Hepatic pseudo-anisotropy: a specific artifact in hepatic diffusion-weighted images obtained with respiratory triggering
Hepatic pseudo-anisotropy: a specific artifact in hepatic diffusion-weighted images obtained with respiratory triggering
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DOI：
10.1007/s10334-007-0084-0
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发表时间：
2007-10-01
影响因子：
2.3
通讯作者：
Minami, Manabu
中科院分区：
文献类型：
--
作者：
Nasu, Katsuhiro;Kuroki, Yoshifumi;Minami, Manabu
目的：肝脏伪各向异性是在呼吸触发下肝脏弥散加权成像（RT-DWI）中观察到的伪影。为了确定这种现象的临床意义，肝脏RT-DW图像review.Methods：一百零五MR检查，包括RT-DWI，进行了评估。患者组包括62名非糖尿病患者和43名糖尿病患者。所有图像均由两名放射科医生从伪各向异性发生率和伪各向异性与迹线图像质量之间的相关性的角度进行评价。结果：正常肝实质的ADC值在正常肝实质中占60%（37/62），在正常肝实质中占30%（13/43）。两组比较差异有统计学意义（P < 0.001）。迹线图像的质量表现出恶化的趋势，伪各向异性变得显着。然而，迹线图像的质量总体上令人满意，只有两名患者的迹线图像由于伪各向异性而难以解释。伪各向异性区ADC值明显高于非伪各向异性区（P < 0.001）。即使采用呼吸触发，由于假各向异性，肝脏的ADC测量也不准确，特别是在非胰腺炎患者中。
Purpose: Hepatic pseudo-anisotropy is an artifact observed in hepatic diffusion-weighted imaging under respiratory triggering (RT-DWI). To determine the clinical significance of this phenomenon, hepatic RT-DW images were reviewed.Methods: One hundred and five MR examinations, including RT-DWI, were assessed. The patient group included 62 non-cirrhotic and 43 cirrhotic individuals. All images were evaluated by mutual agreement of two radiologists from the viewpoints of incidence of pseudo-anisotropy and correlation between pseudo-anisotropy and the quality of trace images. The ADC of normal hepatic parenchyma of non-cirrhotic livers were measured in both areas with and without pseudoanisotropy.Results: Pseudo-anisotropy was observed in 60% of non-cirrhotic (37/62) and 30% of cirrhotic (13/43) images. The difference between the two groups was statistically significant (P < 0.001). The quality of trace images showed a tendency to worsen as pseudo-anisotropy became significant. However, the quality of trace images was generally satisfactory, with only two patients whose trace images were difficult to interpret due to pseudo-anisotropy. The areas with pseudo-anisotropy showed higher ADC than those without pseudo-anisotropy (P < 0.001).Conclusion: Pseudo-anisotropy is a type of artifact that originates from respiratory movement. Even though respiratory triggering is employed, ADC measurement of the liver is inaccurate because of pseudo-anisotropy, especially in noncirrhoticpatients.