The determination of iodine contrast agent threshold for cranial digital subtraction angiography: An image-based phantom study

The digital subtraction angiography (DSA) procedure cannot be separated from the use of contrast media which can increase the visibility of blood vessels. However, the use of inappropriate contrast will have a negative impact, especially on the resulting image quality. This study aims to determine the optimal limit for the use of contrast media for DSA adult patient heads (55-70 kg) with cerebral mode 6 fps with the image quality parameter, namely the signal difference to noise ratio (SDNR). In this study, Dynamic flow phantom and phantom slabs were used which were assembled with a total thickness of 16 cm according to an adult's head. Preliminary studies suggest the use of 0.9% NaCl instead of blood, and an iodine concentration of 350 mg/ml to provide closeness to the clinical setting. The study used contrast media volume variations (1, 3, 5, 7, 10 ml) and injection rates (1, 2, 3, 4, 5 ml/s) which were regulated by automatic injectors. The SDNR value for each frame of each data variation is presented on the graph of the relationship between time and SDNR, and compared with the baseline of several patient images with the same mode. Based on the analysis results, it can be concluded that the optimum use of contrast media is with a volume of 5 ml and an injection rate of 5 ml/s. This value corresponds to the contrast enhancement at baseline and is an optimization of image quality to produce optimum image quality by minimizing the risks that can occur due to the addition of contrast media volume.