New MR sequences in daily practice: susceptibility weighted imaging. A pictorial essay.
New MR sequences in daily practice: susceptibility weighted imaging. A pictorial essay.
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DOI：
10.1007/s13244-011-0086-3
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发表时间：
2011-06
影响因子：
4.7
通讯作者：
Liserre, Roberto
中科院分区：
文献类型：
--
作者：
Gasparotti, Roberto;Pinelli, Lorenzo;Liserre, Roberto
磁化率加权成像（SWI）是一种相对较新的磁共振（MR）技术，它利用各种组织（如血液、铁和钙化）的磁化率差异作为对比增强的新来源。这一图片审查的目的是说明和讨论其主要的临床应用。SWI基于高分辨率、三维（3D）、完全速度补偿的梯度回波序列，使用幅度和相位图像。将从MR相位图像获得的相位掩模与幅度图像相乘，以增加较小静脉和其他敏感性效应源的可视化，这些静脉和敏感性效应源最好在使用最小强度投影（minIP）算法对3D数据集进行后处理后显示。SWI在检测衰老和隐匿性低血流血管畸形中的脑微出血、表征脑肿瘤和脑退行性疾病以及识别各种病理条件下的钙化方面非常有用。相位图像在区分血液的顺磁磁化率效应和钙的反磁效应方面特别有用。SWI也可用于评估不同神经退行性疾病中铁含量的变化。SWI有助于区分和表征各种脑部疾病。
Susceptibility-weighted imaging (SWI) is a relatively new magnetic resonance (MR) technique that exploits the magnetic susceptibility differences of various tissues, such as blood, iron and calcification, as a new source of contrast enhancement. This pictorial review is aimed at illustrating and discussing its main clinical applications. SWI is based on high-resolution, three-dimensional (3D), fully velocity-compensated gradient-echo sequences using both magnitude and phase images. A phase mask obtained from the MR phase images is multiplied with magnitude images in order to increase the visualisation of the smaller veins and other sources of susceptibility effects, which are displayed at best after post-processing of the 3D dataset with the minimal intensity projection (minIP) algorithm. SWI is very useful in detecting cerebral microbleeds in ageing and occult low-flow vascular malformations, in characterising brain tumours and degenerative diseases of the brain, and in recognizing calcifications in various pathological conditions. The phase images are especially useful in differentiating between paramagnetic susceptibility effects of blood and diamagnetic effects of calcium. SWI can also be used to evaluate changes in iron content in different neurodegenerative disorders. SWI is useful in differentiating and characterising diverse brain disorders.