Department of Radiology, VA San Diego Healthcare System, San Diego, CA 92161, USA.
Department of Radiology, Siriraj Hospital, Bangkok 10700, Thailand.
Sensors (Basel). 2024 Sep 9;24(17):5842. doi: 10.3390/s24175842.
The disco-vertebral junction (DVJ) of the lumbar spine contains thin structures with short T2 values, including the cartilaginous endplate (CEP) sandwiched between the bony vertebral endplate (VEP) and the nucleus pulposus (NP). We previously demonstrated that ultrashort-echo-time (UTE) MRI, compared to conventional MRI, is able to depict the tissues at the DVJ with improved contrast. In this study, we sought to further optimize UTE MRI by characterizing the contrast-to-noise ratio (CNR) of these tissues when either single echo or echo subtraction images are used and with varying echo times (TEs).
In four cadaveric lumbar spines, we acquired 3D Cones (a UTE sequence) images at varying TEs from 0.032 ms to 16 ms. Additionally, spin echo T1- and T2-weighted images were acquired. The CNRs of CEP-NP and CEP-VEP were measured in all source images and 3D Cones echo subtraction images.
In the spin echo images, it was challenging to distinguish the CEP from the VEP, as both had low signal intensity. However, the 3D Cones source images at the shortest TE of 0.032 ms provided an excellent contrast between the CEP and the VEP. As the TE increased, the contrast decreased in the source images. In contrast, the 3D Cones echo subtraction images showed increasing CNR values as the second TE increased, reaching statistical significance when the second TE was above 10 ms ( < 0.05).
Our study highlights the feasibility of incorporating UTE MRI for the evaluation of the DVJ and its advantages over conventional spin echo sequences for improving the contrast between the CEP and adjacent tissues. Additionally, modulation of the contrast for the target tissues can be achieved using either source images or subtraction images, as well as by varying the echo times.
腰椎的椎间关节（DVJ）包含 T2 值较短的薄结构，包括夹在骨性椎体终板（VEP）和髓核（NP）之间的软骨终板（CEP）。我们之前的研究表明，与常规 MRI 相比，超短回波时间（UTE）MRI 能够以更好的对比度描绘 DVJ 处的组织。在这项研究中，我们通过对使用单回波或回波相减图像以及不同回波时间（TE）时这些组织的对比噪声比（CNR）进行特征描述，旨在进一步优化 UTE MRI。
在四个尸体腰椎中，我们获取了从 0.032 ms 到 16 ms 不等的 3D 圆锥（UTE 序列）图像。此外，还获取了自旋回波 T1 和 T2 加权图像。在所有原始图像和 3D 圆锥回波相减图像中测量 CEP-NP 和 CEP-VEP 的 CNR。
在自旋回波图像中，CEP 与 VEP 之间的区分具有挑战性，因为它们的信号强度均较低。然而，最短 TE（0.032 ms）的 3D 圆锥原始图像提供了 CEP 和 VEP 之间极好的对比度。随着 TE 的增加，原始图像中的对比度降低。相比之下，3D 圆锥回波相减图像显示，随着第二 TE 的增加，CNR 值逐渐增加，当第二 TE 大于 10 ms 时具有统计学意义（<0.05）。
我们的研究强调了将 UTE MRI 纳入评估 DVJ 的可行性，并且与传统的自旋回波序列相比，它可以改善 CEP 与相邻组织之间的对比度。此外，可以通过使用原始图像或相减图像以及改变回波时间来实现对目标组织的对比度进行调节。
