Table 1.

Conventional and optional sequences for MRI in MS patients.

Contrast	Contrast mechanism	Sequence	Relevance for MS
T2-weighted	T2 (spin–spin or “transverse”) relaxation	(fast) spin echo or FLAIR, 2D or 3D	Detection of white matter abnormalities
T1-weighted	T1 (spin-lattice or “longitudinal”) relaxation	2D (fast) spin echo at lower field strength, 3D gradient echo at higher field strengths (≥3 T)	Detection of acute contrast enhancing lesions, assessment of more severe tissue damage (“black holes” and atrophy)
DIR	Two consecutive inversion radiofrequency pulses act as a T1-filter	2D or 3D (fast) spin echo	Detection of cortical lesions
Susceptibility-based imaging	Paramagnetic shifts due to iron deposits and deoxygenized blood	T2∗-weighted gradient echo sequences, with different acquisition modalities, such as 3D spoiled gradient echo or 3D echo planar imaging (low flip angle, echo time 20–30 ms)	Detection of central vein in MS lesions and iron rims
Magnetization transfer	Proportion of macromolecular bound protons and rate of exchange with tissue water	3D spoiled gradient echo (low flip angle, short echo time) sequence needs to be performed with and without MT saturation pulse	Reduced MT ratio is considered as a marker for demyelination
Diffusion weighted	Restriction of water mobility and orientational effects	Spin echo sequence with diffusion sensitizing gradient and echo planar readout	Sensitive for microstructural damage, higher diffusion models offer more specific assessment

Abbreviations: 2D, two-dimensional; 3D, three-dimensional; DIR, double inversion recovery; FLAIR, fluid-attenuated inversion recovery; MRI, magnetic resonance imaging; MS, multiple sclerosis; MT, magnetization transfer.