Dynamic Contrast-enhanced MR Imaging, Diffusion-weighted Imaging, And ～1H MR Spectroscopy Of Breast Cancers: Correlation With Prognosis Factors Of Molecular Biology

Objective: The purpose of the exploratory study is to evaluate the association ofdynamic contrast-enhanced MR imaging (DCE-MRI), diffusion-weighted imaging(DWI), ~1H MR spectroscopy (~1H-MRS) of breast cancers with biomarkers of breastcancers (ER, PR, PCNA, p53, HER2/neu). To discuss the technique of DWI and itsdiagnostic ability to differentiate benign from malignant breast lesions.Methods: 126 patients with breast lesions detected by physical examination ormammography underwent MR examinations on a 1.5T scanner (GE, Signa ExciteⅡ)preoperatively. MR examinations included 8 min 3D DEC-MRI by VIBRANTsequence, DWI with b value of 0, 500, t000 s/mm~2 by single-shot EPI sequence andsingle-voxel ~1H-MRS by J-PRESS and Spectral Spatial PRESS. Contrast agentGd-DTPA was injected with bolus and was followed with a 20ml flush of isotonicsaline solution. DCE-MRI time-intensity curves of the lesions were classified as typeⅠ(steady enhancement), typeⅡ(plateau) and typeⅢ(washout). Lesions with typeⅠwere classified as benign, whereas the lesions with typeⅡor typeⅢwereclassified as malignant. The mean apparent diffusion coefficients (ADC) and contrastto noise ratio (CNR) of the lesions were calculated on DWI with b value of 500s/mm~2 and 1000 s/mm~2. Lesions presenting a detectable choline signal in their spectraat 3.2 ppm were diagnosed as maligant. The mastectomy specimens of 93 maligantbreast lesions expression of ER, PR, PCNA, p53, HER2/neu were measured byimmunohistochemical staining. The MR characteristics (TIC, early phase enhancementrate, ADC value, choline signal) were correlated with immunohistochemical detectedbiomarkers.Spearman correlation coefficients; Wilcoxon, t test, x~2 test; and receive operating characteristic curve (ROC) were used for statistical analysis.Results: Among 126 patients, histology revealed 93 malignant and 33 benignlesions. There were 59 ER positive, 62 PR positive, 79 PCNA positive, 31 p53positive and 21 HER2/neu lesions. There was a negative correlation between the MRcharacteristics (TIC type, early phase enhancement rate, ADC value, choline signal)and immunohistochemical detected biomarkers (P＞0.05). For DWI, CNR for b=500s/mm~2 was better than for b=1000 s/mm~2(Z=-6.930, P＜0.001). With b value of 500s/mm~2, the sensitivity was 88.17%, the specificity was 63.64%, and accuracy was83.33%, and with b value of 1000 s/mm~2, the sensitivity was 75.27%, the specificitywas 81.82%, and accuracy was 87.30%.Conclusion: DCE-MRI is the most essential method in the MR imaging of breast,DWI and MRS are helpful to provide functional data, but they can't evaluate theprognosis of breast cancers in molecular biology. High-b-value DWI for b=1000s/mm~2 has high specificity to breast lesions, and DCE-MRI has high sensitivity andgood image quality, therefore, combination of high-b-value DWI and DCE-MRI canimprove our ability to diagnose breast lesions.