Lei Tang MD, Presenter: Nothing to Disclose

Zi-Yu Li, Abstract Co-Author: Nothing to Disclose

Ying-Shi Sun MD, PhD, Abstract Co-Author: Nothing to Disclose

Jia-Fu Ji, Abstract Co-Author: Nothing to Disclose

Xiaoting Li, Abstract Co-Author: Nothing to Disclose

Zhong-Wu Li, Abstract Co-Author: Nothing to Disclose

Xiao-Peng Zhang MD, Abstract Co-Author: Nothing to Disclose

To investigate the potential of iodine concentration (IC) determined by spectral CT in the response prediction of gastric cancer to preoperative neoadjuvant chemotherapy (NC).

The institutional review board approved this prospective study. All patients signed the written informed consent. Twenty enrolled patients with advanced gastric cancer underwent spectral CT examination twice (1 week before NC and after 2 cycles of NC), with anisodamine and effervescent granules administered to guarantee the shape consistency and stability of gastric wall. Spectral CT imaging was performed with fast tube voltage switching between 80 and 140kVp during a single rotation. The percentage changes of the tumor size (%ΔCWT) and the IC values on arterial phase (%ΔIC-a) after NC were calculated on the 70keV monochromatic and iodine-based material decomposition images, respectively and compared among different response groups. The pathological regression grades 1-3 were defined as 50% residual tumor per tumor bed, respectively. Grade 1 was defined as good response (GoodR) and Grades 2-3 as poor response (PoorR). The diagnostic efficacies of the two parameters were evaluated using ROC curves.

The decrease rate of %ΔIC-a in the GoodR group was higher than that of the PoorR group (-0.59 [-0.76, -0.20] vs. -0.11 [-0.75, 0.92], P=0.012). No significant difference was observed between GoodR and PoorR with regard to %ΔCWT (-0.16 [-0.65, 0.20] vs. -0.04 [-0.40, 0.13], P=0.779). The AUCs of ROC were 0.857 and 0.542 for %ΔIC-a and %ΔCWT respectively, in the response prediction of gastric cancer to NC. Taking the decrease rate of %ΔIC-a > 52.9% as the cutoff value to identify good responders, the sensitivity was 0.857 and specificity was 0.833. Taking the decrease rate of %ΔCWT > 17.4% as the cutoff value to judge good responders, the sensitivity and specificity values were 0.643 and 0.500, respectively.

The change of the tumor IC after neoadjuvant chemotherapy measured by spectral CT has good correlation with pathological regression of gastric cancer, which has better prediction efficacy than tumor size.

The iodine concentration in spectral CT has potential in the response prediction of gastric cancer to neoadjuvant chemotherapy, which may provide personalized information for treatment.

Tang, L, Li, Z, Sun, Y, Ji, J, Li, X, Li, Z, Zhang, X, The Correlation of Iodine Concentration in Spectral CT and Pathological Regression in Gastric Cancer to Neoadjuvant Chemotherapy: A Pilot Study.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14003027.html