1 All authors: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
AJR Am J Roentgenol. 2013 Oct;201(4):902-7. doi: 10.2214/AJR.12.10049.
In a clinical setting, lipoma can sometime show low signal intensity on susceptibility-weighted imaging (SWI) mimicking hemorrhage. The purpose of this study was to evaluate the fat-water interface chemical-shift artifacts between SWI and T2*-weighted imaging with a phantom study and evaluate SWI in lipoma cases.
SWI, magnitude, high-pass filtered phase, and T2*-weighted imaging of a lard-water phantom were evaluated in the in-phase, out-of phase, and standard partially out-of-phase TE settings used for clinical 3-T SWI (19.7, 20.9, and 20.0 ms, respectively) to identify the most prominent fat-water interface low signal. SWI of five cases of CNS lipoma were retrospectively evaluated by two neuroradiologists.
TE at 19.7 ms (in-phase) showed the minimum fat-water interface low signal in the phase-encoding direction on magnitude, high-pass filtered phase, and SWI. TE at 20.9 ms (out-of-phase) showed the maximum fat-water interface in the phase-encoding direction on magnitude, high-pass filtered phase, and SWI. TE at 20.0 ms (partially out-of-phase) showed more fat-water interface low signal on SWI than on T2*-weighted imaging, especially in the phase-encoding direction. All lipomas in the five patients showed high signal intensity with surrounding peripheral dark rim on SWI.
Fat-water interface is more prominent on the standard TE setting used for clinical SWI (20.0 ms) than that of T2*-weighted imaging and shows a characteristic surrounding peripheral low-signal-intensity rim in lipoma. Knowing the fat-water appearance on SWI is important to avoid misinterpreting intracranial lipomas as hemorrhages.
在临床环境中，脂肪瘤在磁共振磁敏感加权成像（SWI）上可能会显示出类似出血的低信号强度。本研究旨在通过体模研究评估 SWI 与 T2*-加权成像之间的脂肪-水界面化学位移伪影，并评估 SWI 在脂肪瘤病例中的应用。
评估了猪油-水体模在同相位、反相位和标准部分反相位 TE 设置（分别为临床 3T SWI 所用的 19.7、20.9 和 20.0 ms）下的 SWI、幅度、高通滤波相位和 T2*-加权成像，以确定最明显的脂肪-水界面低信号。对 5 例中枢神经系统脂肪瘤的 SWI 进行回顾性评估，由 2 名神经放射科医生进行。
在相位编码方向上，TE 为 19.7 ms（同相位）在幅度、高通滤波相位和 SWI 上显示最小的脂肪-水界面低信号。在相位编码方向上，TE 为 20.9 ms（反相位）在幅度、高通滤波相位和 SWI 上显示最大的脂肪-水界面。TE 为 20.0 ms（部分反相位）在 SWI 上显示出比 T2*-加权成像更多的脂肪-水界面低信号，尤其是在相位编码方向上。在 5 例患者的所有脂肪瘤中，SWI 上均显示高信号强度，周围有外周暗环。
在临床 SWI（20.0 ms）中使用的标准 TE 设置上，脂肪-水界面比 T2*-加权成像更明显，并显示出脂肪瘤特征性的周围低信号强度环。了解 SWI 上的脂肪-水表现对于避免将颅内脂肪瘤误诊为出血非常重要。
