Department of Radiology, Weill Cornell Medicine, New York, New York, USA.
Department of Radiology, Mayo Clinic, Jacksonville, Florida, USA.
J Magn Reson Imaging. 2023 Jun;57(6):1621-1640. doi: 10.1002/jmri.28624. Epub 2023 Feb 7.
Magnetic materials in tissue, such as iron, calcium, or collagen, can be studied using quantitative susceptibility mapping (QSM). To date, QSM has been overwhelmingly applied in the brain, but is increasingly utilized outside the brain. QSM relies on the effect of tissue magnetic susceptibility sources on the MR signal phase obtained with gradient echo sequence. However, in the body, the chemical shift of fat present within the region of interest contributes to the MR signal phase as well. Therefore, correcting for the chemical shift effect by means of water-fat separation is essential for body QSM. By employing techniques to compensate for cardiac and respiratory motion artifacts, body QSM has been applied to study liver iron and fibrosis, heart chamber blood and placenta oxygenation, myocardial hemorrhage, atherosclerotic plaque, cartilage, bone, prostate, breast calcification, and kidney stone.
组织中的磁性物质，如铁、钙或胶原，可以使用定量磁化率映射（QSM）进行研究。迄今为止，QSM 已经在大脑中得到了广泛应用，但在大脑外的应用也越来越多。QSM 依赖于组织磁化率源对梯度回波序列获得的 MR 信号相位的影响。然而，在体内，感兴趣区域内存在的脂肪的化学位移也会对 MR 信号相位产生影响。因此，通过水脂分离来校正化学位移效应对于体 QSM 至关重要。通过采用补偿心脏和呼吸运动伪影的技术，体 QSM 已应用于研究肝脏铁和纤维化、心脏腔室血液和胎盘氧合、心肌出血、动脉粥样硬化斑块、软骨、骨骼、前列腺、乳腺钙化和肾结石。
