Ruuth Riikka, Kuusela Linda, Mäkelä Teemu, Melkas Susanna, Korvenoja Antti
HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, P.O. Box 340, FI-00029, HUS, Finland.
Department of Physics, Faculty of Science, University of Helsinki, P.O. Box 64, FI-00014, Helsinki, Finland.
Eur J Radiol Open. 2018 Dec 31;6:42-48. doi: 10.1016/j.ejro.2018.12.006. eCollection 2019.
A Gradient Echo Plural Contrast Imaging technique (GEPCI) is a post-processing method, which can be used to obtain quantitative T2* values and generate multiple synthetic contrasts from a single acquisition. However, scan duration and image reconstruction from k-space data present challenges in a clinical workflow. This study aimed at optimizing image reconstruction and acquisition duration to facilitate a post-processing method for synthetic image contrast creation in clinical settings.
This study consists of tests using the American College of Radiology (ACR) image quality phantom, two healthy volunteers, four mild traumatic brain injury patients and four small vessel disease patients. The measurements were carried out on a 3.0 T scanner with multiple echo times. Reconstruction from k-space data and DICOM data with two different coil-channel combination modes were investigated. Partial Fourier techniques were tested to optimize the scanning time.
Sum of squares coil-channel combination produced artifacts in phase images, but images created with adaptive combination were artifact-free. The voxel-wise median signed difference of T2* between the vendor's adaptive channel combination and k-space reconstruction modes was 2.9 ± 0.7 ms for white matter and 4.5 ± 0.6 ms for gray matter. Relative white matter/gray matter contrast of all synthetic images and contrast-to-noise ratio of synthetic T1-weighted images were almost equal between reconstruction modes. Our results indicate that synthetic contrasts can be generated from the vendor's DICOM data with the adaptive combination mode without affecting the quantitative T2* values or white matter/gray matter contrast.
梯度回波多对比成像技术（GEPCI）是一种后处理方法，可用于获取定量T2*值并从单次采集生成多个合成对比图像。然而，扫描持续时间和从k空间数据进行图像重建在临床工作流程中存在挑战。本研究旨在优化图像重建和采集持续时间，以促进在临床环境中创建合成图像对比的后处理方法。
本研究包括使用美国放射学会（ACR）图像质量模体、两名健康志愿者、四名轻度创伤性脑损伤患者和四名小血管疾病患者进行的测试。测量在具有多个回波时间的3.0 T扫描仪上进行。研究了两种不同线圈通道组合模式下从k空间数据和DICOM数据进行的重建。测试了部分傅里叶技术以优化扫描时间。
平方和线圈通道组合在相位图像中产生伪影，但自适应组合创建的图像无伪影。在供应商的自适应通道组合和k空间重建模式之间，白质的T2体素中位数符号差为2.9±0.7 ms，灰质为4.5±0.6 ms。在重建模式之间，所有合成图像的相对白质/灰质对比度和合成T1加权图像的对比度噪声比几乎相等。我们的结果表明，使用自适应组合模式可以从供应商的DICOM数据生成合成对比图像，而不会影响定量T2值或白质/灰质对比度。
