T1ρ, T2 and T2* mapping of lumbar intervertebral disc degeneration: a comparison study

Abstract

Background Early and accurate assessment of lumbar intervertebral disc degeneration (IVDD) is very important to therapeutic strategy. This study aims to correlate and compare the performances of T1ρ, T2 and T2* mapping for Pfirrmann grades and morphologic changes in the IVDD. Methods This prospective study included 39 subjects with 195 lumbar discs. T1ρ, T2 and T2* mapping were performed, and T1ρ, T2 and T2* values of nucleus pulposus (NP), and anterior and posterior annulus fibrosus were measured. IVDD was assessed with Pfirrmann grading and morphologic changes (normal, bulging, herniation and annular fissure). The performances of T1ρ, T2 and T2* relaxation times were compared for detecting early (Pfirrmann grade II-III) and advanced degeneration (Pfirrmann grade IV–V), as well as for morphologic changes. Results T2 relaxation times was strongly corelated with T1ρ and T2* relaxation times. Areas under the curves (AUCs) of T1ρ, T2 and T2* relaxation times of NP were 0.70, 0.87 and 0.80 for early degeneration, and 0.91, 0.95 and 0.82 for advanced degeneration, respectively. AUCs of T1ρ, T2 and T2* relaxation times of NP were 0.78, 0.83 and 0.64 for bulging discs, 0.87, 0.89 and 0.69 for herniated discs, and 0.79, 0.82 and 0.69 for annular tearing, respectively. The AUC of T2 relaxation time was significantly higher than those of T1ρ relaxation times (both P < 0.01) for early IVDD, and the AUCs of T1ρ and T2 relaxation times for assessing advanced degeneration and morphologic changes were similar (P > 0.05) but significantly higher than that of T2*relaxation time (P < 0.01). Conclusions T2 mapping performed better than T1ρ mapping for the detection of early IVDD. T1ρ and T2 mapping performed similarly but better than T2* mapping for advanced degeneration and morphologic changes of IVDD.

Apparent diffusion coefficient and T2* mapping on 3T MRI in normal and degenerative lumbar intervertebral discs

“…Yang et al . described a strong fundamental correlation between relaxation times of T2 and T2* because both are associated with PG and water content [ 37 ]. T2 relaxation times that correlate with the structural integrity of IVDs show differences in different ROIs of disc and reduction in DD across grades due to dehydration and variations in biochemical compositions like reduced water and glycosaminoglycan content in various stages of degeneration [ 38 - 40 ].…”

“…T2* mapping does not differ extensively from T2 mapping, and it depicts the same microstructural changes within IVDs with shorter imaging time; however, T2* is more likely to be affected by susceptibility field artefacts. Yang et al described a strong fundamental correlation between relaxation times of T2 and T2* because both are associated with PG and water content [37]. T2 relaxation times that correlate with the structural integrity of IVDs show differences in different ROIs of disc and reduction in DD across grades due to dehydration and variations in biochemical compositions like reduced water and glycosaminoglycan content in various stages of degeneration [38][39][40].…”

A new four-area method for evaluating biochemical changes in lumbar facet joint degeneration at T2* mapping

“…With the development of MRI protocols over the past two decades, researchers have recently shown increased interests in biochemical quantitative imaging techniques [8][9][10][11] . Among which T2* value generated from T2* mapping re ects the "true" transverse relaxation time and decrease with an increase in cartilage degeneration 12 13 .…”