The vulue of contrast enhanced magnetization transfer imaging in multiple sclerosis

• Main Authors: Kuo-Wei Wang, 王國偉
• Other Authors: Jao-Perng Lin
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/cgm5a5

碩士 === 元培科學技術學院 === 影像醫學研究所 === 94 === Magnetic resonance image (MRI) has been clinically applied on various medical fields for more than twenty years. Recent technical advances and updating of soft and hard wares make it possible to generate a detailed and clear image of anatomy and pathology of disease entities. One of these techniques or scanning pulse sequence is the magnetization transfer contrast (MTC), which saturates the signals of bound proton in the macromolecules by means of off-resonance presaturation and interacts with the free water proton through cross-relaxation or chemical exchange to lower the signal intensity of background tissue. The use of gadolinium contrast-media in MRI studies increases both reliability and sensitivity of detecting active lesion in multiple sclerosis. Utilize MT technique combining with gadolinium contrast-media can improve the contrast between enhancied lesions and normal white matter background on T1-weighted magnetic resonance images. For this reason MT imaging is commonly used in the MR research of Multiple Sclerosis (MS), a disease of the central nervous system (CNS) which is characterized by destruction of myelin. MT imaging can be used to improve the contrast between the lesions which occur in the brain or the spinal cord and the surrounding tissue. MT imaging also enables us to assess the ‘invisible’ lesion burden in the normal appearing white matter. This research was designed to survey four different pulse sequences: pre-contrast transverse T1-weighted Spin Echo, transverse T1-weighted Spin Echo with MT , post-contrast transverse T1-weighted Spin Echo, and transverse T1-weighted Spin Echo with MT. All four techniques were setting to measure the signal intensity of gray matter, white matter, cerebrospinal fluid and MS plaque. The magnetization transfer rate(MTR) of each part was then calculated, thus the differences between brain tissue and pathological changes can be obtained for further comparison. The signal intensities measured from pre-contrast T1-weighted spin echo in four different brain tissues, gray matter, white matter, CSF and multiple sclerosis plaque were 752.2 ± 20.5, 901.5 ± 23.1, 407.2 ± 17.2 and 691.8 ± 45.8, and the signal intensities of post-contrast MT T1-weighted spin echo were 577.3 ± 25.9、612.1 ± 26.3、398.3 ± 20.1 and 1413.0 ± 67.7. The results showed that the MT technique efficiently reduced the signal intensity of normal brain tissue and thus enhanced the contrary difference of the pathological brain tissue, and by combination of contrast agent application, more detailed and sophisticated image of the brain can be produced. Therefore, the application of the MTC is of great benefit for MRI study of the brain. .