Model‐Free and Model‐based Parameters Derived From CAIPIRINHA‐Dixon‐TWIST‐VIBE DCE‐MRI: Associations With Prognostic Factors and Molecular Subtypes of Invasive Ductal Breast Cancer

Background CAIPIRINHA‐Dixon‐TWIST‐VIBE (CDTV) dynamic contrast‐enhanced MRI (DCE‐MRI) can be used to characterize breast cancer. However, the influence of the clinicopathologic factors and molecular subtypes of invasive breast carcinoma (IDC) on the model‐free and model‐based parameters has not been investigated. Purpose To compare model‐free and model‐based parameters of CDTV DCE‐MRI with both clinicopathologic factors and molecular subtypes of IDC. Study Type Prospective. Population A total of 152 patients (mean age, 52 years) with IDC including 42 luminal A, 64 luminal B, 22 human epidermal growth factor receptor‐2 (HER2) positive, and 24 triple‐negative subtypes. Field Strength/Sequence A 3 T; turbo‐FLASH, Dixon VIBE, and CDTV. Assessment Model‐free parameters (initial enhancement rate [IER] and maximum slope [MS]) were estimated from the time‐intensity curve. The mean, minimum, maximum, and range between the minimum and maximum values of inline model‐based parameters ( K trans , k ep , and v e ) were measured to assess intratumoral heterogeneity of IDC lesions. Statistical Tests Student's t tests, Mann–Whitney U tests, Kruskal–Wallis tests, post hoc Steel‐Dwass tests, and receiver operating characteristic (ROC) curves. P < 0.05 was considered significant. Results No significant differences in IER and MS values were seen among the clinicopathologic factors and molecular subtypes (Bonferroni‐corrected P = 0.011–0.862, P = 0.145–0.601, respectively). The minimum k ep values in HER2‐positive IDC were significantly lower than those in HER2‐negative IDC. The mean and range k ep values were independent predictors for distinguishing the high (grade 3) and low (grade 1 or 2) nuclear grade groups according to multivariable analyses. The post hoc test showed that the k ep minimum and k ep range values were significantly different between luminal A and HER2‐positive tumor subtypes, yielding an area‐under‐the‐curve of 0.820. Data Conclusion Compared with the model‐free parameters, inline k ep related model‐based parameters on CDTV DCE‐MRI can be applied as a feasible tool to differentiate luminal A from HER2‐positive breast cancers. Evidence Level 2. Technical Efficacy Stage 2.