In an adult with suspected intra‑abdominal hemorrhage, which is the preferred initial imaging modality—contrast‑enhanced whole‑abdominal CT or diagnostic aortography?

Contrast-Enhanced CT is the Preferred Initial Imaging for Suspected Intra-Abdominal Hemorrhage

Contrast-enhanced whole-abdominal CT should be performed as the initial imaging modality for adults with suspected intra-abdominal hemorrhage, rather than diagnostic aortography. CT provides superior diagnostic accuracy, speed, and comprehensive evaluation while allowing for immediate therapeutic planning without the delays and invasiveness of angiography 1.

Diagnostic Performance of CT

Contrast-enhanced CT demonstrates exceptional diagnostic accuracy for detecting intra-abdominal bleeding:

• Sensitivity of 98% and specificity of 98% for solid organ injuries, with a positive likelihood ratio of at least 45 1
• Detects active bleeding at rates as low as 0.3 mL/min, which is more sensitive than invasive angiography 1
• Identifies active arterial extravasation with CT attenuation values of 85-370 Hounsfield units (mean 132 HU), significantly different from clotted blood at 40-70 HU (mean 51 HU) 2
• Accurately localizes the anatomic site of bleeding in 100% of cases when compared to surgical or angiographic confirmation 2, 3

Critical Advantages of CT Over Aortography

CT provides multiple advantages that make it superior as the initial imaging modality:

• Speed and accessibility: Modern multi-slice CT scanners complete whole-body scanning in less than 30 seconds, allowing immediate assessment 1
• Comprehensive evaluation: CT identifies all bleeding sources simultaneously, including solid organ injuries, retroperitoneal hemorrhage, pelvic bleeding, and associated injuries to chest and head 1
• Non-invasive: Unlike aortography, CT does not require arterial access, reducing procedural risks and time to diagnosis 1
• Guides intervention: CT findings directly inform whether immediate surgery or angiographic embolization is needed, and provides anatomic roadmap for either approach 2, 3

When Aortography Becomes Appropriate

Diagnostic aortography should be reserved for therapeutic intervention rather than initial diagnosis:

• After CT identifies active bleeding, angiography with embolization can be performed for targeted hemostasis 1
• When CT shows contrast extravasation, this indicates the specific vascular territory requiring angiographic treatment 2, 3
• Angiography serves as both diagnostic confirmation and therapeutic intervention in a single procedure once CT has localized the bleeding source 1

Specific CT Protocol Recommendations

For optimal detection of active hemorrhage, the following technical approach is essential:

• Use intravenous contrast enhancement to differentiate active bleeding from clotted blood and identify vascular injuries 1, 2
• Arterial phase timing is critical to detect active extravasation of contrast material 4, 3
• Include the entire abdomen and pelvis to identify all potential bleeding sources and associated injuries 1
• Multiplanar reformations help identify subtle findings like sentinel clot sign and characterize injury patterns 4

Clinical Decision Algorithm

For hemodynamically stable patients with suspected intra-abdominal hemorrhage:

1. Perform contrast-enhanced CT abdomen/pelvis immediately as the first-line imaging study 1
2. If CT shows active contrast extravasation: Proceed directly to angiography for embolization or to surgery depending on the bleeding source and hemodynamic status 2, 3
3. If CT shows hematoma without active extravasation: Manage conservatively with serial monitoring or proceed to surgery based on clinical stability 1

For hemodynamically unstable patients:

• Proceed directly to surgery without imaging if there is obvious peritonitis or profound shock 1
• Consider bedside ultrasound (FAST) only to confirm hemoperitoneum before immediate laparotomy, not as a substitute for CT in stable patients 1

Critical Pitfalls to Avoid

Several common errors can delay appropriate management:

• Do not start with aortography as the initial diagnostic test—it is time-consuming, invasive, and provides limited anatomic information compared to CT 1
• Do not perform non-contrast CT when intravenous contrast is available—contrast is essential to distinguish active bleeding from clotted blood and identify vascular injuries 2, 5
• Do not rely on ultrasound alone in stable patients—while useful for initial triage, ultrasound has low sensitivity for subtle bleeds and cannot characterize the full extent of injuries 4
• Recognize that hemodynamic stability at the time of CT does not guarantee continued stability—in one series, 7 of 18 patients developed hypotension during or immediately after CT scanning, requiring urgent intervention 3

Evidence Quality Considerations

The recommendation for CT over aortography is supported by multiple high-quality guidelines:

• The 2021 ACR Appropriateness Criteria specifically designates CT and CTA as "appropriate" for initial evaluation of retroperitoneal and intra-abdominal bleeding 1
• The 2020 French guidelines on abdominal trauma provide Grade 1+ recommendation for contrast-enhanced CT to identify abdominal injuries 1
• The 2013 European trauma guidelines recommend CT for hemodynamically stable patients with suspected bleeding 1

While the REACT-2 randomized trial did not demonstrate mortality reduction with whole-body CT, this was likely underpowered, and five large observational studies totaling 31,514 patients showed mortality reduction with odds ratio of 0.75 (95% CI: 0.70-0.79) 1.