Comparison of readout segmented echo planar imaging (EPI) and EPI with reduced field-of-VIew diffusion-weighted imaging at 3t in patients with breast cancer.

Abstract

To qualitatively and quantitatively compare the diagnostic performance of rs-EPI (readout segmented echo planar imaging) and reduced FOV (field-of-view) EPI in patients with biopsy-proven breast cancer at 3T. Between November 2013 and July 2014, 96 patients (age range, 30-75 years: mean, 52 years) with breast cancer were retrospectively enrolled in this study. In all patients, rs-EPI and rFOV EPI were performed using a 3T MR scanner. Differences between two sequences were compared quantitatively by measuring the tumor apparent diffusion coefficient (ADC), signal-to-noise ratio (SNR), contrast, and contrast-to-noise ratio (CNR). Two independent readers visually assessed overall image quality, lesion conspicuity, and reader preference. The regions of interest (ROIs) were drawn in the whole tumor and in the normal breast parenchyma. Comparisons of quantitative and qualitative parameters between two sequences were performed using the Mann-Whitney and the paired t-test. SNR was significantly higher in rFOV EPI than in rs-EPI (51.88 ± 27.68 vs. 76.46 ± 50.20, P < 0.001). Mean tumor ADC value and normal tissue ADC were significantly lower in rFOV EPI (P < 0.001). Absolute tumor mean and minimum ADCs of rFOV EPI were significantly lower than those of rs-EPI (P < 0.001 for both). However, normalized ADC did not show a significant difference between the two sequences (P = 0.737). Lesion conspicuity and overall image quality of rFOV EPI were significantly higher than those of rs-EPI for both readers (P = 0.025 and < 0.001). In breast cancer, rFOV EPI provided significantly higher image quality, lesion conspicuity, and SNR than rs-EPI.