Comprehensive assessment of lumbar spine intervertebral discs using a 3D adiabatic T prepared ultrashort echo time (UTE-Adiab-T) pulse sequence.

Background: T has been extensively reported as a sensitive biomarker of biochemical changes in the nucleus pulposus (NP) and annulus fibrosis of intervertebral discs (IVDs). However, no T study of cartilaginous endplates (CEPs) has yet been reported because the relatively long echo times (TEs) of conventional clinical T sequences cannot effectively capture the fast-decaying magnetic resonance signals of CEPs, which have very short T/T*s. This can be overcome by using ultrashort echo time (UTE) T acquisitions.

Methods: Seventeen subjects underwent UTE with adiabatic T preparation (UTE-Adiab-T) and T-weighted fast spin echo imaging of their lumbar spines. Each IVD was manually segmented into seven regions (i.e., outer anterior annulus fibrosis, inner anterior annulus fibrosis, outer posterior annulus fibrosis, inner posterior annulus fibrosis, superior CEP, inferior CEP, and NP). T values of these sub-regions were correlated with IVD modified Pfirrmann grades and subjects' ages. In addition, T values were compared in subjects with and without low back pain (LBP).

Results: Correlations of T values of the outer posterior annulus fibrosis, superior CEP, inferior CEP, and NP with modified Pfirrmann grades were significant (P<0.05) with R values of 0.51, 0.36, 0.38, and -0.94, respectively. Correlations of T values of the outer anterior annulus fibrosis, outer posterior annulus fibrosis, and NP with ages were significant with R equal to 0.52, 0.71, and -0.76, respectively. T differences of the outer posterior annulus fibrosis, inferior CEP, and NP between the subjects with and without LBP were significant (P=0.005, 0.020, and 0.000, respectively).

Conclusions: The UTE-Adiab-T sequence can quantify T of whole IVDs including CEPs. This is an advance, and of value for comprehensive assessment of IVD degeneration.