MRI Brain

Protocol sequences

Introduction

MRI brain scan is one of the routine examinations performed in MR imaging and is used to investigate the causes of symptoms including, but not limited to, headaches, dizziness, tumours, stroke, infections, psychological conditions, and trauma. Post-contrast imaging may be requested to assist in the diagnosis of infections, carcinomas, or for post-surgical assessment. In such cases, gadolinium-based contrast media are administered intravenously.

Patient preparation

• Ask the patient to remove metallic items such as jewellery and remove any clothing that contains ferromagnetic materials and change into a patient gown.
• Obtain MR safety consent after evaluating possible MR contraindications.
• Explain that gradient noise and couch movements are normal.
• Demonstrate how to use the nurse call system and explain when to use it.
• Explain the importance of remaining still during the scan.
• Help claustrophobic patients overcome their fear through demonstrations, or allow a companion to stay with the patient during the scan.
• Inform the patient of the expected duration of the scan.

Patient positioning

• Use the head coil for imaging and position the patient’s head centrally and symmetrically within the coil.
• Place soft pads on either side of the head to immobilize the head and reduce gradient noise.
• Position the patient’s limbs without forming body loops.

Explanation: Body loops may generate eddy currents, which can cause RF burns on the skin. Insulating soft pads may be used to break conductive loops that may form between the feet and thighs or between the trunk and the arm.

• Centre on the glabella.

Sequences in detail

I. T1_Sagittal_Brain

Planning

• Scan coverage: From Right temporal lobe to Left.
• Plan block Angulation: Align the slices parallel to the midsagittal plane (MSP) of the brain in both the coronal and axial planes.

Parameters

Purpose

• Anatomical evaluation.

II. T2_Axial_Brain

Planning

• Scan coverage: Vertex to foramen magnum.
• Plan block Angulation: Align the slices parallel to the line joining the genu and the splenium of the corpus callosum and, in the coronal plane, angle the slices perpendicular to the MSP of the brain.

Parameters

Purpose

• Anatomical evaluation.

III. T2_Coronal_Brain

Planning

• Scan coverage: From frontal sinus to occipital protuberance.
• Plan block Angulation: Align the slices parallel to the brainstem in the sagittal plane and perpendicular to the MSP in the axial plane.

Parameters

Purpose

• Anatomical evaluation.

IV. FLAIR_FS_Axial_Brain

Planning

• Scan coverage: Vertex to foramen magnum.
• Plan block Angulation: Align the slices parallel to the line joining the genu and the splenium of the corpus callosum and, in the coronal plane, angle the slices perpendicular to the MSP of the brain.

Parameters

Purpose

• Anatomical evaluation (white matter disorders).

V. DWI_Axial_Brain (with ADC)

Planning

• Scan coverage: Vertex to foramen magnum.
• Plan block Angulation: Align the slices parallel to the line joining the genu and the splenium of the corpus callosum and, in the coronal plane, angle the slices perpendicular to the MSP of the brain.

Parameters

Purpose

• Assessment of infarction, abscess, dermoid or epidermoid, active demyelination and hypercellular neoplasm.

VI. SWI_Axial_Brain

Planning

• Scan coverage: Vertex to foramen magnum
• Plan block Angulation: Align the slices parallel to the line joining the genu and the splenium of the corpus callosum and, in the coronal plane, angle the slices perpendicular to the MSP of the brain.

Parameters

Purpose

• Detection of calcifications, microhemorrhages and intravascular thrombosis

Reference

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