Linear reference region model and Tofts model in dynamic contrast-enhanced MRI of discriminating benign and malignant breast lesions comparative study

Abstract

Objective To investigate and compare the diagnostic values of linear reference region model (LRRM) and Extended Tofts model in quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) analysis of benign and malignant breast lesions under different temporal resolutions. Methods Eight five suspicious breast cancer women underwent bilateral DCE-MRI exam, 37 patients were benigns and 48 patients were malignants. Among those, 31 patients(15 malignant, 16 benign) were scanned with 18 s per phase, and 54 patients(33 malignant, 21 benign) were scanned with 7 s per phase, and they were assigned into breast cancer group, benign lesion group and healthy gland group proven by surgery or biopsies. For the same model, Ktrans values of the three groups under different time resolution were first analyzed using Kruskal-Wallis H rank sum test. Receiver operator curve (ROC) was used to analyse the diagnostic efficiency of Ktrans values. Results Under high and low temporal resolutions, Ktrans values of the healthy group were (0.048 ± 0.022) and (0.090 ± 0.040)/min for extended Tofts model,(0.301 ± 0.197) and (0.287±0.225)/min for LRRM model respectively.Ktrans values of the benign group were (0.289±0.163) and (0.211 ± 0.080)/min for extended Tofts,(0.624 ± 0.358) and (0.593 ± 0.165)/min for LRRM respectively.Ktrans values of the malignant group were (0.959±0.451) and (0.524±0.285)/min for extended Tofts,(1.576±0.935) and (0.956±0.180)/min for LRRM respectively.There were significant differences among the three different groups(P<0.05).Area under the ROC to differentiate benign and malignant breast lesions for Extended Tofts in high temporal, LRRM in high temporal, Tofts in low temporal and LRRM in low temporal were 0.941, 0.876, 0.850 and 0.933, with Ktrans cutoff values of 0.304, 0.917, 0.252 and 0.789/min,and sensitivity of 93.9%, 80.0%,80.0%, 80.0%;specificity of 85.7%, 90.5%, 81.2%, 87.5% respectively. Conclusion Under low temporal resolutions, Ktrans of LRRM model had better sensitivities and specificities in differentiation of benign and malignant breast lesions than Extended Tofts model, which was the opposite in high temporal resolutions. Key words: Breast neoplasms; Magnetic resonance imaging; Comparative study