Log subtracted inversion recovery

Abstract

Magnetic resonance imaging (MRI) techniques have recently been developed for obtaining high T₁ contrast images using inversion recovery (IR) images at two inversion times (TIs) rather than a single TI. They use simple mathematical operations - multiplication, addition, subtraction, division - to create images not attainable by conventional IR. The present study describes a novel two-point IR technique formed by the subtraction of log images. Results show it has a near-linear response to T₁ between the nullpoints that peaks sharply at the nullpoints. This produces a bright isoT₁ contour at interfaces between tissues where partial volume mixing generates specific T₁s. This can provide anatomical information in areas where the signal is not well-differentiated on conventional images.

Keywords: FLAWS; Inversion recovery; MP2RAGE; T1 mapping; dSIR.