To solve the problem that the method based on tumor morphology or overall average parameters of tumor cannot conduct the early evaluation of tumor treatment response, we proposed a voxel-wise method. The voxel-wise method uses the method combining rigid and elastic registration algorithm to align the tumor area before and after treatment on the images which are acquired by the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI). We calculated voxel-wise volume transport constant (Ktrans) using pharmacokinetic model, and designed a threshold d to get the volume fraction of voxels which Ktrans increased significantly (F+), Ktrans decreased significantly (F-) or had no significant change (F0). Linear regression analysis was performed to get the correlation between volume fractions and pathological tumor cell necrosis rate (TCNR). We then determined the ability of volume fractions to evaluate treatment response at early stage by receiver operating characteristic (ROC) curve analysis. We performed experiments on 10 patients with soft tissue sarcomas. The results indicated that F- had significant negative correlation with TCNR (R2=0.832 8, P=0.0002), F0 has significant positively correlation with TCNR (R2=0.788 4, P=0.0006). In addition, F-(AUC=0.905,P=0.053), F0 (AUC=0.857,P=0.087) had a good ability in early tumor treatment response evaluation. Therefore, F- and F0 can be used as effective imaging biomarkers for early evaluation of tumor treatment.
ObjectiveTo summarize the research progress of magnetic resonance imaging (MRI) for diagnosis of nonalcoholic steatohepatitis (NASH).MethodRelevant literatures at home and abroad were collected to make an review, then summarized the research status and progress of MRI for diagnosis of NASH. Their advantages and disadvantages were summarized.ResultsA variety of MRI techniques, including MR elastography, gadolinium-ethoxybenzyldiethylenetriaminepentaacetic acid (Gd-EOB-DTPA) enhanced MRI, diffusion-weighted MR imaging, and quantitative MR imaging of fat and iron, had been widely used in diagnosing NASH and shown to have some value. However, there were currently no effective MRI techniques recommended for diagnosing NASH.ConclusionsMRI plays an important role in noninvasive assessment of NASH. Future studies are needed to investigate more efficient noninvasive biomarkers and models consisting of imaging and non-imaging biomarkers for diagnosing NASH, to reduce unnecessary biopsies.
