Quantitative assessment of iron in heart and liver phantoms using dual-energy computed tomography.

The aim of the present study was to determine the correlation between dual-energy computed tomography (DECT) Hounsfield units (HU) and iron concentration, as well as the correlation between HU and magnetic resonance imaging (MRI)-derived R2* values, in phantoms of the heart and liver tissue. Phantoms were constructed containing pig heart or liver tissue and varying concentrations of iron (0.1, 5, 10, 15, 20 and 25 mg/ml). The phantoms were then examined by DECT and MRI. Linear regression analysis was used to determine the correlations between HU and iron concentration and HU and R2* values. The HU value of DECT increased with increasing iron concentrations in the liver and heart phantoms in a linear manner. The slope of the HU value change against iron concentration revealed that ΔH80-140 provided a better discernment of iron concentration as compared with ΔH100-140. The derived R2 values were all >0.9 for the associations of DECT and MRI measurements with iron concentrations. Therefore, DECT may be used for the determination of iron concentration in the liver and heart tissue, with the results correlating with those obtained with MRI.

Nitroglycerine use in transcatheter arterial (chemo)embolization in patients with hepatocellular carcinoma and dual-energy CT assessment of Lipiodol retention.

OBJECTIVES: To investigate whether the addition of nitroglycerine to transcatheter arterial (chemo)embolization (TAE/TACE) can increase the delivery and effectiveness of TAE/TACE in patients with hepatocellular carcinoma (HCC) by dual-energy CT. METHODS: HCC patients (BCLC stage A or B) were randomized to (n = 51) or not to (n = 50) receive nitroglycerine and an emulsion of Lipiodol with or without doxorubicin, followed by embolization with Gelfoam pledgets. Dual-energy CT was performed pre- and 1 to 3 months post-embolization to assess changes in tumour diameter and Lipiodol levels in tumours. RESULTS: Median tumour diameter decreased from baseline in both groups with and without nitroglycerine (7.11 % vs. 12.5 %, respectively), and was statistically significant in the group receiving nitroglycerine (P = 0.023). There was no difference between the two groups in disease response (P = 0.237). The concentration and percentage of Lipiodol retained in tumours were significantly greater in patients treated with nitroglycerine compared to those without (median concentration 15.05 mg/mL vs. 4.40 mg/mL, respectively, P < 0.001; median percentage 82.01 % vs. 36.75 %, respectively, P < 0.001). CONCLUSIONS: Nitroglycerine increased delivery of the Lipiodol emulsion via TAE/TACE to HCC tumours with significant tumour reduction. Dual-energy CT can accurately quantify the amount of Lipiodol deposited in tumours. KEY POINTS: • Nitroglycerine improves delivery of tumour-targeted therapy via enhanced permeability and retention. • In hepatocellular carcinoma, nitroglycerine added to TAE/TACE showed greater tumour reduction. • Dual-energy CT can reliably quantify the amount of Lipiodol in TAE/TACE.