In a 54‑year‑old woman with metastatic endometrial cancer who underwent intra‑hepatic arterial embolization 5 days ago and now presents with right‑upper‑quadrant and right‑shoulder tip pain and fever, what findings should be evaluated on a triple‑phase abdominal CT (arterial ≈21 seconds, portal‑venous ≈60 seconds, delayed ≈180 seconds) and how should they be reported to assess for post‑procedure infection or hepatic abscess?

Post-Embolization CT Evaluation for Hepatic Abscess

You're looking for hepatic abscess, biliary complications, and post-embolization syndrome complications on this triple-phase CT—specifically focus on fluid collections with rim enhancement, gas formation, biliary dilatation, and gallbladder ischemia.

Primary Imaging Targets

Your clinical scenario screams post-embolization infection given the timeline (5 days post-procedure) and classic presentation (RUQ pain, shoulder tip pain, fever). The triple-phase protocol is actually overkill for abscess detection but gives you comprehensive vascular and parenchymal assessment 1.

Critical Findings to Report

Hepatic Abscess:

• Look for hypoattenuating fluid collections with peripheral rim enhancement on portal venous phase (60 seconds)—this is your money shot for pyogenic abscess 2, 3
• Gas formation within collections is pathognomonic for infection with gas-forming organisms 4
• The portal venous phase (60 sec) is most sensitive for detecting these collections 5
• Delayed phase (180 sec) helps characterize rim enhancement and assess for biliary communication 3

Post-Embolization Complications:

• Gallbladder wall thickening/pericholecystic fluid: Cystic artery embolization causes ischemic cholecystitis in up to 1% of cases 1, 6, 7
• Biliary dilatation or biloma: Central biliary stenosis from excessive embolization can cause catastrophic liver damage 1
• Pleural effusion and basal atelectasis: Seen in 35% of right hepatic artery interventions, though usually benign 8

Tumor-Related Findings:

• Document the known liver metastases using standard criteria: look for peripheral rim enhancement in arterial phase (21 sec) with hypoenhancement in portal venous phase 5
• The arterial phase shows hypervascular tumor periphery where viable tumor cells concentrate 9, 5

Structured Reporting Algorithm

1. Arterial Phase (21 seconds)

• Assess embolized hepatic artery patency
• Look for arterial-phase hyperenhancement in metastases (peripheral rim pattern) 5
• Check for vascular complications (pseudoaneurysm, arteriovenous shunting)

2. Portal Venous Phase (60 seconds) - YOUR KEY PHASE

• Systematically search for fluid collections with rim enhancement
• Measure size and document location relative to embolized territory
• Assess gallbladder (wall thickening >3mm, pericholecystic fluid, intramural gas)
• Evaluate intrahepatic bile ducts for dilatation
• Document pleural effusions (right-sided expected in 35% 8)

3. Delayed Phase (180 seconds)

• Confirm persistent rim enhancement of suspected abscesses
• Look for biliary communication (contrast/fluid tracking into bile ducts) 3
• Assess for biloma (non-enhancing fluid collections near bile ducts)

Critical Pitfalls to Avoid

Don't confuse post-embolization syndrome with infection: Post-embolization syndrome causes RUQ pain and fever within 72 hours but lacks imaging findings of abscess 1. Your patient is at day 5 with persistent symptoms—this timing plus imaging findings will differentiate.

Shoulder tip pain is diaphragmatic irritation: This suggests either subphrenic collection, pleural effusion, or diaphragmatic involvement from the embolization procedure itself 8. Specifically look at the hepatic dome and right hemidiaphragm.

Metastases can mimic abscess: Necrotic metastases show rim enhancement but typically lack the thick, irregular enhancing wall and internal gas of pyogenic abscess 9, 5. Clinical context (fever, elevated WBC) is key.

Report Template Structure

1. Procedure-related findings:

   • Embolized vessel patency
   • Lipiodol/embolic material distribution
   • Vascular complications

2. Infectious complications:

   • Presence/absence of rim-enhancing fluid collections (size, location, internal gas)
   • Gallbladder status (wall thickness, enhancement, pericholecystic fluid)
   • Biliary tree (dilatation, biloma)

3. Tumor assessment:

   • Known metastases (size, enhancement pattern, interval change)
   • New lesions

4. Secondary findings:

   • Pleural effusion (expected in 35% 8)
   • Ascites
   • Lymphadenopathy

If you find a rim-enhancing collection >3cm with clinical sepsis, this requires urgent percutaneous drainage 3. Collections <3cm may respond to antibiotics alone, but given her metastatic cancer and immunocompromised state, lower your threshold for intervention 2, 3.

The combination of fever, persistent pain beyond 72 hours post-procedure, and any rim-enhancing collection on CT mandates immediate communication with the clinical team for potential drainage and blood cultures 1, 2.