Acute cholangitis: A warning sign - Heterogeneous liver enhancement

Clinical History

64-year-old patient who reported 5 days of high fever with right upper quadrant pain. Previous medical history included DM2 (not well-controlled), severe acute cholangitis (Enterobacter cloacae), chronic alcoholic hepatopathy and hepatocellular carcinoma (IV segment - segmentectomy) and a deep venous thrombosis. Due to his previous medical history, a programmed MRI was performed.

Imaging Findings

- MRI: 4 years before the acute episode

Heterogeneous enhancement of liver parenchyma on venous-phase, with multiple focal and subcapsular enhancing areas, compatible with areas of altered perfusion. They remained stable at follow-up (Fig. 1).

- MRI: 2 years before

Appearance of pseudonodular steatosis with a decrease in signal between T1 in-phase and out-of-phase. (Fig. 2).

- MRI: Acute episode

Markedly heterogeneous enhancement of parenchyma on arterial-phase, without biliary tree dilation (Fig. 3a; Fig. 3b).
Multiple parenchymal areas showing restricted diffusion, predominantly in the left lobe (Fig. 3c; Fig. 3d; Fig. 3e).
Wall enhancement of distal choledochum as well as an enlarged enhancing papilla (Fig. 4).
Due to his previous medical history, a biopsy of the left lobe was performed to rule-out infiltrative hepatocellular carcinoma, atypical cells were not found.

- Programmed MRI: 1 year after the acute episode

Similar findings appear again, but without clinical symptoms. 3 days after this incidental finding, the patient came to the emergency room with fever, jaundice and right upper quadrant pain (Fig. 5).

Discussion

A- BACKGROUND

Bacteria cause most cases of acute cholangitis in Western countries (parasites in the rest of the world).
Cholangitis are mainly secondary to biliary tree obstruction.
Obstruction may cause intrahepatic ductal dilation with increased pressure and reflux of bacteria. The resultant acute infectious cholangitis can be life-threatening.
Imaging and clinical features are in close relation to pathogenic agents, immune status and degree of biliary obstruction [1, 2]

B- CLINICAL PERSPECTIVE

Charcot triad: Fever, pain and jaundice.
Reynolds pentad: Fever, pain and jaundice + Shock and lethargy.
Classic symptoms are often missing in elderly patients, leading to delayed diagnosis.
Complications as portal vein thrombosis or hepatic abscesses can be clinically silent. [2, 3]

C- IMAGING PERSPECTIVE:
Acute cholangitis is a clinical diagnosis, and imaging tests are solely supportive.
Diagnostic imaging of cholangitis is necessary to assess biliary tree changes, parenchymal changes and vascular complications. [4, 5]

BILIARY TREE [4]:

- The most common imaging finding is a dilation of intrahepatic bile ducts with concentric wall thickening and enhancement (gadolinium-enhanced delayed phase fat-suppressed sequences). The dilation tends to be central or segmental (less likely diffuse).

- Obstructive choledocholithiasis could be seen as hypointense on T1 and T2 images (cholesterol stones) or hyperintense on T1 and hypointense on T2 (pigmented stones, excess of bilirubin).

- Periportal oedema (hyperintense on T2) and pneumobilia are supportive findings.

- Pus in the biliary tree may be visualized as hypointense on T2-weighted images.

LIVER PARENCHYMA [1, 4, 5]:

- Altered patterns of parenchymal enhancement on late-portal-phase: they can be wedge-shaped (most frequent), peripheral patchy or peribiliary.

- Heterogeneous hepatic enhancement on arterial-phase has been described as an early sign of severe cholangitis (acute suppurative cholangitis). In these patients, an inflammatory process may dilate the periportal/peribiliary plexus and increase hepatic arterial blood flow. This causes a "splenization" of the hepatic enhancement on arterial-phase.

- An enlarged (>10mm) and enhancing papilla has also been related to acute suppurative cholangitis (pus in the biliary tree).

- Liver abscesses: Low-signal T1 and high-signal T2, which could be heterogeneous if haemorrhage or proteinaceous content is present.
Adjacent soft tissue oedema (high T2 signal) - inflammatory response.
Restricted diffusion (high signal on DWI, low ADC values).
Enhancing peripheral rim on T1WI C+ sequences.

VASCULAR COMPLICATIONS:

- Portal vein thrombosis (less likely in acute cholangitis than in infiltrative hepatocellular carcinomas). [1]

D-OUTCOME

If biliary tree is obstructed, antibiotic therapy alone is inadequate for treatment. Endoscopic or percutaneous biliary drainage is necessary to decompress the biliary tree. [1]

E-TAKE HOME MESSAGE

- Heterogenenous hepatic enhancement on arterial-phase has been described as a warning sign for severe cholangitis.

Differential Diagnosis List

Final Diagnosis

Acute cholangitis - A WARNING SIGN: Heterogenenous arterial hepatic enhancement

URL:	https://www.eurorad.org/case/13930
DOI:	10.1594/EURORAD/CASE.13930
ISSN:	1563-4086