High resolution MRI of the deep gray nuclei at 8 tesla

Purpose: High resolution MR images obtained from a normal human volunteer a t 8 T are utilized to describe the appearance of iron-containing deep gray nuclei at this field strength. Method: High resolution (1,024 x 1,024 matrix) near-axial gradient echo ima ges of the deep gray nuclei were acquired on a human volunteer by using an 8 T scanner. The images were acquired using a transverse electromagnetic re sonator operating in quadrature. The following parameters were utilized: TR = 750 ms, TE = 17 ms, flip angle = 45 degrees, receiver bandwidth = 50 kHz , slice thickness = 2 mm, FOV = 20 cm. The 8 T images were reviewed and cor related to the known anatomy of the deep nuclei by comparing them with imag es observed at lower field strength, published diagrams, and histologic sec tions. In addition, the appearance of the nuclei was related to the known i maging characteristics of brain iron at lower fields. Results: The caudate, globus pallidus, putamen, thalami, substantia nigra, and red nuclei were clearly identified. The structures with the highest lev els of iron, the globus pallidus, substantia nigra, and red nuclei, demonst rated significantly decreased signal, providing a map of iron distribution in the human brain. Conclusion: Preliminary imaging at 8 T demonstrates the ability to acquire ultra high resolution images of the deep nuclei, with signal characteristic s believed to represent the distribution of brain iron. This may prove to b e important in the early diagnosis of several neurodegenerative disorders.