CT remains superior to clinical evaluation (90% vs 76% sensitivity) even in patients with known abdominal pathology
• Management changes occurred in 25% of patients after CT 4

If symptoms are present for less than 24 hours: 4

• CT is still superior to clinical evaluation and changes management significantly
• Early imaging prevents diagnostic delays that could worsen morbidity 4