MRCP — standard unenhanced

Intrahepatic and extrahepatic biliary tree, gallbladder, cystic duct, and the full length of the pancreatic duct to the ampulla.

Typical, not policy

Timings, volumes and delays here are representative values drawn from published guidance. Scanner generation, injector, cardiac output and local preference all move them. Confirm against your department's own protocol before you rely on a number.

When to use it

Suspected choledocholithiasis with intermediate probability, to decide whether ERCP is needed.
Obstructive jaundice with an unclear level or cause on ultrasound.
Suspected biliary stricture, including primary sclerosing cholangitis.
Mapping biliary anatomy before cholecystectomy, liver resection or transplantation.
Recurrent pancreatitis of unclear cause, looking for ductal anomaly or small stones.

Technique

Coronal and coronal-oblique breath-hold thick-slab single-shot heavily T2-weighted acquisitions, typically 40-60 mm thick, obtained in a radial set of projections around the duct axis.
A respiratory-triggered high-resolution 3D heavily T2-weighted acquisition with thin partitions, typically of the order of 1-2 mm, as the volumetric dataset.
Axial and coronal T2 and T1 of the upper abdomen for the surrounding organs.
Compressed-sensing single-breath-hold 3D acquisitions are an increasingly used alternative to respiratory triggering; image quality comparisons are still being debated.

Where it goes wrong

Failure to fast, leaving a fluid-filled stomach and duodenum that overlie the distal common bile duct on the projections.
Reading maximum intensity projections only: small stones are volume-averaged away and are seen on the thin source images.
Pneumobilia, surgical clips and stents producing signal voids that mimic stones.
Irregular respiration corrupting the 3D acquisition, which is the sequence carrying the spatial resolution.
Assuming a normal MRCP excludes microlithiasis or a very small ampullary stone.

Clinical questions that reach this study

Acute pancreatitis — severity and complication assessment Suspected acute cholecystitis Obstructive jaundice and suspected biliary obstruction Suspected cholangiocarcinoma Incidental pancreatic cyst and IPMN surveillance

Contrast

NoneOral, neutral

No intravenous contrast. A negative oral agent such as pineapple or blueberry juice is often given to null gastric and duodenal fluid that would otherwise overlap the ducts.

Acquisition

Breathing: A mixture of breath-hold thick-slab acquisitions and a respiratory-triggered 3D acquisition; the 3D sequence is the one that suffers most from irregular breathing.
Reconstruction: Thin-slice maximum intensity projections and curved reformats from the 3D dataset; the source images remain the primary data for small stones.
Preparation: Fast for approximately 4-6 hours: a contracted gallbladder and fluid-filled stomach both degrade the study. Confirm the local interval. Negative oral contrast (for example pineapple or blueberry juice) is often given to suppress overlying gastric and duodenal fluid. MRCP does not require gadolinium; add it only when the question includes a mass, inflammation or vascular assessment.

Safety checks this protocol carries

Derived from the contrast agent and phases above, not authored here — which is why they cannot drift apart from what the protocol actually does.

MR safety screening for implants and foreign bodies· radiographer at scan