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[Value of double contrast-enhanced ultrasound QontraXt three-dimensional pseudocolor quantitative analysis to therapeutic effect evaluation of preoperative neoadjuvant chemotherapy in advanced gastric cancer patients].

Objective: To investigate the value of tumor perfusion parameter measured by using double contrast-enhanced ultrasound (DCEUS) QontraXt three-dimensional pseudocolor quantitative analysis to the therapeutic effect evaluation of preoperative neoadjuvant chemotherapy (NAC) in advanced gastric cancer (AGC) patients. Methods: Eighty-nine AGC patients underwent 3 cycles of preoperative NAC (XELOX) followed by complete resection of lesion. The DCEUS QontraXt three-dimensional pseudocolor was performed one or two weeks before the NAC and operation were applied, respectively. The peak enhancement (PE), time to peak (TP), sharpness of the bolus (β) and area under the enhancement curve (AUC) of primary gastric tumor were measured by QontraXt three-dimensional pseudocolor quantitative analysis. These DCEUS parameters between respond and non-respond groups before and after NAC therapy were compared. The prediction accuracy of DCEUS to the therapeutic effect evaluation of preoperative NAC was determined by the receive operating characteristic (ROC) curves. Results: Among 89 AGC patients, 52 patients responded to NAC therapy, while 37 patients resisted to NAC therapy. Twelve cases in respond group and 26 cases in non-respond group were mucinous carcinoma. Forty cases in respond group and 11 cases in non-respond group were non-mucinous carcinoma (P<0.05). In responder group, the PE and TP before NAC were (53.7±9.3)% and (14 521±2 667) ms, and (32.2±5.5)% and (17 235±1 898) ms after NAC. The ratio of changes of PE (ΔPE) and TP (ΔTP) were 0.43±0.17 and 0.36±0.14, respectively. In non-respond group, the PE and TP before NAC were (54.4±7.2)% and (13 869±3 247) ms, and (45.3±6.1)% and (15 127±1 423) ms after NAC therapy. The ratio of ΔPE and ΔTP were 0.24±0.20 and 0.22±0.12. The PE and TP after NAC, the ratio of ΔPE and ΔTP were significant different among these two groups (all of P<0.05). The ROC curves showed that the ratio of ΔPE in assessing the respond of gastric cancer patients to NAC was superior compared to other parameters (AUC=0.784, P=0.004). The optimal cut-off value of the ratio of ΔPE was 24% and its sensitivity and specificity to the therapeutic effect evaluation of NAC in gastric cancer were 82.7% and 64.9%. Conclusion: DCEUS QontraXt three-dimensional pseudocolor quantitative analysis might be a novel, noninvasive and reliable method to evaluate the therapeutic effect of preoperative NAC in AGC patients.