Korean J Radiol.  2016 Dec;17(6):903-911. 10.3348/kjr.2016.17.6.903.

Interobserver and Test-Retest Reproducibility of T1ρ and T2 Measurements of Lumbar Intervertebral Discs by 3T Magnetic Resonance Imaging

• Yoo YH
• Yoon CS
• Eun NL
• Hwang MJ
• Yoo H
• Peters RD
• Chung TS
• Lee YH
• Suh JS
• Kim S

• KMID: 2466287
• DOI: http://doi.org/10.3348/kjr.2016.17.6.903

Abstract

OBJECTIVE
To investigate the interobserver and test-retest reproducibility of T1ρ and T2 measurements of lumbar intervertebral discs using 3T magnetic resonance imaging (MRI).
MATERIALS AND METHODS
This study included a total of 51 volunteers (female, 26; male, 25; mean age, 54 ± 16.3 years) who underwent lumbar spine MRI with a 3.0 T scanner. Amongst these subjects, 40 underwent repeat T1ρ and T2 measurement acquisitions with identical image protocol. Two observers independently performed the region of interest measurements in the nuclei pulposi of the discs from L1-2 through L5-S1 levels. Statistical analysis was performed using intraclass correlation coefficient (ICC) with a two-way random model of absolute agreement. Comparison of the ICC values was done after acquisition of ICC values using Z test. Statistical significance was defined as p value < 0.05.
RESULTS
The ICCs of interobserver reproducibility were 0.951 and 0.672 for T1ρ and T2 mapping, respectively. The ICCs of test-retest reproducibility (40 subjects) for T1ρ and T2 measurements were 0.922 and 0.617 for observer A and 0.914 and 0.628 for observer B, respectively. In the comparison of the aforementioned ICCs, ICCs of interobserver and test-retest reproducibility for T1ρ mapping were significantly higher than T2 mapping (p < 0.001).
CONCLUSION
The interobserver and test-retest reproducibility of T1ρ mapping were significantly higher than those of T2 mapping for the quantitative assessment of nuclei pulposi of lumbar intervertebral discs.

Keyword

T1 rho; Intervertebral disc; Reproducibility; Magnetic resonance imaging; T2 mapping; Disc degeneration

MeSH Terms

Adult
Aged
Female
Humans
Intervertebral Disc/diagnostic imaging
Intervertebral Disc Degeneration/*diagnosis/diagnostic imaging/pathology
Lumbar Vertebrae/diagnostic imaging
*Magnetic Resonance Imaging
Male
Middle Aged
Nucleus Pulposus/diagnostic imaging
Prospective Studies
Reproducibility of Results
Severity of Illness Index