The value of whole-lesion histogram analysis based on field‑of‑view (FOV) and FOCUS diffusion‑weighted imaging (DWI) for predicting axillary lymph node status in early-stage breast cancer

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) and constrained undistorted single-shot (FOCUS) diffusion-weighted imaging (DWI) approach, as well as a whole-lesion histogram analysis. Methods: : This retrospective analysis involved 65 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 of 0.856. All parameters revealed excellent inter-observer agreement with inter-reader consistencies data ranging from 0.931 to 0.987. 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.