Christoph Schleich, Presenter: Nothing to Disclose

Anja Lutz, Abstract Co-Author: Nothing to Disclose

Benjamin Schmitt, Abstract Co-Author: Nothing to Disclose

Hans-Joerg Wittsack PhD, Abstract Co-Author: Nothing to Disclose

Gerald Antoch MD, Abstract Co-Author: Speaker, Siemens Medical AG Speaker, Bayer AG Speaker, BTG International Ltd

Falk Roland Miese MD, Abstract Co-Author: Nothing to Disclose

The objective of this study was to investigate the age dependency of glycosaminoglycan (GAG) content in the human intervertebral disc (IVD) using biochemical MRI with glycosaminoglycan chemical exchange saturation transfer (gagCEST).

25 healthy volunteers (mean age 46, range: 24 - 69 years, 17 females, and 8 males) were examined with a prototype gagCEST imaging sequence at a 3T MR scanner (Magnetom Trio; Siemens Healthcare). The CEST presaturation module consisted of a series of 6 Gaussian-shaped RF pulses with B1 amplitude of 1.5 µT averaged over time (B1-CWAE). The duration of each saturation pulse and interpulse delay was 100 msec. In order to increase SNR, 6 signal averages were used. After motion correction with the prototype software fMRLung (Siemens Healthcare), CEST evaluation was performed in the lumbar IVDs L2/3 - L5/S1 using the magnetization transfer asymmetry (MTRasym = MSat/M0(-Δω) - MSat/M0(Δω)) value as a method to assess gagCEST effects (figure 1). Region of interest based analysis was performed for the nucleus pulposus (NP) and the annulus fibrosus (AF). The volunteers were categorized in five age classes: 20-29 years, 30-39 years, 40-49 years, 50-59 years and 60-69 years (figure 1). Each group consisted of five volunteers. Only IVDs with Pfirrmann grade 2 were included.

We found significantly lower gagCEST values in NP and AF with increasing age. NP showed higher gagCEST values compared to AF (figure 1). There was a significant correlation between age and GAG content of nucleus pulposus (r = -0.592; p = 0.01). There was a significant correlation between age and gag content of annulus fibrosus (r = -0.582; p = 0.01; figure 2).

Our study suggests age dependency of intervertebral disc composition. gagCEST imaging is sensitive to age dependent cartilage visualization, despite morphologically healthy intervertebral discs (Pfirrmann grade 2).

Biochemical imaging with gagCEST of cartilage composition is feasible in IVDs. Our study suggests age dependency of intervertebral disc composition. Lumbar IVD degeneration is a condition with high incidence and clinical as well as economical relevance. gagCEST at 3T is a new and promising tool for the research of this disease.

Schleich, C, Lutz, A, Schmitt, B, Wittsack, H, Antoch, G, Miese, F, Magnetic Resonance gagCEST Imaging of the Human Lumbar Intervertebral Disc: Age Dependency of Glycosaminoglycan Content.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14009344.html