High contrast cartilaginous endplate imaging in spine using three dimensional dual-inversion recovery prepared ultrashort echo time (3D DIR-UTE) sequence

Purpose To investigate the feasibility and application of a novel imaging technique, a three-dimensional dual adiabatic inversion recovery prepared ultrashort echo time (3D DIR-UTE) sequence, for high contrast assessment of cartilaginous endplate (CEP) imaging with head-to-head comparisons between other UTE imaging techniques. Method The DIR-UTE sequence employs two narrow-band adiabatic full passage (AFP) pulses to suppress signals from long T 2 water (e.g., nucleus pulposus (NP)) and bone marrow fat (BMF) independently, followed by multispoke UTE acquisition to detect signals from the CEP with short T 2 relaxation times. The DIR-UTE sequence, in addition to three other UTE sequences namely, an IR-prepared and fat-saturated UTE (IR-FS-UTE), a T 1 -weighted and fat-saturated UTE sequence (T 1w -FS-UTE), and a fat-saturated UTE (FS-UTE) was used for MR imaging on a 3 T scanner to image six asymptomatic volunteers, six patients with low back pain, as well as a human cadaveric specimen. The contrast-to-noise ratio of the CEP relative to the adjacent structures—specifically the NP and BMF—was then compared from the acquired images across the different UTE sequences. Results For asymptomatic volunteers, the DIR-UTE sequence showed significantly higher contrast-to-noise ratio values between the CEP and BMF (CNR CEP-BMF ) (19.9 ± 3.0) and between the CEP and NP (CNR CEP-NP ) (23.1 ± 1.7) compared to IR-FS-UTE (CNR CEP-BMF : 17.3 ± 1.2 and CNR CEP-NP : 19.1 ± 1.8), T 1w -FS-UTE (CNR CEP-BMF : 9.0 ± 2.7 and CNR CEP-NP : 10.4 ± 3.5), and FS-UTE (CNR CEP-BMF : 7.7 ± 2.2 and CNR CEP-NP : 5.8 ± 2.4) for asymptomatic volunteers (all P -values < 0.001). For the spine sample and patients with low back pain, the DIR-UTE technique detected abnormalities such as irregularities and focal defects in the CEP regions. Conclusion The 3D DIR-UTE sequence is able to provide high-contrast volumetric CEP imaging for human spines on a clinical 3 T scanner.