Rui Qi, Presenter: Nothing to Disclose

Zhenlin Li MD, Abstract Co-Author: Nothing to Disclose

Xiaohui Zhang, Abstract Co-Author: Employee, Siemens AG

To evaluate the value of iodine quantification by dual-source dual-energy computed tomography(DSDECT) in appraising chemotherapy effect of liver metastases of rectal cancer.

A total of 7 patients (2 female, 5 male, mean age 52y) with liver metastases from unresectable rectal cancer were retrospectively analyzed. 37 lesions were evaluated, range 4-7 lesions each. In all cases, a first line therapy with oxaliplatin was stopped and second line therapy with Zaltrap+FOLFIRI was initiated. Time interval between first cycle of second line and stop of last cycle of primary therapy was minimum 1 month each. DSDECT scans were performed (SOMATOM Definition Flash, Siemens) before application of second line therapy as base line and directly after end of each cycle according to clinical standards. Iodine quantification was based on portal venous phase (PVP, standardized iodine load and injection rate). According to RECIST criteria, number of patients classified as partial response / progressive disease (PR/PD) were 4/3 (total number of metastases per group 23/14). Iodine quantification was performed on the manufactures workstation (MMWP, Siemens) and region of interest to evaluate the iodine concentration (standardized iodine value used, SIV, normalization by iodine uptake of surrounding liver parenchyma) were placed in areas with maximal enhancement within solid tumor tissue. A two sample t-test was used for statistical analysis.

SIV for PR (0.46±0.24) and PD(0.71±0.28)group in DSDECT before chemotherapy were significantly different  in the PVP scan(P=0.011). The change of SIV between pre-chemotherapy and first cycle of the chemotherapy for PR group (0.13±0.20) were significantly different with that in PD group (-0.12±0.14)(P=0.00). The change of SIV between pre-chemotherapy and second cycle of the chemotherapy for PR group (0.19±0.19) was also significantly higher than that in PD group (-0.19±0.28)(P=0.00). For PR group the SIV increased in most target lesions after chemotherapy, while for PD group the SIV decreased.

SIV  provided information in the base line scanning and reflected the early response on second line chemotherapy in liver metastases of advanced rectal cancer. This preliminary study  may be a robust and simple parameter for therapy assessment.

SIV may be a easy obtained parameter to therapy follow-up and predication for second line chemotherapy of liver metastases.

Qi, R, Li, Z, Zhang, X, Is Iodine Quantification Able to Reflect Early Chemotherapy Response of Liver Metastases Origination from Rectal Cancer?—Preliminary Results.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14008476.html