Effect of temporal resolution of breast dynamic contrast-enhancing MRI on pharmacokinetic parameters / 中华放射学杂志

ABSTRACT

Objective To evaluate the effect of temporal resolution of breast dynamic contrast-enhancing (DCE)-MRI on pharmacokinetic parameters and diagnostic performance in benign and malignant breast lesions.Methods Retrospective review was performed on 26 benign and 29 malignant breast lesions which were proven pathologically by surgery or biopsy.Dynamic contrast enhanced breast MRI using a new volume-interpolated-breath-hold examination sequence combining parallel acquisition, Dixon fat separation and time-resolved imaging with interleaved stochastic trajectories (CDT-VIBE) was performed in all patients.The original time resolution of this sequence was 12 s and based on which, dynamic sequences with different temporal resolutions of 24 s, 36 s, 48 s and 60 s were simulated by a sample-removing method and were used for the calculation of pharmacokinetic parameters, including volume transfer constant (Ktrans), constant flux rate (Kep), volume of extravascular extracellular space (Ve) and area under the curve at initial 60 s (iAUC), to observe their changes with different temporal resolution.The repeated measurement of analysis of variance was used to explore significant changes in pharmacokinetics parameters with different temporal resolution.To evaluate the diagnostic efficiency of parameters with different temporal resolution, ROC analysis was performed in accordance with pathological findings.Results With decrease of temporal resolution from 12 to 60 s, there was a significant increase in Ktrans and Kep of benign lesions [Ktrans (0.147±0.084)/min to (0.170 ± 0.085)/min, Kep (0.321± 0.176)/min to (0.433± 0.175)/min] and steady decrease in Ktrans and Kep of malignant lesions [Ktrans (0.373±0.210)/min to (0.259± 0.122)/min, Kep (0.929 ±0.402)/min to (0.581 ± 0.143)/min];the changes of Ve were less significant and irregular;the values of iAUC decreased both in benign [(9.192± 4.660) to (7.388± 3.065)] and malignant [(20.221±9.876) to (12.850±5.194)] lesions.The changes in all parameters with different time resolution were statistically significant in benign and malignant lesions (all P＜0.05).By pair-wise comparison between different time resolution, the changes of K among 12 s, 24 s and 36 s (all P＜0.05), the changes of Kep between 12 s and others (all P＜0.01), the changes of Ve between 24 s and others (all P＜0.01), and the changes among all pairs of iAUC were significant (all P＜0.05) except for 12 s and 24 s (P=1.000).The best AUC value of Ktrans and Kep between benign and malignant lesions were achieved with 12 s dynamic sequences (0.887, 0.939), and the best AUC value of iAUC was with 24 s sequences (0.877).The AUC values of Ve were between 0.511 to 0.601, which was lower than that of other three parameters.Conclusion A 24 s or higher temporal resolution of DCE-MRI should be able to provide consistent differentiation of pharmacokinetic parameters in benign and malignant breast lesions.