Clinical Study Of Prediction Of Response To Chemotherapy In Gastrointestinal Hepatic Metastases:Value Of Apparent Diffusion Coefficients

Objective:The purposes of this study were to determine whether the apparentdiffusion coefficients (ADCs) of hepatic metastatic lesions from colorectal and gastriccancer are predictive of response to chemotherapy and to compare the ADCs of metastaticlesions before and after chemotherapy.Materials and MethodsSubjects of study:20patients with gastrointestinal hepatic metastases were collectedduring the period of January2012to January2014in our hospital.65lesions of livermetastases were included the gastric cancer with8patients,22lesions,12patients with43lesions of liver metastases of colorectal cancer.Method of examination:All patients received examination by using Philips PulsarHP1.5T MR with an eight channel coil.Image analysis:All patients received MR examination in before chemotherapy,2weeks,12weeks; original imagings of analysis and post-processing would spread toPhilips EWS2.6.3.2workstation, its own software would be used to generate ADC mapsand measure ADC values. The maximum diameters and ADCs were measured beforechemotherapy,2weeks,12weeks after chemotherapy.According to metastases sizes after12weeks of chemotherapy, all metastases classified as sensitive group and ineffectivegroup.The ADC and maximum diameter of metastases were judged in three time points ofbefore chemotherapy,2weeks,12weeks.Statistical analysis: All data was performed to analysis using SPSS18.0softwarepackage. Then compared two groups of metastatic tumor by before and after treatment, theADC value and the maximum diameter and age difference. Between the maximumdiameters and ADCs of the pretreatment lesions,between the maximum diameters and ADCs by treatment lesions, between pretreatment ADCs and reduction rate of themaximum diameters following treatment,between rate of changes of the ADCs and rate ofchanges of maximum diameter following treatment,between the pretreatment maximumdiameter and after treatment reduction rate of metastases were tested respectively using byspearman rank correlation.The receiver operating characteristic (ROC) curve weredetermined before chemotherapy optimal ADCs to determine the predictive sensitivity andspecificity of the ineffectiveness of chemotherapy lesions of liver metastases ofgastrointestinal tract cancer, and the positive and negative predictive values.The results:65metastases in20patients were analyzed. The30lesions of all total of65lesions after chemotherapy were sensitive group,the remaining35lesions wereineffective group. Pretreatment mean ADC (1.05±0.07×10-3mm2/s) of responders wassignificantly lower than that of nonresponders (1.26±0.09×10-3mm2/s)(P<0.001);after2weeks treatment,an early increase in ADCs was observed in responding lesions（1.30±0.02×10-3mm2/s,P<0.001) but not in non-responding lesions（1.29±0.10×10-3mm2/s,P=0.128),similarly,after12weeks treatment,an increase in ADCwas observed only in responding lesions(1.35±0.06×10-3mm2/s,P<0.001)but not innon-responding lesions(1.27±0.06×10-3mm2/s,P=0.146).Before treatment mean ADCs andthe maximum diameter of the lesions was no significant correlation (r=0.191,P=0.127);posttreatment mean ADCs and posttreatment lesion sizes (r=0.067,P=0.597);while between before treatment ADCs and reduction rate of metastases following treatmentshowed a significant negative correlation (r=-0.670, P <0.001); the rate of increase inADCs after treatment was positively correlated with tumor sizes reduction rate (r=0.685,P<0.001); reduction rate of metastases following treatment had no significant correlationwith the pretreatment maximum diameter (r=-0.112, P=0.374).Areas of under the curvewere0.913,pretreatment ADCs of1.17×10-3mm2/s concluded metastases to chemotherapyineffective sensitivity, specificity, positive predictive value and negative predictive valuewere80%,90%,90%and91.4%.Conclusion:(1)High pretreatment mean ADCs of hepatic metastasis from gastric or colorectal carcinomas were predictive of poor response to chemotherapy.(2) Followingchemotherapy,early ADC values increase of liver metastases was only in sensitive groupbut not in ineffective group.(3) The ADC value to predict hepatic metastases are sensitiveto chemotherapy.A mean pretreatment ADC of1.17×10-3mm2/s had80%sensitivity and90%specificity for identification of metastatic lesions not responding to chemotherapy.