Lee Hye-Won, Lee Ji-Yun, Lee Joo-Young, Yu Seung-Man, Lee Kija, Lee Sang-Kwon
Department of Veterinary Medical Imaging, College of Veterinary Medicine, Kyungpook National University, Daegu, Republic of Korea.
Department of Radiological Science, College of Medical Sciences, Jeonju University, Jeonju, Republic of Korea.
Front Vet Sci. 2024 Sep 25;11:1412552. doi: 10.3389/fvets.2024.1412552. eCollection 2024.
Fatty degeneration of the vertebral bodies and paravertebral muscles is associated with the presence, severity, and prognosis of spinal disease such as intervertebral disc degeneration. Therefore, the fat fraction (FF) of the vertebral bodies and paraspinal muscles has been considered a potential biomarker for assessing the pathophysiology, progression, and treatment response of spinal disease. Magnetic resonance spectroscopy (MRS) is considered the reference standard for fat quantification; however, it has limitations of a long acquisition time and is technically demanding. Chemical shift-encoding water-fat imaging, called the Dixon method, has recently been applied for rapid fat quantification with high spatial resolution. However, the Dixon method has not been validated in veterinary medicine, and we hypothesized that the Dixon method would provide a comparable assessment of the FF to MRS but would be faster and easier to implement in dogs.
In this prospective study, we assessed the FF of the lumbar vertebral bodies and paravertebral muscles from the first to sixth lumbar vertebrae using MRS, the two-point Dixon method (LAVA-FLEX), and the six-point Dixon method (IDEAL-IQ) and compared these techniques.
The FFs of vertebral bodies and paravertebral muscles derived from LAVA-FLEX and IDEAL-IQ showed significant correlations and agreement with those obtained with MRS. In particular, the FFs obtained with IDEAL-IQ showed higher correlations and better agreement with those obtained with MRS than those derived by LAVA-FLEX. Both Dixon methods showed excellent intra- and interobserver reproducibility for FF analysis of the vertebral bodies and paraspinal muscles. However, the test-retest repeatability of vertebral body and paraspinal muscle FF analysis was low for all three sequences, especially for the paraspinal muscles. The results of this study showed that LAVA-FLEX and IDEAL-IQ have high reproducibility and that their findings were highly correlated with the FFs of the lumber vertebral bodies and paraspinal muscles determined by MRS in dogs. The FF analysis could be performed much more easily and quickly using LAVA-FLEX and IDEAL-IQ than using MRS. In conclusion, LAVA-FLEX and IDEAL-IQ can be used as routine procedures in spinal magnetic resonance imaging in dogs for FF analysis of the vertebral bodies and paraspinal muscles.
椎体和椎旁肌的脂肪变性与椎间盘退变等脊柱疾病的存在、严重程度及预后相关。因此，椎体和椎旁肌的脂肪分数（FF）被视为评估脊柱疾病病理生理学、进展及治疗反应的潜在生物标志物。磁共振波谱（MRS）被认为是脂肪定量的参考标准；然而，其采集时间长且技术要求高。化学位移编码水脂成像，即狄克逊法，最近已被用于高空间分辨率的快速脂肪定量。然而，狄克逊法尚未在兽医学中得到验证，我们推测狄克逊法对FF的评估与MRS相当，但在犬类中实施起来会更快且更容易。
在这项前瞻性研究中，我们使用MRS、两点狄克逊法（LAVA-FLEX）和六点狄克逊法（IDEAL-IQ）评估了第一至第六腰椎椎体和椎旁肌的FF，并比较了这些技术。
LAVA-FLEX和IDEAL-IQ得出的椎体和椎旁肌FF与MRS获得的结果显示出显著的相关性和一致性。特别是，IDEAL-IQ获得的FF与MRS获得的结果相比，与LAVA-FLEX得出的结果显示出更高的相关性和更好的一致性。两种狄克逊法在椎体和椎旁肌FF分析中均显示出极好的观察者内和观察者间重复性。然而，所有三个序列的椎体和椎旁肌FF分析的重测重复性都很低，尤其是椎旁肌。本研究结果表明，LAVA-FLEX和IDEAL-IQ具有高重复性，且其结果与犬类中通过MRS测定的腰椎椎体和椎旁肌FF高度相关。与使用MRS相比，使用LAVA-FLEX和IDEAL-IQ进行FF分析要容易得多且速度更快。总之，LAVA-FLEX和IDEAL-IQ可作为犬类脊柱磁共振成像中椎体和椎旁肌FF分析的常规程序。
