High-resolution multi-T₁ -weighted contrast and T₁ mapping with low sensitivity using the fluid and white matter...

To demonstrate that fluid and white matter suppression (FLAWS) imaging can be used for high-resolution T₁ mapping with low transmitted bias field ( $$ ) sensitivity at 7T.

The FLAWS sequence was optimized for 0.8-mm isotropic resolution imaging. The theoretical accuracy and precision of the FLAWS T₁ mapping was compared with the one of the magnetization-prepared two rapid gradient echoes (MP2RAGE) sequence optimized for low $$ sensitivity. FLAWS images were acquired at 7T on six healthy volunteers (21 to 48 years old; two women). MP2RAGE and saturation-prepared with two rapid gradient echoes (SA2RAGE) datasets were also acquired to obtain T₁ mapping references and $$ maps. The contrast-to-noise ratio (CNR) between brain tissues was measured in the FLAWS-hco and MP2RAGE-uni images. The Pearson correlation was measured between the MP2RAGE and FLAWS T₁ maps. The effect of $$ on FLAWS T₁ mapping was assessed using the Pearson correlation.

The FLAWS-hco images were characterized by a higher brain tissue CNR ( $$ , $$ , $$ ) than the MP2RAGE-uni images ( $$ , $$ , $$ ). The theoretical accuracy and precision of the FLAWS T₁ mapping ( $$ ) were in agreement with those provided by the MP2RAGE T₁ mapping ( $$ ). A good agreement was found between in vivo T₁ values measured with the MP2RAGE and FLAWS sequences (r = 0.91). A weak correlation was found between the FLAWS T₁ map and the $$ map within cortical gray matter and white matter segmentations ( $$ ; $$ ).

The results from this study suggest that FLAWS is a good candidate for high-resolution T₁ -weighted imaging and T₁ mapping at the field strength of 7T.