Impact of Different Analytic Approaches on the Analysis of the Breast Fibroglandular Tissue Using Diffusion Weighted Imaging.

Yoon Jung Choi,Min-Ying Su,Hon J Yu,Jeon-Hor Chen,Yifan Li

doi:10.1155/2017/1094354

Abstract

Purpose. This study investigated the impact of the different region of interest (ROI) approaches on measurement of apparent diffusion coefficient (ADC) values in the breast firbroglandular tissue (FT). Methods. Breast MR images of 38 women diagnosed with unilateral breast cancer were studied. Percent density (PD) and ADC were measured from the contralateral normal breast. Four different ROIs were used for ADC measurement. The measured PD and ADC were correlated. Results. Among the four ROIs, the manually placed small ROI on FT gave the highest mean ADC (ADC = 1839 ± 343 [×10−6 mm2/s]), while measurement from the whole breast gave the lowest mean ADC (ADC = 933 ± 383 [×10−6 mm2/s]). The ADC measured from the whole breast was highly correlated with PD with r = 0.95. In slice-to-slice comparison, the central slices with more FT had higher ADC values than the peripheral slices did, presumably due to less partial volume effect from fat. Conclusions. Our results indicated that the measured ADC heavily depends on the composition of breast tissue contained in the ROI used for the ADC measurements. Women with low breast density showing lower ADC values were most likely due to the partial volume effect of fatty tissues.

Highlights

Dense areas of the breast differ histologically from nondense areas: they have greater proportions of stroma and/or epithelium and smaller proportions of fat [1, 2]
The results in this study showed that the apparent diffusion coefficient (ADC) measured from the manually placed fibroglandular tissue region of interest (ROI) was the highest, while the ADC measured from the whole breast was the lowest; in addition, the ADC values measured from the single slice containing the largest amount of fibroglandular tissue were significantly higher than the ADC values measured from the whole fibroglandular tissue volume
We performed a systematic analysis to investigate the ADC values measured in the normal breast by coregistering ADC maps with segmented breast and fibroglandular tissues

Summary

Introduction

Dense areas of the breast differ histologically from nondense areas: they have greater proportions of stroma and/or epithelium and smaller proportions of fat [1, 2]. The breast stromal microenvironment is composed of extracellular matrix (ECM) and different cell types, including endothelial and immune cells, fibroblasts, myoepithelial cells, and adipocytes, which are all capable of modulating epithelial function [3] and mammary duct morphogenesis [4]. Dense tissues are associated with increased collagen-1 deposition in the stromal tissue [7]. Higher collagen levels in the mammary gland increase tumor formation and invasive behavior [8]. Mammographic density is a moderate risk factor for breast cancer, and studies of both epithelial and stromal components are important in understanding the association with breast cancer risk. New imaging methods are used to investigate the histological and functional aspects of the dense tissue

Objectives

Methods

Conclusion