Lee Dongjae, Kim Eunjee, Woo Hyeonjae, Jeon Chang-Yeop, Yoon Junghee, Choi Jihye
Department of Veterinary Medical Imaging, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Republic of Korea.
Front Bioeng Biotechnol. 2024 Feb 27;12:1297675. doi: 10.3389/fbioe.2024.1297675. eCollection 2024.
Magnetic resonance imaging (MRI) is essential for evaluating cerebellar compression in patients with craniocervical junction abnormalities (CJA). However, it is limited in depicting cortical bone because of its short T2 relaxation times, low proton density, and organized structure. Fast field echo resembling a computed tomography (CT) scan using restricted echo-spacing (FRACTURE) MRI, is a new technique that offers CT-like bone contrast without radiation. This study aimed to assess the feasibility of using FRACTURE MRI for craniocervical junction (CCJ) assessment compared with CT and conventional MRI, potentially reducing the need for multiple scans and radiation exposure, and simplifying procedures in veterinary medicine. CT and MRI of the CCJ were obtained from five healthy beagles. MRI was performed using three-dimensional (3D) T1-weighted, T2-weighted, proton density-weighted (PDW), single echo-FRACTURE (sFRACTURE), and multiple echo-FRACTURE (mFRACTURE) sequences. For qualitative assessment, cortical delineation, trabecular bone visibility, joint space visibility, vertebral canal definition, overall quality, and artifacts were evaluated for each sequence. The geometrical accuracy, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were quantified. Both sFRACTURE and CT images provided significantly higher scores for cortical delineation and trabecular bone visibility than conventional MRI. Joint space visibility and vertebral canal definition were similar to those observed on CT images, regardless of the MR sequence. In the quantitative assessment, the distances measured on T2-weighted images differed significantly from those measured on CT. There were no significant differences between the distances taken using T1-weighted, PD-weighted, sFRACTURE, mFRACTURE and those taken using CT. T1-weighted and sFRACTURE had a higher SNR for trabecular bone than CT. The CNR between the cortical bone and muscle was high on CT and FRACTURE images. However, the CNR between the cortical and trabecular bones was low in mFRACTURE. Similar to CT, FRACTURE sequences showed higher cortical delineation and trabecular bone visibility than T2-weighted, T1-weighted, and PDW CCJ sequences. In particular, sFRACTURE provided a high signal-to-noise ratio (SNR) of the trabecular bone and a high CNR between the cortical bone and muscle and between the cortical and trabecular bones. FRACTURE sequences can complement conventional MR sequences for bone assessment of the CCJ in dogs.
磁共振成像（MRI）对于评估颅颈交界区异常（CJA）患者的小脑受压情况至关重要。然而，由于其T2弛豫时间短、质子密度低且组织结构有序，在描绘皮质骨方面存在局限性。快速场回波类似计算机断层扫描（CT）扫描的受限回波间距（FRACTURE）MRI是一种新技术，可提供类似CT的骨对比度且无辐射。本研究旨在评估与CT和传统MRI相比，使用FRACTURE MRI评估颅颈交界区（CCJ）的可行性，这可能减少多次扫描的需求和辐射暴露，并简化兽医学中的检查程序。从五只健康的比格犬获取CCJ的CT和MRI图像。使用三维（3D）T1加权、T2加权、质子密度加权（PDW）、单回波 - FRACTURE（sFRACTURE）和多回波 - FRACTURE（mFRACTURE）序列进行MRI检查。对于定性评估，对每个序列评估皮质轮廓、小梁骨可见性、关节间隙可见性、椎管清晰度、整体质量和伪影。对几何精度、信噪比（SNR）和对比噪声比（CNR）进行量化。与传统MRI相比，sFRACTURE和CT图像在皮质轮廓和小梁骨可见性方面的得分均显著更高。无论MR序列如何，关节间隙可见性和椎管清晰度与CT图像上观察到的相似。在定量评估中，T2加权图像上测量的距离与CT上测量的距离有显著差异。使用T1加权、PD加权、sFRACTURE、mFRACTURE测量的距离与使用CT测量的距离之间无显著差异。T1加权和sFRACTURE的小梁骨SNR高于CT。CT和FRACTURE图像上皮质骨与肌肉之间的CNR较高。然而，mFRACTURE中皮质骨与小梁骨之间的CNR较低。与CT类似，FRACTURE序列在皮质轮廓和小梁骨可见性方面比T2加权、T1加权和PDW CCJ序列更高。特别是，sFRACTURE提供了较高的小梁骨信噪比（SNR）以及皮质骨与肌肉之间和皮质骨与小梁骨之间较高的CNR。FRACTURE序列可补充传统MR序列用于犬CCJ的骨评估。
