The Studies Of3.0T MR Dynamic Contrast-enhanced Quantitative Assessment Analysis In Differential Diagnosis Of Breast Lesions

Objective:1. To analysis the value of3.0T MR quantitative assessment analysis in differential diagnosis of breast lesions.2. Discussing the scanning time of breast perfusion imaging with3.0T MR to optimized the window of scanning time and increased scanning efficiency.Materials and Methods:Select56patients with breast lesions which were detected by clinical examination, ultrasound or X-ray from2012to2013in Qian Foshan hospital, taken the DCE-MRI examination who were not performed breast biopsy before the examination. Patients were female, age range from23to68years old. Final52patients was confirmed with pathologically. All patients underwent breast MR scan and dynamic enhanced MRI T1.Using Siemens Magnetom Skyra3.0T MR scanner, a dedicated eight-channel phased bilateral breast coil. With the patient prone position, bilateral breast naturally suspended in the coil. After conventional axial, sagittal, coronal position scanning, using T1dynamic contrast-enhanced scan, firstly scanning the original image that is using multiple T1flip angle technique(TR/TE7.84ms/3.37ms; FOV340mm; matrix224×224; thickness1.5mm; layer from0.3mm; excitation frequency1; flip angle of3°/16°), then using T1enhanced continuous sequence(TR/TE5.61ms/1.74ms; FOV340 mm; matrix224×224; thickness1.5mm; layer from0.3mm; excitation frequency1; flip angle10°; the total scan time of52; single-phase scan time of30s; the total time26min).When the end of the second data collection phase, vein injection of contrast agent Gd-BOPTA20ml under high-pressure,20ml of physiological saline after the injection, the flow rate was5ml/s, and then collected50consecutive phase images.All data are transmitted to SYGNO VE40A after processing workstation, using the software of TISSUE4D to post-process analysis work.After the injection of contrast agents were10(5min),20(10min),30(15min),40(20min),50(25min) period, manually select the more obvious artery which is in the breast or internal thoracic artery, and access different periods of the arterial input function (AIF). Select the substantive component of the tumor as a region of interest (ROI) to obtain the following quantitative parameters:①volume transfer constant (Ktrans), refers to the velocity constant which means that the contrast agent transfer from the intravascular to the extravascular by diffusion,②rte constant (KeP), refers to the velocity constant which means that after some time, the contrast agent within the interstitial space back intravascular by diffusion.③extravascular extracellular volume fraction (Ve), is the extravascular extracellular space accounted for the entire voxel volume ratio. Select three levels from each lesion: maximum cross-sectional area level and one each at the upper and lower levels,avoiding the necrotic tissue, empty, calcification and blood vessels, etc, then take three levels of vascular permeability parameters average as vascular permeability parameters of the lesions, and at the same time show the pseudo color map.Results:1. The values of Ktrans and KeP, in every stages, had statistical significance(P<0.05) between benign and malignant tumors. While the value of Ve had statistical significance only in10stage, but no in any other stages (P>0.05). Compared the trend of Ve values in different periods, as the scanning time went, the value of Ve in benign tumors grew up increasingly; but it had no obvious variation trend in malignant ones. The lower bound of malignant group’s Ktrans values95%confidence interval (0.743min’1) as value of the vicious circles the diagnostic sensitivity is96.7%and specificity reach to92.9%; the lower bound of malignant group’s Kep values95%confidence interval (1.338min-1) as value for the vicious circles, the diagnostic sensitivity is91.5%and specificity reach to84.6%. So the value of Ktrans in the identification of benign and malignant lesions was more meaningful.2. Compared the Ktrans and Kep values in different periods, the difference between30and50,30and40period had no statistically significant in malignant group; the difference between40and50period had no statistically significant in benign group, therefore the best scanning stage of Ktrans and Kep value was between10stage and30stage after injected contrasts. The best scanning stage of breast perfusion imaging was between10stage and30stage after injected. And the best scanning time was between5and15min.Conclusion:In the identification of benign and malignant lesions, the vascular function parameters of Ktrans and Kep has higher performance. The trend of Ve values in different periods can be a diagnostic reference. The value of Ktrans in the identification of benign and malignant lesions was more meaningful.2. To increase scanning efficiency, the best scanning time of breast perfusion imaging is5min after injecting contrasts. When combining with the Ve value’s variation trend, the best time of scanning is15min after injecting.