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Objective To investigate the value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) permeability parameters in monitoring the early response to bevacizumab plus chemotherapy in colorectal cancer patients with liver metastases. Methods Magnetic resonance examinations including plain and DCE-MRI were performed in 28 colorectal cancer patients with liver metastases. The permeability parameters including the volume transfer constant (K trans ),extravascular extracellular volume fraction (V e ),reverse volume transfer constant (K ep ),and percentage of plasma volume (V p ) were measured before chemotherapy and at the first chemotherapy cycle. All the target lesions were grouped into the hypersensitivity and hyposensitivity groups,and t test was used to calculate the statistical significance between these two groups. The receiver operating characteristic (ROC) curve analysis was also performed for evaluating the diagnostic efficacy in monitoring the early response to chemotherapy. Results Totally 64 target lesions,including 29 lesions in the hypersensitivity group and 35 lesions in the hyposensitivity group,were confirmed. The K trans 0 and K ep0 values of the hypersensitivity group were significantly higher than those of the hyposensitivity group before chemotherapy (P=0.040,P=0.049),whereas the V e0 and V p0 values showed no significant change between these two groups (P>0.05). When the K trans 0 value was 1.129 min -1 ,the area under curve was 0.726,the sensitivity was 65.5%,and the specificity was 71.4%. Conclusion The DCE-MRI permeability parameters is useful for monitoring the early response to chemotherapy,and the K trans value can be a quantitative indicator to predict early response.

Unlabelled: OBJECTIVE To investigate the diagnostic value of combining permeability with T1 perfusion parameters in quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in glioma grading., Methods: Magnetic resonance imaging was performed in 16 patients with high grade gliomas (HGG) and 12 patients with low grade gliomas(LGG) confirmed by pathology. The permeability was quantitatively analyzed and the T1 perfusion parameters of the tumor were calculated by the pharmacokinetic model,including volume transfer constant (K(trans)),volume fraction of extravascular extracellular space (ve),reflux constant (kep),fractional plasma volume (vp),cerebral blood flow (CBF),cerebral blood volume (CBV),and mean transit time (MTT). A t-test was used to calculate the statistical significance of quantitative analysis parameters between HGG and LGG. The receiver operating characteristic curve analysis was also performed for evaluating the sensitivity,specificity,and area under curve (AUC) of the permeability parameters and perfusion parameters and the combination of these parameters., Results: The differences of the K(trans),ve,CBF,and CBV values [(0.276<0.164)/min vs. (0.084<0.044)/min;0.486<0.191 vs. 0.274<0.132;(1.755<1.164)ml/(g·min) vs. (0.761<0.625) ml/(g·min);(0.204<0.101) ml/g vs. (0.115<0.097)ml/g] were statistically significant (t=3.934,3.293,2.672,2.338,P<0.05) between HGG and LGG. The differences of the kep,vp, and MTT value [(1.632<1.204)/min vs. (1.537<1.194)/min;0.114<0.107 vs. 0.055<0.039;(0.128<0.070)min vs. (0.145<0.066)min] were not statistically significant (t=0.208,1.823,0.688,P>0.05). When the K(trans) value was 0.105/min,the AUC was the largest (0.919) by the single parameter in glioma grading,and meanwhile the sensitivity and specificity were 87.5% and 83.3%,respectively. When the ve-CBF value was 0.631,the AUC was the largest (0.974) by the multiple parameter,and meanwhile the sensitivity and specificity were 93.7% and 100.0%,respectively., Conclusion: Combining permeability with perfusion parameters in quantitative DCE-MRI can improve the accuracy of the glioma grading.

Objective: To compare the value of liver acquisition with volume acceleration (LAVA) and magnetic resonance cholangiopancreatography (MRCP) in diagnosing benign and malignant intraductal papillary mucinous neoplasms (IPMN) of the pancreas., Methods: The MR findings of 35 IPMN patients confirmed by pathology were analyzed retrospectively, and the sequences included T1WI, T2WI, LAVA, and MRCP. All patients were divided into two groups: the group of MRI enhancement (including T1WI, T2WI, and MRI enhancement) and the group of MRCP (including T1WI, T2WI, and MRCP). Two groups were evaluated by the receiver operating characteristic (ROC) curve., Results: Totally 23 cases of intraductal papillary mucinous tumors and 12 cases of intraductal papillary mucinous carcinomas were diagnosed. Finally, 29 cases (29/35) of IPMN were diagnosed correctly in the group of MR enhancement, and 25 cases (25/35) diagnosed correctly in the group of MRCP. The differential diagnostic accuracy of the group of MRI enhancement (82.9%) was higher than that of the group of MRCP (71.4%), although the difference was not statistically significant (P=0.068). The sensitivity, specificity, positive predictive value, and the area under the ROC curve (AUC) of the group of MRI enhancement were 83.3%, 82.6%, 71.4%, and 0.850, and those of the group of MRCP were 75.0%, 69.6%, 52.3%, and 0.723. The AUC of the group of MRI enhancement was significantly larger than that of the group of MRCP (P=0.0465)., Conclusion: MRI enhancement is more valuable than MRCP in the differential diagnosis of benign and malignant IPMN.

Objective: To compare the roles of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) using the liver acquisition with volume acceleration(LAVA) sequence and diffusion-weighted imaging(DWI) in the detection of hepatic metastases sized ≤3 cm., Methods: We retrospectively analyzed the MRI data of 16 patients with hepatic metastases. All the sequences used included T1WI, T2WI,3D-LAVA, and DWI (b value=500 s/mm(2)). All patients were divided into two groups based on the sequences: group A (T1WI, T2WI, and 3D-LAVA enhanced MR) and group B(T1WI,T2WI and DWI). The hepatic metastases were evaluated by analyzing the receiver operating characteristic (ROC) curves., Results: A total of 39 hepatic metastatic lesions were identified. The sensitivity, specificity, Youden index and the area under the ROC curve (AUC) were 97.4%, 88.2%, 0.856, and 0.944 in group A and 82.1%, 91.2%, 0.733, and 0.834 in group B. The ROC curves (p=0.040) and Youden index(p=0.043) in group A were significantly larger than in group B., Conclusion: Gadolinium-EOB-DTPA-enhanced MRI has higher accuracy than DWI in the detection of small metastases.