Three-dimensional Ultrashort Echo Time MRI of the Normal and Degenerative Diskovertebral Complex at 4.7 T: A Feasibility Study with Longitudinal Evaluation

Presentation Format: Oral presentation.

Purpose or Learning Objective: (1) To examine the feasibility of a three-dimensional ultrashort echo time (3D-UTE) sequence to evaluate the normal and pathologic diskovertebral complex (DVC), with assessment of its different portions in a rat model of degenerative disk disease (DDD) with histologic correlation. (2) To assess whether this sequence, in comparison with a long echo time T2-weighted-sequence, is able to monitor DDD and differentiate early from chronic DVC changes in pathologic mechanical conditions.

Methods or Background: Five rats were induced with DDD by percutaneous disk trituration of the tail with an 18G needle under ultrasonography guidance and imaged at 4.7 T. The magnetic resonance imaging (MRI) protocol consisted of fat-saturated T2 (rapid acquisition with relaxation enhancement [RARE]) and 3D-UTE sequences performed at baseline (day 0: n = 5 animals/10 DVC) and each week (W) from W1 to W10 postoperatively. Visual analysis and signal intensity measurements of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of all DVC portions were performed on RARE and UTE images. Following death (baseline: n = 1/2 DVC; W2: n = 2/4 DVC; W10: n = 2/4 DVC), histologic analysis was performed and compared with MRI.

Results or Findings: In normal DVC, unlike conventional RARE sequences, 3D-UTE allowed complete identification of DVC zonal anatomy including on-sight analysis and CNR measurements. In pathologic conditions, SNR and CNR measurements of the annulus fibrosus and nucleus pulposus on 3D-UTE distinguished early diskitis at W1 from chronic diskopathy (p < 0.001 for SNR and p < 0.001 for CNR). Neither the normal complete anatomy of the DVC nor its pathologic patterns could be assessed on conventional sequences.

Conclusion: Unlike conventional sequences, 3D-UTE facilitates visualization of the complete normal DVC anatomy and enables monitoring of DDD, differentiating between early DVC changes and chronic changes.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
03 June 2021