Koch Kevin M, Bhave Sampada, Kaushik S Sivaram, Nencka Andrew S, Budde Matthew D
Department of Radiology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, 53202, USA.
GE Healthcare, Milwaukee, WI, USA.
Eur Spine J. 2020 May;29(5):1071-1077. doi: 10.1007/s00586-019-06239-z. Epub 2019 Dec 12.
Diffusion-weighted imaging has undergone substantial investigation as a potential tool for advanced assessment of spinal cord health. Unfortunately, commonly encountered surgically implanted spinal hardware has historically disrupted these studies. This preliminary investigation applies the recently developed multispectral diffusion-weighted PROPELLER technique to quantitative assessment of the spinal cord immediately adjacent to metallic spinal fusion instrumentation.
Morphological and diffusion-weighted MRI of the spinal cord was collected from 5 subjects with implanted cervical spinal fusion hardware. Conventional and multispectral diffusion-weighted images were also collected on a normative non-instrumented control cohort and utilized for methodological stability analysis. Variance of the ADC values derived from the normative control group was then analyzed on a subject-by-subject basis and qualitatively correlated with clinical morphological interpretations.
Normative control ADC values within the spinal cord were stable across DWI methods for a b value of 600 s/mm, though this stability degraded at lower b value levels. Susceptibility artifacts precluded conventional DWI analysis of the cord in subjects with spinal fusion hardware in 4 of the 5 test cases. On the contrary, multispectral PROPELLER DWI produced viable ADC measurements within the cord of all 5 instrumented subjects. Instrumented cord regions without obvious pathology (N = 4) showed ADC values that were lower than expected, whereas one subject with diagnosed myelomalacia showed abnormally elevated ADC.
In the absence of instrumentation, multispectral DWI provides quantitative capabilities that match with those of conventional DWI approaches. In a preliminary instrumented subject analysis, cord ADC values showed both expected and unexpected variations from the normative cohort. These slides can be retrieved under Electronic Supplementary Material.
扩散加权成像作为一种评估脊髓健康状况的潜在工具，已得到大量研究。遗憾的是，以往常见的外科植入式脊柱硬件干扰了这些研究。本初步研究应用最近开发的多光谱扩散加权螺旋桨技术，对紧邻金属脊柱融合器械的脊髓进行定量评估。
收集了5例植入颈椎融合硬件患者的脊髓形态学和扩散加权磁共振成像数据。还在一个正常的未植入器械的对照组中采集了传统和多光谱扩散加权图像，并用于方法学稳定性分析。然后逐例分析正常对照组的ADC值方差，并与临床形态学解释进行定性关联。
对于b值为600 s/mm的情况，脊髓内正常对照组的ADC值在不同扩散加权成像方法中是稳定的，但在较低b值水平时这种稳定性下降。在5个测试病例中的4例中，脊柱融合硬件患者脊髓的传统扩散加权成像分析因磁化率伪影而受阻。相反，多光谱螺旋桨扩散加权成像在所有5例植入器械的患者脊髓内均产生了可行的ADC测量值。无明显病变的植入器械脊髓区域（N = 4）显示ADC值低于预期，而1例诊断为脊髓软化症的患者显示ADC异常升高。
在没有植入器械的情况下，多光谱扩散加权成像提供的定量能力与传统扩散加权成像方法相当。在一项初步的植入器械患者分析中，脊髓ADC值与正常队列相比呈现出预期和意外的变化。这些幻灯片可在电子补充材料中获取。
