Reduced contrast medium in abdominal aorta CTA using a multiphasic injection technique

Purpose: The purpose of this study was to determine if with a multiphasic injection technique the admin- istered amount of contrast medium for abdominal computerized tomographic angiography (CTA) can be decreased, whilst improving CT image quality. Materials and methods: In 30 patients a multiphasic injection method was compared to the standard uniphasic contrast medium injection protocol. Fifteen patients underwent abdominal CTA with a standard uniphasic injection protocol (protocol I) receiving 100 mL of a non-ionic radiopaque contrast agent (Iover- sol). The second group of 15 patients underwent CTA with a multiphasic injection protocol (protocol II) receiving a total of 89 mL Ioversol. Vascular contrast enhancement and difference in enhancement uni- formity were assessed quantitatively and image quality was assessed by three independent radiologists. Results: Quantitative assessment of the vascular contrast enhancement showed that there was no signif- icant difference in enhancement uniformity for patients between the protocols. The image quality was rated as being good to excellent in 81.8% and 88.0% of the scans, for protocol I and protocol II, respectively. However these differences were not statistically significant. Conclusion: By using a multiphasic injection technique with CTA of the abdominal aorta a reduction of 11 percent of contrast medium can be realized. Enhancement patterns are quantitatively as well as qualitatively comparable to the standard contrast medium injection protocol.