Dynamic contrast-enhanced MRI versus ^(18)F-FDG PET/CT: Which is better in differentiation between malignant and benign solitary pulmonary nodules?

Objective： To prospectively compare the discriminative capacity of dynamic contrast enhanced-magnetic resonance imaging（DCE-MRI） with that of^18F-fluorodeoxyglucose（^18F-FDG） positron emission tomography/computed tomography（PET/CT） in the differentiation of malignant and benign solitary pulmonary nodules（SPNs）.Methods： Forty-nine patients with SPNs were included in this prospective study. Thirty-two of the patients had malignant SPNs, while the other 17 had benign SPNs. All these patients underwent DCE-MRI and ^18F-FDG PET/CT examinations. The quantitative MRI pharmacokinetic parameters, including the trans-endothelial transfer constant（K^trans）, redistribution rate constant（Kep）, and fractional volume（Ve）, were calculated using the Extended-Tofts Linear two-compartment model. The ^18F-FDG PET/CT parameter, maximum standardized uptake value（SUV（max））, was also measured. Spearman＇s correlations were calculated between the MRI pharmacokinetic parameters and the SUV（max） of each SPN. These parameters were statistically compared between the malignant and benign nodules. Receiver operating characteristic（ROC） analyses were used to compare the diagnostic capability between the DCE-MRI and ^18F-FDG PET/CT indexes.Results： Positive correlations were found between K^trans and SUV（max）, and between K（ep） and SUV（max）（P〈0.05）.There were significant differences between the malignant and benign nodules in terms of the K^trans, K（ep） and SUV（max） values（P〈0.05）. The areas under the ROC curve（AUC） of K^trans） K（ep） and SUV（max） between the malignant and benign nodules were 0.909, 0.838 and 0.759, respectively. The sensitivity and specificity in differentiating malignant from benign SPNs were 90.6% and 82.4% for K^trans; 87.5% and 76.5% for K（ep）; and 75.0% and 70.6%for SUV（max）, respectively. The sensitivity and specificity of K^trans and K（ep） were higher than those of SUV（max）, but there was no significant difference between them（P〉0.05）.Conclusions： DCE-MRI can be used to differentiate between benign and malignant SPNs and has the advantage of being radiation free.

Changes of CT dynamic contrast-enhanced scan parameters in patients with lung cancer before and after radiofrequency ablation

Objective:To study the changes of CT dynamic contrast-enhanced scan parameters in patients with lung cancer before and after radiofrequency ablation (RFA) and their correlation with serum tumor markers.Methods:A total of 60 patients who were diagnosed with lung adenocarcinoma in the Second Hospital of Yulin City between May 2015 and January 2017 were selected and randomly divided into the RFA group and control group who received RFA combined with GP chemotherapy and GP chemotherapy alone respectively. Before and after treatment, CT dynamic contrast-enhanced scan was performed to calculate blood perfusion parameters, and serum was collected to determine the contents of cancer cell proliferation activity molecules, angiogenesis molecules and cell invasion molecules.Results: After treatment, BF, BV, MTT and PS levels as well as serum CYFRA21-1, SCC-Ag, TK-1, HE-4, TPS, HDGF, VEGF, PCDGF, bFGF, NGAL, MMP7, MMP9 and OPN contents of both groups of patients were significantly lower than those before treatment, and BF, BV, MTT and PS levels as well as serum CYFRA21-1, SCC-Ag, TK-1, HE-4, TPS, HDGF, VEGF, PCDGF, bFGF, NGAL, MMP7, MMP9 and OPN contents of RFA group after treatment were significantly lower than those of control group.Conclusions:The changes of CT dynamic contrast-enhanced scan parameters in patients with lung cancer before and after radiofrequency ablation suggest that the blood perfusion significantly reduces and is closely related to cancer cell proliferation and invasion as well as angiogenesis.