mrimaster

MRI Kidneys (Renal MRI)

Indications for MRI kidney scan

Contraindications

Patient preparation for MRI kidney scan

Positioning for MRI kidney scan

MRI kidneys positioning image

Recommended MRI kidney Protocols, Parameters, and Planning

MRI Kidney 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.

mri kidney scan localiser image

T2 HASTE\t2 tse coronal 4mm

Plan the coronal slices on the axial plane and angle the positioning block parallel to the right and left kidneys. Check the positioning block in the other two planes. Provide an appropriate angle in the sagittal plane (parallel to the long axis of the kidney). Ensure that the slices are sufficient to cover both kidneys from anterior to posterior. Phase oversampling must be used to avoid wrap-around artifacts. Instruct the patient to hold their breath during image acquisition. (In our department, we instruct patients to take two breaths in and out before giving the instruction to ‘breathe in and hold’.)

mri kidneys planning of coronal images

Parameters haste

TR

2000-2500

TE

90-110

FLIP

130

NEX

1

SLICE

4MM

MATRIX

320×256

FOV

300

PHASE

R>L

OVERSAMPLE

50%

TRIGGER

NO

Parameters t2 tse

TR 5000-6000

TE

150

FLIP

150

NEX

1

SLICE

4MM

MATRIX

256×224

FOV

300

PHASE

R>L

OVERSAMPLE

50%

IPAT

ON

T1 vibe DIXON breath hold coronal 4mm

Plan the coronal slices on the axial plane and angle the positioning block parallel to the right and left kidneys. Check the positioning block in the other two planes. An appropriate angle must be given in the sagittal plane, parallel to the long axis of the kidneys. Ensure that the slices are sufficient to cover both kidneys from anterior to posterior. Phase oversampling and slice oversampling must be used to avoid wrap-around artifacts. Instruct the patient to hold their breath during image acquisition. In our department, we instruct patients to breathe in and out twice before giving the ‘breathe in and hold’ instruction.

mri kidney scan coronal planning and protocol image

Parameters VIBE dixon

TR

6-7

TE

2.39   4.77

FLIP

10

NXA

1

SLICE

4 MM

MATRIX

320×320

FOV

320-350

PHASE

A>P

OVERSAMPLE

20%

BH

YES

T2 tse\haste breath hold 4mm axial

Plan the axial slices on the coronal plane; angle the position block parallel to the right and left renal pelvis. Check the positioning block in the other two planes. An appropriate angle must be given in the sagittal plane (perpendicular to the long axis of kidney). Slices must be sufficient to cover both kidneys from two slices above the upper pole of kidneys down to two slices below the lower pole of kidney. Phase oversampling and, in the case of 3D blocks, slice oversample, must be used to avoid wrap around artefacts. Consider adding saturation bands at the top and bottom of the block to minimize artifacts caused by fat signal, arterial pulsation, and breathing. Instruct the patient to hold their breath during image acquisition.

mri kidneys planning of axial images

When planning the axial breath-hold scans, it is crucial to utilize the breath-hold vibe coronal sequence. This is because during inhalation, the diaphragm exerts downward pressure on the liver, causing a shift in its position from the initial localizer scans. Therefore, to accurately capture the desired imaging area of the liver, it is important to account for this positional change by utilizing the breath-hold vibe coronal sequence.

Parameters haste

TR

2000-2500

TE

90-110

FLIP

130

NEX

1

SLICE

4MM

MATRIX

320×256

FOV

300

PHASE

R>L

OVERSAMPLE

50%

TRIGGER

NO

Parameters t2 tse

TR 5000-6000

TE

150

FLIP

150

NEX

1

SLICE

4MM

MATRIX

256×256

FOV

280-300

PHASE

A>P

OVERSAMPLE

80%

IPAT

ON

T2 tse\haste fat sat breath hold 4mm axial

Plan the axial slices on the coronal plane; angle the position block parallel to the right and left renal pelvis. Check the positioning block in the other two planes. An appropriate angle must be given in the sagittal plane (perpendicular to the long axis of kidney). Slices must be sufficient to cover both kidneys from two slices above the upper pole of kidneys down to two slices below the lower pole of kidney. Phase oversampling and, in the case of 3D blocks, slice oversample, must be used to avoid wrap around artefacts. Consider adding saturation bands at the top and bottom of the block to minimize artifacts caused by fat signal, arterial pulsation, and breathing. Instruct the patient to hold their breath during image acquisition.

mri kidneys planning of axial images

Parameters HASTE FAT SAT

TR

2000-2500

TE

90-110

FAT SAT

SPAIR

NEX

1

SLICE

4MM

MATRIX

320×256

FOV

300

PHASE

R>L

OVERSAMPLE

50%

TRIGGER

NO

Parameters T2 FAT SAT

TR 6000-7000

TE

150

FAT SAT

SPAIR

NEX

1

SLICE

4MM

MATRIX

256×208

FOV

280-300

PHASE

A>P

OVERSAMPLE

80%

IPAT

ON

DWI epi 3 scan trace axial 3mm free breathing

Plan the axial slices on the coronal free-breathing localizer; angle the position block parallel to the right and left renal pelvis. Check the positioning block in the other two planes. An appropriate angle must be given in the sagittal plane (perpendicular to the long axis of kidney). Slices must be sufficient to cover both kidneys from two slices above the upper pole of kidneys down to two slices below the lower pole of kidney. Phase oversampling and, in the case of 3D blocks, slice oversample, must be used to avoid wrap around artefacts. Consider adding saturation bands at the top and bottom of the block to minimize artifacts caused by fat signal, arterial pulsation, and breathing.

Note: Scan must be planned in a free breathing localizer
mri kidneys planning of axial images

Parameters epI DWI

TR

6000-7000

TE

90

IPAT

ON

NEX

 3     5     8

SLICE

3 MM

MATRIX

192X192

FOV

200-250

PHASE

R>L

GAP

10%

B VALUE

0
500
1000

T1 VIBE DIXON 3mm axial BH pre GD(In-opposed phase and water sat)

Plan the axial slices on the coronal plane; angle the position block parallel to the right and left renal pelvis. Check the positioning block in the other two planes. An appropriate angle must be given in the sagittal plane (perpendicular to the long axis of kidney). Slices must be sufficient to cover both kidneys from two slices above the upper pole of kidneys down to two slices below the lower pole of kidney. Phase oversampling and, in the case of 3D blocks, slice oversample, must be used to avoid wrap around artefacts. Consider adding saturation bands at the top and bottom of the block to minimize artifacts caused by fat signal, arterial pulsation, and breathing. Instruct the patient to hold their breath during image acquisition.

mri kidney scan axial planning and protocol image

Parameters

TR

6-7

TE

2.39   4.77

FLIP

10

NXA

1

SLICE

3 MM

MATRIX

320×320

FOV

320-350

PHASE

A>P

OVERSAMPLE

20%

BH

YES

Now administer the IV gadolinium DTPA injection. The document below provides access to the recommended dosage of gadolinium DTPA injection as advised by the manufacturer.

contrast administration and timing of scans

Guess timing technique:-

This is one of the simplest methods. It works by estimating the time it takes for contrast to travel from the site of injection to the vascular structures of the liver. This technique is highly dependent on factors such as the site of contrast injection, patient’s age, cardiac output, and vascular anatomy. Generally, it takes about 18-25 seconds for the contrast to travel from the antecubital vein to the abdominal aorta and 45-60 seconds to reach the portal veins. Therefore, the first acquisition of the dynamic sequence should begin within 20 seconds of contrast administration.

Care bolus technique:-

The care bolus technique is the most commonly used method for bolus detection. This technique involves employing a coronal fast gradient refocused sequence to obtain real-time images every second through the vascular structure of interest, typically positioned over the heart. By monitoring the arrival of the contrast bolus in the heart, the operator can then switch to the centric 3D dynamic sequence for further imaging.

Planning care bolus

Plan the coronal care bolus slice on the sagittal plane. Position the block over the mid-heart and angle the slice parallel to the ascending aorta. Verify the position in the other two planes. Establish an appropriate angle in the axial plane, aligning it vertically across the liver.

Care bolus scans should commence one second before contrast administration. The operator can then observe the scans in real-time and monitor the arrival of the contrast bolus in the heart. Once the contrast reaches the heart, the care bolus should be promptly halted, and the patient should be instructed to hold their breath before initiating the centric 3D dynamic sequence.

T1 vibe dixon\ flash 3D fat sat axial breath hold dynamic 2 RUN

Plan the axial slices on the coronal plane; angle the position block parallel to the right and left renal pelvis. Check the positioning block in the other two planes. An appropriate angle must be given in the sagittal plane (perpendicular to the long axis of kidney). Slices must be sufficient to cover both kidneys from two slices above the upper pole of kidneys down to two slices below the lower pole of kidney. Phase oversampling and, in the case of 3D blocks, slice oversample, must be used to avoid wrap around artefacts. Consider adding saturation bands at the top and bottom of the block to minimize artifacts caused by fat signal, arterial pulsation, and breathing. Instruct the patient to hold their breath during image acquisition.

mri kidney scan axial planning and protocol image

A dynamic VIBE Dixon 3D sequence comprises two VIBE 3mm 3D scans with a 10-second delay between the first and second scans. The first scan captures the arterial phase, while the second scan captures the venous phase. Timing for each scan is crucial. Proper breathing instructions should be given during both scans. After the arterial phase scan, the patient should be instructed to breathe normally, and then asked to hold their breath when there are approximately 4 seconds remaining for the venous scan.

Alternatively, the post-contrast dynamic scans can be performed by splitting the sequence into two separate scans and conducting them individually according to their respective timelines. In our department, we prefer to perform them separately.

Some radiologists prefer to generate subtraction images between the pre-contrast and post-contrast images. To enable image subtraction, it is essential that the measurements of pre- and post-contrast T1 scans are identical. Any variations in slice thickness, field of view (FOV), or planning would impede the ability to perform image subtraction.

Arterial and venous phase timing of kidney mri scan

Parameters FLASH

TR 4-5

TE

2

FAT SAT

ON

NEX

1

SLICE

3MM

MATRIX

320X320

FOV

350

PHASE

A>P

DYNAMIC

3 SCANS

IPAT

ON

Parameters VIBE DIXON

TR

6-7

TE

2.39   4.77

FLIP

10

NXA

1

SLICE

3 MM

MATRIX

320×320

FOV

320-350

PHASE

A>P

OVERSAMPLE

20%

BH

YES

T1 vibe DIXON breath hold coronal 4mm post contrast

Plan the coronal slices on the axial plane and angle the positioning block parallel to the right and left kidneys. Check the positioning block in the other two planes. An appropriate angle must be given in the sagittal plane, parallel to the long axis of the kidneys. Ensure that the slices are sufficient to cover both kidneys from anterior to posterior. Phase oversampling and slice oversampling must be used to avoid wrap-around artifacts. Instruct the patient to hold their breath during image acquisition. In our department, we instruct patients to breathe in and out twice before giving the ‘breathe in and hold’ instruction.

mri kidney scan coronal planning and protocol image

Parameters VIBE dixon

TR

6-7

TE

2.39   4.77

FLIP

10

NXA

1

SLICE

4 MM

MATRIX

320×320

FOV

320-350

PHASE

A>P

OVERSAMPLE

20%

BH

YES