Relaxation times of breast tissue at 1.5T and 3T measured using IDEAL

Abstract

Purpose: To accurately measure T1 and T2 of breast fibroglandular tissue and fat at 1.5T and 3T, and note the partial volume effects of the admixture of fibroglandular tissue and fat on the relaxation rates using an approach termed iterative decomposition of water and fat with echo asymmetry and least squares estimation (IDEAL) imaging.

Materials and methods: T1 and T2 values were measured on the right breasts of five healthy women at 1.5T and 3T. T1 data were collected using two sequences: inversion recovery without IDEAL, and inversion recovery with IDEAL. T2 data were collected using Hahn Echo scans. SNR and CNR analyses were conducted on collected data.

Results: T1 increased for both fat (21%) and glandular tissue (17%) from 1.5T to 3T. Thus, the TR and TI of breast protocols at 3T should be lengthened accordingly. SNR more than doubled for both tissue types from 1.5T to 3T. IDEAL imaging demonstrated the partial volume effects of fat and glandular tissue on measuring relaxation rates of independent tissue types.

Conclusion: With separated fat and water images, more precise measurements can be made for the lipid component in fat, and the water component in fibroglandular tissue.