Correlation between tumor size and blood volume in lung tumors: a prospective study on dual-energy gemstone spectral CT imaging

Abstract

The purpose of this study was to investigate the relationship between tumor size and blood volume for patients with lung tumors, using dual-energy computed tomography (DECT) and a gemstone spectral imaging (GSI) viewer. During the period from March 2011 to March 2013, 50 patients with 57 medically inoperable lung tumors underwent DECT before stereotactic body radiotherapy (SBRT) of 50–60 Gy in 5–6 fractions. DECT was taken for pretreatment evaluation. The region-of-interest for a given spatial placement of the tumors was set, and averages for CT value, water density and iodine density were compared with tumor size. The average values for iodine density in tumors of ≤2 cm, 2–3 cm, and >3 cm maximum diameter were 24.7, 19.6 and 16.0 (100 µg/cm3), respectively. The average value of the iodine density was significantly lower in larger tumors. No significant correlation was detected between tumor size and average CT value or between tumor size and average water density. Both the average water density and the average CT value were affected by the amount of air in the tumor, but the average iodine density was not affected by air in the tumor. The average water density and the average CT value were significantly correlated, but the average iodine density and the average CT value showed no significant correlation. The blood volume of tumors can be indicated by the average iodine density more accurately than it can by the average CT value. The average iodine density as assessed by DECT might be a non-invasive and quantitative assessment of the radio-resistance ascribable to the hypoxic cell population in a tumor.

Analysis of pulmonary pure ground-glass nodule in enhanced dual energy CT imaging for predicting invasive adenocarcinoma: comparing with conventional thin-section CT imaging

“…Gemstone spectral imaging (GSI) analysis software is a specific tool in dual energy computed tomography (DECT) with the fast-kVp-switching mode, and it provides material density measurement using the material decomposition images and generates CT attenuation value as function of photon energy using the 101 sets of virtual monochromatic images generated in the dual energy spectral CT imaging (14). Using iodine decomposition imaging of DECT, some researchers have observed enhancement of GGNs (14)(15)(16).…”

“…Using iodine decomposition imaging of DECT, some researchers have observed enhancement of GGNs (14)(15)(16). Because iodine concentration (IC) would not be affected by air in lesions, it is considered to reflect blood volume better than CT number in GGNs (14).…”

“…Using iodine decomposition imaging of DECT, some researchers have observed enhancement of GGNs (14)(15)(16). Because iodine concentration (IC) would not be affected by air in lesions, it is considered to reflect blood volume better than CT number in GGNs (14). Additionally, DECT can also provide information about the attenuation changes in different materials as a function of X-ray photon energy (17,18).…”

Comparison of radiomic features in diagnostic CT images with and without contrast enhancement in the delayed phase for NSCLC patients

“…The reason may be that the "ever" group includes all patients who had ever smoked and was thus larger than the sample size of patients in dataset CE who had "never" smoked, which was only 10, as shown in Table 1. For the GTV volume, Aoki et al reported that the mean CT value increased slightly for large tumor sizes with contrast enhancement [39]; in their study, the tumor size and mean CT values were acquired from only the maximum cross-section, and the CT scan was started 25 s after the start of contrast injection. In our study, CT images were acquired in the delayed phase, and the number of radiomic features extracted from the three-dimensional ROIs with a significant difference between datasets NE and CE increased with the GTV volume.…”

Is there any correlation between spectral CT imaging parameters and PD‐L1 expression of lung adenocarcinoma?

“…Fourth, monochromatic CT number was measured only enhanced monochromatic spectral CT imaging at the energy level 40 and 70 keV based on previous studies, ignoring the other keV selection. Fifth, quantifying microvessel densities previously described in a previous study were not included in this study.…”