From the Guidelines
T2 FLAIR is a crucial MRI sequence for detecting lesions adjacent to CSF spaces, and its inclusion in brain MRI protocols is highly recommended due to its high sensitivity for pathological changes. This technique is particularly valuable for detecting lesions in conditions such as multiple sclerosis, stroke, demyelinating diseases, infections, and inflammatory processes 1. The T2 FLAIR sequence works by combining a T2-weighted sequence with an inversion recovery pulse that nullifies the signal from free water, making fluid appear dark while abnormal tissues appear bright.
Some key points to consider when using T2 FLAIR include:
- The typical acquisition time for a T2 FLAIR sequence is 3-5 minutes, which is a relatively short period compared to other MRI sequences 1.
- T2-weighted FLAIR techniques increase lesion conspicuity, allowing for better visualization of vasogenic edema, surgery-induced and radiation-induced gliosis, and infiltrating tumor, particularly near the cortex and ventricles where cerebrospinal fluid can inhibit lesion detection 1.
- The recommended protocol for T2-weighted FLAIR imaging includes a slice thickness of 3 mm with no interslice gap for 3 T scans, and 1.5 T scanners should acquire images up to 4 mm slice thickness with no interslice gap 1.
In terms of clinical implementation, the inclusion of T2 FLAIR in brain MRI protocols can significantly improve the detection of pathological changes, particularly in conditions such as multiple sclerosis. As noted in the Magnims consensus guidelines, a standardized brain MRI protocol that includes T2 FLAIR can help to ensure a minimum delay of 5 min between gadolinium injection and acquisition of the T1-weighted sequence, which is essential for accurate diagnosis 1. Overall, T2 FLAIR is a valuable tool for clinicians, and its use can significantly improve patient outcomes by enabling earlier and more accurate diagnosis of a range of neurological conditions.
From the Research
MRI T2 Flair Overview
- MRI T2 Flair is a type of magnetic resonance imaging sequence used to detect and characterize lesions in the brain, particularly in multiple sclerosis (MS) and other neurological conditions 2, 3, 4, 5, 6.
- The T2 Flair sequence is designed to suppress signal from fluids, such as cerebrospinal fluid, and highlight lesions in the brain tissue.
Clinical Applications
- In MS, T2 Flair is used to quantify disease pathology and predict disease progression 2.
- In high-grade gliomas, T2 Flair and T2 weighted MRIs are used to delineate tumor volumes and surrounding edema for radiation treatment planning 3.
- T2 Flair is also used to detect cortical and leucocortical lesions in MS patients, with improved lesion visibility compared to T2 weighted images 4.
Technical Aspects
- The T2 Flair sequence can be combined with other MRI sequences, such as T2 weighted images, to improve lesion detection and characterization 4.
- Post-processing techniques, such as FLAIR2, can be applied to T2 Flair images to enhance lesion visibility and improve diagnostic accuracy 4.
- The T2 Flair mismatch sign is a radiogenomic marker that can be used to diagnose IDH-mutant diffuse astrocytoma with high specificity 6.
Research Findings
- Studies have shown that T2 Flair measures can substitute for standard research-quality MRI measures in predicting neurologic disability and disease progression in MS patients 2.
- The use of T2 Flair and T2 weighted MRIs can result in different tumor volumes and locations, which can impact radiation treatment planning and clinical trials 3.
- T2 weighted difference imaging can provide a more sensitive measure of disease activity in MS patients, by separately measuring new and resolving T2 weighted lesions 5.