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MRI Internal Auditory Meatus(IAM'S)

Indications for internal auditory meatus(iams) MRI scan

Contraindications of internal auditory meatus (iams) MRI scan

Patient preparation internal auditory meatus(iams) MRI scan

Positioning

MRI Internal Auditory Meatus(IAM'S) scan positioning

Recommended MRI IAM'S Protocols, Parameters and Planning

localiser

A three-plane localizer must be taken at the beginning to localize and plan the sequences. Localizers are usually less than 25 seconds and are T1-weighted low-resolution scans.

T2 tse axial 5mm

Plan the axial slices on the sagittal plane and position the block parallel to the genu and splenium of the corpus callosum. Verify the planning block in the other two planes and ensure that an appropriate angle is maintained in the coronal plane, making it perpendicular to the line of the midline of the brain and the 4th ventricle. Ensure that the number of slices is sufficient to cover the entire brain from the vertex to the line of the foramen magnum.

mri brain protocol and planning of axial scans

Parameters

TR

3000-4000

TE

100-120

SLICE

5MM

FLIP

130-150

PHASE

R>L

MATRIX

320X320

FOV

210-230

GAP

10%

NEX(AVRAGE)

2

T2 TSE coronal 3mm

Plan the coronal slices on the axial plane and angle the planning block parallel to the line along the right and left Internal Auditory Meatus (IAMS) (as shown in the diagram). Verify the planning block in the other two planes. Ensure an appropriate angle is maintained in the sagittal plane, parallel to the brain stem. The number of slices should be sufficient to cover the IAMS from the posterior border of the sphenoid sinus up to the line of the fourth ventricle.These coronal T2 scans are performed to aid in the planning of axial 3D scans.

mri planing and protocol of Internal Auditory Meatus (IAMS) coronal planning

Parameters

TR

3000-4000

TE

110

FLIP

130

NEX

2

SLICE

3MM

MATRIX

256X256

FOV

150-180

PHASE

R>L

GAP

10%

SLICE

10-20%

3D SPACE (3D CISSor 3DFIESTA) axial .5mm

Plan the axial slices on the coronal plane and angle the planning block parallel to the line along the right and left internal auditory meatus (IAMS), as shown in the diagram. Verify the planning block in the other two planes. Ensure an appropriate angle is maintained in the sagittal plane, perpendicular to the brain stem. The number of slices should be sufficient to cover the IAMS from the hippocampus up to the line of the C1 vertebral body.

mri planing of iam axial cissor SPACE 3D

Parameters CISS

TR

12-15

TE

6-7

SLICE

.8mm

FLIP

80

PHASE

R>L

MATRIX

384X320

FOV

210-230

GAP

10%

NEX(AVRAGE)

1

T1 pre contrast and post contrast scans are only required in case of tumor present in internal auditory canal.

T1 TSE coronal 2mm

Plan the coronal slices on the axial plane and angle the planning block parallel to the line along the right and left Internal Auditory Meatus (IAMS) (as shown in the diagram). Verify the planning block in the other two planes. Ensure an appropriate angle is maintained in the sagittal plane, parallel to the brain stem. The number of slices should be sufficient to cover the IAMS from the posterior border of the sphenoid sinus up to the line of the fourth ventricle.These coronal T2 scans are performed to aid in the planning of axial 3D scans.

MRI planing and protocol of iam coronal T1 scans

Parameters

TR

400-500

TE

15

FLIP

150

NXA

4

SLICE

2MM

MATRIX

256X256

FOV

150-180

PHASE

R>L

GAP

10%

SLICE

10-20%

T1 TSE axial 2mm

Plan the axial slices on the coronal plane and angle the planning block parallel to the line along the right and left internal auditory meatus (IAMS), as shown in the diagram. Verify the planning block in the other two planes. Ensure an appropriate angle is maintained in the sagittal plane, perpendicular to the brain stem. The number of slices should be sufficient to cover the IAMS from the hippocampus up to the line of the C1 vertebral body.

MRI planing of iam axial T1 scans

Parameters

TR

400-600

TE

150

SLICE

2mm

FLIP

90

PHASE

R>L

MATRIX

256X256

FOV

170-180

GAP

10%

NXA(AVRAGE)

4

Use T1 tse fat saturated sequences  in both axial and coronal planes after the administration of IV gadolinium DTPA injection (copy the planning outlined above).The document below provides access to the recommended dosage of gadolinium DTPA injection as advised by the manufacturer.