Data from: A rotational cylindrical fMRI phantom for image quality control

Purpose: A novel phantom for image quality testing for functional magnetic resonance imaging (fMRI) scans is described. Methods: The cylindrical, rotatable, ~4.5L phantom, with eight wedge-shaped compartments, is used to simulate rest and activated states. The compartments contain NiCl2 doped agar gel with alternating concentrations of agar (1.4%, 1.6%) to produce T1 and T2 values approximating brain grey matter. The Jacard index was used to compare the image distortions for echo planar imaging (EPI) and gradient recalled echo (GRE) scans. Contrast to noise ratio (CNR) was compared across the imaging volume for GRE and EPI. Results: The mean T2 for the two agar concentrations were found to be 106.5±4.8, 94.5±4.7 ms, and T1 of 1500±40 and 1485±30 ms, respectively. The Jacard index for GRE was generally found to be higher than for EPI (0.95 versus 0.8). The CNR varied from 20 to 50 across the slices and echo times used for EPI scans, and from 20 to 40 across the slices for the GRE scans. The phantom provided a reproducible CNR over 25 days. Conclusions: The phantom provides a quantifiable signal change over a head-size imaging volume with EPI and GRE sequences, which was used for image quality assessment.

研究目的：本文描述了一种用于功能性磁共振成像（functional magnetic resonance imaging, fMRI）扫描图像质量检测的新型体模。研究方法：该圆柱形可旋转体模容积约4.5L，包含八个楔形隔室，用于模拟大脑静息态与激活态。隔室内填充掺杂氯化镍（NiCl2）的琼脂凝胶，通过交替设置1.4%、1.6%两种琼脂浓度，使凝胶的T1、T2值近似大脑灰质。本研究采用雅卡尔指数（Jaccard index）对比回波平面成像（echo planar imaging, EPI）与梯度回波成像（gradient recalled echo, GRE）扫描的图像畸变程度，并对比了两种成像序列在全成像容积内的对比噪声比（contrast to noise ratio, CNR）。研究结果：两种琼脂浓度对应的平均T2值分别为106.5±4.8 ms与94.5±4.7 ms，平均T1值分别为1500±40 ms与1485±30 ms。梯度回波成像的雅卡尔指数整体高于回波平面成像（0.95 vs 0.8）。回波平面成像扫描的对比噪声比在各切片与回波时间参数下介于20至50之间，梯度回波成像的对比噪声比在各切片下介于20至40之间。该体模在25天内可获得稳定可重复的对比噪声比结果。研究结论：该体模可在匹配头部尺寸的成像容积内，通过回波平面成像与梯度回波序列产生可量化的信号变化，可用于图像质量评估。