Dual-energy CT iodine map in predicting the efficacy of neoadjuvant chemotherapy for hypopharyngeal carcinoma: a preliminary study

Neoadjuvant chemotherapy has become one of the important means for advanced hypopharyngeal carcinoma. So far, there is no effective index to predict the curative effect. To investigate the value of iodine map of dual-energy computed tomography (CT) in predicting the efficacy of neoadjuvant chemotherapy for hypopharyngeal carcinoma. A total of 54 hypopharyngeal carcinomapatients who underwent two courses of TPF neoadjuvant chemotherapy were recruited in this study. Three cases had a complete response (CR), thirty-six cases had a partial response (PR), eleven cases had stable disease (SD), and four cases had a progressive disease (PD) after the chemotherapy. All patients underwent a dual-source CT scan before chemotherapy and rescanned after chemotherapy. The normalized iodine-related attenuation (NIRA) of the mean of maximum slice and most enhanced region of lesion at arterial and parenchymal phase were measured: NIRA(mean-A), NIRA(max-A), NIRA(mean-P), and NIRA(max-P), respectively. Correlation analysis was conducted between different metrics of NIRA and the diameter change rate of lesions, and the curative effect was evaluated based on the receiver operating characteristic (ROC) curve. There were a significant correlation between NIRA(mean-A), NIRA(max-A), NIRA(mean-P), NIRA(max-P) and the change rate of lesion’s maximum diameter (ΔD%) (all P < 0.01). The NIRA(max-A), NIRA(mean-P), NIRA(max-P) had significant differences between CR, PR, SD, PD groups, but NIRA(mean-A) did not reach a significant difference. All NIRA(mean-A), NIRA(max-A), NIRA(mean-P), NIRA(max-P) had significant differences between effective (CR + PR) and ineffective (SD + PD) groups. The ROC analysis revealed that NIRA(mean-P) had the largest AUC and prediction efficacy (AUC = 0.809). Dual-energy CT iodine map could predict the efficacy of neoadjuvant chemotherapy and provides imaging evidence to assist in treatment decisions for hypopharyngeal carcinoma patients.