Abstract
BACKGROUND: This study aims to estimate the amount of axillary lymph node (ALN) involvement in early-stage breast cancer utilizing a field of view (FOV) optimized and constrained undistorted single-shot (FOCUS) diffusion-weighted imaging (DWI) approach, as well as a whole-lesion histogram analysis. METHODS: This retrospective analysis involved 81 individuals with invasive breast cancer. The patients were divided into three groups: N(0) (negative ALN metastasis), N(1-2) (low metastatic burden with 1-2 ALNs), and N(≥3) (heavy metastatic burden with ≥ 3 ALNs) based on their sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND). Histogram parameters of apparent diffusion coefficient (ADC) depending basically on FOCUS DWI were performed using 3D-Slicer software for whole lesions. The typical histogram characteristics for N(0), N(1-2), and N(≥ 3) were compared to identify the significantly different parameters. To determine the diagnostic efficacy of significantly different factors, the area under their receiver operating characteristic (ROC) curves was examined. RESULTS: There were significant differences in the energy, maximum, 90 percentile, range, and lesion size among N(0), N(1-2), and N(≥ 3) groups (P < 0.05). The energy differed significantly between N(0) and N(1-2) groups (P < 0.05), and some certain ADC histogram parameters and lesion sizes differed significantly between N(0) and N(≥3), or N(1-2) and N(≥3) groups. For ROC analysis, the energy yielded the best diagnostic performance in distinguishing N(0) and N(1-2) groups from N(≥3) group with an AUC value of0.853. All parameters revealed excellent inter-observer agreement with inter-reader consistencies data ranging from0.919 to 0.982. CONCLUSION: By employing FOCUS DWI method, the analysis of whole-lesion ADC histogram quantitatively provides a non-invasive way to evaluate the degree of ALN metastatic spread in early-stage breast cancer.