Nölte Ingo, Gerigk Lars, Brockmann Marc A, Kemmling André, Groden Christoph
Department of Neuroradiology, Medical Faculty Mannheim of the University of Heidelberg, Mannheim, Germany.
Neuroradiology. 2008 May;50(5):403-9. doi: 10.1007/s00234-008-0363-0.
Parallel imaging techniques such as GRAPPA have been introduced to optimize image quality and acquisition time. For spinal imaging in a clinical setting no data exist on the equivalency of conventional and parallel imaging techniques. The purpose of this study was to determine whether T1- and T2-weighted GRAPPA sequences are equivalent to conventional sequences for the evaluation of degenerative lumbar spine disease in terms of image quality and artefacts.
In patients with clinically suspected degenerative lumbar spine disease two neuroradiologists independently compared sagittal GRAPPA (acceleration factor 2, time reduction approximately 50%) and non-GRAPPA images (25 patients) and transverse GRAPPA (acceleration factor 2, time reduction approximately 50%) and non-GRAPPA images (23 lumbar segments in six patients). Comparative analyses included the minimal diameter of the spinal canal, disc abnormalities, foraminal stenosis, facet joint degeneration, lateral recess, nerve root compression and osteochondrotic vertebral and endplate changes. Image inhomogeneity was evaluated by comparing the nonuniformity in the two techniques. Image quality was assessed by grading the delineation of pathoanatomical structures. Motion and aliasing artefacts were classified from grade 1 (severe) to grade 5 (absent).
There was no significant difference between GRAPPA and non-accelerated MRI in the evaluation of degenerative lumbar spine disease (P>0.05), and there was no difference in the delineation of pathoanatomical structures. For inhomogeneity there was a trend in favour of the conventional sequences. No significant artefacts were observed with either technique.
The GRAPPA technique can be used effectively to reduce scanning time in patients with degenerative lumbar spine disease while preserving image quality.
诸如GRAPPA之类的并行成像技术已被引入以优化图像质量和采集时间。在临床环境中进行脊柱成像时，尚无关于传统成像技术与并行成像技术等效性的数据。本研究的目的是确定T1加权和T2加权GRAPPA序列在图像质量和伪影方面是否等同于传统序列，用于评估退行性腰椎疾病。
在临床怀疑患有退行性腰椎疾病的患者中，两名神经放射科医生独立比较矢状面GRAPPA（加速因子2，时间减少约50%）和非GRAPPA图像（25例患者）以及横断面GRAPPA（加速因子2，时间减少约50%）和非GRAPPA图像（6例患者的23个腰椎节段）。比较分析包括椎管的最小直径、椎间盘异常、椎间孔狭窄、小关节退变、侧隐窝、神经根受压以及骨软骨性椎体和终板改变。通过比较两种技术中的不均匀性来评估图像不均匀性。通过对病理解剖结构的描绘进行分级来评估图像质量。运动和混叠伪影从1级（严重）到5级（无）进行分类。
在评估退行性腰椎疾病方面，GRAPPA与非加速MRI之间无显著差异（P>0.05），病理解剖结构的描绘也无差异。对于不均匀性，有倾向于传统序列的趋势。两种技术均未观察到明显伪影。
GRAPPA技术可有效用于减少退行性腰椎疾病患者的扫描时间，同时保持图像质量。
