The Value Of 3.0T MRI T1 Weighted Imaging Perfusion And IVIM In The Diagnosis Of Breast Benign And Malignant Lesions

Objective:1. To analysis the value of T1 perfusion in the diagnosis with 3.0T MRI in differentiating benign and malignant breast lesions.2. To investigate the value of delaying scan-time and optimal scan-delay time for 3.0T MRI T1 perfusion imaging.3. To analysis of the value of IVIM in differentiating the benign and malignant breast lesionsMaterials and Methods:A retrospective analysis was done for A total of 123 lesions in 109 patients from 2012 September to 2015 February in Shandong Province Qianfoshan Hospital. All the lesions were finally confirmed by biopsy or operation pathology, and all patients wre underwent IVIM scan and dynamic contrast-enhanced T1WI perfusion. Before the examination, all patients were not done invasive breast Operation, such as biopsy or surgical operation. All patients were female, ranging in age from 18 to 65 years old.All patients underwent breast MR scan with Siemens Magnetom Skyra 3.0T scanner, using breast eight channel phased array coil, the prone position, the foot is advanced, bilateral breast droop in coil naturally. The scanning sequences included:axial, sagittal, coronal FS-T2WI and axial vibe T1WI; axial IVIM; dynamic enhanced T1WI sequence. At the end of the second phase, Contrast agent Gd-BOPTA wae injected in the vein of arm, with the dose of 0.2mmol/kg, the rate of 5ml/s, and After that the same amount of normal saline was injected in the same speed. After contrast agent injection 55 phases continuous acquisition were obtained. The scan time of each phase of is about 30s, and the total of the scanning time was about 27 minutes. The patient was asked to breathe in small range.T1WI perfusion analysis was performed by the SYGNO VE40A workstation, using the software of TISSUE 4D,for the data acquireed After the injection of contrast agents 11 phase (5’30"),22 phase (11’),33 phase (16’30"),44 phase (22’),55 phase (27’30"). By manually selecting the obvious artery,such as bigger artery in the breast or the internal thoracic artery, the arterial input function (AIF) was obtained. Select the substantive component of the tumor as a region of interest (ROI) to obtain the following parameters: volume transfer constant (Ktrans);rate constant (KeP); extravascular extracellular volume fraction (Ve). Select three sections from each lesion:maximum axial—diameter section, one each at the upper 1/3 and lower 1/3 levels。The necrotic tissue, empty, calcification and blood vessels, etc should be avoided. Take average of the three parameter-numbers as the last result of the parameters.IVIM analysis was performed in Pride dwi software, and ROI measurement was obtained by processing images J software (the National Institute of Health, Bethesda, MD). Conventional and contrast enhanced T1 weighted MR imaging and DWI imaging (b=1000s/mm2) in the corresponding IVIM parameters mapping was used as reference to decide the leisions.The principle and the method of Placing ROI was the same as mentioned before as T1 perfusion analysis. At first ROI painted on a good signal-to-noise ratio (SNR) of D reflects image, then copy the ROI by J software to the imge of f and D*, according to D* and f to confirm and adjust that in the D images.All image measurements (T1 perfusion parameters and IVIM) were observed by 2 experienced radiologists independly.Results:1. There were significant differences of the Ktrans and Kep in diagnosis of the benign and malignant breast lesions in any of the five phases(P<0.05); there was significant difference of the Ve in diagnosis of the benign and malignant breast lesions only in 11 phase(P<0.05),and there were no statistically significant difference in the remaining phases (P>0.05). as setting the lower number(0.743 min-1) of Ktrans’s 95% confidence interval as the diagnostic standard, the diagnostic sensitivity and specificity were 96.7% and 91.5%; As setting the lower number(1.338 min-1)of the Kep’s 95% confidence interval as the diagnostic criteria, the diagnostic sensitivity and specificity were 86.3%, 84.6%.2. The correlation of T1 perfusion parameters with the scan delay time:For malignant leisions, the Ktrans and Kep between 33 phases and 44(or 55) phases had no significant statistically difference;For benign lesions, the Ktrans and Kep between 44 phases and 55 phases had no significant statistically difference; The Ve value of benign lesions was slowly rising with the delay time, while that of the malignant lesions had no significant changes with the delay time.3. The value of IVIM parameters in diagnosis of the benign and malignant breast lesions. There were significantly difference of the D,D*, f values between the benign lesions and malignant tumors (P= 0). The D values of malignant leisions were much smaller than that of the benign lesions (P=0.000). The f values of the malignant leisions were significantly higher than that of the benign lesions (P= 0.001). The D value value has higher sensitivity and specificity In differentiation of the benign and malignant lesions.Conclusion:1.The T1 perfusion parameters Ktrans and Kep had high efficiency for the identification of benign and malignant breast lesions,and the value of Ktrans in differentiating benign and malignant breast lesions had relatively greater significance.2.For the T1 perfusion scanning the best delay time is about 5 min after injection of contrast agent.There was no significant value for longer-delaying time of T1 perfusion scanning to differciate the benign and malignant breast lesions,espacialy it was more than 15min.3. IVIM can provide valuable information on tissue structure and microvasculature beneficial for the diagnosis of breast cancer lesions, and is helpful in the differential diagnosis of benign and malignant breast lesions.