Brain MRI scan protocols, positioning and planning

Summary

This script outlines the procedure for conducting a brain MRI scan, emphasizing patient safety and comfort. It details the setup, including positioning the patient and using a head coil and emergency buzzer. The script also explains the importance of accurate patient details for dosage calculation and describes the planning of various imaging sequences, including axial, coronal, and sagittal views. It further discusses the significance of different MRI sequences like T1, T2, FLAIR, diffusion, and post-contrast scans in identifying brain pathologies.

Takeaways

• 🛡️ Safety checks are essential before bringing the patient into the scanner room.
• 🛏️ Position the patient supine with their head in the head coil for proper scanning.
• 🚨 Provide an emergency buzzer and ensure the patient knows how to use it for safety.
• 🎧 Use headphones to protect the patient's ears from scanner noise.
• 🔬 Center the head coil to the glabella and carefully move the patient into the scanner.
• 📋 Verify patient details in the control room, including weight for accurate dosage calculations.
• 📚 Select the correct protocol based on hospital and radiologist guidelines.
• 📐 Plan the initial scout or localizer sequence in three planes for accurate brain imaging.
• 🧠 Ensure the axial sequence slices cover the brain from vertex to below the foramen magnum.
• 🔄 Plan subsequent sequences, including T1 and axial, by copying and adjusting from the initial plan.
• 💉 If a gadolinium injection is requested, check the patient's kidney function before proceeding.
• 📈 Post-contrast sequences can be planned by copying pre-contrast T1 and coronal sequences.
• 🔍 Review images during the scan to identify pathologies, with T2 showing bright fluids and most pathologies.
• 🌐 FLAIR sequences differentiate pathologies by showing dark fluids and bright pathologies.
• 🎛️ T1 sequences show dark fluids, bright fat, and dark pathologies, aiding in diagnosis.
• 🚨 ADC maps in diffusion sequences highlight areas of restricted diffusion, such as strokes, by appearing dark.

Q & A

What is the initial position a patient should be in when entering the MRI scanner room?

The patient should lie supine on the bed with their head in the head coil.

What safety measure is provided to the patient inside the MRI scanner room?

An emergency buzzer is provided to the patient to use in case of any issues during the scan.

Why are headphones given to the patient during the MRI scan?

Headphones are provided to protect the patient's ears from the loud noises produced during the MRI scanning process.

What is the importance of centering the head coil to the glabella when preparing for an MRI scan?

Centering the head coil to the glabella ensures accurate positioning and alignment for the MRI scan, which is crucial for obtaining clear and precise images.

Why is it essential to verify the patient's details in the control room before starting the MRI scan?

Verifying the patient's details ensures that the correct patient is being scanned and that the appropriate imaging protocols are followed, including the accurate calculation of the contrast dosage based on the patient's weight.

What is the purpose of an initial Scout or localizer sequence in an MRI scan?

The initial Scout or localizer sequence helps in planning the axial sequence in all three planes, ensuring proper coverage and positioning of the slices for the subsequent MRI sequences.

How should the slices be aligned in the sagittal localizer for optimal brain imaging?

The slices should pass parallel to a line joining the inferior border of the genu of the corpus callosum and the splenium, covering the brain from the vertex to below the foramen magnum.

What is the significance of planning the coronal sequence on all three localizer planes?

Planning the coronal sequence on all three localizer planes ensures that the slices run perpendicular to the line from the genu to the splenium of the corpus callosum, covering the entire brain from the frontal sinus to the posterior occipital lobe.

Why is it necessary to check a patient's kidney function before administering gadolinium for a contrast MRI scan?

Checking kidney function is necessary because gadolinium-based contrast agents can be nephrotoxic, and it's important to ensure it's safe for the patient to receive the contrast based on their kidney function and hospital guidelines.

What is the difference between T2 and FLAIR sequences in MRI imaging?

In T2 sequences, fluids and most pathologies appear bright, while in FLAIR sequences, fat appears bright but fluid appears dark, making it useful for showing pathologies close to the ventricles and sulci where CSF is bright on normal T2 sequences.

How does the appearance of fluids, fat, and pathologies differ in T1 sequences compared to T2 sequences?

In T1 sequences, fluids appear dark, fat is bright, and most pathologies appear dark, which is the opposite of T2 sequences where fluids and most pathologies appear bright.

What does the ADC or apparent diffusion coefficient map show in the context of diffusion MRI sequences?

The ADC map shows areas of restricted diffusion, such as strokes, appearing dark, which helps in identifying regions with limited water molecule movement.