Prognostic impact of average iodine density assessed by dual-energy spectral imaging for predicting lung tumor recurrence after stereotactic body radiotherapy

Abstract

The purpose of this study was to investigate the prognostic significance of average iodine density as assessed by dual-energy computed tomography (DE-CT) for lung tumors treated with stereotactic body radiotherapy (SBRT). From March 2011 to August 2014, 93 medically inoperable patients with 74 primary lung cancers and 19 lung metastases underwent DE-CT prior to SBRT of a total dose of 45–60 Gy in 5–10 fractions. Of these 93 patients, nine patients had two lung tumors. Thus, 102 lung tumors were included in this study. DE-CT was performed for pretreatment evaluation. Regions of interest were set for the entire tumor, and average iodine density was obtained using a dedicated imaging software and evaluated with regard to local control. The median follow-up period was 23.4 months (range, 1.5–54.5 months). The median value of the average iodine density was 1.86 mg/cm3 (range, 0.40–9.27 mg/cm3). Two-year local control rates for the high and low average iodine density groups divided by the median value of the average iodine density were 96.9% and 75.7% (P = 0.006), respectively. Tumors with lower average iodine density showed a worse prognosis, possibly reflecting a hypoxic cell population in the tumor. The average iodine density exhibited a significant impact on local control. Our preliminary results indicate that iodine density evaluated using dual-energy spectral CT may be a useful, noninvasive and quantitative assessment of radio-resistance caused by presumably hypoxic cell populations in tumors.

Single-source Dual-energy CT as a Part of 18F-FDG PET/CT: Direct Comparison of Iodine-related and Metabolic Parameters in Non-small Cell Lung Cancer

“…Our findings regarding the very strong correlation of MTV and TLG with iodine content may contribute to the further implementation of DE-CT in algorithms for the evaluation of NSCLC. While studies using FDG uptake to determine patient prognosis have already been reported, only a small number have addressed the prognostic value of DE-CT in cancer (26,27). In addition to their prognostic value, MTV and TLG parameters are also beneficial in assessing the actual response to therapy.…”

Iodine-related attenuation in contrast-enhanced dual-energy computed tomography in small-sized solid-type lung cancers is associated with the postoperative prognosis

“…Therefore, it is more important to predict the invasiveness and prognosis of the tumor by radiological imaging before treatment. One previous study reported that the IRA at the early phase of contrast DE-CT is useful in predicting recurrence after SRT [ 19 ]. Although surgery and SRT are different treatment modalities, our results are consistent with their conclusions.…”

“…Several research findings indicate that iodine uptake in the arterial phase on contrast CT of primary lung cancer may be associated with some aspects of tumor histopathology such as angiogenesis, differentiation grade, hypoxic cells, and tumor invasiveness [12,[15][16][17][18]. Moreover, a few studies indicated that iodine uptake of lung cancer correlated with tumor recurrence after radiotherapy and chemoradiotherapy [19,20]. Therefore, we speculated that the three-dimensional iodine-related attenuation (3D-IRA) of solid nodules might be associated with the postoperative recurrence of small-sized lung cancers.…”

Dual energy imaging in cardiothoracic pathologies: A primer for radiologists and clinicians

“…Similarly, Carrascosa et al demonstrated that stress myocardial perfusion protocol by DECT added value in detecting reversible perfusion defects ((area under ROC curve 0.84 (0.80−0.87)) and anatomy of coronary artery disease (area under ROC curve 0.70 (0.65−0.74)) compared to SPECT and CT coronary angiography, respectively [ 66 ]. In radiation therapy planning, studies have demonstrated that average iodine density of tumor from DECT may serve as a noninvasive and quantitative assessment of radio-resistance and predictor of the prognosis and overall treatment response [ 67 ].

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