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Magnetic Resonance Cholangiopancreatography (MRCP): Protocol and Planning

Anatomy of biliary system

The anatomy of the biliary system is of utmost importance in radiology as it plays a crucial role in the diagnosis and treatment of biliary disorders. The biliary system consists of various interconnected structures that facilitate the production, transportation, and storage of bile.

Starting with the liver, the intrahepatic bile ducts collect bile produced by hepatocytes. These ducts merge to form the right and left hepatic ducts, which exit the liver and join together to form the common hepatic duct. The common hepatic duct combines with the cystic duct from the gallbladder to form the common bile duct.

The common bile duct runs through the head of the pancreas and usually joins the main pancreatic duct, forming the hepatopancreatic ampulla (ampulla of Vater). The ampulla opens into the duodenum through the sphincter of Oddi, allowing the release of bile into the digestive system.

Liver,pancreas and biliary system anatomy image

Indications for magnetic resonance cholangiopancreatography

Contraindications

Patient preparation for MRCP

Positioning for MRCP

MRI MRCP positioning photo

Recommended MRI MRCP Protocols, Parameters, and Planning

localiser

To localize and plan the sequences, it is essential to acquire a three-plane T2 HASTE localizer initially. These fast single-shot localizers have an acquisition time of under 25 seconds and are highly effective in accurately localizing abdominal structures.

Planning and protocol of Magnetic resonance cholangiopancreatography (MRCP) localiser

T2 HASTE 5 mm breath hold coronal

Plan the coronal slices on the axial localizer and position the block horizontally across the liver as depicted. Verify the position in the other two planes. Establish an appropriate angle in the sagittal plane, aligning it vertically across the liver. Ensure that the slices adequately cover the entire liver, extending from the anterior abdominal wall to the erector spinae muscles. The phase direction should be from right to left to minimize ghosting artifacts from the lungs and heart. Employ phase oversampling to prevent wrap-around artifacts. Instruct the patient to hold their breath during image acquisition. (In our department, we typically advise patients to breathe in and out twice before providing the instruction to “breathe in and hold”.)

MRCP planning of coronal slices

Parameters

TR

2000-2500

TE

90-110

FLIP

130

NEX

1

SLICE

5MM

MATRIX

320×256

FOV

350

PHASE

R>L

OVERSAMPLE

50%

TRIGGER

NO

T2 HASTE 5 mm breath hold axial

Plan the axial slices on the coronal breath hold images and position the block horizontally across the liver as shown. Verify the positioning in the other two planes. Establish an appropriate angle in the sagittal plane, aligning it horizontally across the liver. The slices must be sufficient to cover the entire liver from the diaphragm down to the C loop of the duodenum. The phase direction should be from right to left to minimize ghosting artifacts from the anterior abdominal wall. Use phase oversampling to prevent wrap-around artifacts. Instruct the patient to hold their breath during image acquisition. (In our department, we typically instruct patients to take two breaths in and out before providing the “breathe in and hold” instruction.)

MRCP planning and protocol of axial slices
Planning should be conducted using the breath hold HASTE coronal sequence because the diaphragm exerts downward pressure on the liver during inhalation, leading to a shift in the liver’s position from the initial localizer scans.

TR

2500-3000

TE

90-110

FLIP

130

NEX

1

SLICE

5MM

MATRIX

256×256

FOV

350

PHASE

R>L

OVERSAMPLE

50%

TRIGGER

NO

T2 HASTE fat sat 5mm breath hold axial

Plan the axial slices on the coronal breath hold images and position the block horizontally across the liver as shown. Verify the positioning in the other two planes. Establish an appropriate angle in the sagittal plane, aligning it horizontally across the liver. The phase direction should be from right to left to minimize ghosting artifacts from the anterior abdominal wall. Use phase oversampling to prevent wrap-around artifacts. Instruct the patient to hold their breath during image acquisition. (In our department, we typically instruct patients to take two breaths in and out before providing the “breathe in and hold” instruction.)

MRCP planning and protocol of axial slices

Parameters

TR

3000-4000

TE

110

FLIP

150

NEX

1

SLICE

5 MM

MATRIX

320X320

FOV

400-450

PHASE

A>P

OVERSAMPLE

50%

IPAT

Off

T2 HASTE thick 40mm breath hold coronal oblique (single slice)

Plan the coronal oblique (left anterior oblique) thick slab on the axial HASTE sequence. Position the block across the common bile duct and rotate it 20-30 degrees clockwise to include both the common bile duct and gall bladder. Verify the positioning in the other two planes. Establish an appropriate angle in the sagittal plane, aligning it horizontally across the bile duct. Ensure that the slice thickness is sufficient to cover the entire common bile duct and gall bladder. Use phase oversampling to prevent wrap-around artifacts. Instruct the patient to hold their breath during image acquisition.

Parameters

TR

4000-5000

TE

500

FLIP

150

NEX

1

SLICE

40MM

MATRIX

320X320

FOV

350-450

PHASE

R>L

OVERSAMPLE

50%

IPAT

ON

T2 HASTE thick 40mm breath hold coronal (single slice)

Plan the coronal thick slab on the axial HASTE sequence. Position the block across both the common bile duct and pancreatic duct (without concern for excluding part of the gallbladder). Verify the positioning in the other two planes. Establish an appropriate angle in the sagittal plane, aligning it horizontally across the bile duct. Ensure that the slice thickness is sufficient to cover the entire common bile duct and pancreatic duct. Use phase oversampling to prevent wrap-around artifacts. Instruct the patient to hold their breath during image acquisition.

MRCP planning and protocol of coronal haste thick slab bile duct and pancreatic duct

Parameters

TR

4000-5000

TE

500

FLIP

150

NEX

1

SLICE

40MM

MATRIX

320X320

FOV

350-450

PHASE

R>L

OVERSAMPLE

50%

IPAT

ON

T2 HASTE thick 40mm breath hold coronal oblique(single slice)

Plan the coronal oblique (right anterior oblique) thick slab on the axial HASTE sequence. Position the block across the common bile duct and rotate it 20-30 degrees counterclockwise to include both the common bile duct and pancreatic duct (without concern for excluding part of the gallbladder). Verify the positioning in the other two planes. Establish an appropriate angle in the sagittal plane, aligning it horizontally across the bile duct. Ensure that the slice thickness is sufficient to cover the entire common bile duct and pancreatic duct. Use phase oversampling to prevent wrap-around artifacts. Instruct the patient to hold their breath during image acquisition.

Parameters

TR

4000-5000

TE

500

FLIP

150

NEX

1

SLICE

40MM

MATRIX

320X320

FOV

350-450

PHASE

R>L

OVERSAMPLE

50%

IPAT

ON

T2 SPACE 3D(or T2 TSE) coronal respiratory gated 1MM

Plan the coronal 3D sequence on the axial HASTE scan. Position the block across the common bile duct and pancreatic duct. Verify the positioning in the other two planes. Establish an appropriate angle in the sagittal plane, aligning it horizontally across the bile duct. Ensure that the slices adequately cover the entire common bile duct, pancreatic duct, and gall bladder. Use phase oversampling to prevent wrap-around artifacts.

For respiratory gated scans, it is crucial to accurately position the respiratory navigator box. Place it in the middle of the right dome of the diaphragm, with half of the box over the right lobe of the liver (segment 8) and the other half over the lungs. Planning should be performed in a non-breath hold localizer, as the diaphragm pushes down the liver during inhalation, which can lead to improper slice planning and positioning of the respiratory navigator box.

Instruct the patient to breathe gently throughout the sequence. Very shallow or erratic breathing can reduce the effectiveness of the navigator.

Parameters

TR

2500-3000

TE

500-700

FLIP

12

NEX

1

SLICE

1MM

MATRIX

320X320

FOV

350

PHASE

R>L

OVERSAMPLE

50%

IPAT

ON

Optional Scans

T2 HASTE thick 40mm breath hold coronal oblique(radial)

Plan the coronal radial thick slab slices on the axial HASTE sequence. Position the center of the block over the common bile duct . Verify the positioning in the other two planes. Establish an appropriate angle in the sagittal plane, aligning it horizontally across the bile duct. Ensure that the slices adequately cover the entire common bile duct and pancreatic duct. Use phase oversampling to prevent wrap-around artifacts. Instruct the patient to hold their breath during image acquisition.

MRCP planning and protocol of coronal haste thick slab radial scans

Parameters

TR

4000-5000

TE

500

FLIP

150

NEX

1

SLICE

40MM

MATRIX

320X320

FOV

300-400

PHASE

R>L

OVERSAMPLE

50%

IPAT

ON