Preliminary Study of Enhancement Pattern Changes in the Assessment of Nonsurgical Treatment in Bronchogenic Carcinoma

Objective To preliminarily evaluate the efficacy of enhancement pattern changes in assessing nonsurgical treatment in bronchogenic carcinoma. Materials and Methods 33 patients with bronchogenic carcinoma underwent dural phase enhanced CT scan before and after stopping nonsurgical treatment more than one month.Dural phase CT scans were obtained at 25 and 90 seconds respectively after injection of nonionic contrast material via the antecubital vein at a rate of 3 ml/sec by using an autoinjector.The sum of the tumor longest diameters before and after treatment,and the sum of the tumor enhancement area longest diameters after treatment on the images obtained at 90 seconds after injection of contrast medium were recorded.Precontrast and postcontrast CT attenuation on every scan was recorded and peak height was calculated.The significance of the difference among groups was analyzed by means of ANOVA,student t test and chi-square test. Results The sum of the tumor longest diameters before treatment,that of after treatment and the sum of the post-treatment tumor enhancement area longest diameters on the images obtained at 90 seconds after injection of contrast medium were (4.49±1.32),(4.05±1.63),(3.36±1.22) cm respectively and there were statistically significant differences among them(F=5.467,P=0.006). The sum of the tumor longest diameters prior to treatment was significantly higher than that of the post-treatment tumor enhancement area(P=0.001).No statistically significant difference in the sum of the tumor longest diameters was found between the pre-treatment and the post-treatment(P=0.207).There was not statistically significant difference between the sum of the tumors longest diameters and that of tumor enhancement area after treatment(P=0.086).The response rate(RR)(21.21%)according to changes in sum of the tumor longest diameters was significantly lower than that (30.30%)according to changes in the sum of the post-treatment tumor enhancement area longest diameters(χ2=15.12,P0.05),and the progressive diseases(PD) rate (21.21%)was significantly higher than that of the sum of the post-treatment tumor enhancement area longest diameters on the images obtained at 90 seconds(12.12%)(χ2=14.12,P0.05).No statistically significant difference was found between precontrast attenuation before treatment(41.77±7.03)HU and that after treatment(41.89±7.63)HU(t=0.335,P=0.740﹥0.05).Peak height of bronchogenic carcinoma prior to treatment (36.50±11.21)HU were significantly higher than that after treatment (29.91±10.35)HU (t=10.081,P=0.001). Conclusion Therapeutic effect may be underestimated with use of changes in sum of the tumor longest diameters. The changes in sum of tumor enhancement area longest diameters combined with peak height are suggested to be used in assessing nonsurgical treatment response in bronchogenic carcinoma.