The objective of this study was to investigate the correlation between dual-energy computed tomography (DECT)–based iodine quantitation and fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) imaging for response evaluation of lung cancers to treatment.
In this prospective study, a total of 32 pairs of DECT and 18F-FDG PET/CT imaging acquired consecutively from 13 patients with primary or metastatic lung cancers receiving either radiotherapy alone or chemoradiotherapy were analyzed. Imaging examinations were performed before, immediately, and no later than 6 months after treatment for response evaluation. Iodine-related parameters including the total iodine uptake (TIU) and vital volume (VIV) from DECT and metabolic metrics such as the standardized uptake value normalized to lean body mass (SULpeak), metabolic tumor volume (MTV), and the total lesion glycolysis (TLG) from 18F-FDG-PET/CT were generated and measured by semiautomatic approaches. Dual-energy CT and PET/CT metrics were calculated and followed up with comparison with response evaluation criteria in solid tumors (RECIST).
Analysis of pretreatment imaging data revealed a strong correlation between DECT metrics (RECIST, TIU, and VIV) and 18F-FDG PET/CT metrics (MTV, TLG) with coefficients of R ranging from 0.86 to 0.90 (P < 0.01). With the delivery of treatment, all measured DECT and PET/CT metrics significantly decreased whereas the descending amplitude in RECIST was significantly smaller than that of the remaining parameters (P < 0.05). During follow-up examinations, both metrics followed a similar changing pattern. Overall, strong consistency was found between RECIST, TIU, VIV and SULpeak, MTV, TLG (R covers 0.78–0.96, P < 0.05).
Semiautomatic iodine-related quantitation in DECT correlated well with metabolism-based measurements in 18F-FDG PET/CT, suggesting that DECT-based iodine quantitation might be a feasible substitute for assessment of lung cancer response to chemoradiotherapy/radiotherapy with comparison with 18F-FDG PET/CT.
From the Departments of *Radiation Oncology,
‡Nuclear Medicine, Fudan University Huadong Hospital;
§Siemens Healthineers; and
∥Zhang Guozhen Diagnosis and Treatment Center of Lung Cancer, Fudan University Huadong Hospital, Shanghai, China.
Received for publication December 4, 2017; accepted January 16, 2018.
Correspondence to: Xiangpeng Zheng, MD, PhD, Department of Radiation Oncology/Zhang Guozhen Diagnosis and Treatment Center of Lung Cancer, Fudan University Huadong Hospital, No 221, West Yan'an Rd, Shanghai, China (e-mail: Zhengxp@fudan.edu.cn).
This work has been financially supported by the National Natural Science Foundation of China (grant numbers 81472794 and 11505029), Shanghai Municipal Commission of Health (20134360), Shanghai Municipal Commission of Science and Technology (24119a0400), the Young Investigator Fund of Fudan University (grant number EYF163006), and a research fund from Siemens Company (981). The authors declare no conflict of interest.
Part of this work in abstract format was submitted to the 59th Annual Meeting of the American Society for Therapeutic Radiology and Oncology (on September 24–27, 2017 in San Diego, CA) and selected as oral presentation in the session of Best of Physics.