Ultrashort time-to-echo T2* and T2* relaxometry for evaluation of lumbar disc degeneration: a comparative study

Abstract

Background To compare potential of ultrashort time-to-echo (UTE) T2* mapping and T2* values from T2*-weighted imaging for assessing lumbar intervertebral disc degeneration (IVDD),with Pfirrmann grading as a reference standard. Methods UTE-T2* and T2* values of 366 lumbar discs (L1/2-L5/S1) in 76 subjects were measured in 3 segmented regions: anterior annulus fibrosus, nucleus pulposus (NP), and posterior annulus fibrosus. Lumbar intervertebral discs were divided into 3 categories based on 5-level Pfirrmann grading: normal (Pfirrmann grade I),early disc degeneration (Pfirrmann grades II-III), and advanced disc degeneration (Pfirrmann grades IV-V). Regional differences between UTE-T2* and T2* relaxometry and correlation with degeneration were statistically analyzed. Results UTE-T2* and T2*value correlated negatively with Pfirrmann grades (P < 0.001). In NP, correlations with Pfirrmann grade were high with UTE-T2* values (r = − 0.733; P < 0.001) and moderate with T2* values (r = -0.654; P < 0.001). Diagnostic accuracy of detecting early IVDD was better with UTE-T2* mapping than T2* mapping (P < 0.05),with receiver operating characteristic analysis area under the curve of 0.715–0.876. Conclusions UTE-T2* relaxometry provides another promising magnetic resonance imaging sequence for quantitatively evaluate lumbar IVDD and was more accurate than T2*mapping in the earlier stage degenerative process.

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

“…Our present finding is consistent with previous studies that T1ρ, T2 and T2* relaxation times of NP decreased linearly with increasing Pfirrmann grades [ 11 – 13 , 21 – 23 ]. Histologically, T1ρ is strong affinity with proteoglycan content in the disc matrix [ 13 ], T2 relaxation time has strong positive correlations with water and glycosaminoglycans content [ 19 ], and T2* relaxation time is highly correlated with glycosaminoglycan content [ 20 ].…”

“…The assessments included Pfirrmann classifications on sagittal T2-weighted images [ 8 ], as well as the presence of disc bulging, herniation (protrusion or extrusion) according to the Lumbar Disc Nomenclature 2.0 [ 27 ], and annular fissure with HIZ of PAF on sagittal and axial T2-weighted images according to Aprill and Bogduk [ 9 ]. For Pfirrmann grades, IVDD with Pfirrmann grade I was normal disc, IVDD with Pfirrmann grade II-III were labeled as early degeneration, and IVDD with Pfirrmann grades IV and V were labeled as advanced degeneration [ 23 ].…”

“…1 ). The anterior and posterior 20% of the disk diameter were labeled as AF with the remaining central 60% representing the NP [ 23 , 28 ]. Values of AAF and PAF were averaged as the value for the AF.…”

“…T1ρ mapping probes slow interactions between extracellular matrix macromolecules and bulk water by applying a “spin lock” pulse [ 19 ], while T2 and T2* relaxation times reflect the content and spatial distribution of macromolecule and water [ 19 , 20 ]. It has been demonstrated that T1ρ, T2 and T2* relaxation times are associated with glycosaminoglycan and water content [ 13 , 19 , 20 ], Pfirrmann grading [ 11 – 13 , 21 – 23 ], histological scores [ 17 , 20 , 21 ] and clinical symptom [ 24 , 25 ] of IVDD. T1ρ is reported to be strong affinity with proteoglycan content in the disc matrix [ 13 ], and its main relaxation induced by chemical exchange [ 14 ].…”

relationship between intervertebralis disc height and pfirrmann’s degenerative degree:

“…The MRI T2 sequence is used as an option in detecting disc degeneration because it is a sensitive sequence in detecting early stage conditions of disc degeneration, according to the findings of signal intensity which has a close relationship in Pfirrmann grading. (Ogon et al, 2021;Wu et al, 2022;Zheng et al, 2022) The results of the MRI scan produced comprehensive disc morphometric data for both male and female patient samples, measurements were made at all levels of the lumbar disc so that significant differences and relationships would be seen in each disc representing the population condition in both normal and lumbar discs. with HNP.…”