Diagnosis of Retroperitoneal Bleed
CT abdomen and pelvis with IV contrast or CT angiography (CTA) with IV contrast is the imaging modality of choice for diagnosing retroperitoneal bleeding, providing rapid, accurate diagnosis with localization of bleeding and identification of active extravasation. 1, 2
Primary Diagnostic Approach
First-Line Imaging
CT with contrast is the gold standard because it provides speed, high spatial resolution, noninvasiveness, and can depict blood, localize bleeding areas, and evaluate for active contrast extravasation 1
CTA is superior when active bleeding is clinically suspected, as it can detect bleeding rates as slow as 0.3 mL/min and provides detailed vascular information with required 3-D rendering 1, 2
Non-contrast CT alone is appropriate in patients with compromised renal function or when additional contrast load is a concern if subsequent angiography may be needed 1, 2
CT Findings That Determine Acuity
High attenuation on non-contrast CT indicates acute bleeding 1, 2
Mixed attenuation suggests rebleeding or subacute hemorrhage 1, 2
Low attenuation indicates subacute to chronic blood products 1, 2
Clinical Recognition
Key Clinical Presentations
Nonspecific symptoms make diagnosis challenging: diffuse abdominal pain, back pain, flank pain, abdominal distension, or palpable flank mass 3, 4, 5
Hemodynamic instability with hypotension and signs of hypovolemia in severe cases 4, 6
Femoral neuropathy occurs in 36% of iatrogenic cases after cardiac catheterization 6
Suprainguinal tenderness and fullness present in 100% of post-procedural cases 6
High-Risk Clinical Scenarios
Suspect retroperitoneal bleeding in anticoagulated patients with groin, flank, abdominal, or back pain 3, 7, 5
Post-interventional procedures (cardiac catheterization, J-tube placement) with unexplained pain or hemodynamic changes 3, 4, 6
Pelvic fractures are associated with retroperitoneal hematoma in 55% of blunt trauma cases 2, 3
Alternative Imaging Modalities (Usually NOT Appropriate)
Ultrasound Limitations
Ultrasound is NOT appropriate for initial diagnosis due to limited acoustic windows, inability to evaluate the entire retroperitoneum reliably, and difficulty detecting smaller volumes of blood 1, 2
US is 99% sensitive for detecting abdominal aortic aneurysm presence but cannot determine if rupture has occurred or identify alternative bleeding etiologies 1
Plain Radiography Limitations
Radiography has low sensitivity and is usually not appropriate, as moderate-volume hematomas may not produce sufficient mass effect for detection 1, 2
Findings are highly nonspecific: displacement of bowel loops or obscuration of psoas muscle contour only visible with large-volume hematoma 1
Nuclear Medicine Limitations
- Tc-99m-labeled RBC scintigraphy is usually not appropriate despite high sensitivity (detects bleeding rates as low as 0.1 mL/min) due to longer examination time and better sensitivity provided by CT in the retroperitoneal location 1
Angiography for Simultaneous Diagnosis and Treatment
When to Consider Immediate Angiography
Hemodynamically unstable patients with high clinical suspicion may proceed directly to aortography for simultaneous diagnosis and transcatheter arterial embolization (TAE) 1, 2
Known active arterial bleeding or contained vascular injury amenable to concomitant treatment 1
Angiography requires bleeding rate of 0.5 to 1.0 mL/min for detection and provides high spatial and temporal resolution 1
Angiography Limitations
Invasive procedure with risks including hematoma or bleeding at access site, iatrogenic dissections, and infection 1
ACR panel did not reach consensus on recommending aortography for initial imaging due to insufficient evidence, though it may be appropriate when simultaneous treatment intervention is needed 1