Free breathing DCE-MRI with motion correction and its values for benign and malignant liver tumor differentiation

Objective3D dynamic contrast enhanced (DCE) MRI with parallel imaging, a novel method to understand tumor vascularization in vivo, has been applied to liver in this work. Pharmacokinetics analysis could be performed with the help of motion correction by non-rigid registration using the first pass data. The purpose of this study was to assess the feasibility of using this framework to differentiate benign and malignant tumor in liver with DCE-MRI.Material and methodsThis prospective study was approved by the institutional review board, and informed consent was given by all patients. 48 Patients (56.1 ± 12.6 years old), with 51 pathologically confirmed liver tumor, were recruited in this study. All subjects underwent DCE-MRI sequence with free-breathing, which was consisted of multi-flip angle contrast free image acquisition for T1 mapping, and a continuous multiphase acquisition to capture contrast media wash in and out. Automatic non-linear image registration was applied to both multi-flip angle data and dynamic phase data for motion correction. Parameters such as Ktrans, Vp, were then extracted by performing pharmacokinetic analysis on the first pass data. Parameters from different types of tumor were evaluated by statistical analysis.ResultsAll 48 patients successfully finished examinations and image quality was good for diagnosis purpose. Subjective comparisons between original images and motion corrected images showed that images registration used in the paper can well control liver respiration motion and ROI time–intensity curve was much smoother after registration. 51 Visible lesions from 48 patients were analyzed. Pathological results revealed that there were 15 benign (hepatic hemangioma) and 36 malignant (14 liver metastasis and 22 liver carcinomas) lesions. Statistical results showed that benign and malignant tumors demonstrated significant differences (p < 0.05) in their Ktrans values, with hepatic hemangioma (Ktrans 0.09 ± 0.04), liver metastasis (Ktrans 0.25 ± 0.08) and hepatic carcinoma (Ktrans 0.25 ± 0.10). Ktrans of malignant tumors was substantially higher than benign ones. Vp values of the three types did not have statistical significance, with hepatic hemangioma (Vp 0.124 ± 0.176), liver metastasis (Vp 0.164 ± 0.184) and hepatic carcinoma (Vp 0.162 ± 0.184).ConclusionDynamic contrast-enhanced MRI combined with tracer kinetic model and non-rigid registration was a feasible method for diagnosing of liver lesions under free breezing mode. In our approach, the contrast agent transfer rate Ktrans was a good biomarker to differentiate benign and malignant tumors of liver.