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Radiation dose and image quality evaluation relative to different contrast media using cone-beam CT

Jijo Paul, Thomas J Vogl and Emmanuel C Mbalisike

Aims: To evaluate the radiation dose and image quality of an adult cone-beam CT (CBCT) with oil-based (OBC) and water-soluble contrast (WSC) material.
Material & Methods: A total of 44 patients, range: 46–82 years, (male:female – 26:18) who underwent CBCT examination during transarterial chemoembolization. Each patient received two CBCT scans; energy used: 94.4 ± 4.75 kV (mean ± standard deviation), current: 424 ± 132 mA for WSC and 94.5 ± 4.7 kV, 423.5 ± 132 mA for OBC. The volume of WSC material injected was 12 ml and OBC was 4 ml.
Result: WSC examination showed significantly (p < 0.05) decreased (5.83%) dose–area product compared with OBC. Hounsfield unit, noise, signal–noise ratio and contrast–noise ratio was higher for OBC (49.4, 19.44, 38 and 58%, respectively) compared with WSC (p < 0.05). Qualitative assessment of WSC data (median: 2, interquartile range: 1.5–2.5) showed higher image quality compared with OBC data (2.7, interquartile range: 2.3–3.9).
Conclusion: A detectable reduction of radiation dose was achieved with WSC compared with OBC in CBCT imaging. Quantitative image-quality parameters reflect higher values for OBC compared with WSC in the liver parenchyma. Subjective analysis showed an exactly opposite result due to the streak artifacts from OBC material.