Recommended MRI Brain Sequences for Comprehensive Assessment
A comprehensive brain MRI protocol should include T2-weighted sequences, contrast-enhanced T1-weighted sequences, FLAIR sequences, and diffusion-weighted imaging to ensure optimal detection of pathology while maintaining reasonable acquisition times. 1
Core MRI Brain Protocol
Essential Sequences
- Axial T2-weighted sequences (conventional or fast spin-echo) - considered the reference standard for detecting focal lesions regardless of location 1
- Axial FLAIR (Fluid-Attenuated Inversion Recovery) - improves detection of juxtacortical and periventricular lesions 1
- Axial diffusion-weighted imaging (DWI) - essential for detecting acute ischemic changes and certain tumors 1
- Pre-contrast T1-weighted sequences - provides baseline for contrast enhancement assessment 1
- Post-contrast T1-weighted sequences - mandatory when lesions are detected on T2-weighted sequences 1
Technical Parameters
- Magnetic field strength: minimum 1.5T (preferably 3.0T) 1
- Maximum slice thickness: 3mm 1
- In-plane spatial resolution: 1 × 1 mm (voxel size 3 × 1 × 1 mm) 1
- Total acquisition time: 25-30 minutes 1
Sequence Acquisition Planes
- T2-weighted sequences should be acquired in at least two planes 1
- Axial T2 and proton-density (and/or T2-FLAIR) combined with sagittal T2-FLAIR is recommended as the best strategy 1
- This approach allows comparison of at least two different T2 sequences in the same plane 1
Contrast Administration
- Gadolinium dose: 0.1 mmol/kg body weight 1
- Minimum delay time of 5 minutes between gadolinium injection and T1-weighted sequence acquisition 1
- The "dead time" during contrast delay can be used to perform T2-FLAIR sequences to optimize total acquisition time 1
Optional/Additional Sequences
- 3D T1-weighted sequences (pre and post-contrast) - provides high-resolution isotropic images 1
- Dual inversion recovery sequences - improves detection of cortical lesions 1
- Single-slab isotropic 3D T2-FLAIR (voxel size = 1 mm³) - could replace 2D T2-FLAIR sequences in some cases 1
Disease-Specific Considerations
For Multiple Sclerosis Assessment
- Axial T2 and proton-density sequences are essential for detecting white matter lesions 1
- Sagittal T2-FLAIR helps evaluate corpus callosum involvement 1
- Post-contrast T1-weighted imaging helps distinguish acute from chronic lesions 1
For Brain Tumor Evaluation
- Pre and post-contrast T1-weighted sequences 1
- T2-weighted and FLAIR sequences 1
- Diffusion-weighted imaging 1
- Consider 3D T1-weighted IR-GRE sequences for better tumor visualization 1
Common Pitfalls and Considerations
- 2D T2-FLAIR sequences are less sensitive for infratentorial lesions but better for juxtacortical and periventricular lesions 1
- Flow-related artifacts can occur in the posterior fossa and anterior temporal lobes, requiring careful interpretation 1
- For longitudinal studies, use the same equipment and protocol to ensure comparability 2
- MRI for neuronavigation purposes should be obtained no more than 7 days before surgical tumor resection 1
By following this standardized protocol, clinicians can ensure comprehensive assessment of brain pathology while maintaining reasonable acquisition times and optimizing diagnostic yield.