Quantitative diffusion imaging in breast cancer: A clinical prospective study

Abstract

Purpose: To study the correlation between apparent diffusion coefficient (ADC) and pathology in patients with undefined breast lesion, to validate how accurately ADC is related to histology, and to define a threshold value of ADC to distinguish malignant from benign lesions. Materials and Methods: Seventy-eight patients (110 lesions) were referred for positive or dubious findings. Three-dimensional fast low-angle shot (3D-FLASH) with contrast injection was applied. EPI diffusion-weighted imaging (DWI) with fat saturation was performed, and ROIs were selected on subtraction 3D-FLASH images before and after contrast injection, and copied on an ADC map. Inter- and intraobserver analyses were performed. Results: At pathology 22 lesions were benign, 65 were malignant, and 23 were excluded. The ADCs of malignant and benign lesions were statistically different. In malignant tumors the ADC was (mean ± SEM) 0.95 ± 0.027 × 10- 3mm2/second, and in benign tumors it was 1.51 ± 0.068 × 10-3mm2/second. According to receiver operating characteristic (ROC) curves, we found a threshold between malignant and benign lesions for highest sensitivity and specificity (both 86%) around 1.13 ± 0. 10 × 10-3mm 2/second, For a threshold of 0.95 ± 0.10 × 10 -3mm2/second, specificity was 100% but sensitivity was very low. Inter- and intraobserver studies showed good reproducibility. Concluson: The ADC may help to differentiate benign and malignant lesions with good specificity, and may increase the overall specificity of breast MRI. © 2006 Wiley-Liss, Inc.