Susceptibility weighted imaging(SWI) is a recently developed magnetic resonance imaging(MRI) technique that is increasingly being used to narrow the differential diagnosis of many neurologic disorders. It exploits the...Susceptibility weighted imaging(SWI) is a recently developed magnetic resonance imaging(MRI) technique that is increasingly being used to narrow the differential diagnosis of many neurologic disorders. It exploits the magnetic susceptibility differences of various compounds including deoxygenated blood, blood products, iron and calcium, thus enabling a new source of contrast in MR. In this review, we illustrate its basic clinical applications in neuroimaging. SWI is based on a fully velocity-compensated, high-resolution, three dimensional gradientecho sequence using magnitude and phase images either separately or in combination with each other, in order to characterize brain tissue. SWI is particularly useful in the setting of trauma and acute neurologic presentations suggestive of stroke, but can also characterize occult low-flow vascular malformations, cerebral microbleeds, intracranial calcifications, neurodegenerative diseases and brain tumors. Furthermore, advanced MRI post-processing technique with quantitative susceptibility mapping, enables detailed anatomical differentiation based on quantification of brain iron from SWI raw data.展开更多
Background Computed tomography （CT） is better than routine magnetic resonance imaging （MRI） in detecting intracranial calcification. This study aimed to assess the value of MR susceptibility weighted imaging （SWI...Background Computed tomography （CT） is better than routine magnetic resonance imaging （MRI） in detecting intracranial calcification. This study aimed to assess the value of MR susceptibility weighted imaging （SWI） in the detection and differentiation of intracranial calcification and hemorrhage. Methods Enrolled in this study were 35 patients including 13 cases of calcification demonstrated by CT and 22 cases of intracerebral hemorrhage. MR sequences used in all the subjects included axial T1WI, T2WI and SWI. The phase shift （PS） of calcification and hemorrhage on SWI was calculated and their signal features on corrected phase images were compared. The sensitivity of T1WI, T2WI and SWI in detecting intracranial calcification and hemorrhage was analyzed statistically. Results The detection rate of SWI for cranial calcification was 98.2%, significantly higher than that of T1WI and T2WI. It was not significantly different from that of CT （P 〉0.05）. There were 49 hemorrhagic lesions at different stages detected on SWI, 30 on T2WI and 18 on T1WI. The average PS of calcification and hemorrhage was ＋0.734±0.073 and -0.112±0.032 respectively （P 〈0.05）. The PS of calcification was positive and presented as a high signal or the mixed signal dominated by a high signal on the corrected phase images, whereas the PS of hemorrhage was negative and presented as a low signal or the mixed signal dominated by a low signal.Conclusions SWI can accurately demonstrate intracranial calcification, not dependant on CT. Being more sensitive than routine MRI in detecting micro-hemorrhage, SWI may play an important role in differentiating cerebral diseases associated with calcification or hemorrhage.展开更多
目的：探讨脑淋巴瘤与胶质母细胞（GMB）的磁敏感加权成像（SWI）影像学特征以及肿瘤内磁敏感信号强度（ITSS）对其鉴别诊断的价值。方法回顾性分析经手术或活检病理证实的13例脑原发性淋巴瘤和19例胶质母细胞瘤的常规MRI及SWI影像学表...目的：探讨脑淋巴瘤与胶质母细胞（GMB）的磁敏感加权成像（SWI）影像学特征以及肿瘤内磁敏感信号强度（ITSS）对其鉴别诊断的价值。方法回顾性分析经手术或活检病理证实的13例脑原发性淋巴瘤和19例胶质母细胞瘤的常规MRI及SWI影像学表现，测量肿瘤内磁敏感信号强度（ITSS），对比分析两者的影像学表现特点。结果13例淋巴瘤ITSS评分为0～1级，ITSS评分0级8例，1级5例。19例胶质母细胞瘤ITSS评级均为3级，胶质母细胞瘤ITSS级别明显高于淋巴瘤，两者ITSS级别有明显统计学差异（ P ＜0．001）。结论定量测量肿瘤内ITSS有助于脑淋巴瘤与胶质母细胞瘤的鉴别诊断，可以作为常规MR检查的补充手段。展开更多
文摘Susceptibility weighted imaging(SWI) is a recently developed magnetic resonance imaging(MRI) technique that is increasingly being used to narrow the differential diagnosis of many neurologic disorders. It exploits the magnetic susceptibility differences of various compounds including deoxygenated blood, blood products, iron and calcium, thus enabling a new source of contrast in MR. In this review, we illustrate its basic clinical applications in neuroimaging. SWI is based on a fully velocity-compensated, high-resolution, three dimensional gradientecho sequence using magnitude and phase images either separately or in combination with each other, in order to characterize brain tissue. SWI is particularly useful in the setting of trauma and acute neurologic presentations suggestive of stroke, but can also characterize occult low-flow vascular malformations, cerebral microbleeds, intracranial calcifications, neurodegenerative diseases and brain tumors. Furthermore, advanced MRI post-processing technique with quantitative susceptibility mapping, enables detailed anatomical differentiation based on quantification of brain iron from SWI raw data.
基金This study was supported by a grant from the National Natural Science Foundation of China （No. 30570531）.
文摘Background Computed tomography （CT） is better than routine magnetic resonance imaging （MRI） in detecting intracranial calcification. This study aimed to assess the value of MR susceptibility weighted imaging （SWI） in the detection and differentiation of intracranial calcification and hemorrhage. Methods Enrolled in this study were 35 patients including 13 cases of calcification demonstrated by CT and 22 cases of intracerebral hemorrhage. MR sequences used in all the subjects included axial T1WI, T2WI and SWI. The phase shift （PS） of calcification and hemorrhage on SWI was calculated and their signal features on corrected phase images were compared. The sensitivity of T1WI, T2WI and SWI in detecting intracranial calcification and hemorrhage was analyzed statistically. Results The detection rate of SWI for cranial calcification was 98.2%, significantly higher than that of T1WI and T2WI. It was not significantly different from that of CT （P 〉0.05）. There were 49 hemorrhagic lesions at different stages detected on SWI, 30 on T2WI and 18 on T1WI. The average PS of calcification and hemorrhage was ＋0.734±0.073 and -0.112±0.032 respectively （P 〈0.05）. The PS of calcification was positive and presented as a high signal or the mixed signal dominated by a high signal on the corrected phase images, whereas the PS of hemorrhage was negative and presented as a low signal or the mixed signal dominated by a low signal.Conclusions SWI can accurately demonstrate intracranial calcification, not dependant on CT. Being more sensitive than routine MRI in detecting micro-hemorrhage, SWI may play an important role in differentiating cerebral diseases associated with calcification or hemorrhage.
文摘目的：探讨脑淋巴瘤与胶质母细胞（GMB）的磁敏感加权成像（SWI）影像学特征以及肿瘤内磁敏感信号强度（ITSS）对其鉴别诊断的价值。方法回顾性分析经手术或活检病理证实的13例脑原发性淋巴瘤和19例胶质母细胞瘤的常规MRI及SWI影像学表现，测量肿瘤内磁敏感信号强度（ITSS），对比分析两者的影像学表现特点。结果13例淋巴瘤ITSS评分为0～1级，ITSS评分0级8例，1级5例。19例胶质母细胞瘤ITSS评级均为3级，胶质母细胞瘤ITSS级别明显高于淋巴瘤，两者ITSS级别有明显统计学差异（ P ＜0．001）。结论定量测量肿瘤内ITSS有助于脑淋巴瘤与胶质母细胞瘤的鉴别诊断，可以作为常规MR检查的补充手段。
