Asian Spine J.  2018 Apr;12(2):317-324. 10.4184/asj.2018.12.2.317.

Evaluation of Lumbar Intervertebral Disc Degeneration Using T1ρ and T2 Magnetic Resonance Imaging in a Rabbit Disc Injury Model

• Ishikawa T
• Watanabe A
• Kamoda H
• Miyagi M
• Inoue G
• Takahashi
• Ohtori S

• KMID: 2410852
• DOI: http://doi.org/10.4184/asj.2018.12.2.317

Abstract

STUDY DESIGN: An in vivo histologic and magnetic resonance imaging (MRI) study of lumbar intervertebral disc (IVD) degeneration was conducted. PURPOSE: To clarify the sensitivity and efficacy of T1ρ/T2 mapping for IVD degeneration, the correlation between T1ρ/T2 mapping and degenerative grades and histological findings in the lumbar IVD were investigated. OVERVIEW OF LITERATURE: The early signs of IVD degeneration are proteoglycan loss, dehydration, and collagen degradation. Recently, several quantitative MRI techniques have been developed; T2 mapping can be used to evaluate hydration and collagen fiber integrity within cartilaginous tissue, and T1ρ mapping can be used to evaluate hydration and proteoglycan content.
METHODS
Using New Zealand White rabbits, annular punctures of the IVD were made 10 times at L2/3, 5 times at L3/4, and one time at L4/5 using an 18-gauge needle (n=6) or a 21-gauge needle (n=6). At 4 and 8 weeks post-surgery, MRI was performed including T1ρ and T2 mapping. The degree of IVD degeneration was macroscopically assessed using the Thompson grading system. All specimens were cut for hematoxylin and eosin, safranin-O, and toluidine blue staining.
RESULTS
Disc degeneration became more severe as the number of punctures increased and when the larger needle was used. T1ρ and T2 values were significantly different between grade 1 and grade 3 IVDs, grade 1 and grade 4 IVDs, grade 2 and grade 3 IVDs, and grade 2 and grade 4 IVDs (p < 0.05). There was a significant difference between grade 1 and grade 2 IVDs only in terms of T1ρ values (p < 0.05).
CONCLUSIONS
T1ρ and T2 quantitative MRI could detect these small differences. Our results suggest that T1ρ and T2 mapping are sensitive to degenerative changes of lumbar IVDs and that T1ρ mapping can be used as a clinical tool to identify early IVD degeneration.

Keyword

Intervertebral disc degeneration; Magnetic resonance imaging; Animal experiment; Histology

MeSH Terms

Animal Experimentation
Collagen
Dehydration
Eosine Yellowish-(YS)
Hematoxylin
Intervertebral Disc Degeneration*
Intervertebral Disc*
Magnetic Resonance Imaging*
Needles
Proteoglycans
Punctures
Rabbits
Tolonium Chloride
Collagen
Eosine Yellowish-(YS)
Hematoxylin
Proteoglycans
Tolonium Chloride