• Hamm, Bernd
• Braun, Jürgen
• Diederichs, Gerd
• Streitberger, Kaspar-Josche
• Guo, Jing
• Sack, Ingolf
• Fehlner, Andreas

Abstract

PurposeTo test in vivo magnetic resonance elastography (MRE) of the human intervertebral disk (IVD).MethodsThe feasibility of MRE in IVD was demonstrated in ex vivo bovine disks. Sixteen asymptomatic volunteers underwent multifrequency MRE of the lumbar spine (IVD L3/4 and L4/5, n = 32) using a posterior plate transducer connected to a loudspeaker and operated at five frequencies from 50 to 70 Hz. Full wave field data were acquired in 10 transverse slices of 2 × 2 × 2 mm3 resolution. High-resolution maps of magnitude |G*| and phase angle φ of complex shear modulus G* were generated by multifrequency dual elasto visco (MDEV) inversion. Disk morphology was assessed by the Pfirrmann score (Pf).ResultsMorphological Pf was 1 in 25, 2 in 3, and 3 in 4 disks. |G*| decreased with Pf by a Pearson's linear correlation coefficient of R = −0.592 (P = 0.0004), while φ remained unchanged. Group mean mechanical parameters for Pf = 1 to 3 were |G*| = 6.51 ± 1.27, 5.29 ± 0.95, 4.03 ± 0.99 kPa, and φ = 1.190 ± 0.181, 1.170 ± 0.156, 1.088 ± 0.084 rad, respectively (p[Pf1-Pf3] < 0.001). The variability of mechanical parameters in one volunteer including diurnal changes was approximately 11%.ConclusionMultifrequency MRE with MDEV inversion allows measurement of in vivo mechanical properties of IVDs and may provide additional information in disc degeneration beyond standard morphological changes. Magn Reson Med 74:1380–1387, 2015. © 2014 Wiley Periodicals, Inc.

Topics

• morphology
• phase