The use of flair imaging in MRI for detecting meningeal lesions

Abstract

FLAIR1 is the acronym of Fluid Attenuated Inversion Recovery. T2-FLAIR2stands for Transverse relaxation time (T2)- Weighted- Fluid-Attenuated Inversion Recovery. Originally called simply “FLAIR” 3, this technique was developed at the beginning of the 90s by the research team Hammersmith led by Graeme Bydder, Joseph Hajnal e Ian Young. Their original sequences used Longitudinal Relaxation Time (T1) values of 2000-2500 for the nulled signal by Cerebrospinal Fluid (CSF), coupled with long Repetition Time (TR) (8000) and Echo Time (TE )(140) in order to develop a heavily weighted T24. The scope of this study is to analyse the characteristics of this magnetic resonance sequence after intravenous contrast administration; understand the benefits, its relation with contrast in T1-weighted (T1W) sequences and its weighting in the T2-weighted (T2W) sequences in order to hypothesize its eventual use in the standard study of the brain for some specific intracranial pathologies, setting it as the reference sequence as compared to the post-contrast T1-weighted sequence. A group of 20 patients, aged 20 to 60, which were affected by various intracranial diseases, such as eg.
Meningeal lesions were studied. We also carried out research and gathered data on the most important international databases (eg. Pub-Med and Science Direct). A study of the FLAIR sequences was performed in order to better outline post-contrast enhancement5.
In this study, the Contrast Enhanced Fluid Attenuated Inversion Recovery (CE-FLAIR) sequence was compared firstly with the FLAIR sequence and then with the T1W post-contrast sequence and we observed a strong enhancement post-contrast when compared with the Flair sequence. The CE-FLAIR sequence, differently from the Contrast Enhanced T1 Weighted Image (CE-T1WI), does not show enhanced contrast in the normal vascular structures and in the meninges, although the data collected and analyzed report that CE-FLAIR images are highly efficacious in the detection of infections, inflammations and in subarachnoid or meningeal metastasis that are adjacent to themselves on the border of the cerebrospinal fluid. We have therefore ascertained that the Contrast Enhanced T1  weighted (CE-T1W) sequence continues to be the par excellence post-contrast sequence in the Magnetic Resonance (MR) imaging in the majority of intracranial pathological disorders.