Estimation of T2* Relaxation Times for the Glandular Tissue and Fat of Breast at 3T MRI System
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Purpose : T2* relaxation time which includes susceptibility information represents unique feature of tissue. The objectiveof this study was to investigate T2* relaxation times of the normal glandular tissue and fat of breast using a 3T MRI system. Materials and Methods: Seven-echo MR Images were acquired from 52 female subjects (age 49 ± 12 years; range, 25to 75) using a three-dimensional (3D) gradient-echo sequence. Echo times were between 2.28 ms to 25.72 ms in 3.91 mssteps. Voxel-based T2* relaxation times and R2* relaxation rate maps were calculated by using the linear curve fitting foreach subject. The 3D regions-of-interest (ROI) of the normal glandular tissue and fat were drawn on the longest echo-timeimage to obtain T2* and R2* values. Mean values of those parameters were calculated over all subjects. Results: The 3D ROI sizes were 4818 ± 4679 voxels and 1455 ± 785 voxels for the normal glandular tissue and fat,respectively. The mean T2* values were 22.40 ± 5.61 ms and 36.36 ± 8.77 ms for normal glandular tissue and fat,respectively. The mean R2* values were 0.0524 ± 0.0134/ms and 0.0297 ± 0.0069/ms for the normal glandular tissueand fat, respectively. Conclusion: T2* and R2* values were measured from human breast tissues. T2* of the normal glandular tissue was shorterthan that of fat. Measurement of T2* relaxation time could be important to understand susceptibility effects in the breast cancer and the normal tissue.
Abstract
Purpose : T2* relaxation time which includes susceptibility information represents unique feature of tissue. The objectiveof this study was to investigate T2* relaxation times of the normal glandular tissue and fat of breast using a 3T MRI system. Materials and Methods: Seven-echo MR Images were acquired from 52 female subjects (age 49 ± 12 years; range, 25to 75) using a three-dimensional (3D) gradient-echo sequence. Echo times were between 2.28 ms to 25.72 ms in 3.91 mssteps. Voxel-based T2* relaxation times and R2* relaxation rate maps were calculated by using the linear curve fitting foreach subject. The 3D regions-of-interest (ROI) of the normal glandular tissue and fat were drawn on the longest echo-timeimage to obtain T2* and R2* values. Mean values of those parameters were calculated over all subjects. Results: The 3D ROI sizes were 4818 ± 4679 voxels and 1455 ± 785 voxels for the normal glandular tissue and fat,respectively. The mean T2* values were 22.40 ± 5.61 ms and 36.36 ± 8.77 ms for normal glandular tissue and fat,respectively. The mean R2* values were 0.0524 ± 0.0134/ms and 0.0297 ± 0.0069/ms for the normal glandular tissueand fat, respectively. Conclusion: T2* and R2* values were measured from human breast tissues. T2* of the normal glandular tissue was shorterthan that of fat. Measurement of T2* relaxation time could be important to understand susceptibility effects in the breast cancer and the normal tissue.
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