Suspected cholangiocarcinoma

Radiology 2018 cholangiocarcinoma imaging review; AJR perihilar review

A tumour defined by its fibrous stroma, which is why its enhancement runs backwards compared with most liver lesions and why a study that stops at the portal venous phase can miss or mischaracterise it entirely.

A hilar or intrahepatic biliary stricture, a mass-forming intrahepatic lesion, or malignant-pattern obstruction, often in primary sclerosing cholangitis or another chronic biliary disease.

Referenced decision support — confirm against your local protocol.

Decision support, not a directive. Protocols and timings shown are typical published ones — your local protocol takes precedence, and the vetting radiologist decides.

The request in front of you

Everything is optional. Leave a field alone and the answer assumes nothing — the verdict updates as you go.

Study requested

What the referrer actually asked for. It is evidence of intent, not a constraint on the right answer.

Contrast as written

What the request form says, not what it should say.

Age

Pick a band, or type an exact age if it matters.

years

Pregnancy status

Renal risk factors

The question a vetter can actually answer from the request. An explicit “none known” is a real answer, and it removes checks rather than deferring them.

Previous contrast reaction

The pathway — tap anything already done

Marking a study complete moves the answer on. A patient arrives partway through a pathway far more often than at the start of one.

Accept as requested

MRI Liver — multiphase with extracellular gadolinium

MRI Liver

What we'd amend, and why

The dense fibrous stroma of a cholangiocarcinoma has a large extracellular space that contrast enters slowly and leaves slowly, so enhancement is peripheral and rim-like early and fills in progressively, with contrast still pooling within the tumour on the delayed acquisition. That progressive retention is the discriminator against hepatocellular carcinoma, which does the opposite and washes out, and it is only visible if a delayed phase is acquired. Capsular retraction and upstream duct dilatation are the supporting features, and MRI shows both alongside the duct itself.

Nothing needs resolving before this goes ahead. Routine checks below are owned downstream.

How was this decided?

pathwayadult — Adults
rulerule-mr-device-screening — MR safety screening for implants and foreign bodies; checked by Radiographer at the scanner
rulerule-contrast-reaction-premed — Prior contrast reaction and elective premedication; checked by Nurse before the scan
rulerule-gadolinium-renal — Kidney function and gadolinium-based contrast; checked by Radiographer at the scanner
rulerule-pregnancy-gadolinium — Gadolinium in known or possible pregnancy; checked by Radiographer at the scanner
rulerule-iv-access — Intravenous access adequate for the planned injection; checked by Radiographer at the scanner

Decision support only. Local protocol takes precedence.

Handled at the scanner(2)nothing for you to do

Settled and owned downstream. Each returns to a radiologist only on the stated trigger.

MR safety screening for implants and foreign bodies
Complete the MR safety questionnaire, verify implant labelling and its stated conditions of use against this scanner and this protocol, and ensure no ferromagnetic object enters Zone IV.
Radiographer at the scannerBefore the scan
Flags back if: An implant or retained foreign body that is MR Unsafe, unlabelled, or cannot be identified; or an MR Conditional device whose stated conditions this scanner or the requested protocol cannot satisfy; or a credible unexcluded intraocular metallic foreign body history.
Intravenous access adequate for the planned injection
Site and test a cannula that supports the protocol flow rate, preferring an antecubital or large forearm vein, and observe the injection for extravasation. A 20-gauge or larger cannula is preferred for flow rates of 3 mL/s or more.
Radiographer at the scannerAt the scanner
Flags back if: No cannula can be sited that supports the protocol flow rate — for example only a 22-gauge hand or foot cannula for a CT angiogram needing 4–5 mL/s; or the only available access is a central line or port that is not labelled power-injectable; or an extravasation occurs.

Pathways

Big forks are separate pathways; the first whose conditions match is the one used.

Adults

Matches your inputsDefault

Role	Study & protocol	Why this answers the question
First line	MRI Liver MRI Liver — multiphase with extracellular gadolinium usually appropriate	The dense fibrous stroma of a cholangiocarcinoma has a large extracellular space that contrast enters slowly and leaves slowly, so enhancement is peripheral and rim-like early and fills in progressively, with contrast still pooling within the tumour on the delayed acquisition. That progressive retention is the discriminator against hepatocellular carcinoma, which does the opposite and washes out, and it is only visible if a delayed phase is acquired. Capsular retraction and upstream duct dilatation are the supporting features, and MRI shows both alongside the duct itself.
Reasonable alternative	MRCP (MR Cholangiopancreatography) MRCP — standard unenhanced	For a perihilar tumour the surgical question is how far along each duct the disease extends, and cholangiography answers it non-invasively: bright static bile outlines the length of the stricture and shows which secondary confluences are involved, without the decompression and contamination that endoscopic injection brings.
Second line	CT Abdomen and Pelvis CT Abdomen and Pelvis — Portal Venous Phase	CT is the practical tool for distant abdominal staging, for arterial and portal venous mapping in the resection plan, and for measuring the future liver remnant. It complements the MRI rather than replacing it.
Second line	CT Chest CT Chest — Contrast-Enhanced (Venous Phase)	Thoracic staging is completed before a major hepatectomy is offered, since occult pulmonary metastases change the operation from curative to inappropriate.
Problem solving	FDG PET-CT FDG PET-CT — skull base to mid-thigh	Reserved for the patient in whom occult nodal or distant disease would abandon a planned major resection. It performs less well for the infiltrating periductal form, where tumour volume is small relative to the fibrous reaction.

Pitfalls

Requesting a hepatobiliary contrast agent for this question. The hepatocyte-specific agent shortens and contaminates the delayed window on which progressive tumour enhancement is judged, and an extracellular agent is the right choice.
Stopping the acquisition at the portal venous phase, which is where this tumour is least conspicuous and most easily mistaken for a metastasis.
Imaging after stenting and then reporting duct wall changes as tumour extent.
Assuming a hilar obstruction is malignant. Immunoglobulin G4-related disease, sclerosing cholangitis and post-surgical stricture all mimic it.
Neglecting the future liver remnant. Vascular and biliary involvement of the intended remnant lobe is what makes an anatomically resectable tumour inoperable.

Priors — what to pull first

In primary sclerosing cholangitis, the diagnosis is made by change: compare with the previous cholangiographic study for a new dominant stricture or new upstream dilatation.
Obtain any pre-stent imaging, which usually depicts the tumour margins far better than a post-stent study.

What makes a good request

Resectability turns on longitudinal duct involvement, vascular encasement and future liver remnant volume — so the imaging question is anatomical extent, not just diagnosis.
Imaging is best obtained before biliary stenting, because a stent distorts the duct and inflames the wall, blurring exactly the margins that determine the operation.

Scoring this once it is done

The classification and risk tools this question ends in.

Liver Volume (CT/MRI/US) + Expected Volume Child-Pugh Score (Child-Turcotte-Pugh)LI-RADS v2018 (CT/MRI)RECIST 1.1 Tumor Response

How these studies are acquired

Contrast, phases and timing for every study on the pathways above.

MRI Liver — multiphase with extracellular gadolinium MRCP — standard unenhanced CT Abdomen and Pelvis — Portal Venous Phase CT Chest — Contrast-Enhanced (Venous Phase)FDG PET-CT — skull base to mid-thigh

Confirm locally

MRI Liver — multiphase with extracellular gadolinium: timings are typical — confirm against local protocol.
Timings, contrast volumes and rates above are typical published values. Your department's protocol, scanner and patient population decide the actual numbers.
Safety thresholds and premedication policy follow local policy where it differs from the cited guidance.

References

Implemented from the cited published sources. Educational and workflow support only; confirm against current guidelines and local policy before clinical use.